1#!/bin/bash 2# SPDX-License-Identifier: GPL-2.0 3# 4# Build a livepatch module 5 6# shellcheck disable=SC1090,SC2155,SC2164 7 8if (( BASH_VERSINFO[0] < 4 || \ 9 (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] < 4) )); then 10 echo "error: this script requires bash 4.4+" >&2 11 exit 1 12fi 13 14set -o errtrace 15set -o pipefail 16set -o nounset 17 18# Allow doing 'cmd | mapfile -t array' instead of 'mapfile -t array < <(cmd)'. 19# This helps keep execution in pipes so pipefail+ERR trap can catch errors. 20shopt -s lastpipe 21 22unset DEBUG_CLONE DIFF_CHECKSUM SKIP_CLEANUP VERBOSE XTRACE 23 24REPLACE=1 25SHORT_CIRCUIT=0 26JOBS="$(getconf _NPROCESSORS_ONLN)" 27shopt -o xtrace | grep -q 'on' && XTRACE=1 28 29# Avoid removing the previous $TMP_DIR until args have been fully processed. 30KEEP_TMP=1 31 32SCRIPT="$(basename "$0")" 33SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)" 34FIX_PATCH_LINES="$SCRIPT_DIR/fix-patch-lines" 35 36OBJTOOL="$PWD/tools/objtool/objtool" 37CONFIG="$PWD/.config" 38TMP_DIR="$PWD/klp-tmp" 39 40ORIG_DIR="$TMP_DIR/1-orig" 41PATCHED_DIR="$TMP_DIR/2-patched" 42ORIG_CSUM_DIR="$TMP_DIR/3-checksum-orig" 43PATCHED_CSUM_DIR="$TMP_DIR/3-checksum-patched" 44DIFF_DIR="$TMP_DIR/4-diff" 45KMOD_DIR="$TMP_DIR/5-kmod" 46 47STASH_DIR="$TMP_DIR/stash" 48TIMESTAMP="$TMP_DIR/timestamp" 49PATCH_TMP_DIR="$TMP_DIR/tmp" 50 51KLP_DIFF_LOG="$DIFF_DIR/diff.log" 52 53# Terminal output colors 54read -r COLOR_RESET COLOR_BOLD COLOR_ERROR COLOR_WARN <<< "" 55if [[ -t 1 && -t 2 ]]; then 56 COLOR_RESET="\033[0m" 57 COLOR_BOLD="\033[1m" 58 COLOR_ERROR="\033[0;31m" 59 COLOR_WARN="\033[0;33m" 60fi 61 62grep0() { 63 # shellcheck disable=SC2317 64 command grep "$@" || true 65} 66 67# Because pipefail is enabled, the grep0 helper should be used instead of 68# grep, otherwise a failed match can propagate to an error. 69grep() { 70 echo "error: $SCRIPT: use grep0 or 'command grep' instead of bare grep" >&2 71 exit 1 72} 73 74status() { 75 echo -e "${COLOR_BOLD}$*${COLOR_RESET}" 76} 77 78warn() { 79 echo -e "${COLOR_WARN}warning${COLOR_RESET}: $SCRIPT: $*" >&2 80} 81 82die() { 83 echo -e "${COLOR_ERROR}error${COLOR_RESET}: $SCRIPT: $*" >&2 84 exit 1 85} 86 87declare -a STASHED_FILES 88 89stash_file() { 90 local file="$1" 91 local rel_file="${file#"$PWD"/}" 92 93 [[ ! -e "$file" ]] && die "no file to stash: $file" 94 95 mkdir -p "$STASH_DIR/$(dirname "$rel_file")" 96 cp -f "$file" "$STASH_DIR/$rel_file" 97 98 STASHED_FILES+=("$rel_file") 99} 100 101restore_files() { 102 local file 103 104 for file in "${STASHED_FILES[@]}"; do 105 mv -f "$STASH_DIR/$file" "$PWD/$file" || warn "can't restore file: $file" 106 done 107 108 STASHED_FILES=() 109} 110 111cleanup() { 112 set +o nounset 113 revert_patches 114 restore_files 115 [[ "$KEEP_TMP" -eq 0 ]] && rm -rf "$TMP_DIR" 116 return 0 117} 118 119trap_err() { 120 die "line ${BASH_LINENO[0]}: '$BASH_COMMAND'" 121} 122 123trap cleanup EXIT INT TERM HUP 124trap trap_err ERR 125 126__usage() { 127 cat <<EOF 128Usage: $SCRIPT [OPTIONS] PATCH_FILE(s) 129Generate a livepatch module. 130 131Options: 132 -f, --show-first-changed Show address of first changed instruction 133 -j, --jobs=<jobs> Build jobs to run simultaneously [default: $JOBS] 134 -o, --output=<file.ko> Output file [default: livepatch-<patch-name>.ko] 135 --no-replace Disable livepatch atomic replace 136 -v, --verbose Pass V=1 to kernel/module builds 137 138Advanced Options: 139 -d, --debug Show symbol/reloc cloning decisions 140 -S, --short-circuit=STEP Start at build step (requires prior --keep-tmp) 141 1|orig Build original kernel (default) 142 2|patched Build patched kernel 143 3|checksum Generate checksums 144 4|diff Diff objects 145 5|kmod Build patch module 146 -T, --keep-tmp Preserve tmp dir on exit 147 148EOF 149} 150 151usage() { 152 __usage >&2 153} 154 155process_args() { 156 local keep_tmp=0 157 local short 158 local long 159 local args 160 local patch 161 162 short="hfj:o:vdS:T" 163 long="help,show-first-changed,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp" 164 165 args=$(getopt --options "$short" --longoptions "$long" -- "$@") || { 166 echo; usage; exit 167 } 168 eval set -- "$args" 169 170 while true; do 171 case "$1" in 172 -h | --help) 173 usage 174 exit 0 175 ;; 176 -f | --show-first-changed) 177 DIFF_CHECKSUM=1 178 shift 179 ;; 180 -j | --jobs) 181 JOBS="$2" 182 shift 2 183 ;; 184 -o | --output) 185 [[ "$2" != *.ko ]] && die "output filename should end with .ko" 186 OUTFILE="$2" 187 NAME="$(basename "$OUTFILE")" 188 NAME="${NAME%.ko}" 189 NAME="$(module_name_string "$NAME")" 190 shift 2 191 ;; 192 --no-replace) 193 REPLACE=0 194 shift 195 ;; 196 -v | --verbose) 197 VERBOSE=1 198 shift 199 ;; 200 -d | --debug) 201 DEBUG_CLONE=1 202 keep_tmp=1 203 shift 204 ;; 205 -S | --short-circuit) 206 [[ ! -d "$TMP_DIR" ]] && die "--short-circuit requires preserved klp-tmp dir" 207 keep_tmp=1 208 case "$2" in 209 1 | orig) SHORT_CIRCUIT=1; ;; 210 2 | patched) SHORT_CIRCUIT=2; ;; 211 3 | checksum) SHORT_CIRCUIT=3; ;; 212 4 | diff) SHORT_CIRCUIT=4; ;; 213 5 | kmod) SHORT_CIRCUIT=5; ;; 214 *) die "invalid short-circuit step '$2'" ;; 215 esac 216 shift 2 217 ;; 218 -T | --keep-tmp) 219 keep_tmp=1 220 shift 221 ;; 222 --) 223 shift 224 break 225 ;; 226 *) 227 usage 228 exit 1 229 ;; 230 esac 231 done 232 233 if [[ $# -eq 0 ]] && (( SHORT_CIRCUIT <= 2 )); then 234 usage 235 exit 1 236 fi 237 238 KEEP_TMP="$keep_tmp" 239 PATCHES=("$@") 240 241 for patch in "${PATCHES[@]}"; do 242 [[ -f "$patch" ]] || die "$patch doesn't exist" 243 done 244} 245 246# temporarily disable xtrace for especially verbose code 247xtrace_save() { 248 [[ -v XTRACE ]] && set +x 249 return 0 250} 251 252xtrace_restore() { 253 [[ -v XTRACE ]] && set -x 254 return 0 255} 256 257validate_config() { 258 xtrace_save "reading .config" 259 source "$CONFIG" || die "no .config file in $(dirname "$CONFIG")" 260 xtrace_restore 261 262 [[ -v CONFIG_LIVEPATCH ]] || \ 263 die "CONFIG_LIVEPATCH not enabled" 264 265 [[ -v CONFIG_KLP_BUILD ]] || \ 266 die "CONFIG_KLP_BUILD not enabled" 267 268 [[ -v CONFIG_GCC_PLUGIN_LATENT_ENTROPY ]] && \ 269 die "kernel option 'CONFIG_GCC_PLUGIN_LATENT_ENTROPY' not supported" 270 271 [[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] && \ 272 die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported" 273 274 [[ -v CONFIG_AS_IS_LLVM ]] && \ 275 [[ "$CONFIG_AS_VERSION" -lt 200000 ]] && \ 276 die "Clang assembler version < 20 not supported" 277 278 [[ -x "$OBJTOOL" ]] && "$OBJTOOL" klp 2>&1 | command grep -q "not implemented" && \ 279 die "objtool not built with KLP support; install xxhash-devel/libxxhash-dev (version >= 0.8) and recompile" 280 281 return 0 282} 283 284# Only allow alphanumerics and '_' and '-' in the module name. Everything else 285# is replaced with '-'. Also truncate to 55 chars so the full name + NUL 286# terminator fits in the kernel's 56-byte module name array. 287module_name_string() { 288 echo "${1//[^a-zA-Z0-9_-]/-}" | cut -c 1-55 289} 290 291# If the module name wasn't specified on the cmdline with --output, give it a 292# name based on the patch name. 293set_module_name() { 294 [[ -v NAME ]] && return 0 295 296 if [[ "${#PATCHES[@]}" -eq 1 ]]; then 297 NAME="$(basename "${PATCHES[0]}")" 298 NAME="${NAME%.*}" 299 else 300 NAME="patch" 301 fi 302 303 NAME="livepatch-$NAME" 304 NAME="$(module_name_string "$NAME")" 305 306 OUTFILE="$NAME.ko" 307} 308 309# Hardcode the value printed by the localversion script to prevent patch 310# application from appending it with '+' due to a dirty working tree. 311set_kernelversion() { 312 local file="$PWD/scripts/setlocalversion" 313 local kernelrelease 314 315 stash_file "$file" 316 317 if [[ -n "$(make -s listnewconfig 2>/dev/null)" ]]; then 318 die ".config mismatch, check your .config or run 'make olddefconfig'" 319 fi 320 make syncconfig &>/dev/null || die "make syncconfig failed" 321 322 kernelrelease="$(make -s kernelrelease)" 323 [[ -z "$kernelrelease" ]] && die "failed to get kernel version" 324 325 sed -i "2i echo $kernelrelease; exit 0" scripts/setlocalversion 326} 327 328get_patch_input_files() { 329 local patch="$1" 330 331 grep0 -E '^--- ' "$patch" \ 332 | grep0 -v -e '/dev/null' -e '1969-12-31' -e '1970-01-01' \ 333 | gawk '{print $2}' \ 334 | sed 's|^[^/]*/||' \ 335 | sort -u 336} 337 338get_patch_output_files() { 339 local patch="$1" 340 341 grep0 -E '^\+\+\+ ' "$patch" \ 342 | grep0 -v -e '/dev/null' -e '1969-12-31' -e '1970-01-01' \ 343 | gawk '{print $2}' \ 344 | sed 's|^[^/]*/||' \ 345 | sort -u 346} 347 348get_patch_files() { 349 local patch="$1" 350 351 { get_patch_input_files "$patch"; get_patch_output_files "$patch"; } \ 352 | sort -u 353} 354 355check_unsupported_patches() { 356 local patch 357 358 for patch in "${PATCHES[@]}"; do 359 local files=() 360 361 get_patch_files "$patch" | mapfile -t files 362 363 for file in "${files[@]}"; do 364 case "$file" in 365 lib/*|*/vdso/*|*/realmode/rm/*|*.S) 366 die "${patch}: unsupported patch to $file" 367 ;; 368 esac 369 done 370 done 371} 372 373apply_patch() { 374 local patch="$1" 375 shift 376 local extra_args=("$@") 377 local drift_regex="with fuzz|offset [0-9]+ line" 378 local output 379 local status 380 381 [[ ! -f "$patch" ]] && die "$patch doesn't exist" 382 status=0 383 output=$(patch -p1 --dry-run --no-backup-if-mismatch -r /dev/null "${extra_args[@]}" < "$patch" 2>&1) || status=$? 384 if [[ "$status" -ne 0 ]]; then 385 echo "$output" >&2 386 die "$patch did not apply" 387 elif [[ "$output" =~ $drift_regex ]]; then 388 [[ -v VERBOSE ]] && echo "$output" >&2 389 warn "${patch} applied with fuzz" 390 fi 391 392 APPLIED_PATCHES+=("$patch") 393 patch -p1 --no-backup-if-mismatch -r /dev/null "${extra_args[@]}" --silent < "$patch" 394} 395 396revert_patch() { 397 local patch="$1" 398 local tmp=() 399 400 patch -p1 -R --force --no-backup-if-mismatch -r /dev/null &> /dev/null < "$patch" || true 401 402 for p in "${APPLIED_PATCHES[@]}"; do 403 [[ "$p" == "$patch" ]] && continue 404 tmp+=("$p") 405 done 406 407 APPLIED_PATCHES=("${tmp[@]}") 408} 409 410apply_patches() { 411 local extra_args=("$@") 412 local patch 413 414 for patch in "${PATCHES[@]}"; do 415 apply_patch "$patch" "${extra_args[@]}" 416 done 417} 418 419revert_patches() { 420 local patches=("${APPLIED_PATCHES[@]}") 421 422 for (( i=${#patches[@]}-1 ; i>=0 ; i-- )) ; do 423 revert_patch "${patches[$i]}" 424 done 425 426 APPLIED_PATCHES=() 427} 428 429validate_patches() { 430 check_unsupported_patches 431 apply_patches 432 revert_patches 433} 434 435do_init() { 436 # We're not yet smart enough to handle anything other than in-tree 437 # builds in pwd. 438 [[ ! "$PWD" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory" 439 440 if (( SHORT_CIRCUIT >= 2 )); then 441 [[ -f "$ORIG_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $ORIG_DIR" 442 fi 443 if (( SHORT_CIRCUIT >= 3 )); then 444 [[ -f "$PATCHED_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $PATCHED_DIR" 445 fi 446 if (( SHORT_CIRCUIT >= 4 )); then 447 [[ -f "$ORIG_CSUM_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $ORIG_CSUM_DIR" 448 [[ -f "$PATCHED_CSUM_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $PATCHED_CSUM_DIR" 449 fi 450 if (( SHORT_CIRCUIT >= 5 )); then 451 [[ -f "$DIFF_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $DIFF_DIR" 452 fi 453 454 (( SHORT_CIRCUIT <= 1 )) && rm -rf "$TMP_DIR" 455 mkdir -p "$TMP_DIR" 456 457 APPLIED_PATCHES=() 458 459 [[ -x "$FIX_PATCH_LINES" ]] || die "can't find fix-patch-lines" 460 command -v recountdiff &>/dev/null || die "recountdiff not found (install patchutils)" 461 462 validate_config 463 set_module_name 464 set_kernelversion 465} 466 467# Refresh the patch hunk headers, specifically the line numbers and counts. 468refresh_patch() { 469 local patch="$1" 470 local tmpdir="$PATCH_TMP_DIR" 471 local input_files=() 472 local output_files=() 473 474 rm -rf "$tmpdir" 475 mkdir -p "$tmpdir/a" 476 mkdir -p "$tmpdir/b" 477 478 # Get all source files affected by the patch 479 get_patch_input_files "$patch" | mapfile -t input_files 480 get_patch_output_files "$patch" | mapfile -t output_files 481 482 # Copy orig source files to 'a' 483 echo "${input_files[@]}" | xargs cp --parents --target-directory="$tmpdir/a" 484 485 # Copy patched source files to 'b' 486 apply_patch "$patch" "--silent" 487 echo "${output_files[@]}" | xargs cp --parents --target-directory="$tmpdir/b" 488 revert_patch "$patch" 489 490 # Diff 'a' and 'b' to make a clean patch 491 ( cd "$tmpdir" && diff -Nupr a b > "$patch" ) || true 492} 493 494# Copy the patches to a temporary directory, fix their lines so as not to 495# affect the __LINE__ macro for otherwise unchanged functions further down the 496# file, and update $PATCHES to point to the fixed patches. 497fix_patches() { 498 local idx 499 local i 500 501 rm -f "$TMP_DIR"/*.patch 502 503 idx=0001 504 for i in "${!PATCHES[@]}"; do 505 local old_patch="${PATCHES[$i]}" 506 local tmp_patch="$TMP_DIR/tmp.patch" 507 local patch="${PATCHES[$i]}" 508 local new_patch 509 510 new_patch="$TMP_DIR/$idx-fixed-$(basename "$patch")" 511 512 cp -f "$old_patch" "$tmp_patch" 513 refresh_patch "$tmp_patch" 514 "$FIX_PATCH_LINES" "$tmp_patch" | recountdiff > "$new_patch" 515 516 PATCHES[i]="$new_patch" 517 518 rm -f "$tmp_patch" 519 idx=$(printf "%04d" $(( 10#$idx + 1 ))) 520 done 521} 522 523clean_kernel() { 524 local cmd=() 525 526 cmd=("make") 527 cmd+=("--silent") 528 cmd+=("-j$JOBS") 529 cmd+=("clean") 530 531 "${cmd[@]}" 532} 533 534build_kernel() { 535 local build="$1" 536 local log="$TMP_DIR/build.log" 537 local cmd=() 538 539 cmd=("make") 540 541 # When a patch to a kernel module references a newly created unexported 542 # symbol which lives in vmlinux or another kernel module, the patched 543 # kernel build fails with the following error: 544 # 545 # ERROR: modpost: "klp_string" [fs/xfs/xfs.ko] undefined! 546 # 547 # The undefined symbols are working as designed in that case. They get 548 # resolved later when the livepatch module build link pulls all the 549 # disparate objects together into the same kernel module. 550 # 551 # It would be good to have a way to tell modpost to skip checking for 552 # undefined symbols altogether. For now, just convert the error to a 553 # warning with KBUILD_MODPOST_WARN, and grep out the warning to avoid 554 # confusing the user. 555 # 556 cmd+=("KBUILD_MODPOST_WARN=1") 557 558 if [[ -v VERBOSE ]]; then 559 cmd+=("V=1") 560 else 561 cmd+=("-s") 562 fi 563 cmd+=("-j$JOBS") 564 cmd+=("KCFLAGS=-ffunction-sections -fdata-sections") 565 cmd+=("vmlinux") 566 cmd+=("modules") 567 568 "${cmd[@]}" \ 569 1> >(tee -a "$log") \ 570 2> >(tee -a "$log" | grep0 -v "modpost.*undefined!" >&2) \ 571 || die "$build kernel build failed" 572} 573 574find_objects() { 575 local opts=("$@") 576 577 # Find root-level vmlinux.o and non-root-level .ko files, 578 # excluding klp-tmp/ and .git/ 579 find "$PWD" \( -path "$TMP_DIR" -o -path "$PWD/.git" -o -regex "$PWD/[^/][^/]*\.ko" \) -prune -o \ 580 -type f "${opts[@]}" \ 581 \( -name "*.ko" -o -path "$PWD/vmlinux.o" \) \ 582 -printf '%P\n' 583} 584 585# Copy all .o archives to $ORIG_DIR 586copy_orig_objects() { 587 local files=() 588 589 rm -rf "$ORIG_DIR" 590 mkdir -p "$ORIG_DIR" 591 592 find_objects | mapfile -t files 593 594 xtrace_save "copying original objects" 595 for _file in "${files[@]}"; do 596 local rel_file="${_file/.ko/.o}" 597 local file="$PWD/$rel_file" 598 local orig_file="$ORIG_DIR/$rel_file" 599 local orig_dir="$(dirname "$orig_file")" 600 601 [[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file" 602 603 mkdir -p "$orig_dir" 604 cp -f "$file" "$orig_dir" 605 done 606 xtrace_restore 607 608 mv -f "$TMP_DIR/build.log" "$ORIG_DIR" 609 touch "$TIMESTAMP" 610 touch "$ORIG_DIR/.complete" 611} 612 613# Copy all changed objects to $PATCHED_DIR 614copy_patched_objects() { 615 local files=() 616 local opts=() 617 local found=0 618 619 rm -rf "$PATCHED_DIR" 620 mkdir -p "$PATCHED_DIR" 621 622 # Note this doesn't work with some configs, thus the 'cmp' below. 623 opts=("-newer") 624 opts+=("$TIMESTAMP") 625 626 find_objects "${opts[@]}" | mapfile -t files 627 628 xtrace_save "copying changed objects" 629 for _file in "${files[@]}"; do 630 local rel_file="${_file/.ko/.o}" 631 local file="$PWD/$rel_file" 632 local orig_file="$ORIG_DIR/$rel_file" 633 local patched_file="$PATCHED_DIR/$rel_file" 634 local patched_dir="$(dirname "$patched_file")" 635 636 [[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file" 637 638 cmp -s "$orig_file" "$file" && continue 639 640 mkdir -p "$patched_dir" 641 cp -f "$file" "$patched_dir" 642 found=1 643 done 644 xtrace_restore 645 646 (( found == 0 )) && die "no changes detected" 647 648 mv -f "$TMP_DIR/build.log" "$PATCHED_DIR" 649 touch "$PATCHED_DIR/.complete" 650} 651 652# Copy .o files to a separate directory and run "objtool klp checksum" on each 653# copy. The checksums are written to a .discard.sym_checksum section. 654# 655# If match_dir is given, only process files which also exist there. 656generate_checksums() { 657 local src_dir="$1" 658 local dest_dir="$2" 659 local match_dir="${3:-}" 660 local files=() 661 local file 662 663 rm -rf "$dest_dir" 664 mkdir -p "$dest_dir" 665 666 find "$src_dir" -type f -name "*.o" | mapfile -t files 667 for file in "${files[@]}"; do 668 local rel="${file#"$src_dir"/}" 669 local dest="$dest_dir/$rel" 670 671 [[ -n "$match_dir" && ! -f "$match_dir/$rel" ]] && continue 672 673 mkdir -p "$(dirname "$dest")" 674 cp -f "$file" "$dest" 675 "$OBJTOOL" klp checksum "$dest" 676 done 677 678 touch "$dest_dir/.complete" 679} 680 681# Diff changed objects, writing output object to $DIFF_DIR 682diff_objects() { 683 local log="$KLP_DIFF_LOG" 684 local files=() 685 local opts=() 686 687 rm -rf "$DIFF_DIR" 688 mkdir -p "$DIFF_DIR" 689 690 find "$PATCHED_CSUM_DIR" -type f -name "*.o" | mapfile -t files 691 [[ ${#files[@]} -eq 0 ]] && die "no changes detected" 692 693 [[ -v DEBUG_CLONE ]] && opts=("--debug") 694 695 # Diff all changed objects 696 for file in "${files[@]}"; do 697 local rel_file="${file#"$PATCHED_CSUM_DIR"/}" 698 local orig_file="$rel_file" 699 local patched_file="$PATCHED_CSUM_DIR/$rel_file" 700 local out_file="$DIFF_DIR/$rel_file" 701 local filter=() 702 local cmd=() 703 704 mkdir -p "$(dirname "$out_file")" 705 706 cmd=("$OBJTOOL") 707 cmd+=("klp") 708 cmd+=("diff") 709 (( ${#opts[@]} > 0 )) && cmd+=("${opts[@]}") 710 cmd+=("$orig_file") 711 cmd+=("$patched_file") 712 cmd+=("$out_file") 713 714 if [[ -v DIFF_CHECKSUM ]]; then 715 filter=("grep0") 716 filter+=("-Ev") 717 filter+=("DEBUG: .*checksum: ") 718 else 719 filter=("cat") 720 fi 721 722 ( 723 cd "$ORIG_CSUM_DIR" 724 [[ -v VERBOSE ]] && echo "cd $ORIG_CSUM_DIR && ${cmd[*]}" 725 "${cmd[@]}" \ 726 1> >(tee -a "$log") \ 727 2> >(tee -a "$log" | "${filter[@]}" >&2) || \ 728 die "objtool klp diff failed" 729 ) 730 done 731 732 touch "$DIFF_DIR/.complete" 733} 734 735# For each changed object, run "objtool klp checksum" with --debug-checksum to 736# get the per-instruction checksums, and then diff those to find the first 737# changed instruction for each function. 738diff_checksums() { 739 local orig_log="$ORIG_DIR/checksum.log" 740 local patched_log="$PATCHED_DIR/checksum.log" 741 local -A funcs 742 local cmd=() 743 local line 744 local file 745 local func 746 747 gawk '/\.o: changed function: / { 748 sub(/:$/, "", $1) 749 print $1, $NF 750 }' "$KLP_DIFF_LOG" | mapfile -t lines 751 752 for line in "${lines[@]}"; do 753 read -r file func <<< "$line" 754 if [[ ! -v funcs["$file"] ]]; then 755 funcs["$file"]="$func" 756 else 757 funcs["$file"]+=" $func" 758 fi 759 done 760 761 cmd=("$OBJTOOL") 762 cmd+=("klp" "checksum") 763 cmd+=("--dry-run") 764 765 for file in "${!funcs[@]}"; do 766 local opt="--debug-checksum=${funcs[$file]// /,}" 767 768 ( 769 cd "$ORIG_DIR" 770 "${cmd[@]}" "$opt" "$file" &> "$orig_log" || \ 771 ( cat "$orig_log" >&2; die "objtool klp checksum failed" ) 772 773 cd "$PATCHED_DIR" 774 "${cmd[@]}" "$opt" "$file" &> "$patched_log" || \ 775 ( cat "$patched_log" >&2; die "objtool klp checksum failed" ) 776 ) 777 778 for func in ${funcs[$file]}; do 779 local -a orig patched 780 paste <(grep0 -E "^DEBUG: .*checksum: $func " "$orig_log") \ 781 <(grep0 -E "^DEBUG: .*checksum: $func " "$patched_log") | 782 while IFS= read -r line; do 783 read -ra orig <<< "${line%%$'\t'*}" 784 read -ra patched <<< "${line#*$'\t'}" 785 786 if [[ ${#patched[@]} -eq 0 ]]; then 787 printf "%s: %s: %s (removed)\n" "${orig[1]%:}" "${orig[3]}" "${orig[-2]}" 788 break 789 elif [[ ${#orig[@]} -eq 0 ]]; then 790 printf "%s: %s: %s (added)\n" "${patched[1]%:}" "${patched[3]}" "${patched[-2]}" 791 break 792 fi 793 794 [[ "${orig[-1]}" == "${patched[-1]}" ]] && continue 795 796 printf "%s: %s: %s" "${orig[1]%:}" "${orig[3]}" "${orig[-2]}" 797 [[ "${orig[-2]}" != "${patched[-2]}" ]] && \ 798 printf " (patched: %s)" "${patched[-2]}" 799 printf "\n" 800 break 801 done || true 802 done 803 done 804} 805 806# Build and post-process livepatch module in $KMOD_DIR 807build_patch_module() { 808 local makefile="$KMOD_DIR/Kbuild" 809 local log="$KMOD_DIR/build.log" 810 local kmod_file 811 local cflags=() 812 local files=() 813 local cmd=() 814 815 rm -rf "$KMOD_DIR" 816 mkdir -p "$KMOD_DIR" 817 818 cp -f "$SCRIPT_DIR/init.c" "$KMOD_DIR" 819 820 echo "obj-m := $NAME.o" > "$makefile" 821 echo -n "$NAME-y := init.o" >> "$makefile" 822 823 find "$DIFF_DIR" -type f -name "*.o" | mapfile -t files 824 [[ ${#files[@]} -eq 0 ]] && die "no changes detected" 825 826 for file in "${files[@]}"; do 827 local rel_file="${file#"$DIFF_DIR"/}" 828 local orig_file="$ORIG_DIR/$rel_file" 829 local orig_dir="$(dirname "$orig_file")" 830 local kmod_file="$KMOD_DIR/$rel_file" 831 local kmod_dir="$(dirname "$kmod_file")" 832 local cmd_file="$kmod_dir/.$(basename "$file").cmd" 833 834 mkdir -p "$kmod_dir" 835 cp -f "$file" "$kmod_dir" 836 837 # Tell kbuild this is a prebuilt object 838 cp -f "$file" "${kmod_file}_shipped" 839 840 # Make modpost happy 841 touch "$cmd_file" 842 843 echo -n " $rel_file" >> "$makefile" 844 done 845 846 echo >> "$makefile" 847 848 cflags=("-ffunction-sections") 849 cflags+=("-fdata-sections") 850 [[ $REPLACE -eq 0 ]] && cflags+=("-DKLP_NO_REPLACE") 851 852 cmd=("make") 853 if [[ -v VERBOSE ]]; then 854 cmd+=("V=1") 855 else 856 cmd+=("-s") 857 fi 858 cmd+=("-j$JOBS") 859 cmd+=("--directory=.") 860 cmd+=("M=$KMOD_DIR") 861 cmd+=("KCFLAGS=${cflags[*]}") 862 863 # Build a "normal" kernel module with init.c and the diffed objects 864 "${cmd[@]}" \ 865 1> >(tee -a "$log") \ 866 2> >(tee -a "$log" >&2) 867 868 kmod_file="$KMOD_DIR/$NAME.ko" 869 870 # Save off the intermediate binary for debugging 871 cp -f "$kmod_file" "$kmod_file.orig" 872 873 # Work around issue where slight .config change makes corrupt BTF 874 objcopy --remove-section=.BTF "$kmod_file" 875 876 # Fix (and work around) linker wreckage for klp syms / relocs 877 "$OBJTOOL" klp post-link "$kmod_file" || die "objtool klp post-link failed" 878 879 cp -f "$kmod_file" "$OUTFILE" 880} 881 882 883################################################################################ 884 885process_args "$@" 886do_init 887 888if (( SHORT_CIRCUIT <= 2 )); then 889 status "Validating patch(es)" 890 validate_patches 891fi 892 893if (( SHORT_CIRCUIT <= 1 )); then 894 status "Building original kernel" 895 clean_kernel 896 build_kernel "original" 897 status "Copying original object files" 898 copy_orig_objects 899fi 900 901if (( SHORT_CIRCUIT <= 2 )); then 902 status "Fixing patch(es)" 903 fix_patches 904 apply_patches "--silent" 905 status "Building patched kernel" 906 build_kernel "patched" 907 revert_patches 908 status "Copying patched object files" 909 copy_patched_objects 910fi 911 912if (( SHORT_CIRCUIT <= 3 )); then 913 status "Generating original checksums" 914 generate_checksums "$ORIG_DIR" "$ORIG_CSUM_DIR" "$PATCHED_DIR" 915 status "Generating patched checksums" 916 generate_checksums "$PATCHED_DIR" "$PATCHED_CSUM_DIR" 917fi 918 919if (( SHORT_CIRCUIT <= 4 )); then 920 status "Diffing objects" 921 diff_objects 922 if [[ -v DIFF_CHECKSUM ]]; then 923 status "Finding first changed instructions" 924 diff_checksums 925 fi 926fi 927 928if (( SHORT_CIRCUIT <= 5 )); then 929 status "Building patch module: $OUTFILE" 930 build_patch_module 931fi 932 933status "SUCCESS" 934