From: Connor Kuehl <[email protected]>
Providing an empty string for the backing file parameter like so:
qemu-img create -f qcow2 -b '' /tmp/foo
allows the flow of control to reach and subsequently fail an assert
statement because passing an empty string to
bdrv_get_full_backing_filename_from_filename()
simply results in NULL being returned without an error being raised.
To fix this, let's check for an empty string when getting the value from
the opts list.
Reported-by: Attila Fazekas <[email protected]>
Fixes: https://bugzilla.redhat.com/1809553
Signed-off-by: Connor Kuehl <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
---
block.c | 4 ++++
tests/qemu-iotests/049 | 4 ++++
tests/qemu-iotests/049.out | 5 +++++
3 files changed, 13 insertions(+)
diff --git a/block.c b/block.c
index 2ba76b2c36..b204b93a2e 100644
--- a/block.c
+++ b/block.c
@@ -6119,6 +6119,10 @@ void bdrv_img_create(const char *filename, const char
*fmt,
"same filename as the backing file");
goto out;
}
+ if (backing_file[0] == '\0') {
+ error_setg(errp, "Expected backing file name, got empty string");
+ goto out;
+ }
}
backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
diff --git a/tests/qemu-iotests/049 b/tests/qemu-iotests/049
index 051a1c79e0..82b1e6c202 100755
--- a/tests/qemu-iotests/049
+++ b/tests/qemu-iotests/049
@@ -119,6 +119,10 @@ test_qemu_img create -f $IMGFMT -o
compat=1.1,lazy_refcounts=on "$TEST_IMG" 64M
test_qemu_img create -f $IMGFMT -o compat=0.10,lazy_refcounts=off "$TEST_IMG"
64M
test_qemu_img create -f $IMGFMT -o compat=0.10,lazy_refcounts=on "$TEST_IMG"
64M
+echo "== Expect error when backing file name is empty string =="
+echo
+test_qemu_img create -f $IMGFMT -b '' $TEST_IMG 1M
+
# success, all done
echo "*** done"
rm -f $seq.full
diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
index a7e220830d..b1d8fd9107 100644
--- a/tests/qemu-iotests/049.out
+++ b/tests/qemu-iotests/049.out
@@ -209,4 +209,9 @@ qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=on
TEST_DIR/t.qcow2 64M
Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off
compression_type=zlib size=67108864 compat=0.10 lazy_refcounts=on
refcount_bits=16
qemu-img: TEST_DIR/t.qcow2: Lazy refcounts only supported with compatibility
level 1.1 and above (use version=v3 or greater)
+== Expect error when backing file name is empty string ==
+
+qemu-img create -f qcow2 -b TEST_DIR/t.qcow2 1M
+qemu-img: TEST_DIR/t.qcow2: Expected backing file name, got empty string
+
*** done
--
2.25.4
