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_LD_DEAD_CODE_DATA_ELIMINATION ]] && \ 275 die "kernel option 'CONFIG_LD_DEAD_CODE_DATA_ELIMINATION' not supported" 276 277 [[ -v CONFIG_AS_IS_LLVM ]] && \ 278 [[ "$CONFIG_AS_VERSION" -lt 200000 ]] && \ 279 die "Clang assembler version < 20 not supported" 280 281 [[ -x "$OBJTOOL" ]] && "$OBJTOOL" klp 2>&1 | command grep -q "not implemented" && \ 282 die "objtool not built with KLP support; install xxhash-devel/libxxhash-dev (version >= 0.8) and recompile" 283 284 return 0 285} 286 287# Only allow alphanumerics and '_' and '-' in the module name. Everything else 288# is replaced with '-'. Also truncate to 55 chars so the full name + NUL 289# terminator fits in the kernel's 56-byte module name array. 290module_name_string() { 291 echo "${1//[^a-zA-Z0-9_-]/-}" | cut -c 1-55 292} 293 294# If the module name wasn't specified on the cmdline with --output, give it a 295# name based on the patch name. 296set_module_name() { 297 [[ -v NAME ]] && return 0 298 299 if [[ "${#PATCHES[@]}" -eq 1 ]]; then 300 NAME="$(basename "${PATCHES[0]}")" 301 NAME="${NAME%.*}" 302 else 303 NAME="patch" 304 fi 305 306 NAME="livepatch-$NAME" 307 NAME="$(module_name_string "$NAME")" 308 309 OUTFILE="$NAME.ko" 310} 311 312# Hardcode the value printed by the localversion script to prevent patch 313# application from appending it with '+' due to a dirty working tree. 314set_kernelversion() { 315 local file="$PWD/scripts/setlocalversion" 316 local kernelrelease 317 318 stash_file "$file" 319 320 if [[ -n "$(make -s listnewconfig 2>/dev/null)" ]]; then 321 die ".config mismatch, check your .config or run 'make olddefconfig'" 322 fi 323 make syncconfig &>/dev/null || die "make syncconfig failed" 324 325 kernelrelease="$(make -s kernelrelease)" 326 [[ -z "$kernelrelease" ]] && die "failed to get kernel version" 327 328 sed -i "2i echo $kernelrelease; exit 0" scripts/setlocalversion 329} 330 331get_patch_input_files() { 332 local patch="$1" 333 334 grep0 -E '^--- ' "$patch" \ 335 | grep0 -v -e '/dev/null' -e '1969-12-31' -e '1970-01-01' \ 336 | gawk '{print $2}' \ 337 | sed 's|^[^/]*/||' \ 338 | sort -u 339} 340 341get_patch_output_files() { 342 local patch="$1" 343 344 grep0 -E '^\+\+\+ ' "$patch" \ 345 | grep0 -v -e '/dev/null' -e '1969-12-31' -e '1970-01-01' \ 346 | gawk '{print $2}' \ 347 | sed 's|^[^/]*/||' \ 348 | sort -u 349} 350 351get_patch_files() { 352 local patch="$1" 353 354 { get_patch_input_files "$patch"; get_patch_output_files "$patch"; } \ 355 | sort -u 356} 357 358check_unsupported_patches() { 359 local patch 360 361 for patch in "${PATCHES[@]}"; do 362 local files=() 363 364 get_patch_files "$patch" | mapfile -t files 365 366 for file in "${files[@]}"; do 367 case "$file" in 368 lib/*|*/vdso/*|*/realmode/rm/*|*.S) 369 die "${patch}: unsupported patch to $file" 370 ;; 371 esac 372 done 373 done 374} 375 376apply_patch() { 377 local patch="$1" 378 shift 379 local extra_args=("$@") 380 local drift_regex="with fuzz|offset [0-9]+ line" 381 local output 382 local status 383 384 [[ ! -f "$patch" ]] && die "$patch doesn't exist" 385 status=0 386 output=$(patch -p1 --dry-run --no-backup-if-mismatch -r /dev/null "${extra_args[@]}" < "$patch" 2>&1) || status=$? 387 if [[ "$status" -ne 0 ]]; then 388 echo "$output" >&2 389 die "$patch did not apply" 390 elif [[ "$output" =~ $drift_regex ]]; then 391 [[ -v VERBOSE ]] && echo "$output" >&2 392 warn "${patch} applied with fuzz" 393 fi 394 395 APPLIED_PATCHES+=("$patch") 396 patch -p1 --no-backup-if-mismatch -r /dev/null "${extra_args[@]}" --silent < "$patch" 397} 398 399revert_patch() { 400 local patch="$1" 401 local tmp=() 402 403 patch -p1 -R --force --no-backup-if-mismatch -r /dev/null &> /dev/null < "$patch" || true 404 405 for p in "${APPLIED_PATCHES[@]}"; do 406 [[ "$p" == "$patch" ]] && continue 407 tmp+=("$p") 408 done 409 410 APPLIED_PATCHES=("${tmp[@]}") 411} 412 413apply_patches() { 414 local extra_args=("$@") 415 local patch 416 417 for patch in "${PATCHES[@]}"; do 418 apply_patch "$patch" "${extra_args[@]}" 419 done 420} 421 422revert_patches() { 423 local patches=("${APPLIED_PATCHES[@]}") 424 425 for (( i=${#patches[@]}-1 ; i>=0 ; i-- )) ; do 426 revert_patch "${patches[$i]}" 427 done 428 429 APPLIED_PATCHES=() 430} 431 432validate_patches() { 433 check_unsupported_patches 434 apply_patches 435 revert_patches 436} 437 438do_init() { 439 # We're not yet smart enough to handle anything other than in-tree 440 # builds in pwd. 441 [[ ! "$PWD" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory" 442 443 if (( SHORT_CIRCUIT >= 2 )); then 444 [[ -f "$ORIG_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $ORIG_DIR" 445 fi 446 if (( SHORT_CIRCUIT >= 3 )); then 447 [[ -f "$PATCHED_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $PATCHED_DIR" 448 fi 449 if (( SHORT_CIRCUIT >= 4 )); then 450 [[ -f "$ORIG_CSUM_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $ORIG_CSUM_DIR" 451 [[ -f "$PATCHED_CSUM_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $PATCHED_CSUM_DIR" 452 fi 453 if (( SHORT_CIRCUIT >= 5 )); then 454 [[ -f "$DIFF_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $DIFF_DIR" 455 fi 456 457 (( SHORT_CIRCUIT <= 1 )) && rm -rf "$TMP_DIR" 458 mkdir -p "$TMP_DIR" 459 460 APPLIED_PATCHES=() 461 462 [[ -x "$FIX_PATCH_LINES" ]] || die "can't find fix-patch-lines" 463 command -v recountdiff &>/dev/null || die "recountdiff not found (install patchutils)" 464 465 validate_config 466 set_module_name 467 set_kernelversion 468} 469 470# Refresh the patch hunk headers, specifically the line numbers and counts. 471refresh_patch() { 472 local patch="$1" 473 local tmpdir="$PATCH_TMP_DIR" 474 local input_files=() 475 local output_files=() 476 477 rm -rf "$tmpdir" 478 mkdir -p "$tmpdir/a" 479 mkdir -p "$tmpdir/b" 480 481 # Get all source files affected by the patch 482 get_patch_input_files "$patch" | mapfile -t input_files 483 get_patch_output_files "$patch" | mapfile -t output_files 484 485 # Copy orig source files to 'a' 486 echo "${input_files[@]}" | xargs cp --parents --target-directory="$tmpdir/a" 487 488 # Copy patched source files to 'b' 489 apply_patch "$patch" "--silent" 490 echo "${output_files[@]}" | xargs cp --parents --target-directory="$tmpdir/b" 491 revert_patch "$patch" 492 493 # Diff 'a' and 'b' to make a clean patch 494 ( cd "$tmpdir" && diff -Nupr a b > "$patch" ) || true 495} 496 497# Copy the patches to a temporary directory, fix their lines so as not to 498# affect the __LINE__ macro for otherwise unchanged functions further down the 499# file, and update $PATCHES to point to the fixed patches. 500fix_patches() { 501 local idx 502 local i 503 504 rm -f "$TMP_DIR"/*.patch 505 506 idx=0001 507 for i in "${!PATCHES[@]}"; do 508 local old_patch="${PATCHES[$i]}" 509 local tmp_patch="$TMP_DIR/tmp.patch" 510 local patch="${PATCHES[$i]}" 511 local new_patch 512 513 new_patch="$TMP_DIR/$idx-fixed-$(basename "$patch")" 514 515 cp -f "$old_patch" "$tmp_patch" 516 refresh_patch "$tmp_patch" 517 "$FIX_PATCH_LINES" "$tmp_patch" | recountdiff > "$new_patch" 518 519 PATCHES[i]="$new_patch" 520 521 rm -f "$tmp_patch" 522 idx=$(printf "%04d" $(( 10#$idx + 1 ))) 523 done 524} 525 526clean_kernel() { 527 local cmd=() 528 529 cmd=("make") 530 cmd+=("--silent") 531 cmd+=("-j$JOBS") 532 cmd+=("clean") 533 534 "${cmd[@]}" 535} 536 537build_kernel() { 538 local build="$1" 539 local log="$TMP_DIR/build.log" 540 local cmd=() 541 542 cmd=("make") 543 544 # When a patch to a kernel module references a newly created unexported 545 # symbol which lives in vmlinux or another kernel module, the patched 546 # kernel build fails with the following error: 547 # 548 # ERROR: modpost: "klp_string" [fs/xfs/xfs.ko] undefined! 549 # 550 # The undefined symbols are working as designed in that case. They get 551 # resolved later when the livepatch module build link pulls all the 552 # disparate objects together into the same kernel module. 553 # 554 # It would be good to have a way to tell modpost to skip checking for 555 # undefined symbols altogether. For now, just convert the error to a 556 # warning with KBUILD_MODPOST_WARN, and grep out the warning to avoid 557 # confusing the user. 558 # 559 cmd+=("KBUILD_MODPOST_WARN=1") 560 561 cmd+=("KLP_SYMIDS=1") 562 563 if [[ -v VERBOSE ]]; then 564 cmd+=("V=1") 565 else 566 cmd+=("-s") 567 fi 568 cmd+=("-j$JOBS") 569 cmd+=("KCFLAGS=-ffunction-sections -fdata-sections") 570 cmd+=("vmlinux") 571 cmd+=("modules") 572 573 "${cmd[@]}" \ 574 1> >(tee -a "$log") \ 575 2> >(tee -a "$log" | grep0 -v "modpost.*undefined!" >&2) \ 576 || die "$build kernel build failed" 577} 578 579find_objects() { 580 local opts=("$@") 581 582 # Find root-level vmlinux.o and non-root-level .ko files, 583 # excluding klp-tmp/ and hidden directories. 584 find "$PWD" -mindepth 1 \ 585 \( -path "$TMP_DIR" -o -name ".*" -o -regex "$PWD/[^/][^/]*\.ko" \) -prune -o \ 586 -type f "${opts[@]}" \ 587 \( -name "*.ko" -o -path "$PWD/vmlinux.o" \) \ 588 -printf '%P\n' 589} 590 591# Copy all .o archives to $ORIG_DIR 592copy_orig_objects() { 593 local files=() 594 595 rm -rf "$ORIG_DIR" 596 mkdir -p "$ORIG_DIR" 597 598 find_objects | mapfile -t files 599 600 xtrace_save "copying original objects" 601 for _file in "${files[@]}"; do 602 local rel_file="${_file/.ko/.o}" 603 local file="$PWD/$rel_file" 604 local orig_file="$ORIG_DIR/$rel_file" 605 local orig_dir="$(dirname "$orig_file")" 606 607 [[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file" 608 609 mkdir -p "$orig_dir" 610 cp -f "$file" "$orig_dir" 611 done 612 xtrace_restore 613 614 mv -f "$TMP_DIR/build.log" "$ORIG_DIR" 615 touch "$TIMESTAMP" 616 touch "$ORIG_DIR/.complete" 617} 618 619# Copy all changed objects to $PATCHED_DIR 620copy_patched_objects() { 621 local files=() 622 local opts=() 623 local found=0 624 625 rm -rf "$PATCHED_DIR" 626 mkdir -p "$PATCHED_DIR" 627 628 # Note this doesn't work with some configs, thus the 'cmp' below. 629 opts=("-newer") 630 opts+=("$TIMESTAMP") 631 632 find_objects "${opts[@]}" | mapfile -t files 633 634 xtrace_save "copying changed objects" 635 for _file in "${files[@]}"; do 636 local rel_file="${_file/.ko/.o}" 637 local file="$PWD/$rel_file" 638 local orig_file="$ORIG_DIR/$rel_file" 639 local patched_file="$PATCHED_DIR/$rel_file" 640 local patched_dir="$(dirname "$patched_file")" 641 642 [[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file" 643 644 cmp -s "$orig_file" "$file" && continue 645 646 mkdir -p "$patched_dir" 647 cp -f "$file" "$patched_dir" 648 found=1 649 done 650 xtrace_restore 651 652 (( found == 0 )) && die "no changes detected" 653 654 mv -f "$TMP_DIR/build.log" "$PATCHED_DIR" 655 touch "$PATCHED_DIR/.complete" 656} 657 658# Copy .o files to a separate directory and run "objtool klp checksum" on each 659# copy. The checksums are written to a .discard.sym_checksum section. 660# 661# If match_dir is given, only process files which also exist there. 662generate_checksums() { 663 local src_dir="$1" 664 local dest_dir="$2" 665 local match_dir="${3:-}" 666 local files=() 667 local file 668 669 rm -rf "$dest_dir" 670 mkdir -p "$dest_dir" 671 672 find "$src_dir" -type f -name "*.o" | mapfile -t files 673 for file in "${files[@]}"; do 674 local rel="${file#"$src_dir"/}" 675 local dest="$dest_dir/$rel" 676 677 [[ -n "$match_dir" && ! -f "$match_dir/$rel" ]] && continue 678 679 mkdir -p "$(dirname "$dest")" 680 cp -f "$file" "$dest" 681 "$OBJTOOL" klp checksum "$dest" 682 done 683 684 touch "$dest_dir/.complete" 685} 686 687# Diff changed objects, writing output object to $DIFF_DIR 688diff_objects() { 689 local log="$KLP_DIFF_LOG" 690 local files=() 691 local opts=() 692 693 rm -rf "$DIFF_DIR" 694 mkdir -p "$DIFF_DIR" 695 696 find "$PATCHED_CSUM_DIR" -type f -name "*.o" | mapfile -t files 697 [[ ${#files[@]} -eq 0 ]] && die "no changes detected" 698 699 [[ -v DEBUG_CLONE ]] && opts=("--debug") 700 701 # Diff all changed objects 702 for file in "${files[@]}"; do 703 local rel_file="${file#"$PATCHED_CSUM_DIR"/}" 704 local orig_file="$rel_file" 705 local patched_file="$PATCHED_CSUM_DIR/$rel_file" 706 local out_file="$DIFF_DIR/$rel_file" 707 local filter=() 708 local cmd=() 709 710 mkdir -p "$(dirname "$out_file")" 711 712 cmd=("$OBJTOOL") 713 cmd+=("klp") 714 cmd+=("diff") 715 (( ${#opts[@]} > 0 )) && cmd+=("${opts[@]}") 716 cmd+=("$orig_file") 717 cmd+=("$patched_file") 718 cmd+=("$out_file") 719 720 if [[ -v DIFF_CHECKSUM ]]; then 721 filter=("grep0") 722 filter+=("-Ev") 723 filter+=("DEBUG: .*checksum: ") 724 else 725 filter=("cat") 726 fi 727 728 ( 729 cd "$ORIG_CSUM_DIR" 730 [[ -v VERBOSE ]] && echo "cd $ORIG_CSUM_DIR && ${cmd[*]}" 731 "${cmd[@]}" \ 732 1> >(tee -a "$log") \ 733 2> >(tee -a "$log" | "${filter[@]}" >&2) || \ 734 die "objtool klp diff failed" 735 ) 736 done 737 738 touch "$DIFF_DIR/.complete" 739} 740 741# For each changed object, run "objtool klp checksum" with --debug-checksum to 742# get the per-instruction checksums, and then diff those to find the first 743# changed instruction for each function. 744diff_checksums() { 745 local orig_log="$ORIG_DIR/checksum.log" 746 local patched_log="$PATCHED_DIR/checksum.log" 747 local -A funcs 748 local cmd=() 749 local line 750 local file 751 local func 752 753 gawk '/\.o: changed function: / { 754 sub(/:$/, "", $1) 755 print $1, $NF 756 }' "$KLP_DIFF_LOG" | mapfile -t lines 757 758 for line in "${lines[@]}"; do 759 read -r file func <<< "$line" 760 if [[ ! -v funcs["$file"] ]]; then 761 funcs["$file"]="$func" 762 else 763 funcs["$file"]+=" $func" 764 fi 765 done 766 767 cmd=("$OBJTOOL") 768 cmd+=("klp" "checksum") 769 cmd+=("--dry-run") 770 771 for file in "${!funcs[@]}"; do 772 local opt="--debug-checksum=${funcs[$file]// /,}" 773 774 ( 775 cd "$ORIG_DIR" 776 "${cmd[@]}" "$opt" "$file" &> "$orig_log" || \ 777 ( cat "$orig_log" >&2; die "objtool klp checksum failed" ) 778 779 cd "$PATCHED_DIR" 780 "${cmd[@]}" "$opt" "$file" &> "$patched_log" || \ 781 ( cat "$patched_log" >&2; die "objtool klp checksum failed" ) 782 ) 783 784 for func in ${funcs[$file]}; do 785 local -a orig patched 786 paste <(grep0 -E "^DEBUG: .*checksum: $func " "$orig_log") \ 787 <(grep0 -E "^DEBUG: .*checksum: $func " "$patched_log") | 788 while IFS= read -r line; do 789 read -ra orig <<< "${line%%$'\t'*}" 790 read -ra patched <<< "${line#*$'\t'}" 791 792 if [[ ${#patched[@]} -eq 0 ]]; then 793 printf "%s: %s: %s (removed)\n" "${orig[1]%:}" "${orig[3]}" "${orig[-2]}" 794 break 795 elif [[ ${#orig[@]} -eq 0 ]]; then 796 printf "%s: %s: %s (added)\n" "${patched[1]%:}" "${patched[3]}" "${patched[-2]}" 797 break 798 fi 799 800 [[ "${orig[-1]}" == "${patched[-1]}" ]] && continue 801 802 printf "%s: %s: %s" "${orig[1]%:}" "${orig[3]}" "${orig[-2]}" 803 [[ "${orig[-2]}" != "${patched[-2]}" ]] && \ 804 printf " (patched: %s)" "${patched[-2]}" 805 printf "\n" 806 break 807 done || true 808 done 809 done 810} 811 812# Build and post-process livepatch module in $KMOD_DIR 813build_patch_module() { 814 local makefile="$KMOD_DIR/Kbuild" 815 local log="$KMOD_DIR/build.log" 816 local kmod_file 817 local cflags=() 818 local files=() 819 local cmd=() 820 821 rm -rf "$KMOD_DIR" 822 mkdir -p "$KMOD_DIR" 823 824 cp -f "$SCRIPT_DIR/init.c" "$KMOD_DIR" 825 826 echo "obj-m := $NAME.o" > "$makefile" 827 echo -n "$NAME-y := init.o" >> "$makefile" 828 829 find "$DIFF_DIR" -type f -name "*.o" | mapfile -t files 830 [[ ${#files[@]} -eq 0 ]] && die "no changes detected" 831 832 for file in "${files[@]}"; do 833 local rel_file="${file#"$DIFF_DIR"/}" 834 local orig_file="$ORIG_DIR/$rel_file" 835 local orig_dir="$(dirname "$orig_file")" 836 local kmod_file="$KMOD_DIR/$rel_file" 837 local kmod_dir="$(dirname "$kmod_file")" 838 local cmd_file="$kmod_dir/.$(basename "$file").cmd" 839 840 mkdir -p "$kmod_dir" 841 cp -f "$file" "$kmod_dir" 842 843 # Tell kbuild this is a prebuilt object 844 cp -f "$file" "${kmod_file}_shipped" 845 846 # Make modpost happy 847 touch "$cmd_file" 848 849 echo -n " $rel_file" >> "$makefile" 850 done 851 852 echo >> "$makefile" 853 854 cflags=("-ffunction-sections") 855 cflags+=("-fdata-sections") 856 [[ $REPLACE -eq 0 ]] && cflags+=("-DKLP_NO_REPLACE") 857 858 cmd=("make") 859 if [[ -v VERBOSE ]]; then 860 cmd+=("V=1") 861 else 862 cmd+=("-s") 863 fi 864 cmd+=("-j$JOBS") 865 cmd+=("--directory=.") 866 cmd+=("M=$KMOD_DIR") 867 cmd+=("KCFLAGS=${cflags[*]}") 868 869 # Build a "normal" kernel module with init.c and the diffed objects 870 "${cmd[@]}" \ 871 1> >(tee -a "$log") \ 872 2> >(tee -a "$log" >&2) 873 874 kmod_file="$KMOD_DIR/$NAME.ko" 875 876 # Save off the intermediate binary for debugging 877 cp -f "$kmod_file" "$kmod_file.orig" 878 879 # Work around issue where slight .config change makes corrupt BTF 880 objcopy --remove-section=.BTF "$kmod_file" 881 882 # Fix (and work around) linker wreckage for klp syms / relocs 883 "$OBJTOOL" klp post-link "$kmod_file" || die "objtool klp post-link failed" 884 885 cp -f "$kmod_file" "$OUTFILE" 886} 887 888 889################################################################################ 890 891process_args "$@" 892do_init 893 894if (( SHORT_CIRCUIT <= 2 )); then 895 status "Validating patch(es)" 896 validate_patches 897fi 898 899if (( SHORT_CIRCUIT <= 1 )); then 900 status "Building original kernel" 901 clean_kernel 902 build_kernel "original" 903 status "Copying original object files" 904 copy_orig_objects 905fi 906 907if (( SHORT_CIRCUIT <= 2 )); then 908 status "Fixing patch(es)" 909 fix_patches 910 apply_patches "--silent" 911 status "Building patched kernel" 912 build_kernel "patched" 913 revert_patches 914 status "Copying patched object files" 915 copy_patched_objects 916fi 917 918if (( SHORT_CIRCUIT <= 3 )); then 919 status "Generating original checksums" 920 generate_checksums "$ORIG_DIR" "$ORIG_CSUM_DIR" "$PATCHED_DIR" 921 status "Generating patched checksums" 922 generate_checksums "$PATCHED_DIR" "$PATCHED_CSUM_DIR" 923fi 924 925if (( SHORT_CIRCUIT <= 4 )); then 926 status "Diffing objects" 927 diff_objects 928 if [[ -v DIFF_CHECKSUM ]]; then 929 status "Finding first changed instructions" 930 diff_checksums 931 fi 932fi 933 934if (( SHORT_CIRCUIT <= 5 )); then 935 status "Building patch module: $OUTFILE" 936 build_patch_module 937fi 938 939status "SUCCESS" 940