diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-04-12 13:03:08 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-04-13 10:04:37 -0700 |
| commit | 1c5950fc6fe996235f1d18539b9c6b64b597f50f (patch) | |
| tree | 70d65ea09555a8eaa1a255c7655cc197e7634807 /net/ipv6 | |
| parent | 306dc21361993f4fe50a15d4db6b1a4de5d0adb0 (diff) | |
udp6: fix potential access to stale information
lena wang reported an issue caused by udpv6_sendmsg()
mangling msg->msg_name and msg->msg_namelen, which
are later read from ____sys_sendmsg() :
/*
* If this is sendmmsg() and sending to current destination address was
* successful, remember it.
*/
if (used_address && err >= 0) {
used_address->name_len = msg_sys->msg_namelen;
if (msg_sys->msg_name)
memcpy(&used_address->name, msg_sys->msg_name,
used_address->name_len);
}
udpv6_sendmsg() wants to pretend the remote address family
is AF_INET in order to call udp_sendmsg().
A fix would be to modify the address in-place, instead
of using a local variable, but this could have other side effects.
Instead, restore initial values before we return from udpv6_sendmsg().
Fixes: c71d8ebe7a44 ("net: Fix security_socket_sendmsg() bypass problem.")
Reported-by: lena wang <lena.wang@mediatek.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Link: https://lore.kernel.org/r/20230412130308.1202254-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/udp.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 9fb2f33ee3a7..a675acfb901d 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1395,9 +1395,11 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) msg->msg_name = &sin; msg->msg_namelen = sizeof(sin); do_udp_sendmsg: - if (ipv6_only_sock(sk)) - return -ENETUNREACH; - return udp_sendmsg(sk, msg, len); + err = ipv6_only_sock(sk) ? + -ENETUNREACH : udp_sendmsg(sk, msg, len); + msg->msg_name = sin6; + msg->msg_namelen = addr_len; + return err; } } |