[PATCH AUTOSEL 4.4 10/65] af_iucv: Move sockaddr length checks to before accessing sa_family in bind and connect handlers

Sasha Levin
2018-10-25T14:17:29Z

From: Mateusz Jurczyk <mjurczyk@google.com>

[ Upstream commit e3c42b61ff813921ba58cfc0019e3fd63f651190 ]

Verify that the caller-provided sockaddr structure is large enough to
contain the sa_family field, before accessing it in bind() and connect()
handlers of the AF_IUCV socket. Since neither syscall enforces a minimum
size of the corresponding memory region, very short sockaddrs (zero or
one byte long) result in operating on uninitialized memory while
referencing .sa_family.

Fixes: 52a82e23b9f2 ("af_iucv: Validate socket address length in iucv_sock_bind()")
Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
[jwi: removed unneeded null-check for addr]
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/iucv/af_iucv.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index aeffb65181f5..5984cc35d508 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -705,10 +705,8 @@ static int iucv_sock_bind(struct socket *sock, struct sockaddr *addr,
char uid[9];

/* Verify the input sockaddr */
- if (!addr || addr->sa_family != AF_IUCV)
- return -EINVAL;
-
- if (addr_len < sizeof(struct sockaddr_iucv))
+ if (addr_len < sizeof(struct sockaddr_iucv) ||
+ addr->sa_family != AF_IUCV)
return -EINVAL;

lock_sock(sk);
@@ -852,7 +850,7 @@ static int iucv_sock_connect(struct socket *sock, struct sockaddr *addr,
struct iucv_sock *iucv = iucv_sk(sk);
int err;

- if (addr->sa_family != AF_IUCV || alen < sizeof(struct sockaddr_iucv))
+ if (alen < sizeof(struct sockaddr_iucv) || addr->sa_family != AF_IUCV)
return -EINVAL;

if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
--
2.17.1