diff options
| author | Paul Chaignon <paul.chaignon@gmail.com> | 2025-08-01 11:48:15 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-08-01 09:22:44 -0700 |
| commit | 9e6448f7b1efb27f8d508b067ecd33ed664a4246 (patch) | |
| tree | a18226d02e40d0e1ccd0c10282e2f694844cdf3a | |
| parent | ead3d7b2b6afa5ee7958620c4329982a7d9c2b78 (diff) | |
bpf: Check netfilter ctx accesses are aligned
Similarly to the previous patch fixing the flow_dissector ctx accesses,
nf_is_valid_access also doesn't check that ctx accesses are aligned.
Contrary to flow_dissector programs, netfilter programs don't have
context conversion. The unaligned ctx accesses are therefore allowed by
the verifier.
Fixes: fd9c663b9ad6 ("bpf: minimal support for programs hooked into netfilter framework")
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/853ae9ed5edaa5196e8472ff0f1bb1cc24059214.1754039605.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | net/netfilter/nf_bpf_link.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c index 3e4fb9ddcd36..46e667a50d98 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -296,6 +296,9 @@ static bool nf_is_valid_access(int off, int size, enum bpf_access_type type, if (off < 0 || off >= sizeof(struct bpf_nf_ctx)) return false; + if (off % size != 0) + return false; + if (type == BPF_WRITE) return false; |