my private gentoo overlay
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From 46485de0cb357b57373e1ca895adedf1f3ed46ec Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Thu, 8 May 2014 13:08:20 +0200
Subject: [PATCH] qcow1: Validate image size (CVE-2014-0223)
A huge image size could cause s->l1_size to overflow. Make sure that
images never require a L1 table larger than what fits in s->l1_size.
This cannot only cause unbounded allocations, but also the allocation of
a too small L1 table, resulting in out-of-bounds array accesses (both
reads and writes).
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/qcow.c | 16 ++++++++++++++--
tests/qemu-iotests/092 | 9 +++++++++
tests/qemu-iotests/092.out | 7 +++++++
3 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/block/qcow.c b/block/qcow.c
index e8038e5..3566c05 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -61,7 +61,7 @@ typedef struct BDRVQcowState {
int cluster_sectors;
int l2_bits;
int l2_size;
- int l1_size;
+ unsigned int l1_size;
uint64_t cluster_offset_mask;
uint64_t l1_table_offset;
uint64_t *l1_table;
@@ -166,7 +166,19 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
/* read the level 1 table */
shift = s->cluster_bits + s->l2_bits;
- s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
+ if (header.size > UINT64_MAX - (1LL << shift)) {
+ error_setg(errp, "Image too large");
+ ret = -EINVAL;
+ goto fail;
+ } else {
+ uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
+ if (l1_size > INT_MAX / sizeof(uint64_t)) {
+ error_setg(errp, "Image too large");
+ ret = -EINVAL;
+ goto fail;
+ }
+ s->l1_size = l1_size;
+ }
s->l1_table_offset = header.l1_table_offset;
s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
--
1.9.3