[PATCH] net: sock: correctly handle failed prog retrieval from fd

[Sasha Levin]

Commit "net: sock: allow eBPF programs to be attached to sockets" didn't
correctly handle the case where there is a failure getting the prog from
a given fd.

This allows for easy NULL ptr deref from userspace.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
 net/core/filter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 8cc3c03..ec9baea 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1103,8 +1103,8 @@ int sk_attach_bpf(u32 ufd, struct sock *sk)
 		return -EPERM;
 
 	prog = bpf_prog_get(ufd);
-	if (!prog)
-		return -EINVAL;
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
 
 	if (prog->aux->prog_type != BPF_PROG_TYPE_SOCKET_FILTER) {
 		/* valid fd, but invalid program type */
-- 
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/