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openSUSE:Leap:15.4:ARM
qemu.35260
qcow2-Do-not-reopen-data_file-in-invalid.patch
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File qcow2-Do-not-reopen-data_file-in-invalid.patch of Package qemu.35260
From: Hanna Reitz <hreitz@redhat.com> Date: Wed, 27 Apr 2022 13:40:55 +0200 Subject: qcow2: Do not reopen data_file in invalidate_cache (bsc#1227322, CVE-2024-4467) qcow2_co_invalidate_cache() closes and opens the qcow2 file, by calling qcow2_close() and qcow2_do_open(). These two functions must thus be usable from both a global-state and an I/O context. As they are, they are not safe to call in an I/O context, because they use bdrv_unref_child() and bdrv_open_child() to close/open the data_file child, respectively, both of which are global-state functions. When used from qcow2_co_invalidate_cache(), we do not need to close/open the data_file child, though (we do not do this for bs->file or bs->backing either), and so we should skip it in the qcow2_co_invalidate_cache() path. To do so, add a parameter to qcow2_do_open() and qcow2_close() to make them skip handling s->data_file, and have qcow2_co_invalidate_cache() exempt it from the memset() on the BDRVQcow2State. (Note that the QED driver similarly closes/opens the QED image by invoking bdrv_qed_close()+bdrv_qed_do_open(), but both functions seem safe to use in an I/O context.) Fixes: https://gitlab.com/qemu-project/qemu/-/issues/945 Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220427114057.36651-3-hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> (cherry picked from commit 06e9cd19a4e9acf8d24327361a999943d846f607) References: bsc#1227322 References: CVE-2024-4467 Signed-off-by: Dario Faggioli <dfaggioli@suse.com> --- block/qcow2.c | 104 ++++++++++++++++++++++++++++++-------------------- 1 file changed, 62 insertions(+), 42 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 193fe2332c1b53095b600899153d..a934db4cf6ac5e8e8019334eb9ff 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1291,7 +1291,8 @@ static int validate_compression_type(BDRVQcow2State *s, Error **errp) /* Called with s->lock held. */ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, - int flags, Error **errp) + int flags, bool open_data_file, + Error **errp) { ERRP_GUARD(); BDRVQcow2State *s = bs->opaque; @@ -1610,50 +1611,52 @@ 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 (open_data_file) { + /* 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; + } } } @@ -1837,7 +1840,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, fail: g_free(s->image_data_file); - if (has_data_file(bs)) { + if (open_data_file && has_data_file(bs)) { bdrv_unref_child(bs, s->data_file); s->data_file = NULL; } @@ -1874,7 +1877,8 @@ static void coroutine_fn qcow2_open_entry(void *opaque) BDRVQcow2State *s = qoc->bs->opaque; qemu_co_mutex_lock(&s->lock); - qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); + qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, true, + qoc->errp); qemu_co_mutex_unlock(&s->lock); } @@ -2682,7 +2686,7 @@ static int qcow2_inactivate(BlockDriverState *bs) return result; } -static void qcow2_close(BlockDriverState *bs) +static void qcow2_do_close(BlockDriverState *bs, bool close_data_file) { BDRVQcow2State *s = bs->opaque; qemu_vfree(s->l1_table); @@ -2708,7 +2712,7 @@ static void qcow2_close(BlockDriverState *bs) g_free(s->image_backing_file); g_free(s->image_backing_format); - if (has_data_file(bs)) { + if (close_data_file && has_data_file(bs)) { bdrv_unref_child(bs, s->data_file); s->data_file = NULL; } @@ -2717,11 +2721,17 @@ static void qcow2_close(BlockDriverState *bs) qcow2_free_snapshots(bs); } +static void qcow2_close(BlockDriverState *bs) +{ + qcow2_do_close(bs, true); +} + static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, Error **errp) { ERRP_GUARD(); BDRVQcow2State *s = bs->opaque; + BdrvChild *data_file; int flags = s->flags; QCryptoBlock *crypto = NULL; QDict *options; @@ -2735,14 +2745,24 @@ static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, crypto = s->crypto; s->crypto = NULL; - qcow2_close(bs); + /* + * Do not reopen s->data_file (i.e., have qcow2_do_close() not close it, + * and then prevent qcow2_do_open() from opening it), because this function + * runs in the I/O path and as such we must not invoke global-state + * functions like bdrv_unref_child() and bdrv_open_child(). + */ + qcow2_do_close(bs, false); + + data_file = s->data_file; memset(s, 0, sizeof(BDRVQcow2State)); + s->data_file = data_file; + options = qdict_clone_shallow(bs->options); flags &= ~BDRV_O_INACTIVE; qemu_co_mutex_lock(&s->lock); - ret = qcow2_do_open(bs, options, flags, errp); + ret = qcow2_do_open(bs, options, flags, false, errp); qemu_co_mutex_unlock(&s->lock); qobject_unref(options); if (ret < 0) {
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