From patchwork Fri Sep 10 10:27:03 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [2/3] vvfat: Fix double free for opening the image rw Date: Fri, 10 Sep 2010 00:27:03 -0000 From: Kevin Wolf X-Patchwork-Id: 64374 Message-Id: <1284114424-11960-3-git-send-email-mail@kevin-wolf.de> To: qemu-devel@nongnu.org Cc: Kevin Wolf Allocation and deallocation of bs->opaque is not in the control of a block driver. Therefore it should not set bs->opaque to a data structure used by another bs, or closing the image will lead to a double free. Signed-off-by: Kevin Wolf --- block/vvfat.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/block/vvfat.c b/block/vvfat.c index 5898d66..0772037 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -2768,12 +2768,12 @@ static int vvfat_is_allocated(BlockDriverState *bs, static int write_target_commit(BlockDriverState *bs, int64_t sector_num, const uint8_t* buffer, int nb_sectors) { - BDRVVVFATState* s = bs->opaque; + BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque); return try_commit(s); } static void write_target_close(BlockDriverState *bs) { - BDRVVVFATState* s = bs->opaque; + BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque); bdrv_delete(s->qcow); free(s->qcow_filename); } @@ -2816,7 +2816,8 @@ static int enable_write_target(BDRVVVFATState *s) s->bs->backing_hd = calloc(sizeof(BlockDriverState), 1); s->bs->backing_hd->drv = &vvfat_write_target; - s->bs->backing_hd->opaque = s; + s->bs->backing_hd->opaque = qemu_malloc(sizeof(void*)); + *(void**)s->bs->backing_hd->opaque = s; return 0; }