diff options
| 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 /block | |
| parent | 2d51c32c4b511db8bb9e58208f1e2c25e4c06c85 (diff) | |
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>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 36395289a9..cc1bfebf29 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); |