From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50550) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSmc2-00022j-Ty for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:07:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSmbw-0004BH-UH for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:07:18 -0400 From: Stefan Hajnoczi Date: Wed, 26 Mar 2014 13:05:58 +0100 Message-Id: <1395835569-21193-37-git-send-email-stefanha@redhat.com> In-Reply-To: <1395835569-21193-1-git-send-email-stefanha@redhat.com> References: <1395835569-21193-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH for-2.0 36/47] dmg: sanitize chunk length and sectorcount (CVE-2014-0145) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , pmatouse@redhat.com, qemu-stable@nongnu.org, Stefan Hajnoczi Chunk length and sectorcount are used for decompression buffers as well as the bdrv_pread() count argument. Ensure that they have reasonable values so neither memory allocation nor conversion from uint64_t to int will cause problems. Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/dmg.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/block/dmg.c b/block/dmg.c index f98c94d..ad253fe 100644 --- a/block/dmg.c +++ b/block/dmg.c @@ -27,6 +27,14 @@ #include "qemu/module.h" #include +enum { + /* Limit chunk sizes to prevent unreasonable amounts of memory being used + * or truncating when converting to 32-bit types + */ + DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */ + DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512, +}; + typedef struct BDRVDMGState { CoMutex lock; /* each chunk contains a certain number of sectors, @@ -208,6 +216,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags, } offset += 8; + if (s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) { + error_report("sector count %" PRIu64 " for chunk %u is " + "larger than max (%u)", + s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX); + ret = -EINVAL; + goto fail; + } + ret = read_uint64(bs, offset, &s->offsets[i]); if (ret < 0) { goto fail; @@ -221,6 +237,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags, } offset += 8; + if (s->lengths[i] > DMG_LENGTHS_MAX) { + error_report("length %" PRIu64 " for chunk %u is larger " + "than max (%u)", + s->lengths[i], i, DMG_LENGTHS_MAX); + ret = -EINVAL; + goto fail; + } + if (s->lengths[i] > max_compressed_size) { max_compressed_size = s->lengths[i]; } -- 1.8.5.3