diff options
author | Tom Parkin <tparkin@katalix.com> | 2024-02-20 15:21:56 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-03-01 15:06:10 +0300 |
commit | 4c3ce64bc9d36ca9164dd6c77ff144c121011aae (patch) | |
tree | 16fc2ab24be15b325f8433b957cc8c01a6b6394f /net | |
parent | f0ecdfa679189d26aedfe24212d4e69e42c2c861 (diff) | |
download | linux-4c3ce64bc9d36ca9164dd6c77ff144c121011aae.tar.xz |
l2tp: pass correct message length to ip6_append_data
commit 359e54a93ab43d32ee1bff3c2f9f10cb9f6b6e79 upstream.
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: 9d4c75800f61 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/l2tp/l2tp_ip6.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index 7342344d99a9..7bcf4b3559ef 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -648,7 +648,7 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) back_from_confirm: lock_sock(sk); - ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0; + ulen = len + (skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0); err = ip6_append_data(sk, ip_generic_getfrag, msg, ulen, transhdrlen, &ipc6, &fl6, (struct rt6_info *)dst, |