[PATCH 3.2 67/79] RDS: Heap OOB write in rds_message_alloc_sgs()

Ben Hutchings
2018-02-11T04:20:06Z

From: Mohamed Ghannam <simo.ghannam@gmail.com>

commit c095508770aebf1b9218e77026e48345d719b17c upstream.

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 <simo.ghannam@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/rds/rdma.c | 3 +++
1 file changed, 3 insertions(+)

--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -516,6 +516,9 @@ int rds_rdma_extra_size(struct rds_rdma_

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],