linux-stable/net/l2tp
Tom Parkin 359e54a93a l2tp: pass correct message length to ip6_append_data
l2tp_ip6_sendmsg needs to avoid accounting for the transport header
twice when splicing more data into an already partially-occupied skbuff.

To manage this, we check whether the skbuff contains data using
skb_queue_empty when deciding how much data to append using
ip6_append_data.

However, the code which performed the calculation was incorrect:

     ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0;

...due to C operator precedence, this ends up setting ulen to
transhdrlen for messages with a non-zero length, which results in
corrupted packets on the wire.

Add parentheses to correct the calculation in line with the original
intent.

Fixes: 9d4c75800f ("ipv4, ipv6: Fix handling of transhdrlen in __ip{,6}_append_data()")
Cc: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240220122156.43131-1-tparkin@katalix.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-02-22 10:42:17 +01:00
..
Kconfig
Makefile
l2tp_core.c udp: annotate data-races around udp->encap_type 2023-09-14 16:16:36 +02:00
l2tp_core.h
l2tp_debugfs.c
l2tp_eth.c net: l2tp_eth: use generic dev->stats fields 2023-10-01 16:33:01 +01:00
l2tp_ip.c inet: introduce inet->inet_flags 2023-08-16 11:09:16 +01:00
l2tp_ip6.c l2tp: pass correct message length to ip6_append_data 2024-02-22 10:42:17 +01:00
l2tp_netlink.c
l2tp_ppp.c
trace.h