1#!/usr/bin/env bash 2# 3# Test case for qcow2's handling of extra data in snapshot table entries 4# (and more generally, how certain cases of broken snapshot tables are 5# handled) 6# 7# Copyright (C) 2019 Red Hat, Inc. 8# 9# This program is free software; you can redistribute it and/or modify 10# it under the terms of the GNU General Public License as published by 11# the Free Software Foundation; either version 2 of the License, or 12# (at your option) any later version. 13# 14# This program is distributed in the hope that it will be useful, 15# but WITHOUT ANY WARRANTY; without even the implied warranty of 16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17# GNU General Public License for more details. 18# 19# You should have received a copy of the GNU General Public License 20# along with this program. If not, see <http://www.gnu.org/licenses/>. 21# 22 23# creator 24owner=mreitz@redhat.com 25 26seq=$(basename $0) 27echo "QA output created by $seq" 28 29status=1 # failure is the default! 30 31_cleanup() 32{ 33 _cleanup_test_img 34 rm -f "$TEST_IMG".v{2,3}.orig 35 rm -f "$TEST_DIR"/sn{0,1,2}{,-pre,-extra,-post} 36} 37trap "_cleanup; exit \$status" 0 1 2 3 15 38 39# get standard environment, filters and checks 40. ./common.rc 41. ./common.filter 42 43# This tests qocw2-specific low-level functionality 44_supported_fmt qcow2 45_supported_proto file 46_supported_os Linux 47# (1) We create a v2 image that supports nothing but refcount_bits=16 48# (2) We do some refcount management on our own which expects 49# refcount_bits=16 50_unsupported_imgopts 'refcount_bits=\([^1]\|.\([^6]\|$\)\)' 51 52# Parameters: 53# $1: image filename 54# $2: snapshot table entry offset in the image 55snapshot_table_entry_size() 56{ 57 id_len=$(peek_file_be "$1" $(($2 + 12)) 2) 58 name_len=$(peek_file_be "$1" $(($2 + 14)) 2) 59 extra_len=$(peek_file_be "$1" $(($2 + 36)) 4) 60 61 full_len=$((40 + extra_len + id_len + name_len)) 62 echo $(((full_len + 7) / 8 * 8)) 63} 64 65# Parameter: 66# $1: image filename 67print_snapshot_table() 68{ 69 nb_entries=$(peek_file_be "$1" 60 4) 70 offset=$(peek_file_be "$1" 64 8) 71 72 echo "Snapshots in $1:" | _filter_testdir | _filter_imgfmt 73 74 for ((i = 0; i < nb_entries; i++)); do 75 id_len=$(peek_file_be "$1" $((offset + 12)) 2) 76 name_len=$(peek_file_be "$1" $((offset + 14)) 2) 77 extra_len=$(peek_file_be "$1" $((offset + 36)) 4) 78 79 extra_ofs=$((offset + 40)) 80 id_ofs=$((extra_ofs + extra_len)) 81 name_ofs=$((id_ofs + id_len)) 82 83 echo " [$i]" 84 echo " ID: $(peek_file_raw "$1" $id_ofs $id_len)" 85 echo " Name: $(peek_file_raw "$1" $name_ofs $name_len)" 86 echo " Extra data size: $extra_len" 87 if [ $extra_len -ge 8 ]; then 88 echo " VM state size: $(peek_file_be "$1" $extra_ofs 8)" 89 fi 90 if [ $extra_len -ge 16 ]; then 91 echo " Disk size: $(peek_file_be "$1" $((extra_ofs + 8)) 8)" 92 fi 93 if [ $extra_len -gt 16 ]; then 94 echo ' Unknown extra data:' \ 95 "$(peek_file_raw "$1" $((extra_ofs + 16)) $((extra_len - 16)) \ 96 | tr -d '\0')" 97 fi 98 99 offset=$((offset + $(snapshot_table_entry_size "$1" $offset))) 100 done 101} 102 103# Mark clusters as allocated; works only in refblock 0 (i.e. before 104# cluster #32768). 105# Parameters: 106# $1: Start offset of what to allocate 107# $2: End offset (exclusive) 108refblock0_allocate() 109{ 110 reftable_ofs=$(peek_file_be "$TEST_IMG" 48 8) 111 refblock_ofs=$(peek_file_be "$TEST_IMG" $reftable_ofs 8) 112 113 cluster=$(($1 / 65536)) 114 ecluster=$((($2 + 65535) / 65536)) 115 116 while [ $cluster -lt $ecluster ]; do 117 if [ $cluster -ge 32768 ]; then 118 echo "*** Abort: Cluster $cluster exceeds refblock 0 ***" 119 exit 1 120 fi 121 poke_file "$TEST_IMG" $((refblock_ofs + cluster * 2)) '\x00\x01' 122 cluster=$((cluster + 1)) 123 done 124} 125 126 127echo 128echo '=== Create v2 template ===' 129echo 130 131# Create v2 image with a snapshot table with three entries: 132# [0]: No extra data (valid with v2, not valid with v3) 133# [1]: Has extra data unknown to qemu 134# [2]: Has the 64-bit VM state size, but not the disk size (again, 135# valid with v2, not valid with v3) 136 137TEST_IMG="$TEST_IMG.v2.orig" IMGOPTS='compat=0.10' _make_test_img 64M 138$QEMU_IMG snapshot -c sn0 "$TEST_IMG.v2.orig" 139$QEMU_IMG snapshot -c sn1 "$TEST_IMG.v2.orig" 140$QEMU_IMG snapshot -c sn2 "$TEST_IMG.v2.orig" 141 142# Copy out all existing snapshot table entries 143sn_table_ofs=$(peek_file_be "$TEST_IMG.v2.orig" 64 8) 144 145# ofs: Snapshot table entry offset 146# eds: Extra data size 147# ids: Name + ID size 148# len: Total entry length 149sn0_ofs=$sn_table_ofs 150sn0_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 36)) 4) 151sn0_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 12)) 2) + 152 $(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 14)) 2))) 153sn0_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn0_ofs) 154sn1_ofs=$((sn0_ofs + sn0_len)) 155sn1_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 36)) 4) 156sn1_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 12)) 2) + 157 $(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 14)) 2))) 158sn1_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn1_ofs) 159sn2_ofs=$((sn1_ofs + sn1_len)) 160sn2_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 36)) 4) 161sn2_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 12)) 2) + 162 $(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 14)) 2))) 163sn2_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn2_ofs) 164 165# Data before extra data 166dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-pre" bs=1 skip=$sn0_ofs count=40 \ 167 &> /dev/null 168dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-pre" bs=1 skip=$sn1_ofs count=40 \ 169 &> /dev/null 170dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-pre" bs=1 skip=$sn2_ofs count=40 \ 171 &> /dev/null 172 173# Extra data 174dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-extra" bs=1 \ 175 skip=$((sn0_ofs + 40)) count=$sn0_eds &> /dev/null 176dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-extra" bs=1 \ 177 skip=$((sn1_ofs + 40)) count=$sn1_eds &> /dev/null 178dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-extra" bs=1 \ 179 skip=$((sn2_ofs + 40)) count=$sn2_eds &> /dev/null 180 181# Data after extra data 182dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-post" bs=1 \ 183 skip=$((sn0_ofs + 40 + sn0_eds)) count=$sn0_ids \ 184 &> /dev/null 185dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-post" bs=1 \ 186 skip=$((sn1_ofs + 40 + sn1_eds)) count=$sn1_ids \ 187 &> /dev/null 188dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-post" bs=1 \ 189 skip=$((sn2_ofs + 40 + sn2_eds)) count=$sn2_ids \ 190 &> /dev/null 191 192# Amend them, one by one 193# Set sn0's extra data size to 0 194poke_file "$TEST_DIR/sn0-pre" 36 '\x00\x00\x00\x00' 195truncate -s 0 "$TEST_DIR/sn0-extra" 196# Grow sn0-post to pad 197truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn0-pre") - 40)) \ 198 "$TEST_DIR/sn0-post" 199 200# Set sn1's extra data size to 42 201poke_file "$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x2a' 202truncate -s 42 "$TEST_DIR/sn1-extra" 203poke_file "$TEST_DIR/sn1-extra" 16 'very important data' 204# Grow sn1-post to pad 205truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn1-pre") - 82)) \ 206 "$TEST_DIR/sn1-post" 207 208# Set sn2's extra data size to 8 209poke_file "$TEST_DIR/sn2-pre" 36 '\x00\x00\x00\x08' 210truncate -s 8 "$TEST_DIR/sn2-extra" 211# Grow sn2-post to pad 212truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn2-pre") - 48)) \ 213 "$TEST_DIR/sn2-post" 214 215# Construct snapshot table 216cat "$TEST_DIR"/sn0-{pre,extra,post} \ 217 "$TEST_DIR"/sn1-{pre,extra,post} \ 218 "$TEST_DIR"/sn2-{pre,extra,post} \ 219 | dd of="$TEST_IMG.v2.orig" bs=1 seek=$sn_table_ofs conv=notrunc \ 220 &> /dev/null 221 222# Done! 223TEST_IMG="$TEST_IMG.v2.orig" _check_test_img 224print_snapshot_table "$TEST_IMG.v2.orig" 225 226echo 227echo '=== Upgrade to v3 ===' 228echo 229 230cp "$TEST_IMG.v2.orig" "$TEST_IMG.v3.orig" 231$QEMU_IMG amend -o compat=1.1 "$TEST_IMG.v3.orig" 232TEST_IMG="$TEST_IMG.v3.orig" _check_test_img 233print_snapshot_table "$TEST_IMG.v3.orig" 234 235echo 236echo '=== Repair botched v3 ===' 237echo 238 239# Force the v2 file to be v3. v3 requires each snapshot table entry 240# to have at least 16 bytes of extra data, so it will not comply to 241# the qcow2 v3 specification; but we can fix that. 242cp "$TEST_IMG.v2.orig" "$TEST_IMG" 243 244# Set version 245poke_file "$TEST_IMG" 4 '\x00\x00\x00\x03' 246# Increase header length (necessary for v3) 247poke_file "$TEST_IMG" 100 '\x00\x00\x00\x68' 248# Set refcount order (necessary for v3) 249poke_file "$TEST_IMG" 96 '\x00\x00\x00\x04' 250 251_check_test_img -r all 252print_snapshot_table "$TEST_IMG" 253 254 255# From now on, just test the qcow2 version we are supposed to test. 256# (v3 by default, v2 by choice through $IMGOPTS.) 257# That works because we always write all known extra data when 258# updating the snapshot table, independent of the version. 259 260if echo "$IMGOPTS" | grep -q 'compat=\(0\.10\|v2\)' 2> /dev/null; then 261 subver=v2 262else 263 subver=v3 264fi 265 266echo 267echo '=== Add new snapshot ===' 268echo 269 270cp "$TEST_IMG.$subver.orig" "$TEST_IMG" 271$QEMU_IMG snapshot -c sn3 "$TEST_IMG" 272_check_test_img 273print_snapshot_table "$TEST_IMG" 274 275echo 276echo '=== Remove different snapshots ===' 277 278for sn in sn0 sn1 sn2; do 279 echo 280 echo "--- $sn ---" 281 282 cp "$TEST_IMG.$subver.orig" "$TEST_IMG" 283 $QEMU_IMG snapshot -d $sn "$TEST_IMG" 284 _check_test_img 285 print_snapshot_table "$TEST_IMG" 286done 287 288echo 289echo '=== Reject too much unknown extra data ===' 290echo 291 292cp "$TEST_IMG.$subver.orig" "$TEST_IMG" 293$QEMU_IMG snapshot -c sn3 "$TEST_IMG" 294 295sn_table_ofs=$(peek_file_be "$TEST_IMG" 64 8) 296sn0_ofs=$sn_table_ofs 297sn1_ofs=$((sn0_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn0_ofs))) 298sn2_ofs=$((sn1_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn1_ofs))) 299sn3_ofs=$((sn2_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn2_ofs))) 300 301# 64 kB of extra data should be rejected 302# (Note that this also induces a refcount error, because it spills 303# over to the next cluster. That's a good way to test that we can 304# handle simultaneous snapshot table and refcount errors.) 305poke_file "$TEST_IMG" $((sn3_ofs + 36)) '\x00\x01\x00\x00' 306 307# Print error 308_img_info 309echo 310_check_test_img 311echo 312 313# Should be repairable 314_check_test_img -r all 315 316echo 317echo '=== Snapshot table too big ===' 318echo 319 320sn_table_ofs=$(peek_file_be "$TEST_IMG.v3.orig" 64 8) 321 322# Fill a snapshot with 1 kB of extra data, a 65535-char ID, and a 323# 65535-char name, and repeat it as many times as necessary to fill 324# 64 MB (the maximum supported by qemu) 325 326touch "$TEST_DIR/sn0" 327 328# Full size (fixed + extra + ID + name + padding) 329sn_size=$((40 + 1024 + 65535 + 65535 + 2)) 330 331# We only need the fixed part, though. 332truncate -s 40 "$TEST_DIR/sn0" 333 334# 65535-char ID string 335poke_file "$TEST_DIR/sn0" 12 '\xff\xff' 336# 65535-char name 337poke_file "$TEST_DIR/sn0" 14 '\xff\xff' 338# 1 kB of extra data 339poke_file "$TEST_DIR/sn0" 36 '\x00\x00\x04\x00' 340 341# Create test image 342_make_test_img 64M 343 344# Hook up snapshot table somewhere safe (at 1 MB) 345poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00' 346 347offset=1048576 348size_written=0 349sn_count=0 350while [ $size_written -le $((64 * 1048576)) ]; do 351 dd if="$TEST_DIR/sn0" of="$TEST_IMG" bs=1 seek=$offset conv=notrunc \ 352 &> /dev/null 353 offset=$((offset + sn_size)) 354 size_written=$((size_written + sn_size)) 355 sn_count=$((sn_count + 1)) 356done 357truncate -s "$offset" "$TEST_IMG" 358 359# Give the last snapshot (the one to be removed) an L1 table so we can 360# see how that is handled when repairing the image 361# (Put it two clusters before 1 MB, and one L2 table one cluster 362# before 1 MB) 363poke_file "$TEST_IMG" $((offset - sn_size + 0)) \ 364 '\x00\x00\x00\x00\x00\x0e\x00\x00' 365poke_file "$TEST_IMG" $((offset - sn_size + 8)) \ 366 '\x00\x00\x00\x01' 367 368# Hook up the L2 table 369poke_file "$TEST_IMG" $((1048576 - 2 * 65536)) \ 370 '\x80\x00\x00\x00\x00\x0f\x00\x00' 371 372# Make sure all of the clusters we just hooked up are allocated: 373# - The snapshot table 374# - The last snapshot's L1 and L2 table 375refblock0_allocate $((1048576 - 2 * 65536)) $offset 376 377poke_file "$TEST_IMG" 60 \ 378 "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')" 379 380# Print error 381_img_info 382echo 383_check_test_img 384echo 385 386# Should be repairable 387_check_test_img -r all 388 389echo 390echo "$((sn_count - 1)) snapshots should remain:" 391echo " qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots" 392echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots" 393 394echo 395echo '=== Snapshot table too big with one entry with too much extra data ===' 396echo 397 398# For this test, we reuse the image from the previous case, which has 399# a snapshot table that is right at the limit. 400# Our layout looks like this: 401# - (a number of snapshot table entries) 402# - One snapshot with $extra_data_size extra data 403# - One normal snapshot that breaks the 64 MB boundary 404# - One normal snapshot beyond the 64 MB boundary 405# 406# $extra_data_size is calculated so that simply by virtue of it 407# decreasing to 1 kB, the penultimate snapshot will fit into 64 MB 408# limit again. The final snapshot will always be beyond the limit, so 409# that we can see that the repair algorithm does still determine the 410# limit to be somewhere, even when truncating one snapshot's extra 411# data. 412 413# The last case has removed the last snapshot, so calculate 414# $old_offset to get the current image's real length 415old_offset=$((offset - sn_size)) 416 417# The layout from the previous test had one snapshot beyond the 64 MB 418# limit; we want the same (after the oversized extra data has been 419# truncated to 1 kB), so we drop the last three snapshots and 420# construct them from scratch. 421offset=$((offset - 3 * sn_size)) 422sn_count=$((sn_count - 3)) 423 424# Assuming we had already written one of the three snapshots 425# (necessary so we can calculate $extra_data_size next). 426size_written=$((size_written - 2 * sn_size)) 427 428# Increase the extra data size so we go past the limit 429# (The -1024 comes from the 1 kB of extra data we already have) 430extra_data_size=$((64 * 1048576 + 8 - sn_size - (size_written - 1024))) 431 432poke_file "$TEST_IMG" $((offset + 36)) \ 433 "$(printf '%08x' $extra_data_size | sed -e 's/\(..\)/\\x\1/g')" 434 435offset=$((offset + sn_size - 1024 + extra_data_size)) 436size_written=$((size_written - 1024 + extra_data_size)) 437sn_count=$((sn_count + 1)) 438 439# Write the two normal snapshots 440for ((i = 0; i < 2; i++)); do 441 dd if="$TEST_DIR/sn0" of="$TEST_IMG" bs=1 seek=$offset conv=notrunc \ 442 &> /dev/null 443 offset=$((offset + sn_size)) 444 size_written=$((size_written + sn_size)) 445 sn_count=$((sn_count + 1)) 446 447 if [ $i = 0 ]; then 448 # Check that the penultimate snapshot is beyond the 64 MB limit 449 echo "Snapshot table size should equal $((64 * 1048576 + 8)):" \ 450 $size_written 451 echo 452 fi 453done 454 455truncate -s $offset "$TEST_IMG" 456refblock0_allocate $old_offset $offset 457 458poke_file "$TEST_IMG" 60 \ 459 "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')" 460 461# Print error 462_img_info 463echo 464_check_test_img 465echo 466 467# Just truncating the extra data should be sufficient to shorten the 468# snapshot table so only one snapshot exceeds the extra size 469_check_test_img -r all 470 471echo 472echo '=== Too many snapshots ===' 473echo 474 475# Create a v2 image, for speeds' sake: All-zero snapshot table entries 476# are only valid in v2. 477IMGOPTS='compat=0.10' _make_test_img 64M 478 479# Hook up snapshot table somewhere safe (at 1 MB) 480poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00' 481# "Create" more than 65536 snapshots (twice that many here) 482poke_file "$TEST_IMG" 60 '\x00\x02\x00\x00' 483 484# 40-byte all-zero snapshot table entries are valid snapshots, but 485# only in v2 (v3 needs 16 bytes of extra data, so we would have to 486# write 131072x '\x10'). 487truncate -s $((1048576 + 40 * 131072)) "$TEST_IMG" 488 489# But let us give one of the snapshots to be removed an L1 table so 490# we can see how that is handled when repairing the image. 491# (Put it two clusters before 1 MB, and one L2 table one cluster 492# before 1 MB) 493poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 0)) \ 494 '\x00\x00\x00\x00\x00\x0e\x00\x00' 495poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 8)) \ 496 '\x00\x00\x00\x01' 497 498# Hook up the L2 table 499poke_file "$TEST_IMG" $((1048576 - 2 * 65536)) \ 500 '\x80\x00\x00\x00\x00\x0f\x00\x00' 501 502# Make sure all of the clusters we just hooked up are allocated: 503# - The snapshot table 504# - The last snapshot's L1 and L2 table 505refblock0_allocate $((1048576 - 2 * 65536)) $((1048576 + 40 * 131072)) 506 507# Print error 508_img_info 509echo 510_check_test_img 511echo 512 513# Should be repairable 514_check_test_img -r all 515 516echo 517echo '65536 snapshots should remain:' 518echo " qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots" 519echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots" 520 521# success, all done 522echo "*** done" 523status=0 524