fetch-pack: fix segfault when fscking without --lock-pack

The fetch-pack internals have multiple options related to creating
".keep" lock-files for the received pack:

  - if args.lock_pack is set, then we tell index-pack to create a .keep
    file. In the fetch-pack plumbing command, this is triggered by
    passing "-k" twice.

  - if the caller passes in a pack_lockfiles string list, then we use it
    to record the path of the keep-file created by index-pack. We get
    that name by reading the stdout of index-pack. In the fetch-pack
    command, this is triggered by passing the (undocumented) --lock-pack
    option; without it, we pass in a NULL string list.

So it's possible to ask index-pack to create the lock-file (using "-k
-k") but not ask to record it (by avoiding "--lock-pack"). This worked
fine until 5476e1efde (fetch-pack: print and use dangling .gitmodules,
2021-02-22), but now it causes a segfault.

Before that commit, if pack_lockfiles was NULL, we wouldn't bother
reading the output from index-pack at all. But since that commit,
index-pack may produce extra output if we asked it to fsck. So even if
nobody cares about the lockfile path, we still need to read it to skip
to the output we do care about.

We correctly check that we didn't get a NULL lockfile path (which can
happen if we did not ask it to create a .keep file at all), but we
missed the case where the lockfile path is not NULL (due to "-k -k") but
the pack_lockfiles string_list is NULL (because nobody passed
"--lock-pack"), and segfault trying to add to the NULL string-list.

We can fix this by skipping the append to the string list when either
the value or the list is NULL. In that case we must also free the
lockfile path to avoid leaking it when it's non-NULL.

Nobody noticed the bug for so long because the transport code used by
"git fetch" always passes in a pack_lockfiles pointer, and remote-curl
(the main user of the fetch-pack plumbing command) always passes
--lock-pack.

Reported-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2 files changed
tree: fa59cbaa00ac0f80456e976229c9a178bd9dcd61
  1. .github/
  2. block-sha1/
  3. builtin/
  4. ci/
  5. compat/
  6. contrib/
  7. Documentation/
  8. ewah/
  9. git-gui/
  10. gitk-git/
  11. gitweb/
  12. mergetools/
  13. negotiator/
  14. oss-fuzz/
  15. perl/
  16. po/
  17. refs/
  18. reftable/
  19. sha1/
  20. sha1dc/
  21. sha256/
  22. t/
  23. templates/
  24. trace2/
  25. xdiff/
  26. .cirrus.yml
  27. .clang-format
  28. .editorconfig
  29. .gitattributes
  30. .gitignore
  31. .gitlab-ci.yml
  32. .gitmodules
  33. .mailmap
  34. .tsan-suppressions
  35. abspath.c
  36. abspath.h
  37. aclocal.m4
  38. add-interactive.c
  39. add-interactive.h
  40. add-patch.c
  41. advice.c
  42. advice.h
  43. alias.c
  44. alias.h
  45. alloc.c
  46. alloc.h
  47. apply.c
  48. apply.h
  49. archive-tar.c
  50. archive-zip.c
  51. archive.c
  52. archive.h
  53. attr.c
  54. attr.h
  55. banned.h
  56. base85.c
  57. base85.h
  58. bisect.c
  59. bisect.h
  60. blame.c
  61. blame.h
  62. blob.c
  63. blob.h
  64. bloom.c
  65. bloom.h
  66. branch.c
  67. branch.h
  68. builtin.h
  69. bulk-checkin.c
  70. bulk-checkin.h
  71. bundle-uri.c
  72. bundle-uri.h
  73. bundle.c
  74. bundle.h
  75. cache-tree.c
  76. cache-tree.h
  77. cbtree.c
  78. cbtree.h
  79. chdir-notify.c
  80. chdir-notify.h
  81. check-builtins.sh
  82. checkout.c
  83. checkout.h
  84. chunk-format.c
  85. chunk-format.h
  86. CODE_OF_CONDUCT.md
  87. color.c
  88. color.h
  89. column.c
  90. column.h
  91. combine-diff.c
  92. command-list.txt
  93. commit-graph.c
  94. commit-graph.h
  95. commit-reach.c
  96. commit-reach.h
  97. commit-slab-decl.h
  98. commit-slab-impl.h
  99. commit-slab.h
  100. commit.c
  101. commit.h
  102. common-main.c
  103. config.c
  104. config.h
  105. config.mak.dev
  106. config.mak.in
  107. config.mak.uname
  108. configure.ac
  109. connect.c
  110. connect.h
  111. connected.c
  112. connected.h
  113. convert.c
  114. convert.h
  115. copy.c
  116. copy.h
  117. COPYING
  118. credential.c
  119. credential.h
  120. csum-file.c
  121. csum-file.h
  122. ctype.c
  123. daemon.c
  124. date.c
  125. date.h
  126. decorate.c
  127. decorate.h
  128. delta-islands.c
  129. delta-islands.h
  130. delta.h
  131. detect-compiler
  132. diagnose.c
  133. diagnose.h
  134. diff-delta.c
  135. diff-lib.c
  136. diff-merges.c
  137. diff-merges.h
  138. diff-no-index.c
  139. diff.c
  140. diff.h
  141. diffcore-break.c
  142. diffcore-delta.c
  143. diffcore-order.c
  144. diffcore-pickaxe.c
  145. diffcore-rename.c
  146. diffcore-rotate.c
  147. diffcore.h
  148. dir-iterator.c
  149. dir-iterator.h
  150. dir.c
  151. dir.h
  152. editor.c
  153. editor.h
  154. entry.c
  155. entry.h
  156. environment.c
  157. environment.h
  158. exec-cmd.c
  159. exec-cmd.h
  160. fetch-negotiator.c
  161. fetch-negotiator.h
  162. fetch-pack.c
  163. fetch-pack.h
  164. fmt-merge-msg.c
  165. fmt-merge-msg.h
  166. fsck.c
  167. fsck.h
  168. fsmonitor--daemon.h
  169. fsmonitor-ipc.c
  170. fsmonitor-ipc.h
  171. fsmonitor-ll.h
  172. fsmonitor-path-utils.h
  173. fsmonitor-settings.c
  174. fsmonitor-settings.h
  175. fsmonitor.c
  176. fsmonitor.h
  177. generate-cmdlist.sh
  178. generate-configlist.sh
  179. generate-hooklist.sh
  180. gettext.c
  181. gettext.h
  182. git-archimport.perl
  183. git-compat-util.h
  184. git-curl-compat.h
  185. git-cvsexportcommit.perl
  186. git-cvsimport.perl
  187. git-cvsserver.perl
  188. git-difftool--helper.sh
  189. git-filter-branch.sh
  190. git-instaweb.sh
  191. git-merge-octopus.sh
  192. git-merge-one-file.sh
  193. git-merge-resolve.sh
  194. git-mergetool--lib.sh
  195. git-mergetool.sh
  196. git-p4.py
  197. git-quiltimport.sh
  198. git-request-pull.sh
  199. git-send-email.perl
  200. git-sh-i18n.sh
  201. git-sh-setup.sh
  202. git-submodule.sh
  203. git-svn.perl
  204. GIT-VERSION-GEN
  205. git-web--browse.sh
  206. git-zlib.c
  207. git-zlib.h
  208. git.c
  209. git.rc
  210. gpg-interface.c
  211. gpg-interface.h
  212. graph.c
  213. graph.h
  214. grep.c
  215. grep.h
  216. hash-ll.h
  217. hash-lookup.c
  218. hash-lookup.h
  219. hash.h
  220. hashmap.c
  221. hashmap.h
  222. help.c
  223. help.h
  224. hex-ll.c
  225. hex-ll.h
  226. hex.c
  227. hex.h
  228. hook.c
  229. hook.h
  230. http-backend.c
  231. http-fetch.c
  232. http-push.c
  233. http-walker.c
  234. http.c
  235. http.h
  236. ident.c
  237. ident.h
  238. imap-send.c
  239. INSTALL
  240. iterator.h
  241. json-writer.c
  242. json-writer.h
  243. khash.h
  244. kwset.c
  245. kwset.h
  246. levenshtein.c
  247. levenshtein.h
  248. LGPL-2.1
  249. line-log.c
  250. line-log.h
  251. line-range.c
  252. line-range.h
  253. linear-assignment.c
  254. linear-assignment.h
  255. list-objects-filter-options.c
  256. list-objects-filter-options.h
  257. list-objects-filter.c
  258. list-objects-filter.h
  259. list-objects.c
  260. list-objects.h
  261. list.h
  262. lockfile.c
  263. lockfile.h
  264. log-tree.c
  265. log-tree.h
  266. ls-refs.c
  267. ls-refs.h
  268. mailinfo.c
  269. mailinfo.h
  270. mailmap.c
  271. mailmap.h
  272. Makefile
  273. match-trees.c
  274. match-trees.h
  275. mem-pool.c
  276. mem-pool.h
  277. merge-blobs.c
  278. merge-blobs.h
  279. merge-ll.c
  280. merge-ll.h
  281. merge-ort-wrappers.c
  282. merge-ort-wrappers.h
  283. merge-ort.c
  284. merge-ort.h
  285. merge-recursive.c
  286. merge-recursive.h
  287. merge.c
  288. merge.h
  289. mergesort.h
  290. midx.c
  291. midx.h
  292. name-hash.c
  293. name-hash.h
  294. neue
  295. notes-cache.c
  296. notes-cache.h
  297. notes-merge.c
  298. notes-merge.h
  299. notes-utils.c
  300. notes-utils.h
  301. notes.c
  302. notes.h
  303. object-file.c
  304. object-file.h
  305. object-name.c
  306. object-name.h
  307. object-store-ll.h
  308. object-store.h
  309. object.c
  310. object.h
  311. oid-array.c
  312. oid-array.h
  313. oidmap.c
  314. oidmap.h
  315. oidset.c
  316. oidset.h
  317. oidtree.c
  318. oidtree.h
  319. pack-bitmap-write.c
  320. pack-bitmap.c
  321. pack-bitmap.h
  322. pack-check.c
  323. pack-mtimes.c
  324. pack-mtimes.h
  325. pack-objects.c
  326. pack-objects.h
  327. pack-revindex.c
  328. pack-revindex.h
  329. pack-write.c
  330. pack.h
  331. packfile.c
  332. packfile.h
  333. pager.c
  334. pager.h
  335. parallel-checkout.c
  336. parallel-checkout.h
  337. parse-options-cb.c
  338. parse-options.c
  339. parse-options.h
  340. parse.c
  341. parse.h
  342. patch-delta.c
  343. patch-ids.c
  344. patch-ids.h
  345. path.c
  346. path.h
  347. pathspec.c
  348. pathspec.h
  349. pkt-line.c
  350. pkt-line.h
  351. preload-index.c
  352. preload-index.h
  353. pretty.c
  354. pretty.h
  355. prio-queue.c
  356. prio-queue.h
  357. progress.c
  358. progress.h
  359. promisor-remote.c
  360. promisor-remote.h
  361. prompt.c
  362. prompt.h
  363. protocol-caps.c
  364. protocol-caps.h
  365. protocol.c
  366. protocol.h
  367. prune-packed.c
  368. prune-packed.h
  369. quote.c
  370. quote.h
  371. range-diff.c
  372. range-diff.h
  373. reachable.c
  374. reachable.h
  375. read-cache-ll.h
  376. read-cache.c
  377. read-cache.h
  378. README.md
  379. rebase-interactive.c
  380. rebase-interactive.h
  381. rebase.c
  382. rebase.h
  383. ref-filter.c
  384. ref-filter.h
  385. reflog-walk.c
  386. reflog-walk.h
  387. reflog.c
  388. reflog.h
  389. refs.c
  390. refs.h
  391. refspec.c
  392. refspec.h
  393. remote-curl.c
  394. remote.c
  395. remote.h
  396. replace-object.c
  397. replace-object.h
  398. repo-settings.c
  399. repository.c
  400. repository.h
  401. rerere.c
  402. rerere.h
  403. reset.c
  404. reset.h
  405. resolve-undo.c
  406. resolve-undo.h
  407. revision.c
  408. revision.h
  409. run-command.c
  410. run-command.h
  411. sane-ctype.h
  412. scalar.c
  413. SECURITY.md
  414. send-pack.c
  415. send-pack.h
  416. sequencer.c
  417. sequencer.h
  418. serve.c
  419. serve.h
  420. server-info.c
  421. server-info.h
  422. setup.c
  423. setup.h
  424. sh-i18n--envsubst.c
  425. sha1dc_git.c
  426. sha1dc_git.h
  427. shallow.c
  428. shallow.h
  429. shared.mak
  430. shell.c
  431. shortlog.h
  432. sideband.c
  433. sideband.h
  434. sigchain.c
  435. sigchain.h
  436. simple-ipc.h
  437. sparse-index.c
  438. sparse-index.h
  439. split-index.c
  440. split-index.h
  441. stable-qsort.c
  442. statinfo.c
  443. statinfo.h
  444. strbuf.c
  445. strbuf.h
  446. streaming.c
  447. streaming.h
  448. string-list.c
  449. string-list.h
  450. strmap.c
  451. strmap.h
  452. strvec.c
  453. strvec.h
  454. sub-process.c
  455. sub-process.h
  456. submodule-config.c
  457. submodule-config.h
  458. submodule.c
  459. submodule.h
  460. symlinks.c
  461. symlinks.h
  462. tag.c
  463. tag.h
  464. tar.h
  465. tempfile.c
  466. tempfile.h
  467. thread-utils.c
  468. thread-utils.h
  469. tmp-objdir.c
  470. tmp-objdir.h
  471. trace.c
  472. trace.h
  473. trace2.c
  474. trace2.h
  475. trailer.c
  476. trailer.h
  477. transport-helper.c
  478. transport-internal.h
  479. transport.c
  480. transport.h
  481. tree-diff.c
  482. tree-walk.c
  483. tree-walk.h
  484. tree.c
  485. tree.h
  486. unicode-width.h
  487. unimplemented.sh
  488. unix-socket.c
  489. unix-socket.h
  490. unix-stream-server.c
  491. unix-stream-server.h
  492. unpack-trees.c
  493. unpack-trees.h
  494. upload-pack.c
  495. upload-pack.h
  496. url.c
  497. url.h
  498. urlmatch.c
  499. urlmatch.h
  500. usage.c
  501. userdiff.c
  502. userdiff.h
  503. utf8.c
  504. utf8.h
  505. varint.c
  506. varint.h
  507. version.c
  508. version.h
  509. versioncmp.c
  510. versioncmp.h
  511. walker.c
  512. walker.h
  513. wildmatch.c
  514. wildmatch.h
  515. worktree.c
  516. worktree.h
  517. wrap-for-bin.sh
  518. wrapper.c
  519. wrapper.h
  520. write-or-die.c
  521. write-or-die.h
  522. ws.c
  523. ws.h
  524. wt-status.c
  525. wt-status.h
  526. xdiff-interface.c
  527. xdiff-interface.h
README.md

Build status

Git - fast, scalable, distributed revision control system

Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.

Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.

Please read the file INSTALL for installation instructions.

Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.

See Documentation/gittutorial.txt to get started, then see Documentation/giteveryday.txt for a useful minimum set of commands, and Documentation/git-<commandname>.txt for documentation of each command. If git has been correctly installed, then the tutorial can also be read with man gittutorial or git help tutorial, and the documentation of each command with man git-<commandname> or git help <commandname>.

CVS users may also want to read Documentation/gitcvs-migration.txt (man gitcvs-migration or git help cvs-migration if git is installed).

The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).

Those wishing to help with error message, usage and informational message string translations (localization l10) should see po/README.md (a po file is a Portable Object file that holds the translations).

To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://marc.info/?l=git and other archival sites.

Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.

The maintainer frequently sends the “What's cooking” reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.

The name “git” was given by Linus Torvalds when he wrote the very first version. He described the tool as “the stupid content tracker” and the name as (depending on your mood):

  • random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of “get” may or may not be relevant.
  • stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
  • “global information tracker”: you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
  • “goddamn idiotic truckload of sh*t”: when it breaks