diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2014-03-26 13:05:43 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2014-04-01 14:19:09 +0200 |
| commit | 5dab2faddc8eaa1fb1abdbe2f502001fc13a1b21 (patch) | |
| tree | 675dd5f26040c117c2f2fb040b5ea9dfb623ecf6 /block | |
| parent | a1b3955c9415b1e767c130a2f59fee6aa28e575b (diff) | |
qcow2: Check refcount table size (CVE-2014-0144)
Limit the in-memory reference count table size to 8 MB, it's enough in
practice. This fixes an unbounded allocation as well as a buffer
overflow in qcow2_refcount_init().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2-refcount.c | 4 | ||||
| -rw-r--r-- | block/qcow2.c | 9 |
2 files changed, 12 insertions, 1 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 4a2df5fb99..e3c7ecdcc9 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -40,8 +40,10 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, int qcow2_refcount_init(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; - int ret, refcount_table_size2, i; + unsigned int refcount_table_size2, i; + int ret; + assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t)); refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); s->refcount_table = g_malloc(refcount_table_size2); if (s->refcount_table_size > 0) { diff --git a/block/qcow2.c b/block/qcow2.c index f0411a9217..b9b6e70264 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -577,10 +577,19 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, s->csize_shift = (62 - (s->cluster_bits - 8)); s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; s->cluster_offset_mask = (1LL << s->csize_shift) - 1; + s->refcount_table_offset = header.refcount_table_offset; s->refcount_table_size = header.refcount_table_clusters << (s->cluster_bits - 3); + if (header.refcount_table_clusters > (0x800000 >> s->cluster_bits)) { + /* 8 MB refcount table is enough for 2 PB images at 64k cluster size + * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */ + error_setg(errp, "Reference count table too large"); + ret = -EINVAL; + goto fail; + } + s->snapshots_offset = header.snapshots_offset; s->nb_snapshots = header.nb_snapshots; |