xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

bpf: fix cb access in socket filter programs

Browse Source 
eBPF socket filter programs may see junk in 'u32 cb[5]' area,
since it could have been used by protocol layers earlier.

For socket filter programs used in af_packet we need to clean
20 bytes of skb->cb area if it could be used by the program.
For programs attached to TCP/UDP sockets we need to save/restore
these 20 bytes, since it's used by protocol layers.

Remove SK_RUN_FILTER macro, since it's no longer used.

Long term we may move this bpf cb area to per-cpu scratch, but that
requires addition of new 'per-cpu load/store' instructions,
so not suitable as a short term fix.

Fixes: d691f9e8d4 ("bpf: allow programs to write to certain skb fields")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexei Starovoitov
2015-10-07 10:55:41 -07:00
committed by David S. Miller
parent d49ae37c61
commit ff936a04e5
5 changed files with 51 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/bpf/verifier.c
View File

@@ -2024,7 +2024,7 @@ static int convert_ctx_accesses(struct verifier_env *env)
cnt = env->prog->aux->ops->
convert_ctx_access(type, insn->dst_reg, insn->src_reg,
insn->off, insn_buf);
insn->off, insn_buf, env->prog);
if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
verbose("bpf verifier is misconfigured\n");
return -EINVAL;