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vmdk: Don't corrupt desc file in vmdk_write_cid

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If the text description file is larger than DESC_SIZE, we force the last
byte in the buffer to be 0 and write it out.

This results in a corruption.

Try to allocate a big buffer in this case.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1923

Signed-off-by: Fam Zheng <fam@euphon.net>
Message-ID: <20231124115654.3239137-1-fam@euphon.net>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 9fb7b350ba9816ebca8a7614fec486fd4269ab2d)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This commit is contained in:
Fam Zheng 2023-11-24 11:56:54 +00:00 committed by Michael Tokarev
parent 6f51114b0e
commit 5cf2cf1f9f
3 changed files with 26 additions and 8 deletions
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28
block/vmdk.c
View file

@ -347,29 +347,41 @@ vmdk_write_cid(BlockDriverState *bs, uint32_t cid)
BDRVVmdkState *s = bs->opaque; BDRVVmdkState *s = bs->opaque;
int ret = 0; int ret = 0;
desc = g_malloc0(DESC_SIZE); size_t desc_buf_size;
tmp_desc = g_malloc0(DESC_SIZE);
ret = bdrv_co_pread(bs->file, s->desc_offset, DESC_SIZE, desc, 0); if (s->desc_offset == 0) {
desc_buf_size = bdrv_getlength(bs->file->bs);
if (desc_buf_size > 16ULL << 20) {
error_report("VMDK description file too big");
return -EFBIG;
}
} else {
desc_buf_size = DESC_SIZE;
}
desc = g_malloc0(desc_buf_size);
tmp_desc = g_malloc0(desc_buf_size);
ret = bdrv_co_pread(bs->file, s->desc_offset, desc_buf_size, desc, 0);
if (ret < 0) { if (ret < 0) {
goto out; goto out;
} }
desc[DESC_SIZE - 1] = '\0'; desc[desc_buf_size - 1] = '\0';
tmp_str = strstr(desc, "parentCID"); tmp_str = strstr(desc, "parentCID");
if (tmp_str == NULL) { if (tmp_str == NULL) {
ret = -EINVAL; ret = -EINVAL;
goto out; goto out;
} }
pstrcpy(tmp_desc, DESC_SIZE, tmp_str); pstrcpy(tmp_desc, desc_buf_size, tmp_str);
p_name = strstr(desc, "CID"); p_name = strstr(desc, "CID");
if (p_name != NULL) { if (p_name != NULL) {
p_name += sizeof("CID"); p_name += sizeof("CID");
snprintf(p_name, DESC_SIZE - (p_name - desc), "%" PRIx32 "\n", cid); snprintf(p_name, desc_buf_size - (p_name - desc), "%" PRIx32 "\n", cid);
pstrcat(desc, DESC_SIZE, tmp_desc); pstrcat(desc, desc_buf_size, tmp_desc);
} }
ret = bdrv_co_pwrite_sync(bs->file, s->desc_offset, DESC_SIZE, desc, 0); ret = bdrv_co_pwrite_sync(bs->file, s->desc_offset, desc_buf_size, desc, 0);
out: out:
g_free(desc); g_free(desc);

2
tests/qemu-iotests/059
View file

@ -84,6 +84,8 @@ echo
echo "=== Testing big twoGbMaxExtentFlat ===" echo "=== Testing big twoGbMaxExtentFlat ==="
_make_test_img -o "subformat=twoGbMaxExtentFlat" 1000G _make_test_img -o "subformat=twoGbMaxExtentFlat" 1000G
_img_info --format-specific | _filter_img_info --format-specific _img_info --format-specific | _filter_img_info --format-specific
$QEMU_IO -c "write 990G 512 -P 89" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read 990G 512 -P 89" "$TEST_IMG" | _filter_qemu_io
_cleanup_test_img _cleanup_test_img
echo echo

4
tests/qemu-iotests/059.out
View file

@ -2032,6 +2032,10 @@ Format specific information:
virtual size: 2147483648 virtual size: 2147483648
filename: TEST_DIR/t-f500.IMGFMT filename: TEST_DIR/t-f500.IMGFMT
format: FLAT format: FLAT
wrote 512/512 bytes at offset 1063004405760
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
read 512/512 bytes at offset 1063004405760
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
=== Testing malformed VMFS extent description line === === Testing malformed VMFS extent description line ===
qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Invalid extent line: RW 12582912 VMFS "dummy.IMGFMT" 1 qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Invalid extent line: RW 12582912 VMFS "dummy.IMGFMT" 1