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qcow2: Check L1 table parameters in qcow2_expand_zero_clusters() 

This function iterates over all snapshots of a qcow2 file in order to
expand all zero clusters, but it does not validate the snapshots' L1
tables first.

We now have a function to take care of this, so let's use it.

We can also take the opportunity to replace the sector-based
bdrv_read() with bdrv_pread().

Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Alberto Garcia 2018-03-06 18:14:08 +02:00 committed by Kevin Wolf
parent 314e8d3928
commit c9a442e450
3 changed files with 23 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
block/qcow2-cluster.c
View File

@ -25,6 +25,7 @@
#include "qemu/osdep.h"
#include <zlib.h>
#include "qapi/error.h"
#include "qemu-common.h"
#include "block/block_int.h"
#include "block/qcow2.h"
@ -2092,11 +2093,21 @@ int qcow2_expand_zero_clusters(BlockDriverState *bs,
}
for (i = 0; i < s->nb_snapshots; i++) {
int l1_sectors = DIV_ROUND_UP(s->snapshots[i].l1_size *
sizeof(uint64_t), BDRV_SECTOR_SIZE);
int l1_size2;
uint64_t *new_l1_table;
Error *local_err = NULL;
uint64_t *new_l1_table =
g_try_realloc(l1_table, l1_sectors * BDRV_SECTOR_SIZE);
ret = qcow2_validate_table(bs, s->snapshots[i].l1_table_offset,
s->snapshots[i].l1_size, sizeof(uint64_t),
QCOW_MAX_L1_SIZE, "Snapshot L1 table",
&local_err);
if (ret < 0) {
error_report_err(local_err);
goto fail;
}
l1_size2 = s->snapshots[i].l1_size * sizeof(uint64_t);
new_l1_table = g_try_realloc(l1_table, l1_size2);
if (!new_l1_table) {
ret = -ENOMEM;
@ -2105,9 +2116,8 @@ int qcow2_expand_zero_clusters(BlockDriverState *bs,
l1_table = new_l1_table;
ret = bdrv_read(bs->file,
s->snapshots[i].l1_table_offset / BDRV_SECTOR_SIZE,
(void *)l1_table, l1_sectors);
ret = bdrv_pread(bs->file, s->snapshots[i].l1_table_offset,
l1_table, l1_size2);
if (ret < 0) {
goto fail;
}

2
tests/qemu-iotests/080
View File

@ -177,6 +177,7 @@ _make_test_img 64M
{ $QEMU_IMG snapshot -c test $TEST_IMG; } 2>&1 | _filter_testdir
poke_file "$TEST_IMG" "$offset_snap1_l1_offset" "\x00\x00\x00\x00\x00\x40\x02\x00"
{ $QEMU_IMG convert -s test $TEST_IMG $TEST_IMG.snap; } 2>&1 | _filter_testdir
{ $QEMU_IMG amend -o compat=0.10 $TEST_IMG; } 2>&1 | _filter_testdir
echo
echo "== Invalid snapshot L1 table size =="
@ -185,6 +186,7 @@ _make_test_img 64M
{ $QEMU_IMG snapshot -c test $TEST_IMG; } 2>&1 | _filter_testdir
poke_file "$TEST_IMG" "$offset_snap1_l1_size" "\x10\x00\x00\x00"
{ $QEMU_IMG convert -s test $TEST_IMG $TEST_IMG.snap; } 2>&1 | _filter_testdir
{ $QEMU_IMG amend -o compat=0.10 $TEST_IMG; } 2>&1 | _filter_testdir
# success, all done
echo "*** done"

4
tests/qemu-iotests/080.out
View File

@ -64,10 +64,14 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
qemu-img: Failed to load snapshot: Snapshot L1 table offset invalid
qemu-img: Snapshot L1 table offset invalid
qemu-img: Error while amending options: Invalid argument
== Invalid snapshot L1 table size ==
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
qemu-img: Failed to load snapshot: Snapshot L1 table too large
qemu-img: Snapshot L1 table too large
qemu-img: Error while amending options: File too large
*** done