projects/linux·blob v7.2 · refs

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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"