[PATCH] [213/223] rds: Integer overflow in RDS cmsg handling

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>

commit 218854af84038d828a32f061858b1902ed2beec6 upstream.

In rds_cmsg_rdma_args(), the user-provided args->nr_local value is
restricted to less than UINT_MAX.  This seems to need a tighter upper
bound, since the calculation of total iov_size can overflow, resulting
in a small sock_kmalloc() allocation.  This would probably just result
in walking off the heap and crashing when calling rds_rdma_pages() with
a high count value.  If it somehow doesn't crash here, then memory
corruption could occur soon after.

Signed-off-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 net/rds/rdma.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/net/rds/rdma.c
===================================================================
--- linux.orig/net/rds/rdma.c
+++ linux/net/rds/rdma.c
@@ -474,7 +474,7 @@ static struct rds_rdma_op *rds_rdma_prep
 		goto out;
 	}
 
-	if (args->nr_local > (u64)UINT_MAX) {
+	if (args->nr_local > UIO_MAXIOV) {
 		ret = -EMSGSIZE;
 		goto out;
 	}
--
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