[Qemu-devel] [PATCH v1 3/6] pvrdma: check number of pages when creating rings

[P J P <ppandit@redhat.com>]

From: Prasad J Pandit <pjp@fedoraproject.org>

When creating CQ/QP rings, an object can have up to
PVRDMA_MAX_FAST_REG_PAGES=128 pages. Check 'npages' parameter
to avoid excessive memory allocation or a null dereference.

Reported-by: Li Qiang <liq3ea@163.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/rdma/vmw/pvrdma_cmd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Update v1: move check before page dir/tbl map
  -> https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg02257.html

diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
index 4f616d4177..e37fb18280 100644
--- a/hw/rdma/vmw/pvrdma_cmd.c
+++ b/hw/rdma/vmw/pvrdma_cmd.c
@@ -259,6 +259,11 @@ static int create_cq_ring(PCIDevice *pci_dev , PvrdmaRing **ring,
     int rc = -EINVAL;
     char ring_name[MAX_RING_NAME_SZ];
 
+    if (!nchunks || nchunks > PVRDMA_MAX_FAST_REG_PAGES) {
+        pr_dbg("invalid nchunks: %d\n", nchunks);
+        return rc;
+    }
+
     pr_dbg("pdir_dma=0x%llx\n", (long long unsigned int)pdir_dma);
     dir = rdma_pci_dma_map(pci_dev, pdir_dma, TARGET_PAGE_SIZE);
     if (!dir) {
@@ -371,6 +376,12 @@ static int create_qp_rings(PCIDevice *pci_dev, uint64_t pdir_dma,
     char ring_name[MAX_RING_NAME_SZ];
     uint32_t wqe_sz;
 
+    if (!spages || spages > PVRDMA_MAX_FAST_REG_PAGES
+        || !rpages || rpages > PVRDMA_MAX_FAST_REG_PAGES) {
+        pr_dbg("invalid pages: %d, %d\n", spages, rpages);
+        return rc;
+    }
+
     pr_dbg("pdir_dma=0x%llx\n", (long long unsigned int)pdir_dma);
     dir = rdma_pci_dma_map(pci_dev, pdir_dma, TARGET_PAGE_SIZE);
     if (!dir) {
-- 
2.19.2