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[Qemu-devel] [PATCH for-2.0 05/47] block/cloop: refuse images with huge
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH for-2.0 05/47] block/cloop: refuse images with huge offsets arrays (CVE-2014-0144) |
Date: |
Wed, 26 Mar 2014 13:05:27 +0100 |
Limit offsets_size to 512 MB so that:
1. g_malloc() does not abort due to an unreasonable size argument.
2. offsets_size does not overflow the bdrv_pread() int size argument.
This limit imposes a maximum image size of 16 TB at 256 KB block size.
Signed-off-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block/cloop.c | 9 +++++++++
tests/qemu-iotests/075 | 6 ++++++
tests/qemu-iotests/075.out | 4 ++++
3 files changed, 19 insertions(+)
diff --git a/block/cloop.c b/block/cloop.c
index 563e916..844665e 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -107,6 +107,15 @@ static int cloop_open(BlockDriverState *bs, QDict
*options, int flags,
return -EINVAL;
}
offsets_size = s->n_blocks * sizeof(uint64_t);
+ if (offsets_size > 512 * 1024 * 1024) {
+ /* Prevent ridiculous offsets_size which causes memory allocation to
+ * fail or overflows bdrv_pread() size. In practice the 512 MB
+ * offsets[] limit supports 16 TB images at 256 KB block size.
+ */
+ error_setg(errp, "image requires too many offsets, "
+ "try increasing block size");
+ return -EINVAL;
+ }
s->offsets = g_malloc(offsets_size);
ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size);
diff --git a/tests/qemu-iotests/075 b/tests/qemu-iotests/075
index 9ce6b1f..9c00fa8 100755
--- a/tests/qemu-iotests/075
+++ b/tests/qemu-iotests/075
@@ -74,6 +74,12 @@ _use_sample_img simple-pattern.cloop.bz2
poke_file "$TEST_IMG" "$n_blocks_offset" "\xff\xff\xff\xff"
$QEMU_IO -c "read 0 512" $TEST_IMG 2>&1 | _filter_qemu_io | _filter_testdir
+echo
+echo "== refuse images that require too many offsets ==="
+_use_sample_img simple-pattern.cloop.bz2
+poke_file "$TEST_IMG" "$n_blocks_offset" "\x04\x00\x00\x01"
+$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/075.out b/tests/qemu-iotests/075.out
index a771789..7cdaee1 100644
--- a/tests/qemu-iotests/075.out
+++ b/tests/qemu-iotests/075.out
@@ -19,4 +19,8 @@ no file open, try 'help open'
== offsets_size overflow ===
qemu-io: can't open device TEST_DIR/simple-pattern.cloop: n_blocks 4294967295
must be 536870911 or less
no file open, try 'help open'
+
+== refuse images that require too many offsets ===
+qemu-io: can't open device TEST_DIR/simple-pattern.cloop: image requires too
many offsets, try increasing block size
+no file open, try 'help open'
*** done
--
1.8.5.3
- [Qemu-devel] [PATCH for-2.0 00/47] block: image format input validation fixes, Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 02/47] qemu-iotests: add cloop input validation tests, Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 01/47] qemu-iotests: add ./check -cloop support, Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 03/47] block/cloop: validate block_size header field (CVE-2014-0144), Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 04/47] block/cloop: prevent offsets_size integer overflow (CVE-2014-0143), Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 05/47] block/cloop: refuse images with huge offsets arrays (CVE-2014-0144),
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH for-2.0 06/47] block/cloop: refuse images with bogus offsets (CVE-2014-0144), Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 08/47] qemu-iotests: Support for bochs format, Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 07/47] block/cloop: fix offsets[] size off-by-one, Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 09/47] bochs: Unify header structs and make them QEMU_PACKED, Stefan Hajnoczi, 2014/03/26
- [Qemu-devel] [PATCH for-2.0 10/47] bochs: Use unsigned variables for offsets and sizes (CVE-2014-0147), Stefan Hajnoczi, 2014/03/26