| Message ID | f7e68191-acff-9ded-4263-c016428a8762@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [net] r8169: fix potential skb double free in an error path | expand |
On Thu, 5 Nov 2020 15:28:42 +0100 Heiner Kallweit wrote: > The caller of rtl8169_tso_csum_v2() frees the skb if false is returned. > eth_skb_pad() internally frees the skb on error what would result in a > double free. Therefore use __skb_put_padto() directly and instruct it > to not free the skb on error. > > Fixes: 25e992a4603c ("r8169: rename r8169.c to r8169_main.c") > Reported-by: Jakub Kicinski <kuba@kernel.org> > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > --- > The Fixes tag refers to the change from which on the patch applies. > However it will apply with a little fuzz only on versions up to 5.9. I think we've been over this, please provide real fixes tags, pointing to where bugs were introduced. I swapped the tag for: Fixes: b423e9ae49d7 ("r8169: fix offloaded tx checksum for small packets.") and applied, thanks.
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index 07d197141..c5d5c1cfc 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -4134,7 +4134,8 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp, opts[1] |= transport_offset << TCPHO_SHIFT; } else { if (unlikely(skb->len < ETH_ZLEN && rtl_test_hw_pad_bug(tp))) - return !eth_skb_pad(skb); + /* eth_skb_pad would free the skb on error */ + return !__skb_put_padto(skb, ETH_ZLEN, false); } return true;
The caller of rtl8169_tso_csum_v2() frees the skb if false is returned. eth_skb_pad() internally frees the skb on error what would result in a double free. Therefore use __skb_put_padto() directly and instruct it to not free the skb on error. Fixes: 25e992a4603c ("r8169: rename r8169.c to r8169_main.c") Reported-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> --- The Fixes tag refers to the change from which on the patch applies. However it will apply with a little fuzz only on versions up to 5.9. --- drivers/net/ethernet/realtek/r8169_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)