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From: Stanislav Fomichev <sdf@google.com>
To: netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net,
	Stanislav Fomichev <sdf@google.com>,
	Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH bpf] bpf: don't leak memory in bpf getsockopt when optlen == 0
Date: Mon, 11 Jan 2021 11:47:38 -0800	[thread overview]
Message-ID: <20210111194738.132139-1-sdf@google.com> (raw)

optlen == 0 indicates that the kernel should ignore BPF buffer
and use the original one from the user. We, however, forget
to free the temporary buffer that we've allocated for BPF.

Reported-by: Martin KaFai Lau <kafai@fb.com>
Fixes: d8fe449a9c51 ("bpf: Don't return EINVAL from {get,set}sockopt when optlen > PAGE_SIZE")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 kernel/bpf/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 6ec088a96302..09179ab72c03 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1395,7 +1395,7 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 	}
 
 out:
-	if (ret)
+	if (*kernel_optval == NULL)
 		sockopt_free_buf(&ctx);
 	return ret;
 }
-- 
2.30.0.284.gd98b1dd5eaa7-goog


             reply	other threads:[~2021-01-11 19:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-11 19:47 Stanislav Fomichev [this message]
2021-01-11 22:31 ` [PATCH bpf] bpf: don't leak memory in bpf getsockopt when optlen == 0 Martin KaFai Lau
2021-01-11 22:38   ` Stanislav Fomichev
2021-01-11 23:10     ` Martin KaFai Lau

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