b1fcd35cf5
The sk_unattached_filter_create() API is used by BPF filters that are not directly attached or related to sockets, and are used in team, ptp, xt_bpf, cls_bpf, etc. As such all users do their own internal managment of obtaining filter blocks and thus already have them in kernel memory and set up before calling into sk_unattached_filter_create(). As a result, due to __user annotation in sock_fprog, sparse triggers false positives (incorrect type in assignment [different address space]) when filters are set up before passing them to sk_unattached_filter_create(). Therefore, let sk_unattached_filter_create() API use sock_fprog_kern to overcome this issue. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/* Xtables module to match packets using a BPF filter.
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* Copyright 2013 Google Inc.
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* Written by Willem de Bruijn <willemb@google.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/filter.h>
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#include <linux/netfilter/xt_bpf.h>
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#include <linux/netfilter/x_tables.h>
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MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
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MODULE_DESCRIPTION("Xtables: BPF filter match");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_bpf");
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MODULE_ALIAS("ip6t_bpf");
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static int bpf_mt_check(const struct xt_mtchk_param *par)
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{
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struct xt_bpf_info *info = par->matchinfo;
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struct sock_fprog_kern program;
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program.len = info->bpf_program_num_elem;
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program.filter = info->bpf_program;
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if (sk_unattached_filter_create(&info->filter, &program)) {
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pr_info("bpf: check failed: parse error\n");
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return -EINVAL;
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}
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return 0;
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}
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static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_bpf_info *info = par->matchinfo;
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return SK_RUN_FILTER(info->filter, skb);
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}
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static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
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{
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const struct xt_bpf_info *info = par->matchinfo;
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sk_unattached_filter_destroy(info->filter);
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}
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static struct xt_match bpf_mt_reg __read_mostly = {
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.name = "bpf",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.checkentry = bpf_mt_check,
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.match = bpf_mt,
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.destroy = bpf_mt_destroy,
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.matchsize = sizeof(struct xt_bpf_info),
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.me = THIS_MODULE,
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};
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static int __init bpf_mt_init(void)
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{
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return xt_register_match(&bpf_mt_reg);
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}
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static void __exit bpf_mt_exit(void)
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{
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xt_unregister_match(&bpf_mt_reg);
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}
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module_init(bpf_mt_init);
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module_exit(bpf_mt_exit);
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