![Daniel Borkmann](/assets/img/avatar_default.png)
Fix the bpf_try_make_writable() helper and all call sites we have in BPF, it's currently defect with regards to skbs when the write_len spans into non-linear parts, no matter if cloned or not. There are multiple issues at once. First, using skb_store_bits() is not correct since even if we have a cloned skb, page frags can still be shared. To really make them private, we need to pull them in via __pskb_pull_tail() first, which also gets us a private head via pskb_expand_head() implicitly. This is for helpers like bpf_skb_store_bytes(), bpf_l3_csum_replace(), bpf_l4_csum_replace(). Really, the only thing reasonable and working here is to call skb_ensure_writable() before any write operation. Meaning, via pskb_may_pull() it makes sure that parts we want to access are pulled in and if not does so plus unclones the skb implicitly. If our write_len still fits the headlen and we're cloned and our header of the clone is not writable, then we need to make a private copy via pskb_expand_head(). skb_store_bits() is a bit misleading and only safe to store into non-linear data in different contexts such as357b40a18b
("[IPV6]: IPV6_CHECKSUM socket option can corrupt kernel memory"). For above BPF helper functions, it means after fixed bpf_try_make_writable(), we've pulled in enough, so that we operate always based on skb->data. Thus, the call to skb_header_pointer() and skb_store_bits() becomes superfluous. In bpf_skb_store_bytes(), the len check is unnecessary too since it can only pass in maximum of BPF stack size, so adding offset is guaranteed to never overflow. Also bpf_l3/4_csum_replace() helpers must test for proper offset alignment since they use __sum16 pointer for writing resulting csum. The remaining helpers that change skb data not discussed here yet are bpf_skb_vlan_push(), bpf_skb_vlan_pop() and bpf_skb_change_proto(). The vlan helpers internally call either skb_ensure_writable() (pop case) and skb_cow_head() (push case, for head expansion), respectively. Similarly, bpf_skb_proto_xlat() takes care to not mangle page frags. Fixes:608cd71a9c
("tc: bpf: generalize pedit action") Fixes:91bc4822c3
("tc: bpf: add checksum helpers") Fixes:3697649ff2
("bpf: try harder on clones when writing into skb") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2795 lines
72 KiB
C
2795 lines
72 KiB
C
/*
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* Linux Socket Filter - Kernel level socket filtering
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*
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* Based on the design of the Berkeley Packet Filter. The new
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* internal format has been designed by PLUMgrid:
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*
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* Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
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*
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* Authors:
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*
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* Jay Schulist <jschlst@samba.org>
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* Alexei Starovoitov <ast@plumgrid.com>
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* Daniel Borkmann <dborkman@redhat.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Andi Kleen - Fix a few bad bugs and races.
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* Kris Katterjohn - Added many additional checks in bpf_check_classic()
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/fcntl.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/if_packet.h>
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#include <linux/gfp.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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#include <net/netlink.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/flow_dissector.h>
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#include <linux/errno.h>
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#include <linux/timer.h>
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#include <asm/uaccess.h>
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#include <asm/unaligned.h>
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#include <linux/filter.h>
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#include <linux/ratelimit.h>
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#include <linux/seccomp.h>
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#include <linux/if_vlan.h>
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#include <linux/bpf.h>
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#include <net/sch_generic.h>
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#include <net/cls_cgroup.h>
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#include <net/dst_metadata.h>
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#include <net/dst.h>
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#include <net/sock_reuseport.h>
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/**
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* sk_filter_trim_cap - run a packet through a socket filter
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* @sk: sock associated with &sk_buff
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* @skb: buffer to filter
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* @cap: limit on how short the eBPF program may trim the packet
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*
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* Run the eBPF program and then cut skb->data to correct size returned by
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* the program. If pkt_len is 0 we toss packet. If skb->len is smaller
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* than pkt_len we keep whole skb->data. This is the socket level
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* wrapper to BPF_PROG_RUN. It returns 0 if the packet should
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* be accepted or -EPERM if the packet should be tossed.
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*
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*/
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int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap)
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{
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int err;
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struct sk_filter *filter;
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/*
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* If the skb was allocated from pfmemalloc reserves, only
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* allow SOCK_MEMALLOC sockets to use it as this socket is
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* helping free memory
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*/
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if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
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return -ENOMEM;
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err = security_sock_rcv_skb(sk, skb);
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if (err)
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return err;
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rcu_read_lock();
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filter = rcu_dereference(sk->sk_filter);
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if (filter) {
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unsigned int pkt_len = bpf_prog_run_save_cb(filter->prog, skb);
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err = pkt_len ? pskb_trim(skb, max(cap, pkt_len)) : -EPERM;
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}
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rcu_read_unlock();
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return err;
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}
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EXPORT_SYMBOL(sk_filter_trim_cap);
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static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
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{
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return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
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}
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static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
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{
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struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
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struct nlattr *nla;
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if (skb_is_nonlinear(skb))
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return 0;
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if (skb->len < sizeof(struct nlattr))
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return 0;
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if (a > skb->len - sizeof(struct nlattr))
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return 0;
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nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
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if (nla)
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return (void *) nla - (void *) skb->data;
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return 0;
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}
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static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
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{
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struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
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struct nlattr *nla;
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if (skb_is_nonlinear(skb))
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return 0;
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if (skb->len < sizeof(struct nlattr))
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return 0;
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if (a > skb->len - sizeof(struct nlattr))
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return 0;
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nla = (struct nlattr *) &skb->data[a];
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if (nla->nla_len > skb->len - a)
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return 0;
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nla = nla_find_nested(nla, x);
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if (nla)
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return (void *) nla - (void *) skb->data;
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return 0;
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}
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static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
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{
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return raw_smp_processor_id();
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}
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static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
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.func = __get_raw_cpu_id,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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};
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static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,
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struct bpf_insn *insn_buf)
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{
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struct bpf_insn *insn = insn_buf;
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switch (skb_field) {
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case SKF_AD_MARK:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
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*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
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offsetof(struct sk_buff, mark));
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break;
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case SKF_AD_PKTTYPE:
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*insn++ = BPF_LDX_MEM(BPF_B, dst_reg, src_reg, PKT_TYPE_OFFSET());
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*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, PKT_TYPE_MAX);
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#ifdef __BIG_ENDIAN_BITFIELD
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*insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 5);
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#endif
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break;
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case SKF_AD_QUEUE:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
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*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
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offsetof(struct sk_buff, queue_mapping));
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break;
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case SKF_AD_VLAN_TAG:
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case SKF_AD_VLAN_TAG_PRESENT:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
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BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
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/* dst_reg = *(u16 *) (src_reg + offsetof(vlan_tci)) */
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*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
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offsetof(struct sk_buff, vlan_tci));
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if (skb_field == SKF_AD_VLAN_TAG) {
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*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg,
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~VLAN_TAG_PRESENT);
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} else {
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/* dst_reg >>= 12 */
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*insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 12);
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/* dst_reg &= 1 */
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*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, 1);
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}
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break;
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}
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return insn - insn_buf;
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}
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static bool convert_bpf_extensions(struct sock_filter *fp,
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struct bpf_insn **insnp)
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{
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struct bpf_insn *insn = *insnp;
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u32 cnt;
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switch (fp->k) {
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case SKF_AD_OFF + SKF_AD_PROTOCOL:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
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/* A = *(u16 *) (CTX + offsetof(protocol)) */
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*insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
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offsetof(struct sk_buff, protocol));
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/* A = ntohs(A) [emitting a nop or swap16] */
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*insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
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break;
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case SKF_AD_OFF + SKF_AD_PKTTYPE:
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cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn);
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insn += cnt - 1;
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break;
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case SKF_AD_OFF + SKF_AD_IFINDEX:
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case SKF_AD_OFF + SKF_AD_HATYPE:
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BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
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BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
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BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0);
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*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
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BPF_REG_TMP, BPF_REG_CTX,
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offsetof(struct sk_buff, dev));
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/* if (tmp != 0) goto pc + 1 */
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*insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
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*insn++ = BPF_EXIT_INSN();
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if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX)
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*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP,
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offsetof(struct net_device, ifindex));
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else
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*insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
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offsetof(struct net_device, type));
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break;
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case SKF_AD_OFF + SKF_AD_MARK:
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cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn);
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insn += cnt - 1;
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break;
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case SKF_AD_OFF + SKF_AD_RXHASH:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
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*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
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offsetof(struct sk_buff, hash));
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break;
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case SKF_AD_OFF + SKF_AD_QUEUE:
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cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn);
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insn += cnt - 1;
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break;
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case SKF_AD_OFF + SKF_AD_VLAN_TAG:
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cnt = convert_skb_access(SKF_AD_VLAN_TAG,
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BPF_REG_A, BPF_REG_CTX, insn);
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insn += cnt - 1;
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break;
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case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
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cnt = convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
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BPF_REG_A, BPF_REG_CTX, insn);
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insn += cnt - 1;
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break;
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case SKF_AD_OFF + SKF_AD_VLAN_TPID:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
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/* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
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*insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
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offsetof(struct sk_buff, vlan_proto));
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/* A = ntohs(A) [emitting a nop or swap16] */
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*insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
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break;
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case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
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case SKF_AD_OFF + SKF_AD_NLATTR:
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case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
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case SKF_AD_OFF + SKF_AD_CPU:
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case SKF_AD_OFF + SKF_AD_RANDOM:
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/* arg1 = CTX */
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*insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
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/* arg2 = A */
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*insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
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/* arg3 = X */
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*insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
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/* Emit call(arg1=CTX, arg2=A, arg3=X) */
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switch (fp->k) {
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case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
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*insn = BPF_EMIT_CALL(__skb_get_pay_offset);
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break;
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case SKF_AD_OFF + SKF_AD_NLATTR:
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*insn = BPF_EMIT_CALL(__skb_get_nlattr);
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break;
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case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
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*insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
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break;
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case SKF_AD_OFF + SKF_AD_CPU:
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*insn = BPF_EMIT_CALL(__get_raw_cpu_id);
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break;
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case SKF_AD_OFF + SKF_AD_RANDOM:
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*insn = BPF_EMIT_CALL(bpf_user_rnd_u32);
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bpf_user_rnd_init_once();
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break;
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}
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break;
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case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
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/* A ^= X */
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*insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
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break;
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default:
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/* This is just a dummy call to avoid letting the compiler
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* evict __bpf_call_base() as an optimization. Placed here
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* where no-one bothers.
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*/
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BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
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return false;
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}
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*insnp = insn;
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return true;
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}
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/**
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* bpf_convert_filter - convert filter program
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* @prog: the user passed filter program
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* @len: the length of the user passed filter program
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* @new_prog: buffer where converted program will be stored
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* @new_len: pointer to store length of converted program
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*
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* Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
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* Conversion workflow:
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*
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* 1) First pass for calculating the new program length:
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* bpf_convert_filter(old_prog, old_len, NULL, &new_len)
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*
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* 2) 2nd pass to remap in two passes: 1st pass finds new
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* jump offsets, 2nd pass remapping:
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* new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
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* bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
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*/
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static int bpf_convert_filter(struct sock_filter *prog, int len,
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struct bpf_insn *new_prog, int *new_len)
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{
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int new_flen = 0, pass = 0, target, i;
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struct bpf_insn *new_insn;
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struct sock_filter *fp;
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int *addrs = NULL;
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u8 bpf_src;
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BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
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BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
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if (len <= 0 || len > BPF_MAXINSNS)
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return -EINVAL;
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|
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if (new_prog) {
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addrs = kcalloc(len, sizeof(*addrs),
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GFP_KERNEL | __GFP_NOWARN);
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if (!addrs)
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return -ENOMEM;
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}
|
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do_pass:
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new_insn = new_prog;
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fp = prog;
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|
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/* Classic BPF related prologue emission. */
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if (new_insn) {
|
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/* Classic BPF expects A and X to be reset first. These need
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* to be guaranteed to be the first two instructions.
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*/
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*new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_A, BPF_REG_A);
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*new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_X, BPF_REG_X);
|
|
|
|
/* All programs must keep CTX in callee saved BPF_REG_CTX.
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* In eBPF case it's done by the compiler, here we need to
|
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* do this ourself. Initial CTX is present in BPF_REG_ARG1.
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*/
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*new_insn++ = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
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} else {
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new_insn += 3;
|
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}
|
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|
|
for (i = 0; i < len; fp++, i++) {
|
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struct bpf_insn tmp_insns[6] = { };
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struct bpf_insn *insn = tmp_insns;
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|
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if (addrs)
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addrs[i] = new_insn - new_prog;
|
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|
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switch (fp->code) {
|
|
/* All arithmetic insns and skb loads map as-is. */
|
|
case BPF_ALU | BPF_ADD | BPF_X:
|
|
case BPF_ALU | BPF_ADD | BPF_K:
|
|
case BPF_ALU | BPF_SUB | BPF_X:
|
|
case BPF_ALU | BPF_SUB | BPF_K:
|
|
case BPF_ALU | BPF_AND | BPF_X:
|
|
case BPF_ALU | BPF_AND | BPF_K:
|
|
case BPF_ALU | BPF_OR | BPF_X:
|
|
case BPF_ALU | BPF_OR | BPF_K:
|
|
case BPF_ALU | BPF_LSH | BPF_X:
|
|
case BPF_ALU | BPF_LSH | BPF_K:
|
|
case BPF_ALU | BPF_RSH | BPF_X:
|
|
case BPF_ALU | BPF_RSH | BPF_K:
|
|
case BPF_ALU | BPF_XOR | BPF_X:
|
|
case BPF_ALU | BPF_XOR | BPF_K:
|
|
case BPF_ALU | BPF_MUL | BPF_X:
|
|
case BPF_ALU | BPF_MUL | BPF_K:
|
|
case BPF_ALU | BPF_DIV | BPF_X:
|
|
case BPF_ALU | BPF_DIV | BPF_K:
|
|
case BPF_ALU | BPF_MOD | BPF_X:
|
|
case BPF_ALU | BPF_MOD | BPF_K:
|
|
case BPF_ALU | BPF_NEG:
|
|
case BPF_LD | BPF_ABS | BPF_W:
|
|
case BPF_LD | BPF_ABS | BPF_H:
|
|
case BPF_LD | BPF_ABS | BPF_B:
|
|
case BPF_LD | BPF_IND | BPF_W:
|
|
case BPF_LD | BPF_IND | BPF_H:
|
|
case BPF_LD | BPF_IND | BPF_B:
|
|
/* Check for overloaded BPF extension and
|
|
* directly convert it if found, otherwise
|
|
* just move on with mapping.
|
|
*/
|
|
if (BPF_CLASS(fp->code) == BPF_LD &&
|
|
BPF_MODE(fp->code) == BPF_ABS &&
|
|
convert_bpf_extensions(fp, &insn))
|
|
break;
|
|
|
|
*insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
|
|
break;
|
|
|
|
/* Jump transformation cannot use BPF block macros
|
|
* everywhere as offset calculation and target updates
|
|
* require a bit more work than the rest, i.e. jump
|
|
* opcodes map as-is, but offsets need adjustment.
|
|
*/
|
|
|
|
#define BPF_EMIT_JMP \
|
|
do { \
|
|
if (target >= len || target < 0) \
|
|
goto err; \
|
|
insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
|
|
/* Adjust pc relative offset for 2nd or 3rd insn. */ \
|
|
insn->off -= insn - tmp_insns; \
|
|
} while (0)
|
|
|
|
case BPF_JMP | BPF_JA:
|
|
target = i + fp->k + 1;
|
|
insn->code = fp->code;
|
|
BPF_EMIT_JMP;
|
|
break;
|
|
|
|
case BPF_JMP | BPF_JEQ | BPF_K:
|
|
case BPF_JMP | BPF_JEQ | BPF_X:
|
|
case BPF_JMP | BPF_JSET | BPF_K:
|
|
case BPF_JMP | BPF_JSET | BPF_X:
|
|
case BPF_JMP | BPF_JGT | BPF_K:
|
|
case BPF_JMP | BPF_JGT | BPF_X:
|
|
case BPF_JMP | BPF_JGE | BPF_K:
|
|
case BPF_JMP | BPF_JGE | BPF_X:
|
|
if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) {
|
|
/* BPF immediates are signed, zero extend
|
|
* immediate into tmp register and use it
|
|
* in compare insn.
|
|
*/
|
|
*insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k);
|
|
|
|
insn->dst_reg = BPF_REG_A;
|
|
insn->src_reg = BPF_REG_TMP;
|
|
bpf_src = BPF_X;
|
|
} else {
|
|
insn->dst_reg = BPF_REG_A;
|
|
insn->imm = fp->k;
|
|
bpf_src = BPF_SRC(fp->code);
|
|
insn->src_reg = bpf_src == BPF_X ? BPF_REG_X : 0;
|
|
}
|
|
|
|
/* Common case where 'jump_false' is next insn. */
|
|
if (fp->jf == 0) {
|
|
insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
|
|
target = i + fp->jt + 1;
|
|
BPF_EMIT_JMP;
|
|
break;
|
|
}
|
|
|
|
/* Convert JEQ into JNE when 'jump_true' is next insn. */
|
|
if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) {
|
|
insn->code = BPF_JMP | BPF_JNE | bpf_src;
|
|
target = i + fp->jf + 1;
|
|
BPF_EMIT_JMP;
|
|
break;
|
|
}
|
|
|
|
/* Other jumps are mapped into two insns: Jxx and JA. */
|
|
target = i + fp->jt + 1;
|
|
insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
|
|
BPF_EMIT_JMP;
|
|
insn++;
|
|
|
|
insn->code = BPF_JMP | BPF_JA;
|
|
target = i + fp->jf + 1;
|
|
BPF_EMIT_JMP;
|
|
break;
|
|
|
|
/* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
|
|
case BPF_LDX | BPF_MSH | BPF_B:
|
|
/* tmp = A */
|
|
*insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A);
|
|
/* A = BPF_R0 = *(u8 *) (skb->data + K) */
|
|
*insn++ = BPF_LD_ABS(BPF_B, fp->k);
|
|
/* A &= 0xf */
|
|
*insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
|
|
/* A <<= 2 */
|
|
*insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
|
|
/* X = A */
|
|
*insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
|
|
/* A = tmp */
|
|
*insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP);
|
|
break;
|
|
|
|
/* RET_K is remaped into 2 insns. RET_A case doesn't need an
|
|
* extra mov as BPF_REG_0 is already mapped into BPF_REG_A.
|
|
*/
|
|
case BPF_RET | BPF_A:
|
|
case BPF_RET | BPF_K:
|
|
if (BPF_RVAL(fp->code) == BPF_K)
|
|
*insn++ = BPF_MOV32_RAW(BPF_K, BPF_REG_0,
|
|
0, fp->k);
|
|
*insn = BPF_EXIT_INSN();
|
|
break;
|
|
|
|
/* Store to stack. */
|
|
case BPF_ST:
|
|
case BPF_STX:
|
|
*insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
|
|
BPF_ST ? BPF_REG_A : BPF_REG_X,
|
|
-(BPF_MEMWORDS - fp->k) * 4);
|
|
break;
|
|
|
|
/* Load from stack. */
|
|
case BPF_LD | BPF_MEM:
|
|
case BPF_LDX | BPF_MEM:
|
|
*insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
|
|
BPF_REG_A : BPF_REG_X, BPF_REG_FP,
|
|
-(BPF_MEMWORDS - fp->k) * 4);
|
|
break;
|
|
|
|
/* A = K or X = K */
|
|
case BPF_LD | BPF_IMM:
|
|
case BPF_LDX | BPF_IMM:
|
|
*insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ?
|
|
BPF_REG_A : BPF_REG_X, fp->k);
|
|
break;
|
|
|
|
/* X = A */
|
|
case BPF_MISC | BPF_TAX:
|
|
*insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
|
|
break;
|
|
|
|
/* A = X */
|
|
case BPF_MISC | BPF_TXA:
|
|
*insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X);
|
|
break;
|
|
|
|
/* A = skb->len or X = skb->len */
|
|
case BPF_LD | BPF_W | BPF_LEN:
|
|
case BPF_LDX | BPF_W | BPF_LEN:
|
|
*insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
|
|
BPF_REG_A : BPF_REG_X, BPF_REG_CTX,
|
|
offsetof(struct sk_buff, len));
|
|
break;
|
|
|
|
/* Access seccomp_data fields. */
|
|
case BPF_LDX | BPF_ABS | BPF_W:
|
|
/* A = *(u32 *) (ctx + K) */
|
|
*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
|
|
break;
|
|
|
|
/* Unknown instruction. */
|
|
default:
|
|
goto err;
|
|
}
|
|
|
|
insn++;
|
|
if (new_prog)
|
|
memcpy(new_insn, tmp_insns,
|
|
sizeof(*insn) * (insn - tmp_insns));
|
|
new_insn += insn - tmp_insns;
|
|
}
|
|
|
|
if (!new_prog) {
|
|
/* Only calculating new length. */
|
|
*new_len = new_insn - new_prog;
|
|
return 0;
|
|
}
|
|
|
|
pass++;
|
|
if (new_flen != new_insn - new_prog) {
|
|
new_flen = new_insn - new_prog;
|
|
if (pass > 2)
|
|
goto err;
|
|
goto do_pass;
|
|
}
|
|
|
|
kfree(addrs);
|
|
BUG_ON(*new_len != new_flen);
|
|
return 0;
|
|
err:
|
|
kfree(addrs);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Security:
|
|
*
|
|
* As we dont want to clear mem[] array for each packet going through
|
|
* __bpf_prog_run(), we check that filter loaded by user never try to read
|
|
* a cell if not previously written, and we check all branches to be sure
|
|
* a malicious user doesn't try to abuse us.
|
|
*/
|
|
static int check_load_and_stores(const struct sock_filter *filter, int flen)
|
|
{
|
|
u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */
|
|
int pc, ret = 0;
|
|
|
|
BUILD_BUG_ON(BPF_MEMWORDS > 16);
|
|
|
|
masks = kmalloc_array(flen, sizeof(*masks), GFP_KERNEL);
|
|
if (!masks)
|
|
return -ENOMEM;
|
|
|
|
memset(masks, 0xff, flen * sizeof(*masks));
|
|
|
|
for (pc = 0; pc < flen; pc++) {
|
|
memvalid &= masks[pc];
|
|
|
|
switch (filter[pc].code) {
|
|
case BPF_ST:
|
|
case BPF_STX:
|
|
memvalid |= (1 << filter[pc].k);
|
|
break;
|
|
case BPF_LD | BPF_MEM:
|
|
case BPF_LDX | BPF_MEM:
|
|
if (!(memvalid & (1 << filter[pc].k))) {
|
|
ret = -EINVAL;
|
|
goto error;
|
|
}
|
|
break;
|
|
case BPF_JMP | BPF_JA:
|
|
/* A jump must set masks on target */
|
|
masks[pc + 1 + filter[pc].k] &= memvalid;
|
|
memvalid = ~0;
|
|
break;
|
|
case BPF_JMP | BPF_JEQ | BPF_K:
|
|
case BPF_JMP | BPF_JEQ | BPF_X:
|
|
case BPF_JMP | BPF_JGE | BPF_K:
|
|
case BPF_JMP | BPF_JGE | BPF_X:
|
|
case BPF_JMP | BPF_JGT | BPF_K:
|
|
case BPF_JMP | BPF_JGT | BPF_X:
|
|
case BPF_JMP | BPF_JSET | BPF_K:
|
|
case BPF_JMP | BPF_JSET | BPF_X:
|
|
/* A jump must set masks on targets */
|
|
masks[pc + 1 + filter[pc].jt] &= memvalid;
|
|
masks[pc + 1 + filter[pc].jf] &= memvalid;
|
|
memvalid = ~0;
|
|
break;
|
|
}
|
|
}
|
|
error:
|
|
kfree(masks);
|
|
return ret;
|
|
}
|
|
|
|
static bool chk_code_allowed(u16 code_to_probe)
|
|
{
|
|
static const bool codes[] = {
|
|
/* 32 bit ALU operations */
|
|
[BPF_ALU | BPF_ADD | BPF_K] = true,
|
|
[BPF_ALU | BPF_ADD | BPF_X] = true,
|
|
[BPF_ALU | BPF_SUB | BPF_K] = true,
|
|
[BPF_ALU | BPF_SUB | BPF_X] = true,
|
|
[BPF_ALU | BPF_MUL | BPF_K] = true,
|
|
[BPF_ALU | BPF_MUL | BPF_X] = true,
|
|
[BPF_ALU | BPF_DIV | BPF_K] = true,
|
|
[BPF_ALU | BPF_DIV | BPF_X] = true,
|
|
[BPF_ALU | BPF_MOD | BPF_K] = true,
|
|
[BPF_ALU | BPF_MOD | BPF_X] = true,
|
|
[BPF_ALU | BPF_AND | BPF_K] = true,
|
|
[BPF_ALU | BPF_AND | BPF_X] = true,
|
|
[BPF_ALU | BPF_OR | BPF_K] = true,
|
|
[BPF_ALU | BPF_OR | BPF_X] = true,
|
|
[BPF_ALU | BPF_XOR | BPF_K] = true,
|
|
[BPF_ALU | BPF_XOR | BPF_X] = true,
|
|
[BPF_ALU | BPF_LSH | BPF_K] = true,
|
|
[BPF_ALU | BPF_LSH | BPF_X] = true,
|
|
[BPF_ALU | BPF_RSH | BPF_K] = true,
|
|
[BPF_ALU | BPF_RSH | BPF_X] = true,
|
|
[BPF_ALU | BPF_NEG] = true,
|
|
/* Load instructions */
|
|
[BPF_LD | BPF_W | BPF_ABS] = true,
|
|
[BPF_LD | BPF_H | BPF_ABS] = true,
|
|
[BPF_LD | BPF_B | BPF_ABS] = true,
|
|
[BPF_LD | BPF_W | BPF_LEN] = true,
|
|
[BPF_LD | BPF_W | BPF_IND] = true,
|
|
[BPF_LD | BPF_H | BPF_IND] = true,
|
|
[BPF_LD | BPF_B | BPF_IND] = true,
|
|
[BPF_LD | BPF_IMM] = true,
|
|
[BPF_LD | BPF_MEM] = true,
|
|
[BPF_LDX | BPF_W | BPF_LEN] = true,
|
|
[BPF_LDX | BPF_B | BPF_MSH] = true,
|
|
[BPF_LDX | BPF_IMM] = true,
|
|
[BPF_LDX | BPF_MEM] = true,
|
|
/* Store instructions */
|
|
[BPF_ST] = true,
|
|
[BPF_STX] = true,
|
|
/* Misc instructions */
|
|
[BPF_MISC | BPF_TAX] = true,
|
|
[BPF_MISC | BPF_TXA] = true,
|
|
/* Return instructions */
|
|
[BPF_RET | BPF_K] = true,
|
|
[BPF_RET | BPF_A] = true,
|
|
/* Jump instructions */
|
|
[BPF_JMP | BPF_JA] = true,
|
|
[BPF_JMP | BPF_JEQ | BPF_K] = true,
|
|
[BPF_JMP | BPF_JEQ | BPF_X] = true,
|
|
[BPF_JMP | BPF_JGE | BPF_K] = true,
|
|
[BPF_JMP | BPF_JGE | BPF_X] = true,
|
|
[BPF_JMP | BPF_JGT | BPF_K] = true,
|
|
[BPF_JMP | BPF_JGT | BPF_X] = true,
|
|
[BPF_JMP | BPF_JSET | BPF_K] = true,
|
|
[BPF_JMP | BPF_JSET | BPF_X] = true,
|
|
};
|
|
|
|
if (code_to_probe >= ARRAY_SIZE(codes))
|
|
return false;
|
|
|
|
return codes[code_to_probe];
|
|
}
|
|
|
|
static bool bpf_check_basics_ok(const struct sock_filter *filter,
|
|
unsigned int flen)
|
|
{
|
|
if (filter == NULL)
|
|
return false;
|
|
if (flen == 0 || flen > BPF_MAXINSNS)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* bpf_check_classic - verify socket filter code
|
|
* @filter: filter to verify
|
|
* @flen: length of filter
|
|
*
|
|
* Check the user's filter code. If we let some ugly
|
|
* filter code slip through kaboom! The filter must contain
|
|
* no references or jumps that are out of range, no illegal
|
|
* instructions, and must end with a RET instruction.
|
|
*
|
|
* All jumps are forward as they are not signed.
|
|
*
|
|
* Returns 0 if the rule set is legal or -EINVAL if not.
|
|
*/
|
|
static int bpf_check_classic(const struct sock_filter *filter,
|
|
unsigned int flen)
|
|
{
|
|
bool anc_found;
|
|
int pc;
|
|
|
|
/* Check the filter code now */
|
|
for (pc = 0; pc < flen; pc++) {
|
|
const struct sock_filter *ftest = &filter[pc];
|
|
|
|
/* May we actually operate on this code? */
|
|
if (!chk_code_allowed(ftest->code))
|
|
return -EINVAL;
|
|
|
|
/* Some instructions need special checks */
|
|
switch (ftest->code) {
|
|
case BPF_ALU | BPF_DIV | BPF_K:
|
|
case BPF_ALU | BPF_MOD | BPF_K:
|
|
/* Check for division by zero */
|
|
if (ftest->k == 0)
|
|
return -EINVAL;
|
|
break;
|
|
case BPF_ALU | BPF_LSH | BPF_K:
|
|
case BPF_ALU | BPF_RSH | BPF_K:
|
|
if (ftest->k >= 32)
|
|
return -EINVAL;
|
|
break;
|
|
case BPF_LD | BPF_MEM:
|
|
case BPF_LDX | BPF_MEM:
|
|
case BPF_ST:
|
|
case BPF_STX:
|
|
/* Check for invalid memory addresses */
|
|
if (ftest->k >= BPF_MEMWORDS)
|
|
return -EINVAL;
|
|
break;
|
|
case BPF_JMP | BPF_JA:
|
|
/* Note, the large ftest->k might cause loops.
|
|
* Compare this with conditional jumps below,
|
|
* where offsets are limited. --ANK (981016)
|
|
*/
|
|
if (ftest->k >= (unsigned int)(flen - pc - 1))
|
|
return -EINVAL;
|
|
break;
|
|
case BPF_JMP | BPF_JEQ | BPF_K:
|
|
case BPF_JMP | BPF_JEQ | BPF_X:
|
|
case BPF_JMP | BPF_JGE | BPF_K:
|
|
case BPF_JMP | BPF_JGE | BPF_X:
|
|
case BPF_JMP | BPF_JGT | BPF_K:
|
|
case BPF_JMP | BPF_JGT | BPF_X:
|
|
case BPF_JMP | BPF_JSET | BPF_K:
|
|
case BPF_JMP | BPF_JSET | BPF_X:
|
|
/* Both conditionals must be safe */
|
|
if (pc + ftest->jt + 1 >= flen ||
|
|
pc + ftest->jf + 1 >= flen)
|
|
return -EINVAL;
|
|
break;
|
|
case BPF_LD | BPF_W | BPF_ABS:
|
|
case BPF_LD | BPF_H | BPF_ABS:
|
|
case BPF_LD | BPF_B | BPF_ABS:
|
|
anc_found = false;
|
|
if (bpf_anc_helper(ftest) & BPF_ANC)
|
|
anc_found = true;
|
|
/* Ancillary operation unknown or unsupported */
|
|
if (anc_found == false && ftest->k >= SKF_AD_OFF)
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* Last instruction must be a RET code */
|
|
switch (filter[flen - 1].code) {
|
|
case BPF_RET | BPF_K:
|
|
case BPF_RET | BPF_A:
|
|
return check_load_and_stores(filter, flen);
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int bpf_prog_store_orig_filter(struct bpf_prog *fp,
|
|
const struct sock_fprog *fprog)
|
|
{
|
|
unsigned int fsize = bpf_classic_proglen(fprog);
|
|
struct sock_fprog_kern *fkprog;
|
|
|
|
fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL);
|
|
if (!fp->orig_prog)
|
|
return -ENOMEM;
|
|
|
|
fkprog = fp->orig_prog;
|
|
fkprog->len = fprog->len;
|
|
|
|
fkprog->filter = kmemdup(fp->insns, fsize,
|
|
GFP_KERNEL | __GFP_NOWARN);
|
|
if (!fkprog->filter) {
|
|
kfree(fp->orig_prog);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void bpf_release_orig_filter(struct bpf_prog *fp)
|
|
{
|
|
struct sock_fprog_kern *fprog = fp->orig_prog;
|
|
|
|
if (fprog) {
|
|
kfree(fprog->filter);
|
|
kfree(fprog);
|
|
}
|
|
}
|
|
|
|
static void __bpf_prog_release(struct bpf_prog *prog)
|
|
{
|
|
if (prog->type == BPF_PROG_TYPE_SOCKET_FILTER) {
|
|
bpf_prog_put(prog);
|
|
} else {
|
|
bpf_release_orig_filter(prog);
|
|
bpf_prog_free(prog);
|
|
}
|
|
}
|
|
|
|
static void __sk_filter_release(struct sk_filter *fp)
|
|
{
|
|
__bpf_prog_release(fp->prog);
|
|
kfree(fp);
|
|
}
|
|
|
|
/**
|
|
* sk_filter_release_rcu - Release a socket filter by rcu_head
|
|
* @rcu: rcu_head that contains the sk_filter to free
|
|
*/
|
|
static void sk_filter_release_rcu(struct rcu_head *rcu)
|
|
{
|
|
struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
|
|
|
|
__sk_filter_release(fp);
|
|
}
|
|
|
|
/**
|
|
* sk_filter_release - release a socket filter
|
|
* @fp: filter to remove
|
|
*
|
|
* Remove a filter from a socket and release its resources.
|
|
*/
|
|
static void sk_filter_release(struct sk_filter *fp)
|
|
{
|
|
if (atomic_dec_and_test(&fp->refcnt))
|
|
call_rcu(&fp->rcu, sk_filter_release_rcu);
|
|
}
|
|
|
|
void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
|
|
{
|
|
u32 filter_size = bpf_prog_size(fp->prog->len);
|
|
|
|
atomic_sub(filter_size, &sk->sk_omem_alloc);
|
|
sk_filter_release(fp);
|
|
}
|
|
|
|
/* try to charge the socket memory if there is space available
|
|
* return true on success
|
|
*/
|
|
bool sk_filter_charge(struct sock *sk, struct sk_filter *fp)
|
|
{
|
|
u32 filter_size = bpf_prog_size(fp->prog->len);
|
|
|
|
/* same check as in sock_kmalloc() */
|
|
if (filter_size <= sysctl_optmem_max &&
|
|
atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) {
|
|
atomic_inc(&fp->refcnt);
|
|
atomic_add(filter_size, &sk->sk_omem_alloc);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp)
|
|
{
|
|
struct sock_filter *old_prog;
|
|
struct bpf_prog *old_fp;
|
|
int err, new_len, old_len = fp->len;
|
|
|
|
/* We are free to overwrite insns et al right here as it
|
|
* won't be used at this point in time anymore internally
|
|
* after the migration to the internal BPF instruction
|
|
* representation.
|
|
*/
|
|
BUILD_BUG_ON(sizeof(struct sock_filter) !=
|
|
sizeof(struct bpf_insn));
|
|
|
|
/* Conversion cannot happen on overlapping memory areas,
|
|
* so we need to keep the user BPF around until the 2nd
|
|
* pass. At this time, the user BPF is stored in fp->insns.
|
|
*/
|
|
old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter),
|
|
GFP_KERNEL | __GFP_NOWARN);
|
|
if (!old_prog) {
|
|
err = -ENOMEM;
|
|
goto out_err;
|
|
}
|
|
|
|
/* 1st pass: calculate the new program length. */
|
|
err = bpf_convert_filter(old_prog, old_len, NULL, &new_len);
|
|
if (err)
|
|
goto out_err_free;
|
|
|
|
/* Expand fp for appending the new filter representation. */
|
|
old_fp = fp;
|
|
fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0);
|
|
if (!fp) {
|
|
/* The old_fp is still around in case we couldn't
|
|
* allocate new memory, so uncharge on that one.
|
|
*/
|
|
fp = old_fp;
|
|
err = -ENOMEM;
|
|
goto out_err_free;
|
|
}
|
|
|
|
fp->len = new_len;
|
|
|
|
/* 2nd pass: remap sock_filter insns into bpf_insn insns. */
|
|
err = bpf_convert_filter(old_prog, old_len, fp->insnsi, &new_len);
|
|
if (err)
|
|
/* 2nd bpf_convert_filter() can fail only if it fails
|
|
* to allocate memory, remapping must succeed. Note,
|
|
* that at this time old_fp has already been released
|
|
* by krealloc().
|
|
*/
|
|
goto out_err_free;
|
|
|
|
/* We are guaranteed to never error here with cBPF to eBPF
|
|
* transitions, since there's no issue with type compatibility
|
|
* checks on program arrays.
|
|
*/
|
|
fp = bpf_prog_select_runtime(fp, &err);
|
|
|
|
kfree(old_prog);
|
|
return fp;
|
|
|
|
out_err_free:
|
|
kfree(old_prog);
|
|
out_err:
|
|
__bpf_prog_release(fp);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp,
|
|
bpf_aux_classic_check_t trans)
|
|
{
|
|
int err;
|
|
|
|
fp->bpf_func = NULL;
|
|
fp->jited = 0;
|
|
|
|
err = bpf_check_classic(fp->insns, fp->len);
|
|
if (err) {
|
|
__bpf_prog_release(fp);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/* There might be additional checks and transformations
|
|
* needed on classic filters, f.e. in case of seccomp.
|
|
*/
|
|
if (trans) {
|
|
err = trans(fp->insns, fp->len);
|
|
if (err) {
|
|
__bpf_prog_release(fp);
|
|
return ERR_PTR(err);
|
|
}
|
|
}
|
|
|
|
/* Probe if we can JIT compile the filter and if so, do
|
|
* the compilation of the filter.
|
|
*/
|
|
bpf_jit_compile(fp);
|
|
|
|
/* JIT compiler couldn't process this filter, so do the
|
|
* internal BPF translation for the optimized interpreter.
|
|
*/
|
|
if (!fp->jited)
|
|
fp = bpf_migrate_filter(fp);
|
|
|
|
return fp;
|
|
}
|
|
|
|
/**
|
|
* bpf_prog_create - create an unattached filter
|
|
* @pfp: the unattached filter that is created
|
|
* @fprog: the filter program
|
|
*
|
|
* Create a filter independent of any socket. We first run some
|
|
* sanity checks on it to make sure it does not explode on us later.
|
|
* If an error occurs or there is insufficient memory for the filter
|
|
* a negative errno code is returned. On success the return is zero.
|
|
*/
|
|
int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog)
|
|
{
|
|
unsigned int fsize = bpf_classic_proglen(fprog);
|
|
struct bpf_prog *fp;
|
|
|
|
/* Make sure new filter is there and in the right amounts. */
|
|
if (!bpf_check_basics_ok(fprog->filter, fprog->len))
|
|
return -EINVAL;
|
|
|
|
fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
|
|
if (!fp)
|
|
return -ENOMEM;
|
|
|
|
memcpy(fp->insns, fprog->filter, fsize);
|
|
|
|
fp->len = fprog->len;
|
|
/* Since unattached filters are not copied back to user
|
|
* space through sk_get_filter(), we do not need to hold
|
|
* a copy here, and can spare us the work.
|
|
*/
|
|
fp->orig_prog = NULL;
|
|
|
|
/* bpf_prepare_filter() already takes care of freeing
|
|
* memory in case something goes wrong.
|
|
*/
|
|
fp = bpf_prepare_filter(fp, NULL);
|
|
if (IS_ERR(fp))
|
|
return PTR_ERR(fp);
|
|
|
|
*pfp = fp;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_create);
|
|
|
|
/**
|
|
* bpf_prog_create_from_user - create an unattached filter from user buffer
|
|
* @pfp: the unattached filter that is created
|
|
* @fprog: the filter program
|
|
* @trans: post-classic verifier transformation handler
|
|
* @save_orig: save classic BPF program
|
|
*
|
|
* This function effectively does the same as bpf_prog_create(), only
|
|
* that it builds up its insns buffer from user space provided buffer.
|
|
* It also allows for passing a bpf_aux_classic_check_t handler.
|
|
*/
|
|
int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
|
|
bpf_aux_classic_check_t trans, bool save_orig)
|
|
{
|
|
unsigned int fsize = bpf_classic_proglen(fprog);
|
|
struct bpf_prog *fp;
|
|
int err;
|
|
|
|
/* Make sure new filter is there and in the right amounts. */
|
|
if (!bpf_check_basics_ok(fprog->filter, fprog->len))
|
|
return -EINVAL;
|
|
|
|
fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
|
|
if (!fp)
|
|
return -ENOMEM;
|
|
|
|
if (copy_from_user(fp->insns, fprog->filter, fsize)) {
|
|
__bpf_prog_free(fp);
|
|
return -EFAULT;
|
|
}
|
|
|
|
fp->len = fprog->len;
|
|
fp->orig_prog = NULL;
|
|
|
|
if (save_orig) {
|
|
err = bpf_prog_store_orig_filter(fp, fprog);
|
|
if (err) {
|
|
__bpf_prog_free(fp);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
/* bpf_prepare_filter() already takes care of freeing
|
|
* memory in case something goes wrong.
|
|
*/
|
|
fp = bpf_prepare_filter(fp, trans);
|
|
if (IS_ERR(fp))
|
|
return PTR_ERR(fp);
|
|
|
|
*pfp = fp;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_create_from_user);
|
|
|
|
void bpf_prog_destroy(struct bpf_prog *fp)
|
|
{
|
|
__bpf_prog_release(fp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_destroy);
|
|
|
|
static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk)
|
|
{
|
|
struct sk_filter *fp, *old_fp;
|
|
|
|
fp = kmalloc(sizeof(*fp), GFP_KERNEL);
|
|
if (!fp)
|
|
return -ENOMEM;
|
|
|
|
fp->prog = prog;
|
|
atomic_set(&fp->refcnt, 0);
|
|
|
|
if (!sk_filter_charge(sk, fp)) {
|
|
kfree(fp);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
old_fp = rcu_dereference_protected(sk->sk_filter,
|
|
lockdep_sock_is_held(sk));
|
|
rcu_assign_pointer(sk->sk_filter, fp);
|
|
|
|
if (old_fp)
|
|
sk_filter_uncharge(sk, old_fp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __reuseport_attach_prog(struct bpf_prog *prog, struct sock *sk)
|
|
{
|
|
struct bpf_prog *old_prog;
|
|
int err;
|
|
|
|
if (bpf_prog_size(prog->len) > sysctl_optmem_max)
|
|
return -ENOMEM;
|
|
|
|
if (sk_unhashed(sk) && sk->sk_reuseport) {
|
|
err = reuseport_alloc(sk);
|
|
if (err)
|
|
return err;
|
|
} else if (!rcu_access_pointer(sk->sk_reuseport_cb)) {
|
|
/* The socket wasn't bound with SO_REUSEPORT */
|
|
return -EINVAL;
|
|
}
|
|
|
|
old_prog = reuseport_attach_prog(sk, prog);
|
|
if (old_prog)
|
|
bpf_prog_destroy(old_prog);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static
|
|
struct bpf_prog *__get_filter(struct sock_fprog *fprog, struct sock *sk)
|
|
{
|
|
unsigned int fsize = bpf_classic_proglen(fprog);
|
|
struct bpf_prog *prog;
|
|
int err;
|
|
|
|
if (sock_flag(sk, SOCK_FILTER_LOCKED))
|
|
return ERR_PTR(-EPERM);
|
|
|
|
/* Make sure new filter is there and in the right amounts. */
|
|
if (!bpf_check_basics_ok(fprog->filter, fprog->len))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
prog = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
|
|
if (!prog)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (copy_from_user(prog->insns, fprog->filter, fsize)) {
|
|
__bpf_prog_free(prog);
|
|
return ERR_PTR(-EFAULT);
|
|
}
|
|
|
|
prog->len = fprog->len;
|
|
|
|
err = bpf_prog_store_orig_filter(prog, fprog);
|
|
if (err) {
|
|
__bpf_prog_free(prog);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* bpf_prepare_filter() already takes care of freeing
|
|
* memory in case something goes wrong.
|
|
*/
|
|
return bpf_prepare_filter(prog, NULL);
|
|
}
|
|
|
|
/**
|
|
* sk_attach_filter - attach a socket filter
|
|
* @fprog: the filter program
|
|
* @sk: the socket to use
|
|
*
|
|
* Attach the user's filter code. We first run some sanity checks on
|
|
* it to make sure it does not explode on us later. If an error
|
|
* occurs or there is insufficient memory for the filter a negative
|
|
* errno code is returned. On success the return is zero.
|
|
*/
|
|
int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
|
|
{
|
|
struct bpf_prog *prog = __get_filter(fprog, sk);
|
|
int err;
|
|
|
|
if (IS_ERR(prog))
|
|
return PTR_ERR(prog);
|
|
|
|
err = __sk_attach_prog(prog, sk);
|
|
if (err < 0) {
|
|
__bpf_prog_release(prog);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(sk_attach_filter);
|
|
|
|
int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk)
|
|
{
|
|
struct bpf_prog *prog = __get_filter(fprog, sk);
|
|
int err;
|
|
|
|
if (IS_ERR(prog))
|
|
return PTR_ERR(prog);
|
|
|
|
err = __reuseport_attach_prog(prog, sk);
|
|
if (err < 0) {
|
|
__bpf_prog_release(prog);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct bpf_prog *__get_bpf(u32 ufd, struct sock *sk)
|
|
{
|
|
if (sock_flag(sk, SOCK_FILTER_LOCKED))
|
|
return ERR_PTR(-EPERM);
|
|
|
|
return bpf_prog_get_type(ufd, BPF_PROG_TYPE_SOCKET_FILTER);
|
|
}
|
|
|
|
int sk_attach_bpf(u32 ufd, struct sock *sk)
|
|
{
|
|
struct bpf_prog *prog = __get_bpf(ufd, sk);
|
|
int err;
|
|
|
|
if (IS_ERR(prog))
|
|
return PTR_ERR(prog);
|
|
|
|
err = __sk_attach_prog(prog, sk);
|
|
if (err < 0) {
|
|
bpf_prog_put(prog);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk)
|
|
{
|
|
struct bpf_prog *prog = __get_bpf(ufd, sk);
|
|
int err;
|
|
|
|
if (IS_ERR(prog))
|
|
return PTR_ERR(prog);
|
|
|
|
err = __reuseport_attach_prog(prog, sk);
|
|
if (err < 0) {
|
|
bpf_prog_put(prog);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct bpf_scratchpad {
|
|
union {
|
|
__be32 diff[MAX_BPF_STACK / sizeof(__be32)];
|
|
u8 buff[MAX_BPF_STACK];
|
|
};
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp);
|
|
|
|
static inline int bpf_try_make_writable(struct sk_buff *skb,
|
|
unsigned int write_len)
|
|
{
|
|
int err;
|
|
|
|
err = skb_ensure_writable(skb, write_len);
|
|
bpf_compute_data_end(skb);
|
|
|
|
return err;
|
|
}
|
|
|
|
static inline void bpf_push_mac_rcsum(struct sk_buff *skb)
|
|
{
|
|
if (skb_at_tc_ingress(skb))
|
|
skb_postpush_rcsum(skb, skb_mac_header(skb), skb->mac_len);
|
|
}
|
|
|
|
static inline void bpf_pull_mac_rcsum(struct sk_buff *skb)
|
|
{
|
|
if (skb_at_tc_ingress(skb))
|
|
skb_postpull_rcsum(skb, skb_mac_header(skb), skb->mac_len);
|
|
}
|
|
|
|
static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
unsigned int offset = (unsigned int) r2;
|
|
void *from = (void *) (long) r3;
|
|
unsigned int len = (unsigned int) r4;
|
|
void *ptr;
|
|
|
|
if (unlikely(flags & ~(BPF_F_RECOMPUTE_CSUM | BPF_F_INVALIDATE_HASH)))
|
|
return -EINVAL;
|
|
if (unlikely(offset > 0xffff))
|
|
return -EFAULT;
|
|
if (unlikely(bpf_try_make_writable(skb, offset + len)))
|
|
return -EFAULT;
|
|
|
|
ptr = skb->data + offset;
|
|
if (flags & BPF_F_RECOMPUTE_CSUM)
|
|
__skb_postpull_rcsum(skb, ptr, len, offset);
|
|
|
|
memcpy(ptr, from, len);
|
|
|
|
if (flags & BPF_F_RECOMPUTE_CSUM)
|
|
__skb_postpush_rcsum(skb, ptr, len, offset);
|
|
if (flags & BPF_F_INVALIDATE_HASH)
|
|
skb_clear_hash(skb);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_store_bytes_proto = {
|
|
.func = bpf_skb_store_bytes,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_PTR_TO_STACK,
|
|
.arg4_type = ARG_CONST_STACK_SIZE,
|
|
.arg5_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_skb_load_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
const struct sk_buff *skb = (const struct sk_buff *)(unsigned long) r1;
|
|
unsigned int offset = (unsigned int) r2;
|
|
void *to = (void *)(unsigned long) r3;
|
|
unsigned int len = (unsigned int) r4;
|
|
void *ptr;
|
|
|
|
if (unlikely(offset > 0xffff))
|
|
goto err_clear;
|
|
|
|
ptr = skb_header_pointer(skb, offset, len, to);
|
|
if (unlikely(!ptr))
|
|
goto err_clear;
|
|
if (ptr != to)
|
|
memcpy(to, ptr, len);
|
|
|
|
return 0;
|
|
err_clear:
|
|
memset(to, 0, len);
|
|
return -EFAULT;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_load_bytes_proto = {
|
|
.func = bpf_skb_load_bytes,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_PTR_TO_RAW_STACK,
|
|
.arg4_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
unsigned int offset = (unsigned int) r2;
|
|
__sum16 *ptr;
|
|
|
|
if (unlikely(flags & ~(BPF_F_HDR_FIELD_MASK)))
|
|
return -EINVAL;
|
|
if (unlikely(offset > 0xffff || offset & 1))
|
|
return -EFAULT;
|
|
if (unlikely(bpf_try_make_writable(skb, offset + sizeof(*ptr))))
|
|
return -EFAULT;
|
|
|
|
ptr = (__sum16 *)(skb->data + offset);
|
|
switch (flags & BPF_F_HDR_FIELD_MASK) {
|
|
case 0:
|
|
if (unlikely(from != 0))
|
|
return -EINVAL;
|
|
|
|
csum_replace_by_diff(ptr, to);
|
|
break;
|
|
case 2:
|
|
csum_replace2(ptr, from, to);
|
|
break;
|
|
case 4:
|
|
csum_replace4(ptr, from, to);
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_l3_csum_replace_proto = {
|
|
.func = bpf_l3_csum_replace,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_ANYTHING,
|
|
.arg5_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
bool is_pseudo = flags & BPF_F_PSEUDO_HDR;
|
|
bool is_mmzero = flags & BPF_F_MARK_MANGLED_0;
|
|
unsigned int offset = (unsigned int) r2;
|
|
__sum16 *ptr;
|
|
|
|
if (unlikely(flags & ~(BPF_F_MARK_MANGLED_0 | BPF_F_PSEUDO_HDR |
|
|
BPF_F_HDR_FIELD_MASK)))
|
|
return -EINVAL;
|
|
if (unlikely(offset > 0xffff || offset & 1))
|
|
return -EFAULT;
|
|
if (unlikely(bpf_try_make_writable(skb, offset + sizeof(*ptr))))
|
|
return -EFAULT;
|
|
|
|
ptr = (__sum16 *)(skb->data + offset);
|
|
if (is_mmzero && !*ptr)
|
|
return 0;
|
|
|
|
switch (flags & BPF_F_HDR_FIELD_MASK) {
|
|
case 0:
|
|
if (unlikely(from != 0))
|
|
return -EINVAL;
|
|
|
|
inet_proto_csum_replace_by_diff(ptr, skb, to, is_pseudo);
|
|
break;
|
|
case 2:
|
|
inet_proto_csum_replace2(ptr, skb, from, to, is_pseudo);
|
|
break;
|
|
case 4:
|
|
inet_proto_csum_replace4(ptr, skb, from, to, is_pseudo);
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (is_mmzero && !*ptr)
|
|
*ptr = CSUM_MANGLED_0;
|
|
return 0;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_l4_csum_replace_proto = {
|
|
.func = bpf_l4_csum_replace,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_ANYTHING,
|
|
.arg5_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_csum_diff(u64 r1, u64 from_size, u64 r3, u64 to_size, u64 seed)
|
|
{
|
|
struct bpf_scratchpad *sp = this_cpu_ptr(&bpf_sp);
|
|
u64 diff_size = from_size + to_size;
|
|
__be32 *from = (__be32 *) (long) r1;
|
|
__be32 *to = (__be32 *) (long) r3;
|
|
int i, j = 0;
|
|
|
|
/* This is quite flexible, some examples:
|
|
*
|
|
* from_size == 0, to_size > 0, seed := csum --> pushing data
|
|
* from_size > 0, to_size == 0, seed := csum --> pulling data
|
|
* from_size > 0, to_size > 0, seed := 0 --> diffing data
|
|
*
|
|
* Even for diffing, from_size and to_size don't need to be equal.
|
|
*/
|
|
if (unlikely(((from_size | to_size) & (sizeof(__be32) - 1)) ||
|
|
diff_size > sizeof(sp->diff)))
|
|
return -EINVAL;
|
|
|
|
for (i = 0; i < from_size / sizeof(__be32); i++, j++)
|
|
sp->diff[j] = ~from[i];
|
|
for (i = 0; i < to_size / sizeof(__be32); i++, j++)
|
|
sp->diff[j] = to[i];
|
|
|
|
return csum_partial(sp->diff, diff_size, seed);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_csum_diff_proto = {
|
|
.func = bpf_csum_diff,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_STACK,
|
|
.arg2_type = ARG_CONST_STACK_SIZE_OR_ZERO,
|
|
.arg3_type = ARG_PTR_TO_STACK,
|
|
.arg4_type = ARG_CONST_STACK_SIZE_OR_ZERO,
|
|
.arg5_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static inline int __bpf_rx_skb(struct net_device *dev, struct sk_buff *skb)
|
|
{
|
|
return dev_forward_skb(dev, skb);
|
|
}
|
|
|
|
static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
|
|
{
|
|
int ret;
|
|
|
|
if (unlikely(__this_cpu_read(xmit_recursion) > XMIT_RECURSION_LIMIT)) {
|
|
net_crit_ratelimited("bpf: recursion limit reached on datapath, buggy bpf program?\n");
|
|
kfree_skb(skb);
|
|
return -ENETDOWN;
|
|
}
|
|
|
|
skb->dev = dev;
|
|
|
|
__this_cpu_inc(xmit_recursion);
|
|
ret = dev_queue_xmit(skb);
|
|
__this_cpu_dec(xmit_recursion);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
struct net_device *dev;
|
|
|
|
if (unlikely(flags & ~(BPF_F_INGRESS)))
|
|
return -EINVAL;
|
|
|
|
dev = dev_get_by_index_rcu(dev_net(skb->dev), ifindex);
|
|
if (unlikely(!dev))
|
|
return -EINVAL;
|
|
|
|
skb = skb_clone(skb, GFP_ATOMIC);
|
|
if (unlikely(!skb))
|
|
return -ENOMEM;
|
|
|
|
bpf_push_mac_rcsum(skb);
|
|
|
|
return flags & BPF_F_INGRESS ?
|
|
__bpf_rx_skb(dev, skb) : __bpf_tx_skb(dev, skb);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_clone_redirect_proto = {
|
|
.func = bpf_clone_redirect,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
|
|
struct redirect_info {
|
|
u32 ifindex;
|
|
u32 flags;
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct redirect_info, redirect_info);
|
|
|
|
static u64 bpf_redirect(u64 ifindex, u64 flags, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
struct redirect_info *ri = this_cpu_ptr(&redirect_info);
|
|
|
|
if (unlikely(flags & ~(BPF_F_INGRESS)))
|
|
return TC_ACT_SHOT;
|
|
|
|
ri->ifindex = ifindex;
|
|
ri->flags = flags;
|
|
|
|
return TC_ACT_REDIRECT;
|
|
}
|
|
|
|
int skb_do_redirect(struct sk_buff *skb)
|
|
{
|
|
struct redirect_info *ri = this_cpu_ptr(&redirect_info);
|
|
struct net_device *dev;
|
|
|
|
dev = dev_get_by_index_rcu(dev_net(skb->dev), ri->ifindex);
|
|
ri->ifindex = 0;
|
|
if (unlikely(!dev)) {
|
|
kfree_skb(skb);
|
|
return -EINVAL;
|
|
}
|
|
|
|
bpf_push_mac_rcsum(skb);
|
|
|
|
return ri->flags & BPF_F_INGRESS ?
|
|
__bpf_rx_skb(dev, skb) : __bpf_tx_skb(dev, skb);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_redirect_proto = {
|
|
.func = bpf_redirect,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_ANYTHING,
|
|
.arg2_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_get_cgroup_classid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
return task_get_classid((struct sk_buff *) (unsigned long) r1);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_get_cgroup_classid_proto = {
|
|
.func = bpf_get_cgroup_classid,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
};
|
|
|
|
static u64 bpf_get_route_realm(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
return dst_tclassid((struct sk_buff *) (unsigned long) r1);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_get_route_realm_proto = {
|
|
.func = bpf_get_route_realm,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
};
|
|
|
|
static u64 bpf_get_hash_recalc(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
/* If skb_clear_hash() was called due to mangling, we can
|
|
* trigger SW recalculation here. Later access to hash
|
|
* can then use the inline skb->hash via context directly
|
|
* instead of calling this helper again.
|
|
*/
|
|
return skb_get_hash((struct sk_buff *) (unsigned long) r1);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_get_hash_recalc_proto = {
|
|
.func = bpf_get_hash_recalc,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
};
|
|
|
|
static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
__be16 vlan_proto = (__force __be16) r2;
|
|
int ret;
|
|
|
|
if (unlikely(vlan_proto != htons(ETH_P_8021Q) &&
|
|
vlan_proto != htons(ETH_P_8021AD)))
|
|
vlan_proto = htons(ETH_P_8021Q);
|
|
|
|
bpf_push_mac_rcsum(skb);
|
|
ret = skb_vlan_push(skb, vlan_proto, vlan_tci);
|
|
bpf_pull_mac_rcsum(skb);
|
|
|
|
bpf_compute_data_end(skb);
|
|
return ret;
|
|
}
|
|
|
|
const struct bpf_func_proto bpf_skb_vlan_push_proto = {
|
|
.func = bpf_skb_vlan_push,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
EXPORT_SYMBOL_GPL(bpf_skb_vlan_push_proto);
|
|
|
|
static u64 bpf_skb_vlan_pop(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
int ret;
|
|
|
|
bpf_push_mac_rcsum(skb);
|
|
ret = skb_vlan_pop(skb);
|
|
bpf_pull_mac_rcsum(skb);
|
|
|
|
bpf_compute_data_end(skb);
|
|
return ret;
|
|
}
|
|
|
|
const struct bpf_func_proto bpf_skb_vlan_pop_proto = {
|
|
.func = bpf_skb_vlan_pop,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
};
|
|
EXPORT_SYMBOL_GPL(bpf_skb_vlan_pop_proto);
|
|
|
|
static int bpf_skb_generic_push(struct sk_buff *skb, u32 off, u32 len)
|
|
{
|
|
/* Caller already did skb_cow() with len as headroom,
|
|
* so no need to do it here.
|
|
*/
|
|
skb_push(skb, len);
|
|
memmove(skb->data, skb->data + len, off);
|
|
memset(skb->data + off, 0, len);
|
|
|
|
/* No skb_postpush_rcsum(skb, skb->data + off, len)
|
|
* needed here as it does not change the skb->csum
|
|
* result for checksum complete when summing over
|
|
* zeroed blocks.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_skb_generic_pop(struct sk_buff *skb, u32 off, u32 len)
|
|
{
|
|
/* skb_ensure_writable() is not needed here, as we're
|
|
* already working on an uncloned skb.
|
|
*/
|
|
if (unlikely(!pskb_may_pull(skb, off + len)))
|
|
return -ENOMEM;
|
|
|
|
skb_postpull_rcsum(skb, skb->data + off, len);
|
|
memmove(skb->data + len, skb->data, off);
|
|
__skb_pull(skb, len);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_skb_net_hdr_push(struct sk_buff *skb, u32 off, u32 len)
|
|
{
|
|
bool trans_same = skb->transport_header == skb->network_header;
|
|
int ret;
|
|
|
|
/* There's no need for __skb_push()/__skb_pull() pair to
|
|
* get to the start of the mac header as we're guaranteed
|
|
* to always start from here under eBPF.
|
|
*/
|
|
ret = bpf_skb_generic_push(skb, off, len);
|
|
if (likely(!ret)) {
|
|
skb->mac_header -= len;
|
|
skb->network_header -= len;
|
|
if (trans_same)
|
|
skb->transport_header = skb->network_header;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int bpf_skb_net_hdr_pop(struct sk_buff *skb, u32 off, u32 len)
|
|
{
|
|
bool trans_same = skb->transport_header == skb->network_header;
|
|
int ret;
|
|
|
|
/* Same here, __skb_push()/__skb_pull() pair not needed. */
|
|
ret = bpf_skb_generic_pop(skb, off, len);
|
|
if (likely(!ret)) {
|
|
skb->mac_header += len;
|
|
skb->network_header += len;
|
|
if (trans_same)
|
|
skb->transport_header = skb->network_header;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int bpf_skb_proto_4_to_6(struct sk_buff *skb)
|
|
{
|
|
const u32 len_diff = sizeof(struct ipv6hdr) - sizeof(struct iphdr);
|
|
u32 off = skb->network_header - skb->mac_header;
|
|
int ret;
|
|
|
|
ret = skb_cow(skb, len_diff);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
|
|
ret = bpf_skb_net_hdr_push(skb, off, len_diff);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
|
|
if (skb_is_gso(skb)) {
|
|
/* SKB_GSO_UDP stays as is. SKB_GSO_TCPV4 needs to
|
|
* be changed into SKB_GSO_TCPV6.
|
|
*/
|
|
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) {
|
|
skb_shinfo(skb)->gso_type &= ~SKB_GSO_TCPV4;
|
|
skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
|
|
}
|
|
|
|
/* Due to IPv6 header, MSS needs to be downgraded. */
|
|
skb_shinfo(skb)->gso_size -= len_diff;
|
|
/* Header must be checked, and gso_segs recomputed. */
|
|
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
|
|
skb_shinfo(skb)->gso_segs = 0;
|
|
}
|
|
|
|
skb->protocol = htons(ETH_P_IPV6);
|
|
skb_clear_hash(skb);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_skb_proto_6_to_4(struct sk_buff *skb)
|
|
{
|
|
const u32 len_diff = sizeof(struct ipv6hdr) - sizeof(struct iphdr);
|
|
u32 off = skb->network_header - skb->mac_header;
|
|
int ret;
|
|
|
|
ret = skb_unclone(skb, GFP_ATOMIC);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
|
|
ret = bpf_skb_net_hdr_pop(skb, off, len_diff);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
|
|
if (skb_is_gso(skb)) {
|
|
/* SKB_GSO_UDP stays as is. SKB_GSO_TCPV6 needs to
|
|
* be changed into SKB_GSO_TCPV4.
|
|
*/
|
|
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) {
|
|
skb_shinfo(skb)->gso_type &= ~SKB_GSO_TCPV6;
|
|
skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
|
|
}
|
|
|
|
/* Due to IPv4 header, MSS can be upgraded. */
|
|
skb_shinfo(skb)->gso_size += len_diff;
|
|
/* Header must be checked, and gso_segs recomputed. */
|
|
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
|
|
skb_shinfo(skb)->gso_segs = 0;
|
|
}
|
|
|
|
skb->protocol = htons(ETH_P_IP);
|
|
skb_clear_hash(skb);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_skb_proto_xlat(struct sk_buff *skb, __be16 to_proto)
|
|
{
|
|
__be16 from_proto = skb->protocol;
|
|
|
|
if (from_proto == htons(ETH_P_IP) &&
|
|
to_proto == htons(ETH_P_IPV6))
|
|
return bpf_skb_proto_4_to_6(skb);
|
|
|
|
if (from_proto == htons(ETH_P_IPV6) &&
|
|
to_proto == htons(ETH_P_IP))
|
|
return bpf_skb_proto_6_to_4(skb);
|
|
|
|
return -ENOTSUPP;
|
|
}
|
|
|
|
static u64 bpf_skb_change_proto(u64 r1, u64 r2, u64 flags, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
__be16 proto = (__force __be16) r2;
|
|
int ret;
|
|
|
|
if (unlikely(flags))
|
|
return -EINVAL;
|
|
|
|
/* General idea is that this helper does the basic groundwork
|
|
* needed for changing the protocol, and eBPF program fills the
|
|
* rest through bpf_skb_store_bytes(), bpf_lX_csum_replace()
|
|
* and other helpers, rather than passing a raw buffer here.
|
|
*
|
|
* The rationale is to keep this minimal and without a need to
|
|
* deal with raw packet data. F.e. even if we would pass buffers
|
|
* here, the program still needs to call the bpf_lX_csum_replace()
|
|
* helpers anyway. Plus, this way we keep also separation of
|
|
* concerns, since f.e. bpf_skb_store_bytes() should only take
|
|
* care of stores.
|
|
*
|
|
* Currently, additional options and extension header space are
|
|
* not supported, but flags register is reserved so we can adapt
|
|
* that. For offloads, we mark packet as dodgy, so that headers
|
|
* need to be verified first.
|
|
*/
|
|
ret = bpf_skb_proto_xlat(skb, proto);
|
|
bpf_compute_data_end(skb);
|
|
return ret;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_change_proto_proto = {
|
|
.func = bpf_skb_change_proto,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_skb_change_type(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
u32 pkt_type = r2;
|
|
|
|
/* We only allow a restricted subset to be changed for now. */
|
|
if (unlikely(skb->pkt_type > PACKET_OTHERHOST ||
|
|
pkt_type > PACKET_OTHERHOST))
|
|
return -EINVAL;
|
|
|
|
skb->pkt_type = pkt_type;
|
|
return 0;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_change_type_proto = {
|
|
.func = bpf_skb_change_type,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_ANYTHING,
|
|
};
|
|
|
|
bool bpf_helper_changes_skb_data(void *func)
|
|
{
|
|
if (func == bpf_skb_vlan_push)
|
|
return true;
|
|
if (func == bpf_skb_vlan_pop)
|
|
return true;
|
|
if (func == bpf_skb_store_bytes)
|
|
return true;
|
|
if (func == bpf_skb_change_proto)
|
|
return true;
|
|
if (func == bpf_l3_csum_replace)
|
|
return true;
|
|
if (func == bpf_l4_csum_replace)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static unsigned long bpf_skb_copy(void *dst_buff, const void *skb,
|
|
unsigned long off, unsigned long len)
|
|
{
|
|
void *ptr = skb_header_pointer(skb, off, len, dst_buff);
|
|
|
|
if (unlikely(!ptr))
|
|
return len;
|
|
if (ptr != dst_buff)
|
|
memcpy(dst_buff, ptr, len);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static u64 bpf_skb_event_output(u64 r1, u64 r2, u64 flags, u64 r4,
|
|
u64 meta_size)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *)(long) r1;
|
|
struct bpf_map *map = (struct bpf_map *)(long) r2;
|
|
u64 skb_size = (flags & BPF_F_CTXLEN_MASK) >> 32;
|
|
void *meta = (void *)(long) r4;
|
|
|
|
if (unlikely(flags & ~(BPF_F_CTXLEN_MASK | BPF_F_INDEX_MASK)))
|
|
return -EINVAL;
|
|
if (unlikely(skb_size > skb->len))
|
|
return -EFAULT;
|
|
|
|
return bpf_event_output(map, flags, meta, meta_size, skb, skb_size,
|
|
bpf_skb_copy);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_event_output_proto = {
|
|
.func = bpf_skb_event_output,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_PTR_TO_STACK,
|
|
.arg5_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
static unsigned short bpf_tunnel_key_af(u64 flags)
|
|
{
|
|
return flags & BPF_F_TUNINFO_IPV6 ? AF_INET6 : AF_INET;
|
|
}
|
|
|
|
static u64 bpf_skb_get_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
struct bpf_tunnel_key *to = (struct bpf_tunnel_key *) (long) r2;
|
|
const struct ip_tunnel_info *info = skb_tunnel_info(skb);
|
|
u8 compat[sizeof(struct bpf_tunnel_key)];
|
|
void *to_orig = to;
|
|
int err;
|
|
|
|
if (unlikely(!info || (flags & ~(BPF_F_TUNINFO_IPV6)))) {
|
|
err = -EINVAL;
|
|
goto err_clear;
|
|
}
|
|
if (ip_tunnel_info_af(info) != bpf_tunnel_key_af(flags)) {
|
|
err = -EPROTO;
|
|
goto err_clear;
|
|
}
|
|
if (unlikely(size != sizeof(struct bpf_tunnel_key))) {
|
|
err = -EINVAL;
|
|
switch (size) {
|
|
case offsetof(struct bpf_tunnel_key, tunnel_label):
|
|
case offsetof(struct bpf_tunnel_key, tunnel_ext):
|
|
goto set_compat;
|
|
case offsetof(struct bpf_tunnel_key, remote_ipv6[1]):
|
|
/* Fixup deprecated structure layouts here, so we have
|
|
* a common path later on.
|
|
*/
|
|
if (ip_tunnel_info_af(info) != AF_INET)
|
|
goto err_clear;
|
|
set_compat:
|
|
to = (struct bpf_tunnel_key *)compat;
|
|
break;
|
|
default:
|
|
goto err_clear;
|
|
}
|
|
}
|
|
|
|
to->tunnel_id = be64_to_cpu(info->key.tun_id);
|
|
to->tunnel_tos = info->key.tos;
|
|
to->tunnel_ttl = info->key.ttl;
|
|
|
|
if (flags & BPF_F_TUNINFO_IPV6) {
|
|
memcpy(to->remote_ipv6, &info->key.u.ipv6.src,
|
|
sizeof(to->remote_ipv6));
|
|
to->tunnel_label = be32_to_cpu(info->key.label);
|
|
} else {
|
|
to->remote_ipv4 = be32_to_cpu(info->key.u.ipv4.src);
|
|
}
|
|
|
|
if (unlikely(size != sizeof(struct bpf_tunnel_key)))
|
|
memcpy(to_orig, to, size);
|
|
|
|
return 0;
|
|
err_clear:
|
|
memset(to_orig, 0, size);
|
|
return err;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_get_tunnel_key_proto = {
|
|
.func = bpf_skb_get_tunnel_key,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_PTR_TO_RAW_STACK,
|
|
.arg3_type = ARG_CONST_STACK_SIZE,
|
|
.arg4_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_skb_get_tunnel_opt(u64 r1, u64 r2, u64 size, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
u8 *to = (u8 *) (long) r2;
|
|
const struct ip_tunnel_info *info = skb_tunnel_info(skb);
|
|
int err;
|
|
|
|
if (unlikely(!info ||
|
|
!(info->key.tun_flags & TUNNEL_OPTIONS_PRESENT))) {
|
|
err = -ENOENT;
|
|
goto err_clear;
|
|
}
|
|
if (unlikely(size < info->options_len)) {
|
|
err = -ENOMEM;
|
|
goto err_clear;
|
|
}
|
|
|
|
ip_tunnel_info_opts_get(to, info);
|
|
if (size > info->options_len)
|
|
memset(to + info->options_len, 0, size - info->options_len);
|
|
|
|
return info->options_len;
|
|
err_clear:
|
|
memset(to, 0, size);
|
|
return err;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_get_tunnel_opt_proto = {
|
|
.func = bpf_skb_get_tunnel_opt,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_PTR_TO_RAW_STACK,
|
|
.arg3_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
static struct metadata_dst __percpu *md_dst;
|
|
|
|
static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
struct bpf_tunnel_key *from = (struct bpf_tunnel_key *) (long) r2;
|
|
struct metadata_dst *md = this_cpu_ptr(md_dst);
|
|
u8 compat[sizeof(struct bpf_tunnel_key)];
|
|
struct ip_tunnel_info *info;
|
|
|
|
if (unlikely(flags & ~(BPF_F_TUNINFO_IPV6 | BPF_F_ZERO_CSUM_TX |
|
|
BPF_F_DONT_FRAGMENT)))
|
|
return -EINVAL;
|
|
if (unlikely(size != sizeof(struct bpf_tunnel_key))) {
|
|
switch (size) {
|
|
case offsetof(struct bpf_tunnel_key, tunnel_label):
|
|
case offsetof(struct bpf_tunnel_key, tunnel_ext):
|
|
case offsetof(struct bpf_tunnel_key, remote_ipv6[1]):
|
|
/* Fixup deprecated structure layouts here, so we have
|
|
* a common path later on.
|
|
*/
|
|
memcpy(compat, from, size);
|
|
memset(compat + size, 0, sizeof(compat) - size);
|
|
from = (struct bpf_tunnel_key *)compat;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
if (unlikely((!(flags & BPF_F_TUNINFO_IPV6) && from->tunnel_label) ||
|
|
from->tunnel_ext))
|
|
return -EINVAL;
|
|
|
|
skb_dst_drop(skb);
|
|
dst_hold((struct dst_entry *) md);
|
|
skb_dst_set(skb, (struct dst_entry *) md);
|
|
|
|
info = &md->u.tun_info;
|
|
info->mode = IP_TUNNEL_INFO_TX;
|
|
|
|
info->key.tun_flags = TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_NOCACHE;
|
|
if (flags & BPF_F_DONT_FRAGMENT)
|
|
info->key.tun_flags |= TUNNEL_DONT_FRAGMENT;
|
|
|
|
info->key.tun_id = cpu_to_be64(from->tunnel_id);
|
|
info->key.tos = from->tunnel_tos;
|
|
info->key.ttl = from->tunnel_ttl;
|
|
|
|
if (flags & BPF_F_TUNINFO_IPV6) {
|
|
info->mode |= IP_TUNNEL_INFO_IPV6;
|
|
memcpy(&info->key.u.ipv6.dst, from->remote_ipv6,
|
|
sizeof(from->remote_ipv6));
|
|
info->key.label = cpu_to_be32(from->tunnel_label) &
|
|
IPV6_FLOWLABEL_MASK;
|
|
} else {
|
|
info->key.u.ipv4.dst = cpu_to_be32(from->remote_ipv4);
|
|
if (flags & BPF_F_ZERO_CSUM_TX)
|
|
info->key.tun_flags &= ~TUNNEL_CSUM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_set_tunnel_key_proto = {
|
|
.func = bpf_skb_set_tunnel_key,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_PTR_TO_STACK,
|
|
.arg3_type = ARG_CONST_STACK_SIZE,
|
|
.arg4_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static u64 bpf_skb_set_tunnel_opt(u64 r1, u64 r2, u64 size, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *) (long) r1;
|
|
u8 *from = (u8 *) (long) r2;
|
|
struct ip_tunnel_info *info = skb_tunnel_info(skb);
|
|
const struct metadata_dst *md = this_cpu_ptr(md_dst);
|
|
|
|
if (unlikely(info != &md->u.tun_info || (size & (sizeof(u32) - 1))))
|
|
return -EINVAL;
|
|
if (unlikely(size > IP_TUNNEL_OPTS_MAX))
|
|
return -ENOMEM;
|
|
|
|
ip_tunnel_info_opts_set(info, from, size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_set_tunnel_opt_proto = {
|
|
.func = bpf_skb_set_tunnel_opt,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_PTR_TO_STACK,
|
|
.arg3_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
static const struct bpf_func_proto *
|
|
bpf_get_skb_set_tunnel_proto(enum bpf_func_id which)
|
|
{
|
|
if (!md_dst) {
|
|
/* Race is not possible, since it's called from verifier
|
|
* that is holding verifier mutex.
|
|
*/
|
|
md_dst = metadata_dst_alloc_percpu(IP_TUNNEL_OPTS_MAX,
|
|
GFP_KERNEL);
|
|
if (!md_dst)
|
|
return NULL;
|
|
}
|
|
|
|
switch (which) {
|
|
case BPF_FUNC_skb_set_tunnel_key:
|
|
return &bpf_skb_set_tunnel_key_proto;
|
|
case BPF_FUNC_skb_set_tunnel_opt:
|
|
return &bpf_skb_set_tunnel_opt_proto;
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_SOCK_CGROUP_DATA
|
|
static u64 bpf_skb_under_cgroup(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
struct sk_buff *skb = (struct sk_buff *)(long)r1;
|
|
struct bpf_map *map = (struct bpf_map *)(long)r2;
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
struct cgroup *cgrp;
|
|
struct sock *sk;
|
|
u32 i = (u32)r3;
|
|
|
|
sk = skb->sk;
|
|
if (!sk || !sk_fullsock(sk))
|
|
return -ENOENT;
|
|
|
|
if (unlikely(i >= array->map.max_entries))
|
|
return -E2BIG;
|
|
|
|
cgrp = READ_ONCE(array->ptrs[i]);
|
|
if (unlikely(!cgrp))
|
|
return -EAGAIN;
|
|
|
|
return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data), cgrp);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_skb_under_cgroup_proto = {
|
|
.func = bpf_skb_under_cgroup,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
#endif
|
|
|
|
static const struct bpf_func_proto *
|
|
sk_filter_func_proto(enum bpf_func_id func_id)
|
|
{
|
|
switch (func_id) {
|
|
case BPF_FUNC_map_lookup_elem:
|
|
return &bpf_map_lookup_elem_proto;
|
|
case BPF_FUNC_map_update_elem:
|
|
return &bpf_map_update_elem_proto;
|
|
case BPF_FUNC_map_delete_elem:
|
|
return &bpf_map_delete_elem_proto;
|
|
case BPF_FUNC_get_prandom_u32:
|
|
return &bpf_get_prandom_u32_proto;
|
|
case BPF_FUNC_get_smp_processor_id:
|
|
return &bpf_get_raw_smp_processor_id_proto;
|
|
case BPF_FUNC_tail_call:
|
|
return &bpf_tail_call_proto;
|
|
case BPF_FUNC_ktime_get_ns:
|
|
return &bpf_ktime_get_ns_proto;
|
|
case BPF_FUNC_trace_printk:
|
|
if (capable(CAP_SYS_ADMIN))
|
|
return bpf_get_trace_printk_proto();
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static const struct bpf_func_proto *
|
|
tc_cls_act_func_proto(enum bpf_func_id func_id)
|
|
{
|
|
switch (func_id) {
|
|
case BPF_FUNC_skb_store_bytes:
|
|
return &bpf_skb_store_bytes_proto;
|
|
case BPF_FUNC_skb_load_bytes:
|
|
return &bpf_skb_load_bytes_proto;
|
|
case BPF_FUNC_csum_diff:
|
|
return &bpf_csum_diff_proto;
|
|
case BPF_FUNC_l3_csum_replace:
|
|
return &bpf_l3_csum_replace_proto;
|
|
case BPF_FUNC_l4_csum_replace:
|
|
return &bpf_l4_csum_replace_proto;
|
|
case BPF_FUNC_clone_redirect:
|
|
return &bpf_clone_redirect_proto;
|
|
case BPF_FUNC_get_cgroup_classid:
|
|
return &bpf_get_cgroup_classid_proto;
|
|
case BPF_FUNC_skb_vlan_push:
|
|
return &bpf_skb_vlan_push_proto;
|
|
case BPF_FUNC_skb_vlan_pop:
|
|
return &bpf_skb_vlan_pop_proto;
|
|
case BPF_FUNC_skb_change_proto:
|
|
return &bpf_skb_change_proto_proto;
|
|
case BPF_FUNC_skb_change_type:
|
|
return &bpf_skb_change_type_proto;
|
|
case BPF_FUNC_skb_get_tunnel_key:
|
|
return &bpf_skb_get_tunnel_key_proto;
|
|
case BPF_FUNC_skb_set_tunnel_key:
|
|
return bpf_get_skb_set_tunnel_proto(func_id);
|
|
case BPF_FUNC_skb_get_tunnel_opt:
|
|
return &bpf_skb_get_tunnel_opt_proto;
|
|
case BPF_FUNC_skb_set_tunnel_opt:
|
|
return bpf_get_skb_set_tunnel_proto(func_id);
|
|
case BPF_FUNC_redirect:
|
|
return &bpf_redirect_proto;
|
|
case BPF_FUNC_get_route_realm:
|
|
return &bpf_get_route_realm_proto;
|
|
case BPF_FUNC_get_hash_recalc:
|
|
return &bpf_get_hash_recalc_proto;
|
|
case BPF_FUNC_perf_event_output:
|
|
return &bpf_skb_event_output_proto;
|
|
case BPF_FUNC_get_smp_processor_id:
|
|
return &bpf_get_smp_processor_id_proto;
|
|
#ifdef CONFIG_SOCK_CGROUP_DATA
|
|
case BPF_FUNC_skb_under_cgroup:
|
|
return &bpf_skb_under_cgroup_proto;
|
|
#endif
|
|
default:
|
|
return sk_filter_func_proto(func_id);
|
|
}
|
|
}
|
|
|
|
static const struct bpf_func_proto *
|
|
xdp_func_proto(enum bpf_func_id func_id)
|
|
{
|
|
return sk_filter_func_proto(func_id);
|
|
}
|
|
|
|
static bool __is_valid_access(int off, int size, enum bpf_access_type type)
|
|
{
|
|
if (off < 0 || off >= sizeof(struct __sk_buff))
|
|
return false;
|
|
/* The verifier guarantees that size > 0. */
|
|
if (off % size != 0)
|
|
return false;
|
|
if (size != sizeof(__u32))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool sk_filter_is_valid_access(int off, int size,
|
|
enum bpf_access_type type,
|
|
enum bpf_reg_type *reg_type)
|
|
{
|
|
switch (off) {
|
|
case offsetof(struct __sk_buff, tc_classid):
|
|
case offsetof(struct __sk_buff, data):
|
|
case offsetof(struct __sk_buff, data_end):
|
|
return false;
|
|
}
|
|
|
|
if (type == BPF_WRITE) {
|
|
switch (off) {
|
|
case offsetof(struct __sk_buff, cb[0]) ...
|
|
offsetof(struct __sk_buff, cb[4]):
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return __is_valid_access(off, size, type);
|
|
}
|
|
|
|
static bool tc_cls_act_is_valid_access(int off, int size,
|
|
enum bpf_access_type type,
|
|
enum bpf_reg_type *reg_type)
|
|
{
|
|
if (type == BPF_WRITE) {
|
|
switch (off) {
|
|
case offsetof(struct __sk_buff, mark):
|
|
case offsetof(struct __sk_buff, tc_index):
|
|
case offsetof(struct __sk_buff, priority):
|
|
case offsetof(struct __sk_buff, cb[0]) ...
|
|
offsetof(struct __sk_buff, cb[4]):
|
|
case offsetof(struct __sk_buff, tc_classid):
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
switch (off) {
|
|
case offsetof(struct __sk_buff, data):
|
|
*reg_type = PTR_TO_PACKET;
|
|
break;
|
|
case offsetof(struct __sk_buff, data_end):
|
|
*reg_type = PTR_TO_PACKET_END;
|
|
break;
|
|
}
|
|
|
|
return __is_valid_access(off, size, type);
|
|
}
|
|
|
|
static bool __is_valid_xdp_access(int off, int size,
|
|
enum bpf_access_type type)
|
|
{
|
|
if (off < 0 || off >= sizeof(struct xdp_md))
|
|
return false;
|
|
if (off % size != 0)
|
|
return false;
|
|
if (size != 4)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool xdp_is_valid_access(int off, int size,
|
|
enum bpf_access_type type,
|
|
enum bpf_reg_type *reg_type)
|
|
{
|
|
if (type == BPF_WRITE)
|
|
return false;
|
|
|
|
switch (off) {
|
|
case offsetof(struct xdp_md, data):
|
|
*reg_type = PTR_TO_PACKET;
|
|
break;
|
|
case offsetof(struct xdp_md, data_end):
|
|
*reg_type = PTR_TO_PACKET_END;
|
|
break;
|
|
}
|
|
|
|
return __is_valid_xdp_access(off, size, type);
|
|
}
|
|
|
|
void bpf_warn_invalid_xdp_action(u32 act)
|
|
{
|
|
WARN_ONCE(1, "Illegal XDP return value %u, expect packet loss\n", act);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);
|
|
|
|
static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,
|
|
int src_reg, int ctx_off,
|
|
struct bpf_insn *insn_buf,
|
|
struct bpf_prog *prog)
|
|
{
|
|
struct bpf_insn *insn = insn_buf;
|
|
|
|
switch (ctx_off) {
|
|
case offsetof(struct __sk_buff, len):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
|
|
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, len));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, protocol):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
|
|
|
|
*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, protocol));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, vlan_proto):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
|
|
|
|
*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, vlan_proto));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, priority):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, priority) != 4);
|
|
|
|
if (type == BPF_WRITE)
|
|
*insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, priority));
|
|
else
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, priority));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, ingress_ifindex):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4);
|
|
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, skb_iif));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, ifindex):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
|
|
|
|
*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
|
|
dst_reg, src_reg,
|
|
offsetof(struct sk_buff, dev));
|
|
*insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1);
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg,
|
|
offsetof(struct net_device, ifindex));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, hash):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
|
|
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, hash));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, mark):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
|
|
|
|
if (type == BPF_WRITE)
|
|
*insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, mark));
|
|
else
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, mark));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, pkt_type):
|
|
return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn);
|
|
|
|
case offsetof(struct __sk_buff, queue_mapping):
|
|
return convert_skb_access(SKF_AD_QUEUE, dst_reg, src_reg, insn);
|
|
|
|
case offsetof(struct __sk_buff, vlan_present):
|
|
return convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
|
|
dst_reg, src_reg, insn);
|
|
|
|
case offsetof(struct __sk_buff, vlan_tci):
|
|
return convert_skb_access(SKF_AD_VLAN_TAG,
|
|
dst_reg, src_reg, insn);
|
|
|
|
case offsetof(struct __sk_buff, cb[0]) ...
|
|
offsetof(struct __sk_buff, cb[4]):
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct qdisc_skb_cb, data) < 20);
|
|
|
|
prog->cb_access = 1;
|
|
ctx_off -= offsetof(struct __sk_buff, cb[0]);
|
|
ctx_off += offsetof(struct sk_buff, cb);
|
|
ctx_off += offsetof(struct qdisc_skb_cb, data);
|
|
if (type == BPF_WRITE)
|
|
*insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
|
|
else
|
|
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, tc_classid):
|
|
ctx_off -= offsetof(struct __sk_buff, tc_classid);
|
|
ctx_off += offsetof(struct sk_buff, cb);
|
|
ctx_off += offsetof(struct qdisc_skb_cb, tc_classid);
|
|
if (type == BPF_WRITE)
|
|
*insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, ctx_off);
|
|
else
|
|
*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, ctx_off);
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, data):
|
|
*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, data)),
|
|
dst_reg, src_reg,
|
|
offsetof(struct sk_buff, data));
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, data_end):
|
|
ctx_off -= offsetof(struct __sk_buff, data_end);
|
|
ctx_off += offsetof(struct sk_buff, cb);
|
|
ctx_off += offsetof(struct bpf_skb_data_end, data_end);
|
|
*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(sizeof(void *)),
|
|
dst_reg, src_reg, ctx_off);
|
|
break;
|
|
|
|
case offsetof(struct __sk_buff, tc_index):
|
|
#ifdef CONFIG_NET_SCHED
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, tc_index) != 2);
|
|
|
|
if (type == BPF_WRITE)
|
|
*insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, tc_index));
|
|
else
|
|
*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
|
|
offsetof(struct sk_buff, tc_index));
|
|
break;
|
|
#else
|
|
if (type == BPF_WRITE)
|
|
*insn++ = BPF_MOV64_REG(dst_reg, dst_reg);
|
|
else
|
|
*insn++ = BPF_MOV64_IMM(dst_reg, 0);
|
|
break;
|
|
#endif
|
|
}
|
|
|
|
return insn - insn_buf;
|
|
}
|
|
|
|
static u32 xdp_convert_ctx_access(enum bpf_access_type type, int dst_reg,
|
|
int src_reg, int ctx_off,
|
|
struct bpf_insn *insn_buf,
|
|
struct bpf_prog *prog)
|
|
{
|
|
struct bpf_insn *insn = insn_buf;
|
|
|
|
switch (ctx_off) {
|
|
case offsetof(struct xdp_md, data):
|
|
*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct xdp_buff, data)),
|
|
dst_reg, src_reg,
|
|
offsetof(struct xdp_buff, data));
|
|
break;
|
|
case offsetof(struct xdp_md, data_end):
|
|
*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct xdp_buff, data_end)),
|
|
dst_reg, src_reg,
|
|
offsetof(struct xdp_buff, data_end));
|
|
break;
|
|
}
|
|
|
|
return insn - insn_buf;
|
|
}
|
|
|
|
static const struct bpf_verifier_ops sk_filter_ops = {
|
|
.get_func_proto = sk_filter_func_proto,
|
|
.is_valid_access = sk_filter_is_valid_access,
|
|
.convert_ctx_access = bpf_net_convert_ctx_access,
|
|
};
|
|
|
|
static const struct bpf_verifier_ops tc_cls_act_ops = {
|
|
.get_func_proto = tc_cls_act_func_proto,
|
|
.is_valid_access = tc_cls_act_is_valid_access,
|
|
.convert_ctx_access = bpf_net_convert_ctx_access,
|
|
};
|
|
|
|
static const struct bpf_verifier_ops xdp_ops = {
|
|
.get_func_proto = xdp_func_proto,
|
|
.is_valid_access = xdp_is_valid_access,
|
|
.convert_ctx_access = xdp_convert_ctx_access,
|
|
};
|
|
|
|
static struct bpf_prog_type_list sk_filter_type __read_mostly = {
|
|
.ops = &sk_filter_ops,
|
|
.type = BPF_PROG_TYPE_SOCKET_FILTER,
|
|
};
|
|
|
|
static struct bpf_prog_type_list sched_cls_type __read_mostly = {
|
|
.ops = &tc_cls_act_ops,
|
|
.type = BPF_PROG_TYPE_SCHED_CLS,
|
|
};
|
|
|
|
static struct bpf_prog_type_list sched_act_type __read_mostly = {
|
|
.ops = &tc_cls_act_ops,
|
|
.type = BPF_PROG_TYPE_SCHED_ACT,
|
|
};
|
|
|
|
static struct bpf_prog_type_list xdp_type __read_mostly = {
|
|
.ops = &xdp_ops,
|
|
.type = BPF_PROG_TYPE_XDP,
|
|
};
|
|
|
|
static int __init register_sk_filter_ops(void)
|
|
{
|
|
bpf_register_prog_type(&sk_filter_type);
|
|
bpf_register_prog_type(&sched_cls_type);
|
|
bpf_register_prog_type(&sched_act_type);
|
|
bpf_register_prog_type(&xdp_type);
|
|
|
|
return 0;
|
|
}
|
|
late_initcall(register_sk_filter_ops);
|
|
|
|
int sk_detach_filter(struct sock *sk)
|
|
{
|
|
int ret = -ENOENT;
|
|
struct sk_filter *filter;
|
|
|
|
if (sock_flag(sk, SOCK_FILTER_LOCKED))
|
|
return -EPERM;
|
|
|
|
filter = rcu_dereference_protected(sk->sk_filter,
|
|
lockdep_sock_is_held(sk));
|
|
if (filter) {
|
|
RCU_INIT_POINTER(sk->sk_filter, NULL);
|
|
sk_filter_uncharge(sk, filter);
|
|
ret = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(sk_detach_filter);
|
|
|
|
int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
|
|
unsigned int len)
|
|
{
|
|
struct sock_fprog_kern *fprog;
|
|
struct sk_filter *filter;
|
|
int ret = 0;
|
|
|
|
lock_sock(sk);
|
|
filter = rcu_dereference_protected(sk->sk_filter,
|
|
lockdep_sock_is_held(sk));
|
|
if (!filter)
|
|
goto out;
|
|
|
|
/* We're copying the filter that has been originally attached,
|
|
* so no conversion/decode needed anymore. eBPF programs that
|
|
* have no original program cannot be dumped through this.
|
|
*/
|
|
ret = -EACCES;
|
|
fprog = filter->prog->orig_prog;
|
|
if (!fprog)
|
|
goto out;
|
|
|
|
ret = fprog->len;
|
|
if (!len)
|
|
/* User space only enquires number of filter blocks. */
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (len < fprog->len)
|
|
goto out;
|
|
|
|
ret = -EFAULT;
|
|
if (copy_to_user(ubuf, fprog->filter, bpf_classic_proglen(fprog)))
|
|
goto out;
|
|
|
|
/* Instead of bytes, the API requests to return the number
|
|
* of filter blocks.
|
|
*/
|
|
ret = fprog->len;
|
|
out:
|
|
release_sock(sk);
|
|
return ret;
|
|
}
|