sctp: Make sure N * sizeof(union sctp_addr) does not overflow.

As noticed by Gabriel Campana, the kmalloc() length arg
passed in by sctp_getsockopt_local_addrs_old() can overflow
if ->addr_num is large enough.

Therefore, enforce an appropriate limit.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index e7e3baf7009ed7d8bca62e4353eebd62b70be7ba..0dbcde6758ea3158216e37af50df35ea56c37135 100644 (file)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4401,7 +4401,9 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
        if (copy_from_user(&getaddrs, optval, len))
                return -EFAULT;
 
-       if (getaddrs.addr_num <= 0) return -EINVAL;
+       if (getaddrs.addr_num <= 0 ||
+           getaddrs.addr_num >= (INT_MAX / sizeof(union sctp_addr)))
+               return -EINVAL;
        /*
         *  For UDP-style sockets, id specifies the association to query.
         *  If the id field is set to the value '0' then the locally bound