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qemu-kvm/kvm-qcow2-Don-t-open-data_file-with-BDRV_O_NO_IO.patch

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* Thu Jul 04 2024 Miroslav Rezanina <mrezanin@redhat.com> - 6.2.0-50 - kvm-qcow2-Don-t-open-data_file-with-BDRV_O_NO_IO.patch [RHEL-35616] - kvm-iotests-244-Don-t-store-data-file-with-protocol-in-i.patch [RHEL-35616] - kvm-iotests-270-Don-t-store-data-file-with-json-prefix-i.patch [RHEL-35616] - kvm-block-introduce-bdrv_open_file_child-helper.patch [RHEL-35616] - kvm-block-Parse-filenames-only-when-explicitly-requested.patch [RHEL-35616] - Resolves: RHEL-35616 (CVE-2024-4467 virt:rhel/qemu-kvm: QEMU: 'qemu-img info' leads to host file read/write [rhel-8.10.z])
2024-07-04 07:01:37 +00:00
From 5cdbc87ab24a8cc4cf926158ec429d43d8a45f15 Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Wed, 5 Jun 2024 19:56:51 -0400
Subject: [PATCH 1/5] qcow2: Don't open data_file with BDRV_O_NO_IO
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 5: EMBARGOED CVE-2024-4467 for rhel-8.10.z (PRDSC)
RH-Jira: RHEL-35616
RH-CVE: CVE-2024-4467
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [1/5] 2e72d21c14d86645cf68eec78f49d5cc5d77581f
Conflicts: qcow2_do_open(): missing boolean ´open_data_file'.
We assume it to be true.
commit f9843ce5c519901654a7d8ba43ee95ce25ca13c2
Author: Kevin Wolf <kwolf@redhat.com>
Date: Thu Apr 11 15:06:01 2024 +0200
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.
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>
Upstream: N/A, embargoed
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
block/qcow2.c | 87 +++++++++++++++++++++++---------------
tests/qemu-iotests/061 | 6 ++-
tests/qemu-iotests/061.out | 8 +++-
3 files changed, 62 insertions(+), 39 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index d509016756..6ee1919612 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1613,50 +1613,67 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
goto fail;
}
- /* Open external data file */
- s->data_file = bdrv_open_child(NULL, options, "data-file", bs,
- &child_of_bds, BDRV_CHILD_DATA,
- true, errp);
- if (*errp) {
- ret = -EINVAL;
- goto fail;
- }
+ if (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 {
+ /* Open external data file */
+ s->data_file = bdrv_open_child(NULL, options, "data-file", bs,
+ &child_of_bds, BDRV_CHILD_DATA,
+ true, errp);
+ if (*errp) {
+ ret = -EINVAL;
+ goto fail;
+ }
- if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
- if (!s->data_file && s->image_data_file) {
- s->data_file = bdrv_open_child(s->image_data_file, options,
- "data-file", bs, &child_of_bds,
- BDRV_CHILD_DATA, false, errp);
+ if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
+ if (!s->data_file && s->image_data_file) {
+ s->data_file = bdrv_open_child(s->image_data_file, options,
+ "data-file", bs, &child_of_bds,
+ BDRV_CHILD_DATA, false, errp);
+ if (!s->data_file) {
+ ret = -EINVAL;
+ goto fail;
+ }
+ }
if (!s->data_file) {
+ error_setg(errp, "'data-file' is required for this image");
ret = -EINVAL;
goto fail;
}
- }
- if (!s->data_file) {
- error_setg(errp, "'data-file' is required for this image");
- ret = -EINVAL;
- goto fail;
- }
- /* No data here */
- bs->file->role &= ~BDRV_CHILD_DATA;
+ /* No data here */
+ bs->file->role &= ~BDRV_CHILD_DATA;
- /* Must succeed because we have given up permissions if anything */
- bdrv_child_refresh_perms(bs, bs->file, &error_abort);
- } else {
- if (s->data_file) {
- error_setg(errp, "'data-file' can only be set for images with an "
- "external data file");
- ret = -EINVAL;
- goto fail;
- }
+ /* Must succeed because we have given up permissions if anything */
+ bdrv_child_refresh_perms(bs, bs->file, &error_abort);
+ } else {
+ if (s->data_file) {
+ error_setg(errp, "'data-file' can only be set for images with an "
+ "external data file");
+ ret = -EINVAL;
+ goto fail;
+ }
- s->data_file = bs->file;
+ s->data_file = bs->file;
- if (data_file_is_raw(bs)) {
- error_setg(errp, "data-file-raw requires a data file");
- ret = -EINVAL;
- goto fail;
+ if (data_file_is_raw(bs)) {
+ error_setg(errp, "data-file-raw requires a data file");
+ ret = -EINVAL;
+ goto fail;
+ }
}
}
diff --git a/tests/qemu-iotests/061 b/tests/qemu-iotests/061
index 9507c223bd..6a5bd47efc 100755
--- a/tests/qemu-iotests/061
+++ b/tests/qemu-iotests/061
@@ -322,12 +322,14 @@ $QEMU_IMG amend -o "data_file=foo" "$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 7ecbd4dea8..99b2307a23 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)
--
2.39.3
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