[v3,11/17] hw/block/nvme: harden cmb access

Commit Message

Klaus Jensen Sept. 22, 2020, 8:45 a.m. UTC

From: Klaus Jensen <[e-mail]>

Since the controller has only supported PRPs so far it has not been
required to check the ending address (addr + len - 1) of the CMB access
for validity since it has been guaranteed to be in range of the CMB.

This changes when the controller adds support for SGLs (next patch), so
add that check.

Signed-off-by: Klaus Jensen <[e-mail]>
Reviewed-by: Keith Busch <[e-mail]>
---
 hw/block/nvme.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Patch

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 7c9ea792483c..3b901efd1ec0 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -142,7 +142,12 @@  static inline void *nvme_addr_to_cmb(NvmeCtrl *n, hwaddr addr)
 
 static int nvme_addr_read(NvmeCtrl *n, hwaddr addr, void *buf, int size)
 {
-    if (n->bar.cmbsz && nvme_addr_is_cmb(n, addr)) {
+    hwaddr hi = addr + size - 1;
+    if (hi < addr) {
+        return 1;
+    }
+
+    if (n->bar.cmbsz && nvme_addr_is_cmb(n, addr) && nvme_addr_is_cmb(n, hi)) {
         memcpy(buf, nvme_addr_to_cmb(n, addr), size);
         return 0;
     }