From: Stanislav Fomichev <sdf@google.com>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org,
Martin KaFai Lau <martin.lau@kernel.org>
Subject: [PATCH bpf-next 1/6] bpf: Don't EFAULT for getsockopt with optval=NULL
Date: Tue, 18 Apr 2023 15:53:38 -0700 [thread overview]
Message-ID: <20230418225343.553806-2-sdf@google.com> (raw)
In-Reply-To: <20230418225343.553806-1-sdf@google.com>
Some socket options do getsockopt with optval=NULL to estimate
the size of the final buffer (which is returned via optlen).
This breaks BPF getsockopt assumptions about permitted
optval buffer size. Let's enforce these assumptions only
when non-NULL optval is provided.
Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks")
Reported-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/ZD7Js4fj5YyI2oLd@google.com/T/#mb68daf700f87a9244a15d01d00c3f0e5b08f49f7
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
kernel/bpf/cgroup.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 53edb8ad2471..a06e118a9be5 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1921,14 +1921,17 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
if (ret < 0)
goto out;
- if (ctx.optlen > max_optlen || ctx.optlen < 0) {
+ if (optval && (ctx.optlen > max_optlen || ctx.optlen < 0)) {
ret = -EFAULT;
goto out;
}
if (ctx.optlen != 0) {
- if (copy_to_user(optval, ctx.optval, ctx.optlen) ||
- put_user(ctx.optlen, optlen)) {
+ if (optval && copy_to_user(optval, ctx.optval, ctx.optlen)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (put_user(ctx.optlen, optlen)) {
ret = -EFAULT;
goto out;
}
--
2.40.0.634.g4ca3ef3211-goog
next prev parent reply other threads:[~2023-04-18 22:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-18 22:53 [PATCH bpf-next 0/6] bpf: handle another corner case in getsockopt Stanislav Fomichev
2023-04-18 22:53 ` Stanislav Fomichev [this message]
2023-04-18 22:53 ` [PATCH bpf-next 2/6] selftests/bpf: Verify optval=NULL case Stanislav Fomichev
2023-04-18 22:53 ` [PATCH bpf-next 3/6] bpf: Don't EFAULT for {g,s}setsockopt with wrong optlen Stanislav Fomichev
2023-04-21 15:24 ` Daniel Borkmann
2023-04-21 16:09 ` Stanislav Fomichev
2023-04-25 0:56 ` Martin KaFai Lau
2023-04-25 17:12 ` Stanislav Fomichev
2023-04-25 18:31 ` Martin KaFai Lau
2023-04-26 17:27 ` Stanislav Fomichev
2023-04-26 18:07 ` Martin KaFai Lau
2023-04-18 22:53 ` [PATCH bpf-next 4/6] selftests/bpf: Update EFAULT {g,s}etsockopt selftests Stanislav Fomichev
2023-04-18 22:53 ` [PATCH bpf-next 5/6] selftests/bpf: Correctly handle optlen > 4096 Stanislav Fomichev
2023-04-18 22:53 ` [PATCH bpf-next 6/6] bpf: Document EFAULT changes for sockopt Stanislav Fomichev
2023-04-19 20:08 ` kernel test robot
2023-04-20 18:17 ` Stanislav Fomichev
2023-04-21 15:20 ` [PATCH bpf-next 0/6] bpf: handle another corner case in getsockopt patchwork-bot+netdevbpf
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