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| author | Kevin Wolf <kwolf@redhat.com> | 2014-03-26 13:05:47 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2014-04-01 14:19:09 +0200 |
| commit | 6d33e8e7dc9d40ea105feed4b39caa3e641569e8 (patch) | |
| tree | dc0f7b63b5d42aa84af6f51dffe16c4193594c59 | |
| parent | 2d51c32c4b511db8bb9e58208f1e2c25e4c06c85 (diff) | |
| download | qemu-6d33e8e7dc9d40ea105feed4b39caa3e641569e8.zip qemu-6d33e8e7dc9d40ea105feed4b39caa3e641569e8.tar.gz qemu-6d33e8e7dc9d40ea105feed4b39caa3e641569e8.tar.bz2 | |
qcow2: Fix backing file name length check
len could become negative and would pass the check then. Nothing bad
happened because bdrv_pread() happens to return an error for negative
length values, but make variables for sizes unsigned anyway.
This patch also changes the behaviour to error out on invalid lengths
instead of silently truncating it to 1023.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | block/qcow2.c | 9 | ||||
| -rwxr-xr-x | tests/qemu-iotests/080 | 8 | ||||
| -rw-r--r-- | tests/qemu-iotests/080.out | 5 |
3 files changed, 19 insertions, 3 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 3639528..cc1bfeb 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -445,7 +445,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVQcowState *s = bs->opaque; - int len, i, ret = 0; + unsigned int len, i; + int ret = 0; QCowHeader header; QemuOpts *opts; Error *local_err = NULL; @@ -721,8 +722,10 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, /* read the backing file name */ if (header.backing_file_offset != 0) { len = header.backing_file_size; - if (len > 1023) { - len = 1023; + if (len > MIN(1023, s->cluster_size - header.backing_file_offset)) { + error_setg(errp, "Backing file name too long"); + ret = -EINVAL; + goto fail; } ret = bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len); diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080 index 7255b6c..f3091a9 100755 --- a/tests/qemu-iotests/080 +++ b/tests/qemu-iotests/080 @@ -45,6 +45,7 @@ _supported_os Linux header_size=104 offset_backing_file_offset=8 +offset_backing_file_size=16 offset_l1_size=36 offset_l1_table_offset=40 offset_refcount_table_offset=48 @@ -135,6 +136,13 @@ poke_file "$TEST_IMG" "$offset_l1_table_offset" "\x12\x34\x56\x78\x90\xab\xcd\xe poke_file "$TEST_IMG" "$offset_l1_size" "\x00\x00\x00\x01" { $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +echo +echo "== Invalid backing file size ==" +_make_test_img 64M +poke_file "$TEST_IMG" "$offset_backing_file_offset" "\x00\x00\x00\x00\x00\x00\x10\x00" +poke_file "$TEST_IMG" "$offset_backing_file_size" "\xff\xff\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out index 4ec2545..8103211 100644 --- a/tests/qemu-iotests/080.out +++ b/tests/qemu-iotests/080.out @@ -58,4 +58,9 @@ qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset no file open, try 'help open' qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset no file open, try 'help open' + +== Invalid backing file size == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-io: can't open device TEST_DIR/t.qcow2: Backing file name too long +no file open, try 'help open' *** done |