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[2/2] hw/nvme: Avoid dynamic stack allocation

Message ID 20230811174751.784620-3-peter.maydell@linaro.org
State New
Headers show
Series nvme: avoid dynamic stack allocations | expand

Commit Message

Peter Maydell Aug. 11, 2023, 5:47 p.m. UTC 
Instead of using a variable-length array in nvme_map_prp(),
allocate on the stack with a g_autofree pointer.

The codebase has very few VLAs, and if we can get rid of them all we
can make the compiler error on new additions.  This is a defensive
measure against security bugs where an on-stack dynamic allocation
isn't correctly size-checked (e.g.  CVE-2021-3527).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Using the approach suggested by RTH in review of Philippe's
original patch:
 https://patchew.org/QEMU/20210505211047.1496765-1-philmd@redhat.com/20210505211047.1496765-9-philmd@redhat.com/
---
 hw/nvme/ctrl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index d99a6f5c9a2..90687b168ae 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -894,7 +894,7 @@  static uint16_t nvme_map_prp(NvmeCtrl *n, NvmeSg *sg, uint64_t prp1,
     len -= trans_len;
     if (len) {
         if (len > n->page_size) {
-            uint64_t prp_list[n->max_prp_ents];
+            g_autofree uint64_t *prp_list = g_new(uint64_t, n->max_prp_ents);
             uint32_t nents, prp_trans;
             int i = 0;