diff options
| -rw-r--r-- | block/qcow2-refcount.c | 26 | ||||
| -rw-r--r-- | block/qcow2.h | 6 | ||||
| -rwxr-xr-x | tests/qemu-iotests/060 | 46 | ||||
| -rw-r--r-- | tests/qemu-iotests/060.out | 22 |
4 files changed, 93 insertions, 7 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 60b8eef..3de1ab5 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -3077,16 +3077,40 @@ done: return ret; } +static int64_t get_refblock_offset(BlockDriverState *bs, uint64_t offset) +{ + BDRVQcow2State *s = bs->opaque; + uint32_t index = offset_to_reftable_index(s, offset); + int64_t covering_refblock_offset = 0; + + if (index < s->refcount_table_size) { + covering_refblock_offset = s->refcount_table[index] & REFT_OFFSET_MASK; + } + if (!covering_refblock_offset) { + qcow2_signal_corruption(bs, true, -1, -1, "Refblock at %#" PRIx64 " is " + "not covered by the refcount structures", + offset); + return -EIO; + } + + return covering_refblock_offset; +} + static int qcow2_discard_refcount_block(BlockDriverState *bs, uint64_t discard_block_offs) { BDRVQcow2State *s = bs->opaque; - uint64_t refblock_offs = get_refblock_offset(s, discard_block_offs); + int64_t refblock_offs; uint64_t cluster_index = discard_block_offs >> s->cluster_bits; uint32_t block_index = cluster_index & (s->refcount_block_size - 1); void *refblock; int ret; + refblock_offs = get_refblock_offset(bs, discard_block_offs); + if (refblock_offs < 0) { + return refblock_offs; + } + assert(discard_block_offs != 0); ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offs, diff --git a/block/qcow2.h b/block/qcow2.h index 782a206..6f0ff15 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -527,12 +527,6 @@ uint32_t offset_to_reftable_index(BDRVQcow2State *s, uint64_t offset) return offset >> (s->refcount_block_bits + s->cluster_bits); } -static inline uint64_t get_refblock_offset(BDRVQcow2State *s, uint64_t offset) -{ - uint32_t index = offset_to_reftable_index(s, offset); - return s->refcount_table[index] & REFT_OFFSET_MASK; -} - /* qcow2.c functions */ int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, int64_t sector_num, int nb_sectors); diff --git a/tests/qemu-iotests/060 b/tests/qemu-iotests/060 index 44141f6..c230696 100755 --- a/tests/qemu-iotests/060 +++ b/tests/qemu-iotests/060 @@ -359,6 +359,52 @@ echo '--- Repairing ---' _check_test_img -q -r all _check_test_img -r all +echo +echo "=== Discarding an out-of-bounds refblock ===" +echo + +_make_test_img 64M + +# Pretend there's a refblock really up high +poke_file "$TEST_IMG" "$(($rt_offset+8))" "\x00\xff\xff\xff\x00\x00\x00\x00" +# Let's try to shrink the qcow2 image so that the block driver tries +# to discard that refblock (and see what happens!) +$QEMU_IMG resize --shrink "$TEST_IMG" 32M + +echo '--- Checking and retrying ---' +# Image should not be resized +_img_info | grep 'virtual size' +# But it should pass this check, because the "partial" resize has +# already overwritten refblocks past the end +_check_test_img -r all +# So let's try again +$QEMU_IMG resize --shrink "$TEST_IMG" 32M +_img_info | grep 'virtual size' + +echo +echo "=== Discarding a non-covered in-bounds refblock ===" +echo + +IMGOPTS='refcount_bits=1' _make_test_img 64M + +# Pretend there's a refblock somewhere where there is no refblock to +# cover it (but the covering refblock has a valid index in the +# reftable) +# Every refblock covers 65536 * 8 * 65536 = 32 GB, so we have to point +# to 0x10_0000_0000 (64G) to point to the third refblock +poke_file "$TEST_IMG" "$(($rt_offset+8))" "\x00\x00\x00\x10\x00\x00\x00\x00" +$QEMU_IMG resize --shrink "$TEST_IMG" 32M + +echo '--- Checking and retrying ---' +# Image should not be resized +_img_info | grep 'virtual size' +# But it should pass this check, because the "partial" resize has +# already overwritten refblocks past the end +_check_test_img -r all +# So let's try again +$QEMU_IMG resize --shrink "$TEST_IMG" 32M +_img_info | grep 'virtual size' + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out index 07dfdca..358e54c 100644 --- a/tests/qemu-iotests/060.out +++ b/tests/qemu-iotests/060.out @@ -348,4 +348,26 @@ The following inconsistencies were found and repaired: Double checking the fixed image now... No errors were found on the image. + +=== Discarding an out-of-bounds refblock === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qcow2: Marking image as corrupt: Refblock at 0xffffff00000000 is not covered by the refcount structures; further corruption events will be suppressed +qemu-img: Failed to discard unused refblocks: Input/output error +--- Checking and retrying --- +virtual size: 64M (67108864 bytes) +No errors were found on the image. +Image resized. +virtual size: 32M (33554432 bytes) + +=== Discarding a non-covered in-bounds refblock === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qcow2: Marking image as corrupt: Refblock at 0x1000000000 is not covered by the refcount structures; further corruption events will be suppressed +qemu-img: Failed to discard unused refblocks: Input/output error +--- Checking and retrying --- +virtual size: 64M (67108864 bytes) +No errors were found on the image. +Image resized. +virtual size: 32M (33554432 bytes) *** done |