Commit bc571404 authored Nov 05, 2020 by Heiner Kallweit Committed by Greg Kroah-Hartman Nov 18, 2020

r8169: fix potential skb double free in an error path



[ Upstream commit cc6528bc9a0c901c83b8220a2e2617f3354d6dd9 ]

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: b423e9ae ("r8169: fix offloaded tx checksum for small packets.")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/f7e68191-acff-9ded-4263-c016428a8762@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 200c2f68

drivers/net/ethernet/realtek/r8169.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -6274,7 +6274,8 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp,
		opts[1] \|= transport_offset << TCPHO_SHIFT;
		} else {
		if (unlikely(rtl_test_hw_pad_bug(tp, skb)))
		return !eth_skb_pad(skb);
		/* eth_skb_pad would free the skb on error */
		return !__skb_put_padto(skb, ETH_ZLEN, false);
		}

		return true;