diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 61 | ||||
| -rw-r--r-- | block/qcow2.h | 7 |
2 files changed, 58 insertions, 10 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 80d32e4..120cb7f 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -37,6 +37,7 @@ void qcow2_free_snapshots(BlockDriverState *bs) for(i = 0; i < s->nb_snapshots; i++) { g_free(s->snapshots[i].name); g_free(s->snapshots[i].id_str); + g_free(s->snapshots[i].unknown_extra_data); } g_free(s->snapshots); s->snapshots = NULL; @@ -51,7 +52,6 @@ int qcow2_read_snapshots(BlockDriverState *bs, Error **errp) QCowSnapshot *sn; int i, id_str_size, name_size; int64_t offset; - uint32_t extra_data_size; int ret; if (!s->nb_snapshots) { @@ -80,31 +80,53 @@ int qcow2_read_snapshots(BlockDriverState *bs, Error **errp) sn->date_sec = be32_to_cpu(h.date_sec); sn->date_nsec = be32_to_cpu(h.date_nsec); sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec); - extra_data_size = be32_to_cpu(h.extra_data_size); + sn->extra_data_size = be32_to_cpu(h.extra_data_size); id_str_size = be16_to_cpu(h.id_str_size); name_size = be16_to_cpu(h.name_size); - /* Read extra data */ + if (sn->extra_data_size > QCOW_MAX_SNAPSHOT_EXTRA_DATA) { + ret = -EFBIG; + error_setg(errp, "Too much extra metadata in snapshot table " + "entry %i", i); + goto fail; + } + + /* Read known extra data */ ret = bdrv_pread(bs->file, offset, &extra, - MIN(sizeof(extra), extra_data_size)); + MIN(sizeof(extra), sn->extra_data_size)); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to read snapshot table"); goto fail; } - offset += extra_data_size; + offset += MIN(sizeof(extra), sn->extra_data_size); - if (extra_data_size >= endof(QCowSnapshotExtraData, - vm_state_size_large)) { + if (sn->extra_data_size >= endof(QCowSnapshotExtraData, + vm_state_size_large)) { sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large); } - if (extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) { + if (sn->extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) { sn->disk_size = be64_to_cpu(extra.disk_size); } else { sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; } + if (sn->extra_data_size > sizeof(extra)) { + /* Store unknown extra data */ + size_t unknown_extra_data_size = + sn->extra_data_size - sizeof(extra); + + sn->unknown_extra_data = g_malloc(unknown_extra_data_size); + ret = bdrv_pread(bs->file, offset, sn->unknown_extra_data, + unknown_extra_data_size); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to read snapshot table"); + goto fail; + } + offset += unknown_extra_data_size; + } + /* Read snapshot ID */ sn->id_str = g_malloc(id_str_size + 1); ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size); @@ -162,7 +184,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) sn = s->snapshots + i; offset = ROUND_UP(offset, 8); offset += sizeof(h); - offset += sizeof(extra); + offset += MAX(sizeof(extra), sn->extra_data_size); offset += strlen(sn->id_str); offset += strlen(sn->name); @@ -209,7 +231,8 @@ static int qcow2_write_snapshots(BlockDriverState *bs) h.date_sec = cpu_to_be32(sn->date_sec); h.date_nsec = cpu_to_be32(sn->date_nsec); h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); - h.extra_data_size = cpu_to_be32(sizeof(extra)); + h.extra_data_size = cpu_to_be32(MAX(sizeof(extra), + sn->extra_data_size)); memset(&extra, 0, sizeof(extra)); extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size); @@ -234,6 +257,22 @@ static int qcow2_write_snapshots(BlockDriverState *bs) } offset += sizeof(extra); + if (sn->extra_data_size > sizeof(extra)) { + size_t unknown_extra_data_size = + sn->extra_data_size - sizeof(extra); + + /* qcow2_read_snapshots() ensures no unbounded allocation */ + assert(unknown_extra_data_size <= BDRV_REQUEST_MAX_BYTES); + assert(sn->unknown_extra_data); + + ret = bdrv_pwrite(bs->file, offset, sn->unknown_extra_data, + unknown_extra_data_size); + if (ret < 0) { + goto fail; + } + offset += unknown_extra_data_size; + } + ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); if (ret < 0) { goto fail; @@ -376,6 +415,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) sn->date_sec = sn_info->date_sec; sn->date_nsec = sn_info->date_nsec; sn->vm_clock_nsec = sn_info->vm_clock_nsec; + sn->extra_data_size = sizeof(QCowSnapshotExtraData); /* Allocate the L1 table of the snapshot and copy the current one there. */ l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); @@ -647,6 +687,7 @@ int qcow2_snapshot_delete(BlockDriverState *bs, * The snapshot is now unused, clean up. If we fail after this point, we * won't recover but just leak clusters. */ + g_free(sn.unknown_extra_data); g_free(sn.id_str); g_free(sn.name); diff --git a/block/qcow2.h b/block/qcow2.h index cc0d5ea..363681c 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -61,6 +61,9 @@ * space for snapshot names and IDs */ #define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS) +/* Maximum amount of extra data per snapshot table entry to accept */ +#define QCOW_MAX_SNAPSHOT_EXTRA_DATA 1024 + /* Bitmap header extension constraints */ #define QCOW2_MAX_BITMAPS 65535 #define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS) @@ -181,6 +184,10 @@ typedef struct QCowSnapshot { uint32_t date_sec; uint32_t date_nsec; uint64_t vm_clock_nsec; + /* Size of all extra data, including QCowSnapshotExtraData if available */ + uint32_t extra_data_size; + /* Data beyond QCowSnapshotExtraData, if any */ + void *unknown_extra_data; } QCowSnapshot; struct Qcow2Cache; |