From 54c42368f57c02b0970bb32b4542f99b913908ba Mon Sep 17 00:00:00 2001 From: aliguori Date: Tue, 21 Apr 2009 23:12:02 +0000 Subject: [PATCH] qcow2: Add plausibility check for L1/L2 entries (Kevin Wolf) From: Kevin Wolf All L1 and L2 entries must point at the start of a cluster. If there is some offset into the cluster, the entry is corrupted. Signed-off-by: Kevin Wolf Signed-off-by: Anthony Liguori git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7217 c046a42c-6fe2-441c-8c8c-71466251a162 --- block-qcow2.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/block-qcow2.c b/block-qcow2.c index eacac4d35d..7840634b57 100644 --- a/block-qcow2.c +++ b/block-qcow2.c @@ -2666,6 +2666,13 @@ static int check_refcounts_l2(BlockDriverState *bs, errors += inc_refcounts(bs, refcount_table, refcount_table_size, offset, s->cluster_size); + + /* Correct offsets are cluster aligned */ + if (offset & (s->cluster_size - 1)) { + fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " + "properly aligned; L2 entry corrupted.\n", offset); + errors++; + } } } } @@ -2734,6 +2741,13 @@ static int check_refcounts_l1(BlockDriverState *bs, l2_offset, s->cluster_size); + /* L2 tables are cluster aligned */ + if (l2_offset & (s->cluster_size - 1)) { + fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " + "cluster aligned; L1 entry corrupted\n", l2_offset); + errors++; + } + /* Process and check L2 entries */ ret = check_refcounts_l2(bs, refcount_table, refcount_table_size, l2_offset, check_copied);