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backport fix for CVE-2024-4467

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This prevents that malicious qcow2 images can already cause bad
effects if being queried via 'qemu-img info'.

For Proxmox VE, this is an additional safe guard, as currently it
directly creates and manages the qcow2 images used by VMs and does not
allow unprivileged users to import them.

Reference: https://access.redhat.com/security/cve/cve-2024-4467

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
This commit is contained in:
Fiona Ebner 2024-07-03 13:03:49 +02:00
parent c2abb73df7
commit b242e7f196
3 changed files with 350 additions and 0 deletions
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107
debian/patches/extra/0019-qcow2-Don-t-open-data_file-with-BDRV_O_NO_IO.patch vendored Normal file
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@ -0,0 +1,107 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 2 Jul 2024 18:39:40 +0200
Subject: [PATCH] qcow2: Don't open data_file with BDRV_O_NO_IO
One use case for 'qemu-img info' is verifying that untrusted images
don't reference an unwanted external file, be it as a backing file or an
external data file. To make sure that calling 'qemu-img info' can't
already have undesired side effects with a malicious image, just don't
open the data file at all with BDRV_O_NO_IO. If nothing ever tries to do
I/O, we don't need to have it open.
This changes the output of iotests case 061, which used 'qemu-img info'
to show that opening an image with an invalid data file fails. After
this patch, it succeeds. Replace this part of the test with a qemu-io
call, but keep the final 'qemu-img info' to show that the invalid data
file is correctly displayed in the output.
Fixes: CVE-2024-4467
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
(picked from https://lore.kernel.org/qemu-devel/20240702163943.276618-2-kwolf@redhat.com/)
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
block/qcow2.c | 17 ++++++++++++++++-
tests/qemu-iotests/061 | 6 ++++--
tests/qemu-iotests/061.out | 8 ++++++--
3 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 956128b409..4c78665bcb 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1636,7 +1636,22 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
goto fail;
}
- if (open_data_file) {
+ if (open_data_file && (flags & BDRV_O_NO_IO)) {
+ /*
+ * Don't open the data file for 'qemu-img info' so that it can be used
+ * to verify that an untrusted qcow2 image doesn't refer to external
+ * files.
+ *
+ * Note: This still makes has_data_file() return true.
+ */
+ if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
+ s->data_file = NULL;
+ } else {
+ s->data_file = bs->file;
+ }
+ qdict_extract_subqdict(options, NULL, "data-file.");
+ qdict_del(options, "data-file");
+ } else if (open_data_file) {
/* Open external data file */
bdrv_graph_co_rdunlock();
s->data_file = bdrv_co_open_child(NULL, options, "data-file", bs,
diff --git a/tests/qemu-iotests/061 b/tests/qemu-iotests/061
index 53c7d428e3..b71ac097d1 100755
--- a/tests/qemu-iotests/061
+++ b/tests/qemu-iotests/061
@@ -326,12 +326,14 @@ $QEMU_IMG amend -o "data_file=foo" "$TEST_IMG"
echo
_make_test_img -o "compat=1.1,data_file=$TEST_IMG.data" 64M
$QEMU_IMG amend -o "data_file=foo" "$TEST_IMG"
-_img_info --format-specific
+$QEMU_IO -c "read 0 4k" "$TEST_IMG" 2>&1 | _filter_testdir | _filter_imgfmt
+$QEMU_IO -c "open -o data-file.filename=$TEST_IMG.data,file.filename=$TEST_IMG" -c "read 0 4k" | _filter_qemu_io
TEST_IMG="data-file.filename=$TEST_IMG.data,file.filename=$TEST_IMG" _img_info --format-specific --image-opts
echo
$QEMU_IMG amend -o "data_file=" --image-opts "data-file.filename=$TEST_IMG.data,file.filename=$TEST_IMG"
-_img_info --format-specific
+$QEMU_IO -c "read 0 4k" "$TEST_IMG" 2>&1 | _filter_testdir | _filter_imgfmt
+$QEMU_IO -c "open -o data-file.filename=$TEST_IMG.data,file.filename=$TEST_IMG" -c "read 0 4k" | _filter_qemu_io
TEST_IMG="data-file.filename=$TEST_IMG.data,file.filename=$TEST_IMG" _img_info --format-specific --image-opts
echo
diff --git a/tests/qemu-iotests/061.out b/tests/qemu-iotests/061.out
index 139fc68177..24c33add7c 100644
--- a/tests/qemu-iotests/061.out
+++ b/tests/qemu-iotests/061.out
@@ -545,7 +545,9 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
qemu-img: data-file can only be set for images that use an external data file
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data
-qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Could not open 'foo': No such file or directory
+qemu-io: can't open device TEST_DIR/t.IMGFMT: Could not open 'foo': No such file or directory
+read 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
image: TEST_DIR/t.IMGFMT
file format: IMGFMT
virtual size: 64 MiB (67108864 bytes)
@@ -560,7 +562,9 @@ Format specific information:
corrupt: false
extended l2: false
-qemu-img: Could not open 'TEST_DIR/t.IMGFMT': 'data-file' is required for this image
+qemu-io: can't open device TEST_DIR/t.IMGFMT: 'data-file' is required for this image
+read 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
image: TEST_DIR/t.IMGFMT
file format: IMGFMT
virtual size: 64 MiB (67108864 bytes)

241
debian/patches/extra/0020-block-Parse-filenames-only-when-explicitly-requested.patch vendored Normal file
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@ -0,0 +1,241 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 2 Jul 2024 18:39:43 +0200
Subject: [PATCH] block: Parse filenames only when explicitly requested
When handling image filenames from legacy options such as -drive or from
tools, these filenames are parsed for protocol prefixes, including for
the json:{} pseudo-protocol.
This behaviour is intended for filenames that come directly from the
command line and for backing files, which may come from the image file
itself. Higher level management tools generally take care to verify that
untrusted images don't contain a bad (or any) backing file reference;
'qemu-img info' is a suitable tool for this.
However, for other files that can be referenced in images, such as
qcow2 data files or VMDK extents, the string from the image file is
usually not verified by management tools - and 'qemu-img info' wouldn't
be suitable because in contrast to backing files, it already opens these
other referenced files. So here the string should be interpreted as a
literal local filename. More complex configurations need to be specified
explicitly on the command line or in QMP.
This patch changes bdrv_open_inherit() so that it only parses filenames
if a new parameter parse_filename is true. It is set for the top level
in bdrv_open(), for the file child and for the backing file child. All
other callers pass false and disable filename parsing this way.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
(picked from https://lore.kernel.org/qemu-devel/20240702163943.276618-5-kwolf@redhat.com/)
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
block.c | 90 ++++++++++++++++++++++++++++++++++++---------------------
1 file changed, 57 insertions(+), 33 deletions(-)
diff --git a/block.c b/block.c
index 468cf5e67d..50bdd197b7 100644
--- a/block.c
+++ b/block.c
@@ -86,6 +86,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
BlockDriverState *parent,
const BdrvChildClass *child_class,
BdrvChildRole child_role,
+ bool parse_filename,
Error **errp);
static bool bdrv_recurse_has_child(BlockDriverState *bs,
@@ -2058,7 +2059,8 @@ static void parse_json_protocol(QDict *options, const char **pfilename,
* block driver has been specified explicitly.
*/
static int bdrv_fill_options(QDict **options, const char *filename,
- int *flags, Error **errp)
+ int *flags, bool allow_parse_filename,
+ Error **errp)
{
const char *drvname;
bool protocol = *flags & BDRV_O_PROTOCOL;
@@ -2100,7 +2102,7 @@ static int bdrv_fill_options(QDict **options, const char *filename,
if (protocol && filename) {
if (!qdict_haskey(*options, "filename")) {
qdict_put_str(*options, "filename", filename);
- parse_filename = true;
+ parse_filename = allow_parse_filename;
} else {
error_setg(errp, "Can't specify 'file' and 'filename' options at "
"the same time");
@@ -3663,7 +3665,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
}
backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
- &child_of_bds, bdrv_backing_role(bs), errp);
+ &child_of_bds, bdrv_backing_role(bs), true,
+ errp);
if (!backing_hd) {
bs->open_flags |= BDRV_O_NO_BACKING;
error_prepend(errp, "Could not open backing file: ");
@@ -3697,7 +3700,8 @@ free_exit:
static BlockDriverState *
bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
BlockDriverState *parent, const BdrvChildClass *child_class,
- BdrvChildRole child_role, bool allow_none, Error **errp)
+ BdrvChildRole child_role, bool allow_none,
+ bool parse_filename, Error **errp)
{
BlockDriverState *bs = NULL;
QDict *image_options;
@@ -3728,7 +3732,8 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
}
bs = bdrv_open_inherit(filename, reference, image_options, 0,
- parent, child_class, child_role, errp);
+ parent, child_class, child_role, parse_filename,
+ errp);
if (!bs) {
goto done;
}
@@ -3738,6 +3743,33 @@ done:
return bs;
}
+static BdrvChild *bdrv_open_child_common(const char *filename,
+ QDict *options, const char *bdref_key,
+ BlockDriverState *parent,
+ const BdrvChildClass *child_class,
+ BdrvChildRole child_role,
+ bool allow_none, bool parse_filename,
+ Error **errp)
+{
+ BlockDriverState *bs;
+ BdrvChild *child;
+
+ GLOBAL_STATE_CODE();
+
+ bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_class,
+ child_role, allow_none, parse_filename, errp);
+ if (bs == NULL) {
+ return NULL;
+ }
+
+ bdrv_graph_wrlock();
+ child = bdrv_attach_child(parent, bs, bdref_key, child_class, child_role,
+ errp);
+ bdrv_graph_wrunlock();
+
+ return child;
+}
+
/*
* Opens a disk image whose options are given as BlockdevRef in another block
* device's options.
@@ -3761,27 +3793,15 @@ BdrvChild *bdrv_open_child(const char *filename,
BdrvChildRole child_role,
bool allow_none, Error **errp)
{
- BlockDriverState *bs;
- BdrvChild *child;
-
- GLOBAL_STATE_CODE();
-
- bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_class,
- child_role, allow_none, errp);
- if (bs == NULL) {
- return NULL;
- }
-
- bdrv_graph_wrlock();
- child = bdrv_attach_child(parent, bs, bdref_key, child_class, child_role,
- errp);
- bdrv_graph_wrunlock();
-
- return child;
+ return bdrv_open_child_common(filename, options, bdref_key, parent,
+ child_class, child_role, allow_none, false,
+ errp);
}
/*
- * Wrapper on bdrv_open_child() for most popular case: open primary child of bs.
+ * This does mostly the same as bdrv_open_child(), but for opening the primary
+ * child of a node. A notable difference from bdrv_open_child() is that it
+ * enables filename parsing for protocol names (including json:).
*
* @parent can move to a different AioContext in this function.
*/
@@ -3796,8 +3816,8 @@ int bdrv_open_file_child(const char *filename,
role = parent->drv->is_filter ?
(BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY) : BDRV_CHILD_IMAGE;
- if (!bdrv_open_child(filename, options, bdref_key, parent,
- &child_of_bds, role, false, errp))
+ if (!bdrv_open_child_common(filename, options, bdref_key, parent,
+ &child_of_bds, role, false, true, errp))
{
return -EINVAL;
}
@@ -3842,7 +3862,8 @@ BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp)
}
- bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, 0, errp);
+ bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, 0, false,
+ errp);
obj = NULL;
qobject_unref(obj);
visit_free(v);
@@ -3932,7 +3953,7 @@ static BlockDriverState * no_coroutine_fn
bdrv_open_inherit(const char *filename, const char *reference, QDict *options,
int flags, BlockDriverState *parent,
const BdrvChildClass *child_class, BdrvChildRole child_role,
- Error **errp)
+ bool parse_filename, Error **errp)
{
int ret;
BlockBackend *file = NULL;
@@ -3980,9 +4001,11 @@ bdrv_open_inherit(const char *filename, const char *reference, QDict *options,
}
/* json: syntax counts as explicit options, as if in the QDict */
- parse_json_protocol(options, &filename, &local_err);
- if (local_err) {
- goto fail;
+ if (parse_filename) {
+ parse_json_protocol(options, &filename, &local_err);
+ if (local_err) {
+ goto fail;
+ }
}
bs->explicit_options = qdict_clone_shallow(options);
@@ -4007,7 +4030,8 @@ bdrv_open_inherit(const char *filename, const char *reference, QDict *options,
parent->open_flags, parent->options);
}
- ret = bdrv_fill_options(&options, filename, &flags, &local_err);
+ ret = bdrv_fill_options(&options, filename, &flags, parse_filename,
+ &local_err);
if (ret < 0) {
goto fail;
}
@@ -4076,7 +4100,7 @@ bdrv_open_inherit(const char *filename, const char *reference, QDict *options,
file_bs = bdrv_open_child_bs(filename, options, "file", bs,
&child_of_bds, BDRV_CHILD_IMAGE,
- true, &local_err);
+ true, true, &local_err);
if (local_err) {
goto fail;
}
@@ -4225,7 +4249,7 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference,
GLOBAL_STATE_CODE();
return bdrv_open_inherit(filename, reference, options, flags, NULL,
- NULL, 0, errp);
+ NULL, 0, true, errp);
}
/* Return true if the NULL-terminated @list contains @str */

2
debian/patches/series vendored
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@ -16,6 +16,8 @@ extra/0015-target-i386-Give-IRQs-a-chance-when-resetting-HF_INH.patch
extra/0016-target-i386-hyper-v-Correct-kvm_hv_handle_exit-retur.patch
extra/0017-target-i386-disable-jmp_opt-if-EFLAGS.RF-is-1.patch
extra/0018-target-i386-no-single-step-exception-after-MOV-or-PO.patch
extra/0019-qcow2-Don-t-open-data_file-with-BDRV_O_NO_IO.patch
extra/0020-block-Parse-filenames-only-when-explicitly-requested.patch
bitmap-mirror/0001-drive-mirror-add-support-for-sync-bitmap-mode-never.patch
bitmap-mirror/0002-drive-mirror-add-support-for-conditional-and-always-.patch
bitmap-mirror/0003-mirror-add-check-for-bitmap-mode-without-bitmap.patch