submodule: reject submodule.update = !command in .gitmodules

commit e904deb89d9a9669a76a426182506a084d3f6308 upstream.

Since ac1fbbda2013 (submodule: do not copy unknown update mode from
.gitmodules, 2013-12-02), Git has been careful to avoid copying

	[submodule "foo"]
		update = !run an arbitrary scary command

from .gitmodules to a repository's local config, copying in the
setting 'update = none' instead.  The gitmodules(5) manpage documents
the intention:

	The !command form is intentionally ignored here for security
	reasons

Unfortunately, starting with v2.20.0-rc0 (which integrated ee69b2a9
(submodule--helper: introduce new update-module-mode helper,
2018-08-13, first released in v2.20.0-rc0)), there are scenarios where
we *don't* ignore it: if the config store contains no
submodule.foo.update setting, the submodule-config API falls back to
reading .gitmodules and the repository-supplied !command gets run
after all.

This was part of a general change over time in submodule support to
read more directly from .gitmodules, since unlike .git/config it
allows a project to change values between branches and over time
(while still allowing .git/config to override things).  But it was
never intended to apply to this kind of dangerous configuration.

The behavior change was not advertised in ee69b2a9's commit message
and was missed in review.

Let's take the opportunity to make the protection more robust, even in
Git versions that are technically not affected: instead of quietly
converting 'update = !command' to 'update = none', noisily treat it as
an error.  Allowing the setting but treating it as meaning something
else was just confusing; users are better served by seeing the error
sooner.  Forbidding the construct makes the semantics simpler and
means we can check for it in fsck (in a separate patch).

As a result, the submodule-config API cannot read this value from
.gitmodules under any circumstance, and we can declare with confidence

	For security reasons, the '!command' form is not accepted
	here.

[jn: backported to 2.11.y:
 - allow submodule-config to read !command after all, since
   v2.15.0-rc0~120^2~10 (submodule--helper: don't overlay config in
   update-clone, 2017-08-03) hasn't happened yet
 - move the code to error out when "git submodule init" encounters
   !command in .gitmodules to module_init()
 - cmd_update in git-submodule.sh is responsible for reading the
   update strategy since v2.20.0-rc0~247^2 (submodule--helper:
   introduce update-module-mode, 2018-08-13) hasn't happened yet.
   cmd_update checks config directly and does not read .gitmodules,
   so we don't have to change it.  Accordingly, t7406 also does
   not need to change its expectation from ignoring to rejecting
   commands from .gitmodules.]

Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
3 files changed
tree: 7f74de00d1a43ca435b6af0b60ac0985cb8d82d8
  1. block-sha1/
  2. builtin/
  3. ci/
  4. compat/
  5. contrib/
  6. Documentation/
  7. ewah/
  8. git-gui/
  9. gitk-git/
  10. gitweb/
  11. mergetools/
  12. perl/
  13. po/
  14. ppc/
  15. refs/
  16. t/
  17. templates/
  18. vcs-svn/
  19. xdiff/
  20. .gitattributes
  21. .gitignore
  22. .mailmap
  23. .travis.yml
  24. abspath.c
  25. aclocal.m4
  26. advice.c
  27. advice.h
  28. alias.c
  29. alloc.c
  30. apply.c
  31. apply.h
  32. archive-tar.c
  33. archive-zip.c
  34. archive.c
  35. archive.h
  36. argv-array.c
  37. argv-array.h
  38. attr.c
  39. attr.h
  40. base85.c
  41. bisect.c
  42. bisect.h
  43. blob.c
  44. blob.h
  45. branch.c
  46. branch.h
  47. builtin.h
  48. bulk-checkin.c
  49. bulk-checkin.h
  50. bundle.c
  51. bundle.h
  52. cache-tree.c
  53. cache-tree.h
  54. cache.h
  55. check-builtins.sh
  56. check-racy.c
  57. check_bindir
  58. color.c
  59. color.h
  60. column.c
  61. column.h
  62. combine-diff.c
  63. command-list.txt
  64. commit-slab.h
  65. commit.c
  66. commit.h
  67. common-main.c
  68. config.c
  69. config.mak.in
  70. config.mak.uname
  71. configure.ac
  72. connect.c
  73. connect.h
  74. connected.c
  75. connected.h
  76. convert.c
  77. convert.h
  78. copy.c
  79. COPYING
  80. credential-cache--daemon.c
  81. credential-cache.c
  82. credential-store.c
  83. credential.c
  84. credential.h
  85. csum-file.c
  86. csum-file.h
  87. ctype.c
  88. daemon.c
  89. date.c
  90. decorate.c
  91. decorate.h
  92. delta.h
  93. diff-delta.c
  94. diff-lib.c
  95. diff-no-index.c
  96. diff.c
  97. diff.h
  98. diffcore-break.c
  99. diffcore-delta.c
  100. diffcore-order.c
  101. diffcore-pickaxe.c
  102. diffcore-rename.c
  103. diffcore.h
  104. dir-iterator.c
  105. dir-iterator.h
  106. dir.c
  107. dir.h
  108. editor.c
  109. entry.c
  110. environment.c
  111. exec_cmd.c
  112. exec_cmd.h
  113. fast-import.c
  114. fetch-pack.c
  115. fetch-pack.h
  116. fmt-merge-msg.h
  117. fsck.c
  118. fsck.h
  119. generate-cmdlist.sh
  120. gettext.c
  121. gettext.h
  122. git-add--interactive.perl
  123. git-archimport.perl
  124. git-bisect.sh
  125. git-compat-util.h
  126. git-cvsexportcommit.perl
  127. git-cvsimport.perl
  128. git-cvsserver.perl
  129. git-difftool--helper.sh
  130. git-difftool.perl
  131. git-filter-branch.sh
  132. git-instaweb.sh
  133. git-merge-octopus.sh
  134. git-merge-one-file.sh
  135. git-merge-resolve.sh
  136. git-mergetool--lib.sh
  137. git-mergetool.sh
  138. git-p4.py
  139. git-parse-remote.sh
  140. git-quiltimport.sh
  141. git-rebase--am.sh
  142. git-rebase--interactive.sh
  143. git-rebase--merge.sh
  144. git-rebase.sh
  145. git-relink.perl
  146. git-remote-testgit.sh
  147. git-request-pull.sh
  148. git-send-email.perl
  149. git-sh-i18n.sh
  150. git-sh-setup.sh
  151. git-stash.sh
  152. git-submodule.sh
  153. git-svn.perl
  154. GIT-VERSION-GEN
  155. git-web--browse.sh
  156. git.c
  157. git.rc
  158. gpg-interface.c
  159. gpg-interface.h
  160. graph.c
  161. graph.h
  162. grep.c
  163. grep.h
  164. hashmap.c
  165. hashmap.h
  166. help.c
  167. help.h
  168. hex.c
  169. http-backend.c
  170. http-fetch.c
  171. http-push.c
  172. http-walker.c
  173. http.c
  174. http.h
  175. ident.c
  176. imap-send.c
  177. INSTALL
  178. iterator.h
  179. khash.h
  180. kwset.c
  181. kwset.h
  182. levenshtein.c
  183. levenshtein.h
  184. LGPL-2.1
  185. line-log.c
  186. line-log.h
  187. line-range.c
  188. line-range.h
  189. list-objects.c
  190. list-objects.h
  191. list.h
  192. ll-merge.c
  193. ll-merge.h
  194. lockfile.c
  195. lockfile.h
  196. log-tree.c
  197. log-tree.h
  198. mailinfo.c
  199. mailinfo.h
  200. mailmap.c
  201. mailmap.h
  202. Makefile
  203. match-trees.c
  204. merge-blobs.c
  205. merge-blobs.h
  206. merge-recursive.c
  207. merge-recursive.h
  208. merge.c
  209. mergesort.c
  210. mergesort.h
  211. mru.c
  212. mru.h
  213. name-hash.c
  214. notes-cache.c
  215. notes-cache.h
  216. notes-merge.c
  217. notes-merge.h
  218. notes-utils.c
  219. notes-utils.h
  220. notes.c
  221. notes.h
  222. object.c
  223. object.h
  224. pack-bitmap-write.c
  225. pack-bitmap.c
  226. pack-bitmap.h
  227. pack-check.c
  228. pack-objects.c
  229. pack-objects.h
  230. pack-revindex.c
  231. pack-revindex.h
  232. pack-write.c
  233. pack.h
  234. pager.c
  235. parse-options-cb.c
  236. parse-options.c
  237. parse-options.h
  238. patch-delta.c
  239. patch-ids.c
  240. patch-ids.h
  241. path.c
  242. pathspec.c
  243. pathspec.h
  244. pkt-line.c
  245. pkt-line.h
  246. preload-index.c
  247. pretty.c
  248. prio-queue.c
  249. prio-queue.h
  250. progress.c
  251. progress.h
  252. prompt.c
  253. prompt.h
  254. quote.c
  255. quote.h
  256. reachable.c
  257. reachable.h
  258. read-cache.c
  259. README.md
  260. ref-filter.c
  261. ref-filter.h
  262. reflog-walk.c
  263. reflog-walk.h
  264. refs.c
  265. refs.h
  266. remote-curl.c
  267. remote-testsvn.c
  268. remote.c
  269. remote.h
  270. replace_object.c
  271. rerere.c
  272. rerere.h
  273. resolve-undo.c
  274. resolve-undo.h
  275. revision.c
  276. revision.h
  277. run-command.c
  278. run-command.h
  279. send-pack.c
  280. send-pack.h
  281. sequencer.c
  282. sequencer.h
  283. server-info.c
  284. setup.c
  285. sh-i18n--envsubst.c
  286. sha1-array.c
  287. sha1-array.h
  288. sha1-lookup.c
  289. sha1-lookup.h
  290. sha1_file.c
  291. sha1_name.c
  292. shallow.c
  293. shell.c
  294. shortlog.h
  295. show-index.c
  296. sideband.c
  297. sideband.h
  298. sigchain.c
  299. sigchain.h
  300. split-index.c
  301. split-index.h
  302. strbuf.c
  303. strbuf.h
  304. streaming.c
  305. streaming.h
  306. string-list.c
  307. string-list.h
  308. submodule-config.c
  309. submodule-config.h
  310. submodule.c
  311. submodule.h
  312. symlinks.c
  313. tag.c
  314. tag.h
  315. tar.h
  316. tempfile.c
  317. tempfile.h
  318. thread-utils.c
  319. thread-utils.h
  320. tmp-objdir.c
  321. tmp-objdir.h
  322. trace.c
  323. trace.h
  324. trailer.c
  325. trailer.h
  326. transport-helper.c
  327. transport.c
  328. transport.h
  329. tree-diff.c
  330. tree-walk.c
  331. tree-walk.h
  332. tree.c
  333. tree.h
  334. unicode_width.h
  335. unimplemented.sh
  336. unix-socket.c
  337. unix-socket.h
  338. unpack-trees.c
  339. unpack-trees.h
  340. update_unicode.sh
  341. upload-pack.c
  342. url.c
  343. url.h
  344. urlmatch.c
  345. urlmatch.h
  346. usage.c
  347. userdiff.c
  348. userdiff.h
  349. utf8.c
  350. utf8.h
  351. varint.c
  352. varint.h
  353. version.c
  354. version.h
  355. versioncmp.c
  356. walker.c
  357. walker.h
  358. wildmatch.c
  359. wildmatch.h
  360. worktree.c
  361. worktree.h
  362. wrap-for-bin.sh
  363. wrapper.c
  364. write_or_die.c
  365. ws.c
  366. wt-status.c
  367. wt-status.h
  368. xdiff-interface.c
  369. xdiff-interface.h
  370. zlib.c
README.md

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 http://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-.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). To subscribe to the list, send an email with just “subscribe git” in the body to majordomo@vger.kernel.org. The mailing list archives are available at http://news.gmane.org/gmane.comp.version-control.git/, http://marc.info/?l=git and other archival sites.

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