hw/nvme fixes

* Fix CVE-2021-3947
 * Controller hotplugging fixes
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Merge tag 'nvme-fixes-for-6.2-pull-request' of git://git.infradead.org/qemu-nvme into staging

hw/nvme fixes

* Fix CVE-2021-3947
* Controller hotplugging fixes

# gpg: Signature made Fri 19 Nov 2021 08:59:03 AM CET
# gpg:                using RSA key 522833AA75E2DCE6A24766C04DE1AF316D4F0DE9
# gpg: Good signature from "Klaus Jensen <its@irrelevant.dk>" [unknown]
# gpg:                 aka "Klaus Jensen <k.jensen@samsung.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: DDCA 4D9C 9EF9 31CC 3468  4272 63D5 6FC5 E55D A838
#      Subkey fingerprint: 5228 33AA 75E2 DCE6 A247  66C0 4DE1 AF31 6D4F 0DE9

* tag 'nvme-fixes-for-6.2-pull-request' of git://git.infradead.org/qemu-nvme:
  hw/nvme: fix buffer overrun in nvme_changed_nslist (CVE-2021-3947)
  hw/nvme: change nvme-ns 'shared' default
  hw/nvme: reattach subsystem namespaces on hotplug

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

docs/system/devices/nvme.rst

@@ -110,28 +110,32 @@ multipath I/O.
 This will create an NVM subsystem with two controllers. Having controllers
 linked to an ``nvme-subsys`` device allows additional ``nvme-ns`` parameters:
 
-``shared`` (default: ``off``)
+``shared`` (default: ``on`` since 6.2)
   Specifies that the namespace will be attached to all controllers in the
-  subsystem. If set to ``off`` (the default), the namespace will remain a
+  subsystem. If set to ``off``, the namespace will remain a private namespace
-  private namespace and may only be attached to a single controller at a time.
+  and may only be attached to a single controller at a time. Shared namespaces
+  are always automatically attached to all controllers (also when controllers
+  are hotplugged).
 
 ``detached`` (default: ``off``)
   If set to ``on``, the namespace will be be available in the subsystem, but
-  not attached to any controllers initially.
+  not attached to any controllers initially. A shared namespace with this set
+  to ``on`` will never be automatically attached to controllers.
 
 Thus, adding
 
 .. code-block:: console
 
    -drive file=nvm-1.img,if=none,id=nvm-1
-   -device nvme-ns,drive=nvm-1,nsid=1,shared=on
+   -device nvme-ns,drive=nvm-1,nsid=1
    -drive file=nvm-2.img,if=none,id=nvm-2
-   -device nvme-ns,drive=nvm-2,nsid=3,detached=on
+   -device nvme-ns,drive=nvm-2,nsid=3,shared=off,detached=on
 
-will cause NSID 1 will be a shared namespace (due to ``shared=on``) that is
+will cause NSID 1 will be a shared namespace that is initially attached to both
-initially attached to both controllers. NSID 3 will be a private namespace
+controllers. NSID 3 will be a private namespace due to ``shared=off`` and only
-(i.e. only attachable to a single controller at a time) and will not be
+attachable to a single controller at a time. Additionally it will not be
-attached to any controller initially (due to ``detached=on``).
+attached to any controller initially (due to ``detached=on``) or to hotplugged
+controllers.
 
 Optional Features
 =================

hw/core/machine.c

@@ -39,6 +39,7 @@
 
 GlobalProperty hw_compat_6_1[] = {
     { "vhost-user-vsock-device", "seqpacket", "off" },
+    { "nvme-ns", "shared", "off" },
 };
 const size_t hw_compat_6_1_len = G_N_ELEMENTS(hw_compat_6_1);
 

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);
 

hw/nvme/ns.c

@@ -465,12 +465,6 @@ static void nvme_ns_realize(DeviceState *dev, Error **errp)
                        "linked to an nvme-subsys device");
             return;
         }
-
-        if (ns->params.shared) {
-            error_setg(errp, "shared requires that the nvme device is "
-                       "linked to an nvme-subsys device");
-            return;
-        }
     } else {
         /*
          * If this namespace belongs to a subsystem (through a link on the
@@ -532,7 +526,7 @@ static void nvme_ns_realize(DeviceState *dev, Error **errp)
 static Property nvme_ns_props[] = {
     DEFINE_BLOCK_PROPERTIES(NvmeNamespace, blkconf),
     DEFINE_PROP_BOOL("detached", NvmeNamespace, params.detached, false),
-    DEFINE_PROP_BOOL("shared", NvmeNamespace, params.shared, false),
+    DEFINE_PROP_BOOL("shared", NvmeNamespace, params.shared, true),
     DEFINE_PROP_UINT32("nsid", NvmeNamespace, params.nsid, 0),
     DEFINE_PROP_UUID("uuid", NvmeNamespace, params.uuid),
     DEFINE_PROP_UINT64("eui64", NvmeNamespace, params.eui64, 0),

hw/nvme/subsys.c

@@ -14,7 +14,7 @@
 int nvme_subsys_register_ctrl(NvmeCtrl *n, Error **errp)
 {
     NvmeSubsystem *subsys = n->subsys;
-    int cntlid;
+    int cntlid, nsid;
 
     for (cntlid = 0; cntlid < ARRAY_SIZE(subsys->ctrls); cntlid++) {
         if (!subsys->ctrls[cntlid]) {
@@ -29,12 +29,20 @@ int nvme_subsys_register_ctrl(NvmeCtrl *n, Error **errp)
 
     subsys->ctrls[cntlid] = n;
 
+    for (nsid = 1; nsid < ARRAY_SIZE(subsys->namespaces); nsid++) {
+        NvmeNamespace *ns = subsys->namespaces[nsid];
+        if (ns && ns->params.shared && !ns->params.detached) {
+            nvme_attach_ns(n, ns);
+        }
+    }
+
     return cntlid;
 }
 
 void nvme_subsys_unregister_ctrl(NvmeSubsystem *subsys, NvmeCtrl *n)
 {
     subsys->ctrls[n->cntlid] = NULL;
+    n->cntlid = -1;
 }
 
 static void nvme_subsys_setup(NvmeSubsystem *subsys)