[PATCH net] bpf/xskmap: Return ERR_PTR for failure case instead of NULL.

When kzalloc() failed, NULL was returned to the caller, which
tested the pointer with IS_ERR(), which didn't match, so the
pointer was used later, resulting in a NULL dereference.

Return ERR_PTR(-ENOMEM) instead of NULL.

Reported-by: syzbot+491c1b7565ba9069ecae@syzkaller.appspotmail.com
Fixes: 0402acd683c6 ("xsk: remove AF_XDP socket from map when the socket is released")
Signed-off-by: Jonathan Lemon <redacted>
---
 kernel/bpf/xskmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 942c662e2eed..82a1ffe15dfa 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c

@@ -37,7 +37,7 @@ static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map,
 
 	node = kzalloc(sizeof(*node), GFP_ATOMIC | __GFP_NOWARN);
 	if (!node)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	err = xsk_map_inc(map);
 	if (err) {

-- 
2.17.1