From 9fb7b350ba9816ebca8a7614fec486fd4269ab2d Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Fri, 24 Nov 2023 11:56:54 +0000 Subject: vmdk: Don't corrupt desc file in vmdk_write_cid 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 Message-ID: <20231124115654.3239137-1-fam@euphon.net> Reviewed-by: Kevin Wolf Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- block/vmdk.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) (limited to 'block/vmdk.c') diff --git a/block/vmdk.c b/block/vmdk.c index d87f6d9aaa..d6971c7067 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -351,29 +351,41 @@ vmdk_write_cid(BlockDriverState *bs, uint32_t cid) BDRVVmdkState *s = bs->opaque; int ret = 0; - desc = g_malloc0(DESC_SIZE); - tmp_desc = g_malloc0(DESC_SIZE); - ret = bdrv_co_pread(bs->file, s->desc_offset, DESC_SIZE, desc, 0); + size_t desc_buf_size; + + 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) { goto out; } - desc[DESC_SIZE - 1] = '\0'; + desc[desc_buf_size - 1] = '\0'; tmp_str = strstr(desc, "parentCID"); if (tmp_str == NULL) { ret = -EINVAL; goto out; } - pstrcpy(tmp_desc, DESC_SIZE, tmp_str); + pstrcpy(tmp_desc, desc_buf_size, tmp_str); p_name = strstr(desc, "CID"); if (p_name != NULL) { p_name += sizeof("CID"); - snprintf(p_name, DESC_SIZE - (p_name - desc), "%" PRIx32 "\n", cid); - pstrcat(desc, DESC_SIZE, tmp_desc); + snprintf(p_name, desc_buf_size - (p_name - desc), "%" PRIx32 "\n", cid); + 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: g_free(desc); -- cgit v1.2.3