| Message ID | 20190902152413.14070-1-pl@kamp.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V2] block/vhdx: add check for truncated image files | expand |
Am 02.09.19 um 17:24 schrieb Peter Lieven: > 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 <pl@kamp.de> > --- > V2: - add error reporting [Kevin] > - use bdrv_getlength instead of bdrv_get_allocated_file_size [Kevin] > - factor out BAT entry check and add error reporting for region > overlaps > - already check on vhdx_open > > block/vhdx.c | 85 +++++++++++++++++++++++++++++++++++++++++----------- > 1 file changed, 68 insertions(+), 17 deletions(-) > > diff --git a/block/vhdx.c b/block/vhdx.c > index 6a09d0a55c..6afba5e8c2 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 +881,60 @@ 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; > + int i, ret = 0; > + > + for (i = 0; i < s->bat_entries; i++) { > + if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == > + PAYLOAD_BLOCK_FULLY_PRESENT) { > + /* > + * Check if fully allocated BAT entries do not reside after > + * end of the image file. > + */ > + if ((s->bat[i] & VHDX_BAT_FILE_OFF_MASK) + s->block_size > > + image_file_size) { > + error_report("VHDX BAT entry %d offset points after end of " > + "file. Image has probably been truncated.", i); > + 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, s->bat[i] & VHDX_BAT_FILE_OFF_MASK, > + s->block_size); > + if (ret2 < 0) { > + ret = -EINVAL; > + if (errcnt) { > + break; > + } This should be if (!errcnt) ... I will respin, but wait for feedback regarding the remainder of the patch. Peter
Am 02.09.2019 um 17:24 hat Peter Lieven geschrieben: > 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 <pl@kamp.de> > --- > V2: - add error reporting [Kevin] > - use bdrv_getlength instead of bdrv_get_allocated_file_size [Kevin] > - factor out BAT entry check and add error reporting for region > overlaps > - already check on vhdx_open > > block/vhdx.c | 85 +++++++++++++++++++++++++++++++++++++++++----------- > 1 file changed, 68 insertions(+), 17 deletions(-) > > diff --git a/block/vhdx.c b/block/vhdx.c > index 6a09d0a55c..6afba5e8c2 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 +881,60 @@ 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; > + int i, ret = 0; bdrv_getlength() can fail. It's probably better to error out immediately instead of reporting that every BAT entry is > -1. > + for (i = 0; i < s->bat_entries; i++) { s->bat_entries is uint32_t, so i should probably be the same. > + if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == > + PAYLOAD_BLOCK_FULLY_PRESENT) { > + /* > + * Check if fully allocated BAT entries do not reside after > + * end of the image file. > + */ > + if ((s->bat[i] & VHDX_BAT_FILE_OFF_MASK) + s->block_size > > + image_file_size) { Didn't we want to introduce an overflow check before making this check? Something like if (bat_offset > UINT64_MAX - s->block_size)? > + error_report("VHDX BAT entry %d offset points after end of " > + "file. Image has probably been truncated.", i); > + 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, s->bat[i] & VHDX_BAT_FILE_OFF_MASK, > + s->block_size); > + if (ret2 < 0) { > + ret = -EINVAL; > + if (errcnt) { This one you already noticed yourself. > + break; > + } > + (*errcnt)++; > + } > + } else { > + payblocks = s->chunk_ratio; > + /* > + * Once differencing files are supported, verify sector bitmap > + * blocks here > + */ > + } > + } > + } > + > + return ret; > +} The rest looks good to me. Kevin
Am 03.09.19 um 15:02 schrieb Kevin Wolf: > Am 02.09.2019 um 17:24 hat Peter Lieven geschrieben: >> 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 <pl@kamp.de> >> --- >> V2: - add error reporting [Kevin] >> - use bdrv_getlength instead of bdrv_get_allocated_file_size [Kevin] >> - factor out BAT entry check and add error reporting for region >> overlaps >> - already check on vhdx_open >> >> block/vhdx.c | 85 +++++++++++++++++++++++++++++++++++++++++----------- >> 1 file changed, 68 insertions(+), 17 deletions(-) >> >> diff --git a/block/vhdx.c b/block/vhdx.c >> index 6a09d0a55c..6afba5e8c2 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 +881,60 @@ 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; >> + int i, ret = 0; > bdrv_getlength() can fail. It's probably better to error out immediately > instead of reporting that every BAT entry is > -1. > >> + for (i = 0; i < s->bat_entries; i++) { > s->bat_entries is uint32_t, so i should probably be the same. > >> + if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == >> + PAYLOAD_BLOCK_FULLY_PRESENT) { >> + /* >> + * Check if fully allocated BAT entries do not reside after >> + * end of the image file. >> + */ >> + if ((s->bat[i] & VHDX_BAT_FILE_OFF_MASK) + s->block_size > >> + image_file_size) { > Didn't we want to introduce an overflow check before making this check? > Something like if (bat_offset > UINT64_MAX - s->block_size)? Sorry, i missed that. The bat entries are UINT64_T so this check will always be false for the default block size of 1MB. In fact we should check for bat_offset > INT64_MAX - s->block_size right? Peter
Am 03.09.2019 um 15:10 hat Peter Lieven geschrieben: > Am 03.09.19 um 15:02 schrieb Kevin Wolf: > > Am 02.09.2019 um 17:24 hat Peter Lieven geschrieben: > > > 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 <pl@kamp.de> > > > --- > > > V2: - add error reporting [Kevin] > > > - use bdrv_getlength instead of bdrv_get_allocated_file_size [Kevin] > > > - factor out BAT entry check and add error reporting for region > > > overlaps > > > - already check on vhdx_open > > > > > > block/vhdx.c | 85 +++++++++++++++++++++++++++++++++++++++++----------- > > > 1 file changed, 68 insertions(+), 17 deletions(-) > > > > > > diff --git a/block/vhdx.c b/block/vhdx.c > > > index 6a09d0a55c..6afba5e8c2 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 +881,60 @@ 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; > > > + int i, ret = 0; > > bdrv_getlength() can fail. It's probably better to error out immediately > > instead of reporting that every BAT entry is > -1. > > > > > + for (i = 0; i < s->bat_entries; i++) { > > s->bat_entries is uint32_t, so i should probably be the same. > > > > > + if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == > > > + PAYLOAD_BLOCK_FULLY_PRESENT) { > > > + /* > > > + * Check if fully allocated BAT entries do not reside after > > > + * end of the image file. > > > + */ > > > + if ((s->bat[i] & VHDX_BAT_FILE_OFF_MASK) + s->block_size > > > > + image_file_size) { > > Didn't we want to introduce an overflow check before making this check? > > Something like if (bat_offset > UINT64_MAX - s->block_size)? > > Sorry, i missed that. > > The bat entries are UINT64_T so this check will always be false for the > default block size of 1MB. In fact we should check for > > bat_offset > INT64_MAX - s->block_size > > right? Hm, VHDX_BAT_FILE_OFF_MASK is 0xFFFFFFFFFFF00000ULL, so 2^64 - 1 MB. With a block size of 1 MB, this check would trigger because the offset would be one byte higher than allowed (because offset + block_size would be 0). For larger block sizes, it's more obvious that we can run into this case. As for INT64_MAX, I'm not sure if it's strictly necessary because the code seems to use unsigned variables everywhere. But it feels safer and shouldn't make any difference in practice, so I agree with using it. Kevin
diff --git a/block/vhdx.c b/block/vhdx.c index 6a09d0a55c..6afba5e8c2 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 +881,60 @@ 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; + int i, ret = 0; + + for (i = 0; i < s->bat_entries; i++) { + if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) == + PAYLOAD_BLOCK_FULLY_PRESENT) { + /* + * Check if fully allocated BAT entries do not reside after + * end of the image file. + */ + if ((s->bat[i] & VHDX_BAT_FILE_OFF_MASK) + s->block_size > + image_file_size) { + error_report("VHDX BAT entry %d offset points after end of " + "file. Image has probably been truncated.", i); + 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, s->bat[i] & VHDX_BAT_FILE_OFF_MASK, + 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 +1039,15 @@ 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 +2120,9 @@ 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; }
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 <pl@kamp.de> --- V2: - add error reporting [Kevin] - use bdrv_getlength instead of bdrv_get_allocated_file_size [Kevin] - factor out BAT entry check and add error reporting for region overlaps - already check on vhdx_open block/vhdx.c | 85 +++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 68 insertions(+), 17 deletions(-)