RDS: Heap OOB write in rds_message_alloc_sgs()

When args->nr_local is 0, nr_pages gets also 0 due some size calculation via rds_rm_size(), which is later used to allocate pages for DMA, this bug produces a heap Out-Of-Bound write access to a specific memory region. Signed-off-by: Mohamed Ghannam <[email protected]> Signed-off-by: David S. Miller <[email protected]>
josf · Jan 3, 2018 · c095508 · c095508
1 parent c0bace7
commit c095508
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
@@ -525,6 +525,9 @@ int rds_rdma_extra_size(struct rds_rdma_args *args)
 
 	local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
 
+	if (args->nr_local == 0)
+		return -EINVAL;
+
 	/* figure out the number of pages in the vector */
 	for (i = 0; i < args->nr_local; i++) {
 		if (copy_from_user(&vec, &local_vec[i],