SCTP: Fix sctp_getsockopt_get_peer_addrs

	This is the split out of the patch that we agreed I should split
out from my last patch.  It changes space_left to be computed in the same
way the to variable is.  I know we talked about changing space_left to an
int, but I think size_t is more appropriate, since we should never have
negative space in our buffer, and computing using offsetof means space_left
should now never drop below zero.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index c1f239ac12b..2fc036699d4 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4019,8 +4019,7 @@ static int sctp_getsockopt_peer_addrs(struct sock *sk, int len,
                 return -EINVAL;
 
         to = optval + offsetof(struct sctp_getaddrs,addrs);
-        space_left = len - sizeof(struct sctp_getaddrs) -
-                        offsetof(struct sctp_getaddrs,addrs);
+        space_left = len - offsetof(struct sctp_getaddrs,addrs);
 
         list_for_each(pos, &asoc->peer.transport_addr_list) {
                 from = list_entry(pos, struct sctp_transport, transports);
@@ -4327,8 +4326,8 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
         }
 
         to = optval + offsetof(struct sctp_getaddrs,addrs);
-        space_left = len - sizeof(struct sctp_getaddrs) -
-                         offsetof(struct sctp_getaddrs,addrs);
+        space_left = len - offsetof(struct sctp_getaddrs,addrs);
+
         addrs = kmalloc(space_left, GFP_KERNEL);
         if (!addrs)
                 return -ENOMEM;