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bpf: Don't leak memory in bpf getsockopt when optlen == 0

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commit 4be34f3d0731b38a1b24566b37fbb39500aaf3a2 upstream.

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.

Fixes: d8fe449a9c51 ("bpf: Don't return EINVAL from {get,set}sockopt when optlen > PAGE_SIZE")
Reported-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210112162829.775079-1-sdf@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stanislav Fomichev 2021-01-12 08:28:29 -08:00 committed by Greg Kroah-Hartman
parent fdcaa4af5e
commit 3ed29995c2
1 changed files with 3 additions and 2 deletions
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5
kernel/bpf/cgroup.c
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@ -1391,12 +1391,13 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
if (ctx.optlen != 0) {
*optlen = ctx.optlen;
*kernel_optval = ctx.optval;
/* export and don't free sockopt buf */
return 0;
}
}
out:
if (ret)
sockopt_free_buf(&ctx);
sockopt_free_buf(&ctx);
return ret;
}