From fca7c0bc430ddd279549cc4a10a529f0b99680fc Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 2 Jun 2014 13:54:47 +0200 Subject: [PATCH 30/31] qcow1: Validate image size (CVE-2014-0223) RH-Author: Kevin Wolf Message-id: <1401717288-3918-6-git-send-email-kwolf@redhat.com> Patchwork-id: 59101 O-Subject: [RHEL-7.1/7.0.z qemu-kvm PATCH 5/6] qcow1: Validate image size (CVE-2014-0223) Bugzilla: 1097236 1097237 RH-Acked-by: Max Reitz RH-Acked-by: Fam Zheng RH-Acked-by: Miroslav Rezanina RH-Acked-by: Stefan Hajnoczi Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1097237 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 (cherry picked from commit 46485de0cb357b57373e1ca895adedf1f3ed46ec) --- block/qcow.c | 16 ++++++++++++++-- tests/qemu-iotests/092 | 9 +++++++++ tests/qemu-iotests/092.out | 7 +++++++ 3 files changed, 30 insertions(+), 2 deletions(-) Signed-off-by: Miroslav Rezanina --- 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 f266701..4fdc751 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; @@ -164,7 +164,19 @@ 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)); diff --git a/tests/qemu-iotests/092 b/tests/qemu-iotests/092 index fb8bacc..ae6ca76 100755 --- a/tests/qemu-iotests/092 +++ b/tests/qemu-iotests/092 @@ -43,6 +43,7 @@ _supported_fmt qcow _supported_proto generic _supported_os Linux +offset_size=24 offset_cluster_bits=32 offset_l2_bits=33 @@ -72,6 +73,14 @@ poke_file "$TEST_IMG" "$offset_l2_bits" "\x0e" poke_file "$TEST_IMG" "$offset_l2_bits" "\x1b" { $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +echo +echo "== Invalid size ==" +_make_test_img 64M +poke_file "$TEST_IMG" "$offset_size" "\xee\xee\xee\xee\xee\xee\xee\xee" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +poke_file "$TEST_IMG" "$offset_size" "\x7f\xff\xff\xff\xff\xff\xff\xff" +{ $QEMU_IO -c "write 0 64M" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/092.out b/tests/qemu-iotests/092.out index 73918b3..ac03302 100644 --- a/tests/qemu-iotests/092.out +++ b/tests/qemu-iotests/092.out @@ -21,4 +21,11 @@ qemu-io: can't open device TEST_DIR/t.qcow: L2 table size must be between 512 an no file open, try 'help open' qemu-io: can't open device TEST_DIR/t.qcow: L2 table size must be between 512 and 64k no file open, try 'help open' + +== Invalid size == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-io: can't open device TEST_DIR/t.qcow: Image too large +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow: Image too large +no file open, try 'help open' *** done -- 1.7.1