From 515837c7319a1e225191962c5e521fc4fc2c2508 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 3 Jun 2014 10:01:32 +0200 Subject: [PATCH 13/26] qcow1: Validate L2 table size (CVE-2014-0222) RH-Author: Kevin Wolf Message-id: <1401789694-14289-5-git-send-email-kwolf@redhat.com> Patchwork-id: 59110 O-Subject: [RHEL-6.6/6.5.z qemu-kvm PATCH 4/6] qcow1: Validate L2 table size (CVE-2014-0222) Bugzilla: 1097228 RH-Acked-by: Max Reitz RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Laszlo Ersek Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1097228 Too large L2 table sizes cause unbounded allocations. Images actually created by qemu-img only have 512 byte or 4k L2 tables. To keep things consistent with cluster sizes, allow ranges between 512 bytes and 64k (in fact, down to 1 entry = 8 bytes is technically working, but L2 table sizes smaller than a cluster don't make a lot of sense). This also means that the number of bytes on the virtual disk that are described by the same L2 table is limited to at most 8k * 64k or 2^29, preventively avoiding any integer overflows. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf Reviewed-by: Benoit Canet (cherry picked from commit 42eb58179b3b215bb507da3262b682b8a2ec10b5) Conflicts: tests/qemu-iotests/092 tests/qemu-iotests/092.out Replaced error_setg() by qerror_report() for RHEL 6. Signed-off-by: Kevin Wolf --- block/qcow.c | 9 +++++++++ 1 file changed, 9 insertions(+) Signed-off-by: Miroslav Rezanina --- block/qcow.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/block/qcow.c b/block/qcow.c index 5a2101e..9c372ff 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -136,6 +136,15 @@ static int qcow_open(BlockDriverState *bs, int flags) goto fail; } + /* l2_bits specifies number of entries; storing a uint64_t in each entry, + * so bytes = num_entries << 3. */ + if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { + qerror_report(QERR_GENERIC_ERROR, + "L2 table size must be between 512 and 64k"); + ret = -EINVAL; + goto fail; + } + if (header.crypt_method > QCOW_CRYPT_AES) { ret = -EINVAL; goto fail; -- 1.7.1