From 707d22d6fe9d2f43d0372472b62d40ddb652385d Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Sat, 13 Jun 2015 16:22:20 +0200 Subject: [PATCH 26/42] qcow2: Fix refcount blocks beyond image end Message-id: <1434212556-3927-27-git-send-email-mreitz@redhat.com> Patchwork-id: 66045 O-Subject: [RHEL-7.2 qemu-kvm PATCH 26/42] qcow2: Fix refcount blocks beyond image end Bugzilla: 1129893 RH-Acked-by: Jeffrey Cody RH-Acked-by: Fam Zheng RH-Acked-by: Stefan Hajnoczi BZ: 1129893 If the qcow2 check function detects a refcount block located beyond the image end, grow the image appropriately. This cannot break anything and is the logical fix for such a case. Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf (cherry picked from commit 001c158defb65e88e6c50c85d6f20501f7149ddd) Signed-off-by: Max Reitz Signed-off-by: Miroslav Rezanina --- block/qcow2-refcount.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 63 insertions(+), 4 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 8f1215c..8ce0447 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1545,7 +1545,7 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res, int64_t *nb_clusters) { BDRVQcowState *s = bs->opaque; - int64_t i; + int64_t i, size; int ret; for(i = 0; i < s->refcount_table_size; i++) { @@ -1562,9 +1562,68 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res, } if (cluster >= *nb_clusters) { - fprintf(stderr, "ERROR refcount block %" PRId64 - " is outside image\n", i); - res->corruptions++; + fprintf(stderr, "%s refcount block %" PRId64 " is outside image\n", + fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i); + + if (fix & BDRV_FIX_ERRORS) { + int64_t old_nb_clusters = *nb_clusters; + uint16_t *new_refcount_table; + + if (offset > INT64_MAX - s->cluster_size) { + ret = -EINVAL; + goto resize_fail; + } + + ret = bdrv_truncate(bs->file, offset + s->cluster_size); + if (ret < 0) { + goto resize_fail; + } + size = bdrv_getlength(bs->file); + if (size < 0) { + ret = size; + goto resize_fail; + } + + *nb_clusters = size_to_clusters(s, size); + assert(*nb_clusters >= old_nb_clusters); + + new_refcount_table = g_try_realloc(*refcount_table, + *nb_clusters * + sizeof(**refcount_table)); + if (!new_refcount_table) { + *nb_clusters = old_nb_clusters; + res->check_errors++; + return -ENOMEM; + } + *refcount_table = new_refcount_table; + + memset(*refcount_table + old_nb_clusters, 0, + (*nb_clusters - old_nb_clusters) * + sizeof(**refcount_table)); + + if (cluster >= *nb_clusters) { + ret = -EINVAL; + goto resize_fail; + } + + res->corruptions_fixed++; + ret = inc_refcounts(bs, res, refcount_table, nb_clusters, + offset, s->cluster_size); + if (ret < 0) { + return ret; + } + /* No need to check whether the refcount is now greater than 1: + * This area was just allocated and zeroed, so it can only be + * exactly 1 after inc_refcounts() */ + continue; + +resize_fail: + res->corruptions++; + fprintf(stderr, "ERROR could not resize image: %s\n", + strerror(-ret)); + } else { + res->corruptions++; + } continue; } -- 1.8.3.1