From fdbe21cc29a983e05b6df725a75b1a1b15d7795e Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 25 Mar 2014 14:23:32 +0100 Subject: [PATCH 25/49] qcow2: Validate active L1 table offset and size (CVE-2014-0144) RH-Author: Kevin Wolf Message-id: <1395753835-7591-26-git-send-email-kwolf@redhat.com> Patchwork-id: n/a O-Subject: [virt-devel] [EMBARGOED RHEL-7.0 qemu-kvm PATCH 25/48] qcow2: Validate active L1 table offset and size (CVE-2014-0144) Bugzilla: 1079455 RH-Acked-by: Jeff Cody RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Paolo Bonzini Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079455 Upstream status: Embargoed This avoids an unbounded allocation. Signed-off-by: Kevin Wolf --- block/qcow2.c | 16 ++++++++++++++++ tests/qemu-iotests/080 | 18 ++++++++++++++++++ tests/qemu-iotests/080.out | 11 +++++++++++ 3 files changed, 45 insertions(+), 0 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 8c74dea..8be82f0 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -641,6 +641,13 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, s->nb_snapshots = header.nb_snapshots; /* read the level 1 table */ + if (header.l1_size > 0x2000000) { + /* 32 MB L1 table is enough for 2 PB images at 64k cluster size + * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */ + error_setg(errp, "Active L1 table too large"); + ret = -EFBIG; + goto fail; + } s->l1_size = header.l1_size; l1_vm_state_index = size_to_l1(s, header.size); @@ -658,7 +665,16 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, ret = -EINVAL; goto fail; } + + ret = validate_table_offset(bs, header.l1_table_offset, + header.l1_size, sizeof(uint64_t)); + if (ret < 0) { + error_setg(errp, "Invalid L1 table offset"); + goto fail; + } s->l1_table_offset = header.l1_table_offset; + + if (s->l1_size > 0) { s->l1_table = g_malloc0( align_offset(s->l1_size * sizeof(uint64_t), 512)); diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080 index 8a8b460..7255b6c 100755 --- a/tests/qemu-iotests/080 +++ b/tests/qemu-iotests/080 @@ -45,6 +45,8 @@ _supported_os Linux header_size=104 offset_backing_file_offset=8 +offset_l1_size=36 +offset_l1_table_offset=40 offset_refcount_table_offset=48 offset_refcount_table_clusters=56 offset_nb_snapshots=60 @@ -117,6 +119,22 @@ poke_file "$TEST_IMG" "$offset_nb_snapshots" "\x00\x01\x00\x00" { $QEMU_IMG snapshot -c test $TEST_IMG; } 2>&1 | _filter_testdir { $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +echo +echo "== Invalid L1 table ==" +_make_test_img 64M +poke_file "$TEST_IMG" "$offset_l1_size" "\xff\xff\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +poke_file "$TEST_IMG" "$offset_l1_size" "\x7f\xff\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + +poke_file "$TEST_IMG" "$offset_l1_table_offset" "\x7f\xff\xff\xff\xff\xff\x00\x00" +poke_file "$TEST_IMG" "$offset_l1_size" "\x00\x00\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + +poke_file "$TEST_IMG" "$offset_l1_table_offset" "\x12\x34\x56\x78\x90\xab\xcd\xef" +poke_file "$TEST_IMG" "$offset_l1_size" "\x00\x00\x00\x01" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out index b06f47f..4ec2545 100644 --- a/tests/qemu-iotests/080.out +++ b/tests/qemu-iotests/080.out @@ -47,4 +47,15 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 qemu-img: Could not create snapshot 'test': -27 (File too large) read 512/512 bytes at offset 0 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +== Invalid L1 table == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-io: can't open device TEST_DIR/t.qcow2: Active L1 table too large +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow2: Active L1 table too large +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset +no file open, try 'help open' *** done -- 1.7.1