From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37224) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XNTvK-00079E-JW for qemu-devel@nongnu.org; Fri, 29 Aug 2014 17:41:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XNTvE-00088W-AL for qemu-devel@nongnu.org; Fri, 29 Aug 2014 17:41:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49622) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XNTvE-00087o-2S for qemu-devel@nongnu.org; Fri, 29 Aug 2014 17:41:28 -0400 From: Max Reitz Date: Fri, 29 Aug 2014 23:40:58 +0200 Message-Id: <1409348463-16627-7-git-send-email-mreitz@redhat.com> In-Reply-To: <1409348463-16627-1-git-send-email-mreitz@redhat.com> References: <1409348463-16627-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v5 06/11] qcow2: Fix refcount blocks beyond image end List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi , =?UTF-8?q?Beno=C3=AEt=20Canet?= , Max Reitz 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 Reviewed-by: Eric Blake --- block/qcow2-refcount.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 4 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index babe6cb..394a402 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1505,7 +1505,8 @@ 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++) { uint64_t offset, cluster; @@ -1521,9 +1522,62 @@ 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; + + if (offset + s->cluster_size < offset || + offset + s->cluster_size > INT64_MAX) + { + 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); + + *refcount_table = g_try_realloc(*refcount_table, + *nb_clusters * sizeof(uint16_t)); + if (!*refcount_table) { + res->check_errors++; + return -ENOMEM; + } + + memset(*refcount_table + old_nb_clusters, 0, + (*nb_clusters - old_nb_clusters) * sizeof(uint16_t)); + + if (cluster >= *nb_clusters) { + ret = -EINVAL; + goto resize_fail; + } + + res->corruptions_fixed++; + inc_refcounts(bs, res, *refcount_table, *nb_clusters, + offset, s->cluster_size); + /* 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; } -- 2.1.0