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authorStefan Hajnoczi <stefanha@redhat.com>2014-03-26 13:05:26 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2014-04-01 13:59:47 +0200
commit509a41bab5306181044b5fff02eadf96d9c8676a (patch)
treed539979df142d4d46cfc0137032d0098fc973dc8 /tests/qemu-iotests
parentd65f97a82c4ed48374a764c769d4ba1ea9724e97 (diff)
downloadqemu-509a41bab5306181044b5fff02eadf96d9c8676a.zip
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block/cloop: prevent offsets_size integer overflow (CVE-2014-0143)
The following integer overflow in offsets_size can lead to out-of-bounds memory stores when n_blocks has a huge value: uint32_t n_blocks, offsets_size; [...] ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4); [...] s->n_blocks = be32_to_cpu(s->n_blocks); /* read offsets */ offsets_size = s->n_blocks * sizeof(uint64_t); s->offsets = g_malloc(offsets_size); [...] for(i=0;i<s->n_blocks;i++) { s->offsets[i] = be64_to_cpu(s->offsets[i]); offsets_size can be smaller than n_blocks due to integer overflow. Therefore s->offsets[] is too small when the for loop byteswaps offsets. This patch refuses to open files if offsets_size would overflow. Note that changing the type of offsets_size is not a fix since 32-bit hosts still only have 32-bit size_t. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'tests/qemu-iotests')
-rwxr-xr-xtests/qemu-iotests/0757
-rw-r--r--tests/qemu-iotests/075.out4
2 files changed, 11 insertions, 0 deletions
diff --git a/tests/qemu-iotests/075 b/tests/qemu-iotests/075
index 8f54a99..9ce6b1f 100755
--- a/tests/qemu-iotests/075
+++ b/tests/qemu-iotests/075
@@ -43,6 +43,7 @@ _supported_proto generic
_supported_os Linux
block_size_offset=128
+n_blocks_offset=132
echo
echo "== check that the first sector can be read =="
@@ -67,6 +68,12 @@ _use_sample_img simple-pattern.cloop.bz2
poke_file "$TEST_IMG" "$block_size_offset" "\xff\xff\xfe\x00"
$QEMU_IO -c "read 0 512" $TEST_IMG 2>&1 | _filter_qemu_io | _filter_testdir
+echo
+echo "== offsets_size overflow ==="
+_use_sample_img simple-pattern.cloop.bz2
+poke_file "$TEST_IMG" "$n_blocks_offset" "\xff\xff\xff\xff"
+$QEMU_IO -c "read 0 512" $TEST_IMG 2>&1 | _filter_qemu_io | _filter_testdir
+
# success, all done
echo "*** done"
rm -f $seq.full
diff --git a/tests/qemu-iotests/075.out b/tests/qemu-iotests/075.out
index d362c95..a771789 100644
--- a/tests/qemu-iotests/075.out
+++ b/tests/qemu-iotests/075.out
@@ -15,4 +15,8 @@ no file open, try 'help open'
== huge block_size ===
qemu-io: can't open device TEST_DIR/simple-pattern.cloop: block_size 4294966784 must be 64 MB or less
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'
*** done