af_iucv: Move sockaddr length checks to before accessing sa_family in bind and connec...

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>

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 0511209..ac033e4 100644 (file)
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -715,10 +715,8 @@ 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);
@@ -862,7 +860,7 @@ 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)