From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
[ Upstream commit a02d83f9947d8f71904eda4de046630c3eb6802c ]
Currently, kernel would set MSG_CTRUNC flag if msg_control buffer
wasn't provided and SO_PASSCRED was set or if there was pending SCM_RIGHTS.
For some reason we have no corresponding check for SO_PASSSEC.
In the recvmsg(2) doc we have:
MSG_CTRUNC
indicates that some control data was discarded due to lack
of space in the buffer for ancillary data.
So, we need to set MSG_CTRUNC flag for all types of SCM.
This change can break applications those don't check MSG_CTRUNC flag.
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
v2:
- commit message was rewritten according to Eric's suggestion
Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/scm.h | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/include/net/scm.h b/include/net/scm.h
index 1ce365f4c2560..585adc1346bd0 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -105,16 +105,27 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
}
}
}
+
+static inline bool scm_has_secdata(struct socket *sock)
+{
+ return test_bit(SOCK_PASSSEC, &sock->flags);
+}
#else
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
{ }
+
+static inline bool scm_has_secdata(struct socket *sock)
+{
+ return false;
+}
#endif /* CONFIG_SECURITY_NETWORK */
static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
struct scm_cookie *scm, int flags)
{
if (!msg->msg_control) {
- if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
+ if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp ||
+ scm_has_secdata(sock))
msg->msg_flags |= MSG_CTRUNC;
scm_destroy(scm);
return;
--
2.39.2
