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Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging
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Block layer patches (CVE-2024-4467)

- Don't open qcow2 data files in 'qemu-img info'
- Disallow protocol prefixes for qcow2 data files, VMDK extent files and
  other child nodes that are neither 'file' nor 'backing'

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# gpg: Signature made Tue 02 Jul 2024 09:21:32 AM PDT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "[email protected]"
# gpg: Good signature from "Kevin Wolf <[email protected]>" [full]

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin:
  block: Parse filenames only when explicitly requested
  iotests/270: Don't store data-file with json: prefix in image
  iotests/244: Don't store data-file with protocol in image
  qcow2: Don't open data_file with BDRV_O_NO_IO

Signed-off-by: Richard Henderson <[email protected]>
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rth7680 committed Jul 3, 2024
2 parents 1a2d52c + 7ead946 commit 727f4a7
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Showing 6 changed files with 110 additions and 44 deletions.
90 changes: 57 additions & 33 deletions block.c
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -2055,7 +2056,8 @@ 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;
Expand Down Expand Up @@ -2097,7 +2099,7 @@ 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");
Expand Down Expand Up @@ -3660,7 +3662,8 @@ 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: ");
Expand Down Expand Up @@ -3694,7 +3697,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
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;
Expand Down Expand Up @@ -3725,7 +3729,8 @@ 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;
}
Expand All @@ -3735,6 +3740,33 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
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.
Expand All @@ -3758,27 +3790,15 @@ 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.
*/
Expand All @@ -3793,8 +3813,8 @@ 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;
}
Expand Down Expand Up @@ -3839,7 +3859,8 @@ 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);
Expand Down Expand Up @@ -3929,7 +3950,7 @@ 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;
Expand Down Expand Up @@ -3977,9 +3998,11 @@ 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);
Expand All @@ -4004,7 +4027,8 @@ 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;
}
Expand Down Expand Up @@ -4073,7 +4097,7 @@ 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;
}
Expand Down Expand Up @@ -4222,7 +4246,7 @@ 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 */
Expand Down
17 changes: 16 additions & 1 deletion block/qcow2.c
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down
6 changes: 4 additions & 2 deletions tests/qemu-iotests/061
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
8 changes: 6 additions & 2 deletions tests/qemu-iotests/061.out
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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)
Expand Down
19 changes: 16 additions & 3 deletions tests/qemu-iotests/244
Original file line number Diff line number Diff line change
Expand Up @@ -215,9 +215,22 @@ $QEMU_IMG convert -f $IMGFMT -O $IMGFMT -n -C "$TEST_IMG.src" "$TEST_IMG"
$QEMU_IMG compare -f $IMGFMT -F $IMGFMT "$TEST_IMG.src" "$TEST_IMG"

# blkdebug doesn't support copy offloading, so this tests the error path
$QEMU_IMG amend -f $IMGFMT -o "data_file=blkdebug::$TEST_IMG.data" "$TEST_IMG"
$QEMU_IMG convert -f $IMGFMT -O $IMGFMT -n -C "$TEST_IMG.src" "$TEST_IMG"
$QEMU_IMG compare -f $IMGFMT -F $IMGFMT "$TEST_IMG.src" "$TEST_IMG"
test_img_with_blkdebug="json:{
'driver': 'qcow2',
'file': {
'driver': 'file',
'filename': '$TEST_IMG'
},
'data-file': {
'driver': 'blkdebug',
'image': {
'driver': 'file',
'filename': '$TEST_IMG.data'
}
}
}"
$QEMU_IMG convert -f $IMGFMT -O $IMGFMT -n -C "$TEST_IMG.src" "$test_img_with_blkdebug"
$QEMU_IMG compare -f $IMGFMT -F $IMGFMT "$TEST_IMG.src" "$test_img_with_blkdebug"

echo
echo "=== Flushing should flush the data file ==="
Expand Down
14 changes: 11 additions & 3 deletions tests/qemu-iotests/270
Original file line number Diff line number Diff line change
Expand Up @@ -60,8 +60,16 @@ _make_test_img -o cluster_size=2M,data_file="$TEST_IMG.orig" \
# "write" 2G of data without using any space.
# (qemu-img create does not like it, though, because null-co does not
# support image creation.)
$QEMU_IMG amend -o data_file="json:{'driver':'null-co',,'size':'4294967296'}" \
"$TEST_IMG"
test_img_with_null_data="json:{
'driver': '$IMGFMT',
'file': {
'filename': '$TEST_IMG'
},
'data-file': {
'driver': 'null-co',
'size':'4294967296'
}
}"

# This gives us a range of:
# 2^31 - 512 + 768 - 1 = 2^31 + 255 > 2^31
Expand All @@ -74,7 +82,7 @@ $QEMU_IMG amend -o data_file="json:{'driver':'null-co',,'size':'4294967296'}" \
# on L2 boundaries, we need large L2 tables; hence the cluster size of
# 2 MB. (Anything from 256 kB should work, though, because then one L2
# table covers 8 GB.)
$QEMU_IO -c "write 768 $((2 ** 31 - 512))" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write 768 $((2 ** 31 - 512))" "$test_img_with_null_data" | _filter_qemu_io

_check_test_img

Expand Down

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