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| author | Max Reitz <mreitz@redhat.com> | 2013-10-09 10:42:56 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2013-10-11 16:49:59 +0200 |
| commit | 998b959c1e59044f5d5f64c482f4ce8facc8e0bc (patch) | |
| tree | 54aeeb7fcc771e456e6bdd761991122f76e65869 | |
| parent | f252080453ec081ba653bba4e0c1ca86c52cf19f (diff) | |
| download | qemu-998b959c1e59044f5d5f64c482f4ce8facc8e0bc.zip qemu-998b959c1e59044f5d5f64c482f4ce8facc8e0bc.tar.gz qemu-998b959c1e59044f5d5f64c482f4ce8facc8e0bc.tar.bz2 | |
qcow2: Use pread for inactive L1 in overlap check
Currently, qcow2_check_metadata_overlap uses bdrv_read to read inactive
L1 tables from disk. The number of sectors to read is calculated through
a truncating integer division, therefore, if the L1 table size is not a
multiple of the sector size, the final entries will not be read and
their entries in memory remain undefined (from the g_malloc).
Using bdrv_pread fixes this.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/qcow2-refcount.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 2d67885..4cb9c23 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1719,12 +1719,11 @@ int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset, for (i = 0; i < s->nb_snapshots; i++) { uint64_t l1_ofs = s->snapshots[i].l1_table_offset; uint32_t l1_sz = s->snapshots[i].l1_size; - uint64_t *l1 = g_malloc(l1_sz * sizeof(uint64_t)); + uint64_t l1_sz2 = l1_sz * sizeof(uint64_t); + uint64_t *l1 = g_malloc(l1_sz2); int ret; - ret = bdrv_read(bs->file, l1_ofs / BDRV_SECTOR_SIZE, (uint8_t *)l1, - l1_sz * sizeof(uint64_t) / BDRV_SECTOR_SIZE); - + ret = bdrv_pread(bs->file, l1_ofs, l1, l1_sz2); if (ret < 0) { g_free(l1); return ret; |