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authorEric Dumazet2023-04-12 13:03:08 +0000
committerGreg Kroah-Hartman2023-04-20 12:35:10 +0200
commitecdf42c23f3f2eb6abde683d3923516e03dff874 (patch)
tree7f5f24964ded5f3b449c48053170254b6c5b7816 /net/ipv6
parent6985701e628a5ea41259135e327edc4231e48530 (diff)
udp6: fix potential access to stale information
[ Upstream commit 1c5950fc6fe996235f1d18539b9c6b64b597f50f ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/udp.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 98a64e8d9bda..17d721a6add7 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1391,9 +1391,11 @@ 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;
}
}