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alistair23-linux/net/core/filter.c
Daniel Borkmann d1c55ab5e4 bpf: prepare bpf_int_jit_compile/bpf_prog_select_runtime apis 
Since the blinding is strictly only called from inside eBPF JITs,
we need to change signatures for bpf_int_jit_compile() and
bpf_prog_select_runtime() first in order to prepare that the
eBPF program we're dealing with can change underneath. Hence,
for call sites, we need to return the latest prog. No functional
change in this patch.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16 13:49:32 -04:00

2380 lines
61 KiB
C
Raw Blame History

/*
* Linux Socket Filter - Kernel level socket filtering
*
* Based on the design of the Berkeley Packet Filter. The new
* internal format has been designed by PLUMgrid:
*
* Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
*
* Authors:
*
* Jay Schulist <jschlst@samba.org>
* Alexei Starovoitov <ast@plumgrid.com>
* Daniel Borkmann <dborkman@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Andi Kleen - Fix a few bad bugs and races.
* Kris Katterjohn - Added many additional checks in bpf_check_classic()
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_packet.h>
#include <linux/gfp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/netlink.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/flow_dissector.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <linux/filter.h>
#include <linux/ratelimit.h>
#include <linux/seccomp.h>
#include <linux/if_vlan.h>
#include <linux/bpf.h>
#include <net/sch_generic.h>
#include <net/cls_cgroup.h>
#include <net/dst_metadata.h>
#include <net/dst.h>
#include <net/sock_reuseport.h>
/**
* sk_filter - run a packet through a socket filter
* @sk: sock associated with &sk_buff
* @skb: buffer to filter
*
* Run the eBPF program and then cut skb->data to correct size returned by
* the program. If pkt_len is 0 we toss packet. If skb->len is smaller
* than pkt_len we keep whole skb->data. This is the socket level
* wrapper to BPF_PROG_RUN. It returns 0 if the packet should
* be accepted or -EPERM if the packet should be tossed.
*
*/
int sk_filter(struct sock *sk, struct sk_buff *skb)
{
int err;
struct sk_filter *filter;
/*
* If the skb was allocated from pfmemalloc reserves, only
* allow SOCK_MEMALLOC sockets to use it as this socket is
* helping free memory
*/
if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
return -ENOMEM;
err = security_sock_rcv_skb(sk, skb);
if (err)
return err;
rcu_read_lock();
filter = rcu_dereference(sk->sk_filter);
if (filter) {
unsigned int pkt_len = bpf_prog_run_save_cb(filter->prog, skb);
err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
}
rcu_read_unlock();
return err;
}
EXPORT_SYMBOL(sk_filter);
static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
}
static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
struct nlattr *nla;
if (skb_is_nonlinear(skb))
return 0;
if (skb->len < sizeof(struct nlattr))
return 0;
if (a > skb->len - sizeof(struct nlattr))
return 0;
nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
if (nla)
return (void *) nla - (void *) skb->data;
return 0;
}
static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
struct nlattr *nla;
if (skb_is_nonlinear(skb))
return 0;
if (skb->len < sizeof(struct nlattr))
return 0;
if (a > skb->len - sizeof(struct nlattr))
return 0;
nla = (struct nlattr *) &skb->data[a];
if (nla->nla_len > skb->len - a)
return 0;
nla = nla_find_nested(nla, x);
if (nla)
return (void *) nla - (void *) skb->data;
return 0;
}
static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
return raw_smp_processor_id();
}
static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,
struct bpf_insn *insn_buf)
{
struct bpf_insn *insn = insn_buf;
switch (skb_field) {
case SKF_AD_MARK:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
offsetof(struct sk_buff, mark));
break;
case SKF_AD_PKTTYPE:
*insn++ = BPF_LDX_MEM(BPF_B, dst_reg, src_reg, PKT_TYPE_OFFSET());
*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, PKT_TYPE_MAX);
#ifdef __BIG_ENDIAN_BITFIELD
*insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 5);
#endif
break;
case SKF_AD_QUEUE:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
offsetof(struct sk_buff, queue_mapping));
break;
case SKF_AD_VLAN_TAG:
case SKF_AD_VLAN_TAG_PRESENT:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
/* dst_reg = *(u16 *) (src_reg + offsetof(vlan_tci)) */
*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
offsetof(struct sk_buff, vlan_tci));
if (skb_field == SKF_AD_VLAN_TAG) {
*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg,
~VLAN_TAG_PRESENT);
} else {
/* dst_reg >>= 12 */
*insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 12);
/* dst_reg &= 1 */
*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, 1);
}
break;
}
return insn - insn_buf;
}
static bool convert_bpf_extensions(struct sock_filter *fp,
struct bpf_insn **insnp)
{
struct bpf_insn *insn = *insnp;
u32 cnt;
switch (fp->k) {
case SKF_AD_OFF + SKF_AD_PROTOCOL:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
/* A = *(u16 *) (CTX + offsetof(protocol)) */
*insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
offsetof(struct sk_buff, protocol));
/* A = ntohs(A) [emitting a nop or swap16] */
*insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
break;
case SKF_AD_OFF + SKF_AD_PKTTYPE:
cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn);
insn += cnt - 1;
break;
case SKF_AD_OFF + SKF_AD_IFINDEX:
case SKF_AD_OFF + SKF_AD_HATYPE:
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0);
*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
BPF_REG_TMP, BPF_REG_CTX,
offsetof(struct sk_buff, dev));
/* if (tmp != 0) goto pc + 1 */
*insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
*insn++ = BPF_EXIT_INSN();
if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX)
*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP,
offsetof(struct net_device, ifindex));
else
*insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
offsetof(struct net_device, type));
break;
case SKF_AD_OFF + SKF_AD_MARK:
cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn);
insn += cnt - 1;
break;
case SKF_AD_OFF + SKF_AD_RXHASH:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
offsetof(struct sk_buff, hash));
break;
case SKF_AD_OFF + SKF_AD_QUEUE:
cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn);
insn += cnt - 1;
break;
case SKF_AD_OFF + SKF_AD_VLAN_TAG:
cnt = convert_skb_access(SKF_AD_VLAN_TAG,
BPF_REG_A, BPF_REG_CTX, insn);
insn += cnt - 1;
break;
case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
cnt = convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
BPF_REG_A, BPF_REG_CTX, insn);
insn += cnt - 1;
break;
case SKF_AD_OFF + SKF_AD_VLAN_TPID:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
/* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
*insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
offsetof(struct sk_buff, vlan_proto));
/* A = ntohs(A) [emitting a nop or swap16] */
*insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
break;
case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
case SKF_AD_OFF + SKF_AD_NLATTR:
case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
case SKF_AD_OFF + SKF_AD_CPU:
case SKF_AD_OFF + SKF_AD_RANDOM:
/* arg1 = CTX */
*insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
/* arg2 = A */
*insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
/* arg3 = X */
*insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
/* Emit call(arg1=CTX, arg2=A, arg3=X) */
switch (fp->k) {
case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
*insn = BPF_EMIT_CALL(__skb_get_pay_offset);
break;
case SKF_AD_OFF + SKF_AD_NLATTR:
*insn = BPF_EMIT_CALL(__skb_get_nlattr);
break;
case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
*insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
break;
case SKF_AD_OFF + SKF_AD_CPU:
*insn = BPF_EMIT_CALL(__get_raw_cpu_id);
break;
case SKF_AD_OFF + SKF_AD_RANDOM:
*insn = BPF_EMIT_CALL(bpf_user_rnd_u32);
bpf_user_rnd_init_once();
break;
}
break;
case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
/* A ^= X */
*insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
break;
default:
/* This is just a dummy call to avoid letting the compiler
* evict __bpf_call_base() as an optimization. Placed here
* where no-one bothers.
*/
BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
return false;
}
*insnp = insn;
return true;
}
/**
* bpf_convert_filter - convert filter program
* @prog: the user passed filter program
* @len: the length of the user passed filter program
* @new_prog: buffer where converted program will be stored
* @new_len: pointer to store length of converted program
*
* Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
* Conversion workflow:
*
* 1) First pass for calculating the new program length:
* bpf_convert_filter(old_prog, old_len, NULL, &new_len)
*
* 2) 2nd pass to remap in two passes: 1st pass finds new
* jump offsets, 2nd pass remapping:
* new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
* bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
*/
static int bpf_convert_filter(struct sock_filter *prog, int len,
struct bpf_insn *new_prog, int *new_len)
{
int new_flen = 0, pass = 0, target, i;
struct bpf_insn *new_insn;
struct sock_filter *fp;
int *addrs = NULL;
u8 bpf_src;
BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
if (len <= 0 || len > BPF_MAXINSNS)
return -EINVAL;
if (new_prog) {
addrs = kcalloc(len, sizeof(*addrs),
GFP_KERNEL | __GFP_NOWARN);
if (!addrs)
return -ENOMEM;
}
do_pass:
new_insn = new_prog;
fp = prog;
/* Classic BPF related prologue emission. */
if (new_insn) {
/* Classic BPF expects A and X to be reset first. These need
* to be guaranteed to be the first two instructions.
*/
*new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_A, BPF_REG_A);
*new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_X, BPF_REG_X);
/* All programs must keep CTX in callee saved BPF_REG_CTX.
* In eBPF case it's done by the compiler, here we need to
* do this ourself. Initial CTX is present in BPF_REG_ARG1.
*/
*new_insn++ = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
} else {
new_insn += 3;
}
for (i = 0; i < len; fp++, i++) {
struct bpf_insn tmp_insns[6] = { };
struct bpf_insn *insn = tmp_insns;
if (addrs)
addrs[i] = new_insn - new_prog;
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];
}
/**
* 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;
if (flen == 0 || flen > BPF_MAXINSNS)
return -EINVAL;
/* 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 (fprog->filter == NULL)
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 (fprog->filter == NULL)
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);
unsigned int bpf_fsize = bpf_prog_size(fprog->len);
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 (fprog->filter == NULL)
return ERR_PTR(-EINVAL);
prog = bpf_prog_alloc(bpf_fsize, 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)
{
struct bpf_prog *prog;
if (sock_flag(sk, SOCK_FILTER_LOCKED))
return ERR_PTR(-EPERM);
prog = bpf_prog_get(ufd);
if (IS_ERR(prog))
return prog;
if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) {
bpf_prog_put(prog);
return ERR_PTR(-EINVAL);
}
return prog;
}
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;
if (!skb_cloned(skb))
return 0;
if (skb_clone_writable(skb, write_len))
return 0;
err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
if (!err)
bpf_compute_data_end(skb);
return err;
}
static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
{
struct bpf_scratchpad *sp = this_cpu_ptr(&bpf_sp);
struct sk_buff *skb = (struct sk_buff *) (long) r1;
int offset = (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;
/* bpf verifier guarantees that:
* 'from' pointer points to bpf program stack
* 'len' bytes of it were initialized
* 'len' > 0
* 'skb' is a valid pointer to 'struct sk_buff'
*
* so check for invalid 'offset' and too large 'len'
*/
if (unlikely((u32) offset > 0xffff || len > sizeof(sp->buff)))
return -EFAULT;
if (unlikely(bpf_try_make_writable(skb, offset + len)))
return -EFAULT;
ptr = skb_header_pointer(skb, offset, len, sp->buff);
if (unlikely(!ptr))
return -EFAULT;
if (flags & BPF_F_RECOMPUTE_CSUM)
skb_postpull_rcsum(skb, ptr, len);
memcpy(ptr, from, len);
if (ptr == sp->buff)
/* skb_store_bits cannot return -EFAULT here */
skb_store_bits(skb, offset, ptr, len);
if (flags & BPF_F_RECOMPUTE_CSUM)
skb_postpush_rcsum(skb, ptr, len);
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;
int offset = (int) r2;
void *to = (void *)(unsigned long) r3;
unsigned int len = (unsigned int) r4;
void *ptr;
if (unlikely((u32) 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;
int offset = (int) r2;
__sum16 sum, *ptr;
if (unlikely(flags & ~(BPF_F_HDR_FIELD_MASK)))
return -EINVAL;
if (unlikely((u32) offset > 0xffff))
return -EFAULT;
if (unlikely(bpf_try_make_writable(skb, offset + sizeof(sum))))
return -EFAULT;
ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
if (unlikely(!ptr))
return -EFAULT;
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;
}
if (ptr == &sum)
/* skb_store_bits guaranteed to not return -EFAULT here */
skb_store_bits(skb, offset, ptr, sizeof(sum));
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;
int offset = (int) r2;
__sum16 sum, *ptr;
if (unlikely(flags & ~(BPF_F_MARK_MANGLED_0 | BPF_F_PSEUDO_HDR |
BPF_F_HDR_FIELD_MASK)))
return -EINVAL;
if (unlikely((u32) offset > 0xffff))
return -EFAULT;
if (unlikely(bpf_try_make_writable(skb, offset + sizeof(sum))))
return -EFAULT;
ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
if (unlikely(!ptr))
return -EFAULT;
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;
if (ptr == &sum)
/* skb_store_bits guaranteed to not return -EFAULT here */
skb_store_bits(skb, offset, ptr, sizeof(sum));
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 u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *) (long) r1, *skb2;
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;
skb2 = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!skb2))
return -ENOMEM;
if (flags & BPF_F_INGRESS) {
if (skb_at_tc_ingress(skb2))
skb_postpush_rcsum(skb2, skb_mac_header(skb2),
skb2->mac_len);
return dev_forward_skb(dev, skb2);
}
skb2->dev = dev;
return dev_queue_xmit(skb2);
}
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;
}
if (ri->flags & BPF_F_INGRESS) {
if (skb_at_tc_ingress(skb))
skb_postpush_rcsum(skb, skb_mac_header(skb),
skb->mac_len);
return dev_forward_skb(dev, skb);
}
skb->dev = dev;
return dev_queue_xmit(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_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);
ret = skb_vlan_push(skb, vlan_proto, vlan_tci);
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;
ret = skb_vlan_pop(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);
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_l3_csum_replace)
return true;
if (func == bpf_l4_csum_replace)
return true;
return false;
}
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;
}
}
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_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_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_perf_event_output:
return bpf_get_event_output_proto();
default:
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)
{
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)
{
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;
}
}
return __is_valid_access(off, size, type);
}
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 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 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 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);
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;
}
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