From f4a2da755a7e1f5d845c52aee71336cee289935a Mon Sep 17 00:00:00 2001 From: Loris Reiff Date: Fri, 22 Jan 2021 17:42:32 +0100 Subject: [PATCH] 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: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") Signed-off-by: Loris Reiff Signed-off-by: Daniel Borkmann Reviewed-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20210122164232.61770-2-loris.reiff@liblor.ch --- 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 6ec8f02f463b64..6aa9e10c6335a2 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -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; }