[PATCH 2/2] hw/block/nvme: assert namespaces array indices

[Klaus Jensen <its@irrelevant.dk>]

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

Coverity complains about a possible memory corruption in the
nvme_ns_attach and _detach functions. While we should not (famous last
words) be able to reach this function without nsid having previously
been validated, this is still an open door for future misuse.

Make Coverity and maintainers happy by asserting that the index into the
array is valid. Also, while not detected by Coverity (yet), add an
assert in nvme_subsys_ns and nvme_subsys_register_ns as well since a
similar issue is exists there.

Fixes: 037953b5b299 ("hw/block/nvme: support namespace detach")
Fixes: CID 1450757
Fixes: CID 1450758
Cc: Minwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
---
 hw/block/nvme-subsys.h |  2 ++
 hw/block/nvme.h        | 10 ++++++++--
 hw/block/nvme-subsys.c |  7 +++++--
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/hw/block/nvme-subsys.h b/hw/block/nvme-subsys.h
index fb66ae752ad5..aafa04b84829 100644
--- a/hw/block/nvme-subsys.h
+++ b/hw/block/nvme-subsys.h
@@ -54,6 +54,8 @@ static inline NvmeNamespace *nvme_subsys_ns(NvmeSubsystem *subsys,
         return NULL;
     }
 
+    assert(nsid && nsid <= NVME_SUBSYS_MAX_NAMESPACES);
+
     return subsys->namespaces[nsid];
 }
 
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 4955d649c7d4..45ba9dbc2131 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -236,12 +236,18 @@ static inline bool nvme_ns_is_attached(NvmeCtrl *n, NvmeNamespace *ns)
 
 static inline void nvme_ns_attach(NvmeCtrl *n, NvmeNamespace *ns)
 {
-    n->namespaces[nvme_nsid(ns) - 1] = ns;
+    uint32_t nsid = ns->params.nsid;
+    assert(nsid && nsid <= NVME_MAX_NAMESPACES);
+
+    n->namespaces[nsid - 1] = ns;
 }
 
 static inline void nvme_ns_detach(NvmeCtrl *n, NvmeNamespace *ns)
 {
-    n->namespaces[nvme_nsid(ns) - 1] = NULL;
+    uint32_t nsid = ns->params.nsid;
+    assert(nsid && nsid <= NVME_MAX_NAMESPACES);
+
+    n->namespaces[nsid - 1] = NULL;
 }
 
 static inline NvmeCQueue *nvme_cq(NvmeRequest *req)
diff --git a/hw/block/nvme-subsys.c b/hw/block/nvme-subsys.c
index af4804a819ee..2f6d3b47bacf 100644
--- a/hw/block/nvme-subsys.c
+++ b/hw/block/nvme-subsys.c
@@ -47,15 +47,18 @@ int nvme_subsys_register_ns(NvmeNamespace *ns, Error **errp)
 {
     NvmeSubsystem *subsys = ns->subsys;
     NvmeCtrl *n;
+    uint32_t nsid = ns->params.nsid;
     int i;
 
-    if (subsys->namespaces[nvme_nsid(ns)]) {
+    assert(nsid && nsid <= NVME_SUBSYS_MAX_NAMESPACES);
+
+    if (subsys->namespaces[nsid]) {
         error_setg(errp, "namespace %d already registerd to subsy %s",
                    nvme_nsid(ns), subsys->parent_obj.id);
         return -1;
     }
 
-    subsys->namespaces[nvme_nsid(ns)] = ns;
+    subsys->namespaces[nsid] = ns;
 
     for (i = 0; i < ARRAY_SIZE(subsys->ctrls); i++) {
         n = subsys->ctrls[i];
-- 
2.30.1