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>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index e7e3baf7009e..0dbcde6758ea 100644
--- 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