hostmem: Validate host-nodes before setting bitmap

PATCH In review Eduardo Habkost 6 participants 10 messages Nov 30, 2018 – Dec 4, 2018 Arm STM32

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Eduardo Habkost

author

2018-11-30 12:28 UTC #0 lore raw

PATCH v2 1/1 hostmem: Validate host-nodes before setting bitmap

host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.

Fix the crash and add a simple regression test for the fix.

While at it, fix memory leak of the list returned by visit_type_uint16List().

Reported-by Markus Armbruster <[email protected]>

Signed-off-by Eduardo Habkost <[email protected]>

---
Changes v1 -> v2:
* Remove extra l = l->next statement
(reported by Stefano Garzarella)
* Fix (existing) leak of host_nodes
(reported by Markus Armbruster)

---
 backends/hostmem.c                   | 17 +++++++++----
 tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 tests/acceptance/host-nodes-limit.py

backends/hostmem.c +13 -4

index 1a89342039..af800284e0 100644
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+
+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif

tests/acceptance/host-nodes-limit.py new file +36 -0

new file mode 100644
index 0000000000..e803e10104
@@ -0,0 +1,36 @@
+# Regression test for host-nodes limit validation
+#
+# Copyright (c) 2018 Red Hat, Inc.
+#
+# Author:
+#  Eduardo Habkost <[email protected]>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+from avocado_qemu import Test
+from subprocess import Popen, PIPE
+
+MAX_NODES = 128
+
+class HostNodesValidation(Test):
+    def test_large_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'Invalid host-nodes', stderr)
+        self.assertEquals(stdout, b'')
+        self.assertEquals(p.returncode, 1)
+
+    def test_valid_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES - 1)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'host-nodes must be empty', stderr)
+        self.assertEquals(p.returncode, 1)

Signature · 1 line

2.18.0.rc1.1.g3f1ff2140

Stefano Garzarella

Reviewed-by on v2 1/1

2018-11-30 12:50 UTC #1 lore raw

Quoted 99 lines · Eduardo Habkost

host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.

Fix the crash and add a simple regression test for the fix.

While at it, fix memory leak of the list returned by visit_type_uint16List().

Reported-by Markus Armbruster <[email protected]>

Signed-off-by Eduardo Habkost <[email protected]>

---
Changes v1 -> v2:
* Remove extra l = l->next statement
(reported by Stefano Garzarella)
* Fix (existing) leak of host_nodes
(reported by Markus Armbruster)

---
 backends/hostmem.c                   | 17 +++++++++----
 tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 tests/acceptance/host-nodes-limit.py

backends/hostmem.c +13 -4

index 1a89342039..af800284e0 100644
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+
+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif

tests/acceptance/host-nodes-limit.py new file +36 -1

new file mode 100644
index 0000000000..e803e10104
@@ -0,0 +1,36 @@
+# Regression test for host-nodes limit validation
+#
+# Copyright (c) 2018 Red Hat, Inc.
+#
+# Author:
+#  Eduardo Habkost <[email protected]>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+from avocado_qemu import Test
+from subprocess import Popen, PIPE
+
+MAX_NODES = 128
+
+class HostNodesValidation(Test):
+    def test_large_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'Invalid host-nodes', stderr)
+        self.assertEquals(stdout, b'')
+        self.assertEquals(p.returncode, 1)
+
+    def test_valid_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES - 1)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'host-nodes must be empty', stderr)
+        self.assertEquals(p.returncode, 1)
--

Quoted 2 lines

2.18.0.rc1.1.g3f1ff2140

Reviewed-by Stefano Garzarella <[email protected]>

Signature · 2 lines

Stefano Garzarella
Red Hat

David Hildenbrand

Reviewed-by on v2 1/1

2018-11-30 12:51 UTC #2 lore raw

In reply to Eduardo Habkost

Quoted 88 lines · Eduardo Habkost

host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.

Fix the crash and add a simple regression test for the fix.

While at it, fix memory leak of the list returned by visit_type_uint16List().

Reported-by Markus Armbruster <[email protected]>

Signed-off-by Eduardo Habkost <[email protected]>

---
Changes v1 -> v2:
* Remove extra l = l->next statement
(reported by Stefano Garzarella)
* Fix (existing) leak of host_nodes
(reported by Markus Armbruster)

---
 backends/hostmem.c                   | 17 +++++++++----
 tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 tests/acceptance/host-nodes-limit.py

backends/hostmem.c +13 -4

index 1a89342039..af800284e0 100644
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+
+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif

tests/acceptance/host-nodes-limit.py new file +26 -0

new file mode 100644
index 0000000000..e803e10104
@@ -0,0 +1,36 @@
+# Regression test for host-nodes limit validation
+#
+# Copyright (c) 2018 Red Hat, Inc.
+#
+# Author:
+#  Eduardo Habkost <[email protected]>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+from avocado_qemu import Test
+from subprocess import Popen, PIPE
+
+MAX_NODES = 128
+
+class HostNodesValidation(Test):
+    def test_large_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'Invalid host-nodes', stderr)
+        self.assertEquals(stdout, b'')
+        self.assertEquals(p.returncode, 1)

tests/acceptance/host-nodes-limit.py line 36

Quoted 10 lines

tests/acceptance/host-nodes-limit.py new file +10 -0

+
+    def test_valid_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES - 1)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'host-nodes must be empty', stderr)
+        self.assertEquals(p.returncode, 1)

Reviewed-by David Hildenbrand <[email protected]>

Signature · 3 lines

Thanks,

David / dhildenb

Markus Armbruster

Reviewed-by on v2 1/1

2018-11-30 13:22 UTC #3 lore raw

In reply to Eduardo Habkost

Quoted 45 lines · Eduardo Habkost

host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.
Fix the crash and add a simple regression test for the fix.
While at it, fix memory leak of the list returned by visit_type_uint16List().
Reported-by Markus Armbruster <[email protected]>
Signed-off-by Eduardo Habkost <[email protected]>
---
Changes v1 -> v2:
* Remove extra l = l->next statement
(reported by Stefano Garzarella)
* Fix (existing) leak of host_nodes
(reported by Markus Armbruster)
---
 backends/hostmem.c                   | 17 +++++++++----
 tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 tests/acceptance/host-nodes-limit.py
backends/hostmem.c +9 -3
index 1a89342039..af800284e0 100644
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+

backends/hostmem.c host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name, · line 125

Quoted 10 lines

backends/hostmem.c +4 -1

+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif

Care to fix the leak in host_memory_backend_get_host_nodes(), too?

[...]

Reviewed-by Markus Armbruster <[email protected]>

Eduardo Habkost

author

2018-11-30 14:27 UTC #4 lore raw

Quoted 51 lines · Markus Armbruster

Quoted 49 lines · Eduardo Habkost
host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.
Fix the crash and add a simple regression test for the fix.
While at it, fix memory leak of the list returned by visit_type_uint16List().
Reported-by Markus Armbruster <[email protected]>
Signed-off-by Eduardo Habkost <[email protected]>
---
Changes v1 -> v2:
* Remove extra l = l->next statement
(reported by Stefano Garzarella)
* Fix (existing) leak of host_nodes
(reported by Markus Armbruster)
---
 backends/hostmem.c                   | 17 +++++++++----
 tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 tests/acceptance/host-nodes-limit.py
backends/hostmem.c +10 -4
index 1a89342039..af800284e0 100644
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+
+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }

Quoted 8 lines

backends/hostmem.c host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name, · line 125
Quoted 6 lines
backends/hostmem.c +3 -0
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif
Care to fix the leak in host_memory_backend_get_host_nodes(), too?

I don't understand yet if there's a leak at host_memory_backend_get_host_nodes(). Won't visit_type_uint16List() take ownership of the list on that case?

Quoted 4 lines

[...]
Reviewed-by Markus Armbruster <[email protected]>

Signature · 1 line

Eduardo

Markus Armbruster

2018-11-30 15:47 UTC #5 lore raw

Quoted 3 lines · Eduardo Habkost

I don't understand yet if there's a leak at host_memory_backend_get_host_nodes(). Won't visit_type_uint16List() take ownership of the list on that case?

Nope. I checked with valgrind:

    $ valgrind --leak-check=full upstream-qemu -nodefaults -S -display none -qmp stdio -object memory-backend-file,id=mem0,mem-path=x,size=4096,host-nodes=1,policy=bind
    [...]
    {"QMP": {"version": {"qemu": {"micro": 92, "minor": 0, "major": 3}, "package": "v3.1.0-rc2-48-g039d4e3df0-dirty"}, "capabilities": []}}
    {"execute": "qmp_capabilities"}
    {"return": {}}
    { "execute": "qom-get", "arguments": { "path": "mem0", "property": "host-nodes" {"execute": "qom-get", "arguments": {"path": "mem0", "property": "host-nodes"}}
    {"return": [1]}
    {"execute": "quit"}
    {"return": {}}
    {"timestamp": {"seconds": 1543592652, "microseconds": 950994}, "event": "SHUTDOWN", "data": {"guest": false}}
    ==4954== 
    ==4954== HEAP SUMMARY:
    ==4954==     in use at exit: 3,631,673 bytes in 14,706 blocks
    ==4954==   total heap usage: 51,347 allocs, 36,641 frees, 24,195,921 bytes allocated
    [...]
    ==4954== 16 bytes in 1 blocks are definitely lost in loss record 1,964 of 5,297
    ==4954==    at 0x4C3111A: calloc (vg_replace_malloc.c:752)
    ==4954==    by 0x574948D: g_malloc0 (in /usr/lib64/libglib-2.0.so.0.5600.3)
    ==4954==    by 0x9E1CE0: opts_start_list (opts-visitor.c:228)
    ==4954==    by 0x9DAB35: visit_start_list (qapi-visit-core.c:78)
    ==4954==    by 0x99BA3A: visit_type_uint16List (qapi-builtin-visit.c:272)
    ==4954==    by 0x5F911B: host_memory_backend_set_host_nodes (hostmem.c:108)
    ==4954==    by 0x8AC7D4: object_property_set (object.c:1183)
    ==4954==    by 0x8AFC82: user_creatable_add_type (object_interfaces.c:73)
    ==4954==    by 0x8AFED2: user_creatable_add_opts (object_interfaces.c:131)
    ==4954==    by 0x8AFFCD: user_creatable_add_opts_foreach (object_interfaces.c:154)
    ==4954==    by 0xA0B9B9: qemu_opts_foreach (qemu-option.c:1171)
    ==4954==    by 0x5C6C44: main (vl.c:4415)
    ==4954== 
    ==4954== 16 bytes in 1 blocks are definitely lost in loss record 1,965 of 5,297
    ==4954==    at 0x4C3111A: calloc (vg_replace_malloc.c:752)
    ==4954==    by 0x574948D: g_malloc0 (in /usr/lib64/libglib-2.0.so.0.5600.3)
    ==4954==    by 0x5F8FF5: host_memory_backend_get_host_nodes (hostmem.c:82)
    ==4954==    by 0x8AC739: object_property_get (object.c:1168)
    ==4954==    by 0x8AF910: object_property_get_qobject (qom-qobject.c:39)
    ==4954==    by 0x5E1736: qmp_qom_get (qmp.c:249)
    ==4954==    by 0x5D872F: qmp_marshal_qom_get (qapi-commands-misc.c:1284)
    ==4954==    by 0x9DF5C1: do_qmp_dispatch (qmp-dispatch.c:129)
    ==4954==    by 0x9DF788: qmp_dispatch (qmp-dispatch.c:171)
    ==4954==    by 0x42C0C1: monitor_qmp_dispatch (monitor.c:4085)
    ==4954==    by 0x42C3E1: monitor_qmp_bh_dispatcher (monitor.c:4157)
    ==4954==    by 0x9EEDB1: aio_bh_call (async.c:90)
    [...]
    ==4954== LEAK SUMMARY:
    ==4954==    definitely lost: 32 bytes in 2 blocks
    ==4954==    indirectly lost: 0 bytes in 0 blocks
    ==4954==      possibly lost: 2,504 bytes in 20 blocks
    ==4954==    still reachable: 3,629,137 bytes in 14,684 blocks
    ==4954==                       of which reachable via heuristic:
    ==4954==                         newarray           : 1,536 bytes in 16 blocks
    ==4954==         suppressed: 0 bytes in 0 blocks
    ==4954== Reachable blocks (those to which a pointer was found) are not shown.
    ==4954== To see them, rerun with: --leak-check=full --show-leak-kinds=all
    ==4954== 
    ==4954== For counts of detected and suppressed errors, rerun with: -v
    ==4954== Use --track-origins=yes to see where uninitialised values come from
    ==4954== ERROR SUMMARY: 24 errors from 24 contexts (suppressed: 0 from 0)

The first block shown is leaked in host_memory_backend_set_host_nodes() on behalf of -object, the second block in host_memory_backend_get_host_nodes() on behalf of qom-get.

Full disclosure: I hacked host_memory_backend_complete() to skip mbind():

backends/hostmem.c +1 -1

index 1a89342039..0e40bb1ad4 100644
@@ -333,7 +333,7 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
         assert(sizeof(backend->host_nodes) >=
                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
         assert(maxnode <= MAX_NODES);
-        if (mbind(ptr, sz, backend->policy,
+        if (0 && mbind(ptr, sz, backend->policy,
                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
                 error_setg_errno(errp, errno,

Eric Blake

2018-11-30 14:54 UTC #6 lore raw

In reply to Eduardo Habkost

Quoted 4 lines · Eduardo Habkost

host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.

Quoted 8 lines

Fix the crash and add a simple regression test for the fix.
While at it, fix memory leak of the list returned by visit_type_uint16List().
Reported-by Markus Armbruster <[email protected]>
Signed-off-by Eduardo Habkost <[email protected]>
---

Looks like we may have 3.1-rc4 due to some CVE fixes; is this worth including in 3.1 as well?

Signature · 3 lines

Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Markus Armbruster

2018-11-30 17:55 UTC #7 lore raw

Quoted 10 lines · Eric Blake

Quoted 9 lines · Eduardo Habkost
host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.
Fix the crash and add a simple regression test for the fix.
While at it, fix memory leak of the list returned by visit_type_uint16List().

Quoted 6 lines

Quoted 3 lines
Reported-by Markus Armbruster <[email protected]>
Signed-off-by Eduardo Habkost <[email protected]>
---
Looks like we may have 3.1-rc4 due to some CVE fixes; is this worth including in 3.1 as well?

You could conceivably crash a running VM with object-add. On the other hand, the bug has been around for a while, and was only found by code inspection.

Eduardo Habkost

author

2018-11-30 18:19 UTC #8 lore raw

Quoted 16 lines · Markus Armbruster

Quoted 14 lines · Eric Blake
Quoted 12 lines · Eduardo Habkost
host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.
Fix the crash and add a simple regression test for the fix.
While at it, fix memory leak of the list returned by visit_type_uint16List().
Reported-by Markus Armbruster <[email protected]>
Signed-off-by Eduardo Habkost <[email protected]>
---

Quoted 6 lines

Quoted 2 lines
Looks like we may have 3.1-rc4 due to some CVE fixes; is this worth including in 3.1 as well?
You could conceivably crash a running VM with object-add. On the other hand, the bug has been around for a while, and was only found by code inspection.

I think the fix would be appropriate for -rc2 or -rc3, but I don't think it's critical enough for -rc4.

Signature · 1 line

Eduardo

Igor Mammedov

Reviewed-by on v2 1/1

2018-12-04 13:29 UTC #9 lore raw

In reply to Eduardo Habkost

Quoted 11 lines · On Fri, 30 Nov 2018 10:28:44 -0200 Eduardo Habkost <[email protected]> wrote:

host_memory_backend_set_host_nodes() was not validating host-nodes before writing to backend->host_nodes, making QEMU write beyond the end of the bitmap.
Fix the crash and add a simple regression test for the fix.
While at it, fix memory leak of the list returned by visit_type_uint16List().
Reported-by Markus Armbruster <[email protected]>
Signed-off-by Eduardo Habkost <[email protected]>

Reviewed-by Igor Mammedov <[email protected]>

Quoted 86 lines

---
Changes v1 -> v2:
* Remove extra l = l->next statement
(reported by Stefano Garzarella)
* Fix (existing) leak of host_nodes
(reported by Markus Armbruster)

---
 backends/hostmem.c                   | 17 +++++++++----
 tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 tests/acceptance/host-nodes-limit.py

backends/hostmem.c +13 -4

index 1a89342039..af800284e0 100644
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+
+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif

tests/acceptance/host-nodes-limit.py new file +36 -0

new file mode 100644
index 0000000000..e803e10104
@@ -0,0 +1,36 @@
+# Regression test for host-nodes limit validation
+#
+# Copyright (c) 2018 Red Hat, Inc.
+#
+# Author:
+#  Eduardo Habkost <[email protected]>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+from avocado_qemu import Test
+from subprocess import Popen, PIPE
+
+MAX_NODES = 128
+
+class HostNodesValidation(Test):
+    def test_large_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'Invalid host-nodes', stderr)
+        self.assertEquals(stdout, b'')
+        self.assertEquals(p.returncode, 1)
+
+    def test_valid_host_nodes(self):
+        p = Popen([self.qemu_bin, '-display', 'none', '-nodefaults',
+                   '-object', 'memory-backend-ram,id=m0,'
+                              'size=4096,host-nodes=%d' % (MAX_NODES - 1)],
+                  stderr=PIPE, stdout=PIPE)
+        stdout,stderr = p.communicate()
+
+        self.assertIn(b'host-nodes must be empty', stderr)
+        self.assertEquals(p.returncode, 1)