Commit f4a2da75 authored by Loris Reiff's avatar Loris Reiff Committed by Daniel Borkmann
Browse files

bpf, cgroup: Fix problematic bounds check 



Since ctx.optlen is signed, a larger value than max_value could be
passed, as it is later on used as unsigned, which causes a WARN_ON_ONCE
in the copy_to_user.

Fixes: 0d01da6a ("bpf: implement getsockopt and setsockopt hooks")
Signed-off-by: default avatarLoris Reiff <loris.reiff@liblor.ch>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarStanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20210122164232.61770-2-loris.reiff@liblor.ch
parent bb8b81e3

kernel/bpf/cgroup.c

+1 −1
Original line number Diff line number Diff line
@@ -1464,7 +1464,7 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level, 
		goto out;

	}



	if (ctx.optlen > max_optlen) {

	if (ctx.optlen > max_optlen || ctx.optlen < 0) {

		ret = -EFAULT;

		goto out;

	}