[PULL for-6.2 3/3] hw/nvme: fix buffer overrun in nvme_changed_nslist (CVE-2021-3947)

[Klaus Jensen <its@irrelevant.dk>]

From: Klaus Jensen <k.jensen@samsung.com>

Fix missing offset verification.

Cc: qemu-stable@nongnu.org
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Reported-by: Qiuhao Li <Qiuhao.Li@outlook.com>
Fixes: f432fdfa121 ("support changed namespace asynchronous event")
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
---
 hw/nvme/ctrl.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 6a571d18cfae..5f573c417b3d 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -4168,6 +4168,11 @@ static uint16_t nvme_changed_nslist(NvmeCtrl *n, uint8_t rae, uint32_t buf_len,
     int i = 0;
     uint32_t nsid;
 
+    if (off >= sizeof(nslist)) {
+        trace_pci_nvme_err_invalid_log_page_offset(off, sizeof(nslist));
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
     memset(nslist, 0x0, sizeof(nslist));
     trans_len = MIN(sizeof(nslist) - off, buf_len);
 
-- 
2.34.0