[PATCH 5.8 004/118] net: handle the return value of pskb_carve_frag_list() correctly

Greg Kroah-Hartman
2020-09-21T16:43:41Z

From: Miaohe Lin <linmiaohe@huawei.com>

commit eabe861881a733fc84f286f4d5a1ffaddd4f526f upstream.

pskb_carve_frag_list() may return -ENOMEM in pskb_carve_inside_nonlinear().
we should handle this correctly or we would get wrong sk_buff.

Fixes: 6fa01ccd8830 ("skbuff: Add pskb_extract() helper function")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/core/skbuff.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5988,9 +5988,13 @@ static int pskb_carve_inside_nonlinear(s
if (skb_has_frag_list(skb))
skb_clone_fraglist(skb);

- if (k == 0) {
- /* split line is in frag list */
- pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask);
+ /* split line is in frag list */
+ if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
+ /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
+ if (skb_has_frag_list(skb))
+ kfree_skb_list(skb_shinfo(skb)->frag_list);
+ kfree(data);
+ return -ENOMEM;
}
skb_release_data(skb);