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vmdk: check l1 size before opening image

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L1 table size is calculated from capacity, granularity and l2 table
size. If capacity is too big or later two are too small, the L1 table
will be too big to allocate in memory. Limit it to a reasonable range.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2013-08-06 15:44:53 +08:00 committed by Kevin Wolf
parent f8ce04036e
commit 2c43e43c8c
3 changed files with 22 additions and 0 deletions
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8
block/vmdk.c
View File

@ -597,6 +597,14 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
}
l1_size = (le64_to_cpu(header.capacity) + l1_entry_sectors - 1)
/ l1_entry_sectors;
if (l1_size > 512 * 1024 * 1024) {
/* although with big capacity and small l1_entry_sectors, we can get a
* big l1_size, we don't want unbounded value to allocate the table.
* Limit it to 512M, which is 16PB for default cluster and L2 table
* size */
error_report("L1 size too big");
return -EFBIG;
}
if (le32_to_cpu(header.flags) & VMDK4_FLAG_RGD) {
l1_backup_offset = le64_to_cpu(header.rgd_offset) << 9;
}

8
tests/qemu-iotests/059
View File

@ -43,6 +43,7 @@ _supported_fmt vmdk
_supported_proto generic
_supported_os Linux
capacity_offset=16
granularity_offset=20
grain_table_size_offset=44
@ -58,6 +59,13 @@ _make_test_img 64M
poke_file "$TEST_IMG" "$grain_table_size_offset" "\xff\xff\xff\xff"
{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
echo "=== Testing too big L1 table size ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "$capacity_offset" "\xff\xff\xff\xff"
poke_file "$TEST_IMG" "$grain_table_size_offset" "\x01\x00\x00\x00"
{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
# success, all done
echo "*** done"
rm -f $seq.full

6
tests/qemu-iotests/059.out
View File

@ -11,4 +11,10 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
L2 table size too big
qemu-io: can't open device TEST_DIR/t.vmdk
no file open, try 'help open'
=== Testing too big L1 table size ===
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
L1 size too big
qemu-io: can't open device TEST_DIR/t.vmdk
no file open, try 'help open'
*** done