IB/rxe: Fix mem_check_range integer overflow

commit 647bf3d8a8e5777319da92af672289b2a6c4dc66 upstream.

Update the range check to avoid integer-overflow in edge case.
Resolves CVE 2016-8636.

Signed-off-by: Eyal Itkin <eyal.itkin@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 1869152f1d23632a8d94f092a9c25437a8487407..9b732c5f89e16cdfed1de7053cabb2e0c91a38e1 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -59,9 +59,11 @@ int mem_check_range(struct rxe_mem *mem, u64 iova, size_t length)
 
        case RXE_MEM_TYPE_MR:
        case RXE_MEM_TYPE_FMR:
-               return ((iova < mem->iova) ||
-                       ((iova + length) > (mem->iova + mem->length))) ?
-                       -EFAULT : 0;
+               if (iova < mem->iova ||
+                   length > mem->length ||
+                   iova > mem->iova + mem->length - length)
+                       return -EFAULT;
+               return 0;
 
        default:
                return -EFAULT;