Blame SOURCES/kvm-qcow1-Stricter-backing-file-length-check.patch

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From 9e8900ff62bb5c0009ca25a98158650e39f99c47 Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Mon, 2 Jun 2014 13:54:48 +0200
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Subject: [PATCH 27/30] qcow1: Stricter backing file length check
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <1401717288-3918-7-git-send-email-kwolf@redhat.com>
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Patchwork-id: 59100
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O-Subject: [RHEL-7.1/7.0.z qemu-kvm PATCH 6/6] qcow1: Stricter backing file length check
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Bugzilla: 1097236
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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Like qcow2 since commit 6d33e8e7, error out on invalid lengths instead
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of silently truncating them to 1023.
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Also don't rely on bdrv_pread() catching integer overflows that make len
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negative, but use unsigned variables in the first place.
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Benoit Canet <benoit@irqsave.net>
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│(cherry picked from commit d66e5cee002c471b78139228a4e7012736b375f9)
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---
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 block/qcow.c               |  7 +++++--
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 tests/qemu-iotests/092     | 11 +++++++++++
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 tests/qemu-iotests/092.out |  7 +++++++
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 3 files changed, 23 insertions(+), 2 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/qcow.c               |    7 +++++--
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 tests/qemu-iotests/092     |   11 +++++++++++
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 tests/qemu-iotests/092.out |    7 +++++++
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 3 files changed, 23 insertions(+), 2 deletions(-)
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diff --git a/block/qcow.c b/block/qcow.c
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index 4fdc751..ad44f78 100644
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--- a/block/qcow.c
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+++ b/block/qcow.c
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@@ -97,7 +97,8 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
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                      Error **errp)
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 {
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     BDRVQcowState *s = bs->opaque;
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-    int len, i, shift, ret;
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+    unsigned int len, i, shift;
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+    int ret;
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     QCowHeader header;
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     ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
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@@ -200,7 +201,9 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
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     if (header.backing_file_offset != 0) {
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         len = header.backing_file_size;
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         if (len > 1023) {
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-            len = 1023;
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+            error_setg(errp, "Backing file name too long");
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+            ret = -EINVAL;
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+            goto fail;
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         }
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         ret = bdrv_pread(bs->file, header.backing_file_offset,
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                    bs->backing_file, len);
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diff --git a/tests/qemu-iotests/092 b/tests/qemu-iotests/092
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index ae6ca76..a8c0c9c 100755
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--- a/tests/qemu-iotests/092
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+++ b/tests/qemu-iotests/092
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@@ -43,6 +43,8 @@ _supported_fmt qcow
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 _supported_proto generic
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 _supported_os Linux
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+offset_backing_file_offset=8
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+offset_backing_file_size=16
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 offset_size=24
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 offset_cluster_bits=32
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 offset_l2_bits=33
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@@ -81,6 +83,15 @@ poke_file "$TEST_IMG" "$offset_size" "\xee\xee\xee\xee\xee\xee\xee\xee"
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 poke_file "$TEST_IMG" "$offset_size" "\x7f\xff\xff\xff\xff\xff\xff\xff"
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 { $QEMU_IO -c "write 0 64M" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
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+echo
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+echo "== Invalid backing file length =="
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+_make_test_img 64M
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+poke_file "$TEST_IMG" "$offset_backing_file_offset" "\x00\x00\x00\xff"
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+poke_file "$TEST_IMG" "$offset_backing_file_size" "\xff\xff\xff\xff"
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+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
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+poke_file "$TEST_IMG" "$offset_backing_file_size" "\x7f\xff\xff\xff"
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+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
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+
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 # success, all done
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 echo "*** done"
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 rm -f $seq.full
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diff --git a/tests/qemu-iotests/092.out b/tests/qemu-iotests/092.out
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index ac03302..496d8f0 100644
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--- a/tests/qemu-iotests/092.out
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+++ b/tests/qemu-iotests/092.out
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@@ -28,4 +28,11 @@ qemu-io: can't open device TEST_DIR/t.qcow: Image too large
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 no file open, try 'help open'
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 qemu-io: can't open device TEST_DIR/t.qcow: Image too large
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 no file open, try 'help open'
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+
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+== Invalid backing file length ==
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+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 
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+qemu-io: can't open device TEST_DIR/t.qcow: Backing file name too long
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+no file open, try 'help open'
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+qemu-io: can't open device TEST_DIR/t.qcow: Backing file name too long
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+no file open, try 'help open'
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 *** done
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-- 
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1.7.1
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