From 6caaad46de02c02fb1eeaae64fcdc74f9e0a5eb0 Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Tue, 10 Sep 2019 17:26:22 +0200 Subject: [PATCH] block/vhdx: add check for truncated image files qemu is currently not able to detect truncated vhdx image files. Add a basic check if all allocated blocks are reachable at open and report all errors during bdrv_co_check. Signed-off-by: Peter Lieven Signed-off-by: Kevin Wolf --- block/vhdx.c | 120 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 103 insertions(+), 17 deletions(-) diff --git a/block/vhdx.c b/block/vhdx.c index 6a09d0a55c..371f226286 100644 --- a/block/vhdx.c +++ b/block/vhdx.c @@ -24,6 +24,7 @@ #include "qemu/option.h" #include "qemu/crc32c.h" #include "qemu/bswap.h" +#include "qemu/error-report.h" #include "vhdx.h" #include "migration/blocker.h" #include "qemu/uuid.h" @@ -235,6 +236,9 @@ static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length) end = start + length; QLIST_FOREACH(r, &s->regions, entries) { if (!((start >= r->end) || (end <= r->start))) { + error_report("VHDX region %" PRIu64 "-%" PRIu64 " overlaps with " + "region %" PRIu64 "-%." PRIu64, start, end, r->start, + r->end); ret = -EINVAL; goto exit; } @@ -877,6 +881,95 @@ static void vhdx_calc_bat_entries(BDRVVHDXState *s) } +static int vhdx_check_bat_entries(BlockDriverState *bs, int *errcnt) +{ + BDRVVHDXState *s = bs->opaque; + int64_t image_file_size = bdrv_getlength(bs->file->bs); + uint64_t payblocks = s->chunk_ratio; + uint64_t i; + int ret = 0; + + if (image_file_size < 0) { + error_report("Could not determinate VHDX image file size."); + return image_file_size; + } + + for (i = 0; i < s->bat_entries; i++) { + if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == + PAYLOAD_BLOCK_FULLY_PRESENT) { + uint64_t offset = s->bat[i] & VHDX_BAT_FILE_OFF_MASK; + /* + * Allow that the last block exists only partially. The VHDX spec + * states that the image file can only grow in blocksize increments, + * but QEMU created images with partial last blocks in the past. + */ + uint32_t block_length = MIN(s->block_size, + bs->total_sectors * BDRV_SECTOR_SIZE - i * s->block_size); + /* + * Check for BAT entry overflow. + */ + if (offset > INT64_MAX - s->block_size) { + error_report("VHDX BAT entry %" PRIu64 " offset overflow.", i); + ret = -EINVAL; + if (!errcnt) { + break; + } + (*errcnt)++; + } + /* + * Check if fully allocated BAT entries do not reside after + * end of the image file. + */ + if (offset >= image_file_size) { + error_report("VHDX BAT entry %" PRIu64 " start offset %" PRIu64 + " points after end of file (%" PRIi64 "). Image" + " has probably been truncated.", + i, offset, image_file_size); + ret = -EINVAL; + if (!errcnt) { + break; + } + (*errcnt)++; + } else if (offset + block_length > image_file_size) { + error_report("VHDX BAT entry %" PRIu64 " end offset %" PRIu64 + " points after end of file (%" PRIi64 "). Image" + " has probably been truncated.", + i, offset + block_length - 1, image_file_size); + ret = -EINVAL; + if (!errcnt) { + break; + } + (*errcnt)++; + } + + /* + * verify populated BAT field file offsets against + * region table and log entries + */ + if (payblocks--) { + /* payload bat entries */ + int ret2; + ret2 = vhdx_region_check(s, offset, s->block_size); + if (ret2 < 0) { + ret = -EINVAL; + if (!errcnt) { + break; + } + (*errcnt)++; + } + } else { + payblocks = s->chunk_ratio; + /* + * Once differencing files are supported, verify sector bitmap + * blocks here + */ + } + } + } + + return ret; +} + static void vhdx_close(BlockDriverState *bs) { BDRVVHDXState *s = bs->opaque; @@ -981,25 +1074,15 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - uint64_t payblocks = s->chunk_ratio; - /* endian convert, and verify populated BAT field file offsets against - * region table and log entries */ + /* endian convert populated BAT field entires */ for (i = 0; i < s->bat_entries; i++) { s->bat[i] = le64_to_cpu(s->bat[i]); - if (payblocks--) { - /* payload bat entries */ - if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == - PAYLOAD_BLOCK_FULLY_PRESENT) { - ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK, - s->block_size); - if (ret < 0) { - goto fail; - } - } - } else { - payblocks = s->chunk_ratio; - /* Once differencing files are supported, verify sector bitmap - * blocks here */ + } + + if (!(flags & BDRV_O_CHECK)) { + ret = vhdx_check_bat_entries(bs, NULL); + if (ret < 0) { + goto fail; } } @@ -2072,6 +2155,9 @@ static int coroutine_fn vhdx_co_check(BlockDriverState *bs, if (s->log_replayed_on_open) { result->corruptions_fixed++; } + + vhdx_check_bat_entries(bs, &result->corruptions); + return 0; }