From f6e6652d7c9251236fc1ecc6cece36104c7af15b Mon Sep 17 00:00:00 2001
From: Peter Wu <peter@lekensteyn.nl>
Date: Tue, 6 Jan 2015 18:48:08 +0100
Subject: [PATCH] block/dmg: validate chunk size to avoid overflow
Previously the chunk size was not checked, allowing for a large memory
allocation. This patch checks whether the chunks size is within the
resource fork length, and whether the resource fork is below the
trailer of the dmg file.
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-6-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/dmg.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/block/dmg.c b/block/dmg.c
index 4f56227fc5..5c2c2c231d 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -317,7 +317,7 @@ static int dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds,
ret = read_uint32(bs, offset, &count);
if (ret < 0) {
goto fail;
- } else if (count == 0) {
+ } else if (count == 0 || count > info_end - offset) {
ret = -EINVAL;
goto fail;
}
@@ -377,6 +377,11 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
if (ret < 0) {
goto fail;
}
+ if (rsrc_fork_offset >= offset ||
+ rsrc_fork_length > offset - rsrc_fork_offset) {
+ ret = -EINVAL;
+ goto fail;
+ }
if (rsrc_fork_length != 0) {
ret = dmg_read_resource_fork(bs, &ds,
rsrc_fork_offset, rsrc_fork_length);
--
2.30.2