The commit dbd50f238dec ("net: move the hsize check to the else
block in skb_segment") introduced a data corruption for devices
supporting scatter-gather.
The problem boils down to signed/unsigned comparison given
unexpected results: if signed 'hsize' is negative, it will be
considered greater than a positive 'len', which is unsigned.
This commit addresses resorting to the old checks order, so that
'hsize' never has a negative value when compared with 'len'.
v1 -> v2:
- reorder hsize checks instead of explicit cast (Alex)
Bisected-by: Matthieu Baerts <matthieu.bae...@tessares.net>
Fixes: dbd50f238dec ("net: move the hsize check to the else block in
skb_segment")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/core/skbuff.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index e835193cabcc3..cf2c4dcf42579 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3938,10 +3938,10 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
skb_release_head_state(nskb);
__skb_push(nskb, doffset);
} else {
+ if (hsize < 0)
+ hsize = 0;
if (hsize > len || !sg)
hsize = len;
- else if (hsize < 0)
- hsize = 0;
nskb = __alloc_skb(hsize + doffset + headroom,
GFP_ATOMIC,
skb_alloc_rx_flag(head_skb),
--
2.26.2
