gpg-interface: prefer check_signature() for GPG verification

This commit refactors the use of verify_signed_buffer() outside of
gpg-interface.c to use check_signature() instead.  It also turns
verify_signed_buffer() into a file-local function since it's now only
invoked internally by check_signature().

There were previously two globally scoped functions used in different
parts of Git to perform GPG signature verification:
verify_signed_buffer() and check_signature().  Now only
check_signature() is used.

The verify_signed_buffer() function doesn't guard against duplicate
signatures as described by Michał Górny [1].  Instead it only ensures a
non-erroneous exit code from GPG and the presence of at least one
GOODSIG status field.  This stands in contrast with check_signature()
that returns an error if more than one signature is encountered.

The lower degree of verification makes the use of verify_signed_buffer()
problematic if callers don't parse and validate the various parts of the
GPG status message themselves.  And processing these messages seems like
a task that should be reserved to gpg-interface.c with the function
check_signature().

Furthermore, the use of verify_signed_buffer() makes it difficult to
introduce new functionality that relies on the content of the GPG status
lines.

Now all operations that does signature verification share a single entry
point to gpg-interface.c.  This makes it easier to propagate changed or
additional functionality in GPG signature verification to all parts of
Git, without having odd edge-cases that don't perform the same degree of
verification.

[1] https://dev.gentoo.org/~mgorny/articles/attack-on-git-signature-verification.html

Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
4 files changed
tree: 50fdf5a566469f65c1b496efaaee77961775322e
  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. perl/
  15. po/
  16. ppc/
  17. refs/
  18. sha1dc/
  19. sha256/
  20. t/
  21. templates/
  22. trace2/
  23. vcs-svn/
  24. xdiff/
  25. .clang-format
  26. .editorconfig
  27. .gitattributes
  28. .gitignore
  29. .gitmodules
  30. .mailmap
  31. .travis.yml
  32. .tsan-suppressions
  33. abspath.c
  34. aclocal.m4
  35. advice.c
  36. advice.h
  37. alias.c
  38. alias.h
  39. alloc.c
  40. alloc.h
  41. apply.c
  42. apply.h
  43. archive-tar.c
  44. archive-zip.c
  45. archive.c
  46. archive.h
  47. argv-array.c
  48. argv-array.h
  49. attr.c
  50. attr.h
  51. azure-pipelines.yml
  52. banned.h
  53. base85.c
  54. bisect.c
  55. bisect.h
  56. blame.c
  57. blame.h
  58. blob.c
  59. blob.h
  60. branch.c
  61. branch.h
  62. builtin.h
  63. bulk-checkin.c
  64. bulk-checkin.h
  65. bundle.c
  66. bundle.h
  67. cache-tree.c
  68. cache-tree.h
  69. cache.h
  70. chdir-notify.c
  71. chdir-notify.h
  72. check-builtins.sh
  73. check_bindir
  74. checkout.c
  75. checkout.h
  76. color.c
  77. color.h
  78. column.c
  79. column.h
  80. combine-diff.c
  81. command-list.txt
  82. commit-graph.c
  83. commit-graph.h
  84. commit-reach.c
  85. commit-reach.h
  86. commit-slab-decl.h
  87. commit-slab-impl.h
  88. commit-slab.h
  89. commit.c
  90. commit.h
  91. common-main.c
  92. config.c
  93. config.h
  94. config.mak.dev
  95. config.mak.in
  96. config.mak.uname
  97. configure.ac
  98. connect.c
  99. connect.h
  100. connected.c
  101. connected.h
  102. convert.c
  103. convert.h
  104. copy.c
  105. COPYING
  106. credential-cache--daemon.c
  107. credential-cache.c
  108. credential-store.c
  109. credential.c
  110. credential.h
  111. csum-file.c
  112. csum-file.h
  113. ctype.c
  114. daemon.c
  115. date.c
  116. decorate.c
  117. decorate.h
  118. delta-islands.c
  119. delta-islands.h
  120. delta.h
  121. detect-compiler
  122. diff-delta.c
  123. diff-lib.c
  124. diff-no-index.c
  125. diff.c
  126. diff.h
  127. diffcore-break.c
  128. diffcore-delta.c
  129. diffcore-order.c
  130. diffcore-pickaxe.c
  131. diffcore-rename.c
  132. diffcore.h
  133. dir-iterator.c
  134. dir-iterator.h
  135. dir.c
  136. dir.h
  137. editor.c
  138. entry.c
  139. environment.c
  140. exec-cmd.c
  141. exec-cmd.h
  142. fast-import.c
  143. fetch-negotiator.c
  144. fetch-negotiator.h
  145. fetch-object.c
  146. fetch-object.h
  147. fetch-pack.c
  148. fetch-pack.h
  149. fmt-merge-msg.h
  150. fsck.c
  151. fsck.h
  152. fsmonitor.c
  153. fsmonitor.h
  154. fuzz-commit-graph.c
  155. fuzz-pack-headers.c
  156. fuzz-pack-idx.c
  157. generate-cmdlist.sh
  158. gettext.c
  159. gettext.h
  160. git-add--interactive.perl
  161. git-archimport.perl
  162. git-bisect.sh
  163. git-compat-util.h
  164. git-cvsexportcommit.perl
  165. git-cvsimport.perl
  166. git-cvsserver.perl
  167. git-difftool--helper.sh
  168. git-filter-branch.sh
  169. git-instaweb.sh
  170. git-legacy-stash.sh
  171. git-merge-octopus.sh
  172. git-merge-one-file.sh
  173. git-merge-resolve.sh
  174. git-mergetool--lib.sh
  175. git-mergetool.sh
  176. git-p4.py
  177. git-parse-remote.sh
  178. git-quiltimport.sh
  179. git-rebase--am.sh
  180. git-rebase--common.sh
  181. git-rebase--preserve-merges.sh
  182. git-request-pull.sh
  183. git-send-email.perl
  184. git-sh-i18n.sh
  185. git-sh-setup.sh
  186. git-submodule.sh
  187. git-svn.perl
  188. GIT-VERSION-GEN
  189. git-web--browse.sh
  190. git.c
  191. git.rc
  192. gpg-interface.c
  193. gpg-interface.h
  194. graph.c
  195. graph.h
  196. grep.c
  197. grep.h
  198. hash.h
  199. hashmap.c
  200. hashmap.h
  201. help.c
  202. help.h
  203. hex.c
  204. http-backend.c
  205. http-fetch.c
  206. http-push.c
  207. http-walker.c
  208. http.c
  209. http.h
  210. ident.c
  211. imap-send.c
  212. INSTALL
  213. interdiff.c
  214. interdiff.h
  215. iterator.h
  216. json-writer.c
  217. json-writer.h
  218. khash.h
  219. kwset.c
  220. kwset.h
  221. levenshtein.c
  222. levenshtein.h
  223. LGPL-2.1
  224. line-log.c
  225. line-log.h
  226. line-range.c
  227. line-range.h
  228. linear-assignment.c
  229. linear-assignment.h
  230. list-objects-filter-options.c
  231. list-objects-filter-options.h
  232. list-objects-filter.c
  233. list-objects-filter.h
  234. list-objects.c
  235. list-objects.h
  236. list.h
  237. ll-merge.c
  238. ll-merge.h
  239. lockfile.c
  240. lockfile.h
  241. log-tree.c
  242. log-tree.h
  243. ls-refs.c
  244. ls-refs.h
  245. mailinfo.c
  246. mailinfo.h
  247. mailmap.c
  248. mailmap.h
  249. Makefile
  250. match-trees.c
  251. mem-pool.c
  252. mem-pool.h
  253. merge-blobs.c
  254. merge-blobs.h
  255. merge-recursive.c
  256. merge-recursive.h
  257. merge.c
  258. mergesort.c
  259. mergesort.h
  260. midx.c
  261. midx.h
  262. name-hash.c
  263. notes-cache.c
  264. notes-cache.h
  265. notes-merge.c
  266. notes-merge.h
  267. notes-utils.c
  268. notes-utils.h
  269. notes.c
  270. notes.h
  271. object-store.h
  272. object.c
  273. object.h
  274. oidmap.c
  275. oidmap.h
  276. oidset.c
  277. oidset.h
  278. pack-bitmap-write.c
  279. pack-bitmap.c
  280. pack-bitmap.h
  281. pack-check.c
  282. pack-objects.c
  283. pack-objects.h
  284. pack-revindex.c
  285. pack-revindex.h
  286. pack-write.c
  287. pack.h
  288. packfile.c
  289. packfile.h
  290. pager.c
  291. parse-options-cb.c
  292. parse-options.c
  293. parse-options.h
  294. patch-delta.c
  295. patch-ids.c
  296. patch-ids.h
  297. path.c
  298. path.h
  299. pathspec.c
  300. pathspec.h
  301. pkt-line.c
  302. pkt-line.h
  303. preload-index.c
  304. pretty.c
  305. pretty.h
  306. prio-queue.c
  307. prio-queue.h
  308. progress.c
  309. progress.h
  310. prompt.c
  311. prompt.h
  312. protocol.c
  313. protocol.h
  314. quote.c
  315. quote.h
  316. range-diff.c
  317. range-diff.h
  318. reachable.c
  319. reachable.h
  320. read-cache.c
  321. README.md
  322. rebase-interactive.c
  323. rebase-interactive.h
  324. ref-filter.c
  325. ref-filter.h
  326. reflog-walk.c
  327. reflog-walk.h
  328. refs.c
  329. refs.h
  330. refspec.c
  331. refspec.h
  332. remote-curl.c
  333. remote-testsvn.c
  334. remote.c
  335. remote.h
  336. replace-object.c
  337. replace-object.h
  338. repository.c
  339. repository.h
  340. rerere.c
  341. rerere.h
  342. resolve-undo.c
  343. resolve-undo.h
  344. revision.c
  345. revision.h
  346. run-command.c
  347. run-command.h
  348. send-pack.c
  349. send-pack.h
  350. sequencer.c
  351. sequencer.h
  352. serve.c
  353. serve.h
  354. server-info.c
  355. setup.c
  356. sh-i18n--envsubst.c
  357. sha1-array.c
  358. sha1-array.h
  359. sha1-file.c
  360. sha1-lookup.c
  361. sha1-lookup.h
  362. sha1-name.c
  363. sha1dc_git.c
  364. sha1dc_git.h
  365. shallow.c
  366. shell.c
  367. shortlog.h
  368. sideband.c
  369. sideband.h
  370. sigchain.c
  371. sigchain.h
  372. split-index.c
  373. split-index.h
  374. strbuf.c
  375. strbuf.h
  376. streaming.c
  377. streaming.h
  378. string-list.c
  379. string-list.h
  380. sub-process.c
  381. sub-process.h
  382. submodule-config.c
  383. submodule-config.h
  384. submodule.c
  385. submodule.h
  386. symlinks.c
  387. tag.c
  388. tag.h
  389. tar.h
  390. tempfile.c
  391. tempfile.h
  392. thread-utils.c
  393. thread-utils.h
  394. tmp-objdir.c
  395. tmp-objdir.h
  396. trace.c
  397. trace.h
  398. trace2.c
  399. trace2.h
  400. trailer.c
  401. trailer.h
  402. transport-helper.c
  403. transport-internal.h
  404. transport.c
  405. transport.h
  406. tree-diff.c
  407. tree-walk.c
  408. tree-walk.h
  409. tree.c
  410. tree.h
  411. unicode-width.h
  412. unimplemented.sh
  413. unix-socket.c
  414. unix-socket.h
  415. unpack-trees.c
  416. unpack-trees.h
  417. upload-pack.c
  418. upload-pack.h
  419. url.c
  420. url.h
  421. urlmatch.c
  422. urlmatch.h
  423. usage.c
  424. userdiff.c
  425. userdiff.h
  426. utf8.c
  427. utf8.h
  428. varint.c
  429. varint.h
  430. version.c
  431. version.h
  432. versioncmp.c
  433. walker.c
  434. walker.h
  435. wildmatch.c
  436. wildmatch.h
  437. worktree.c
  438. worktree.h
  439. wrap-for-bin.sh
  440. wrapper.c
  441. write-or-die.c
  442. ws.c
  443. wt-status.c
  444. wt-status.h
  445. xdiff-interface.c
  446. xdiff-interface.h
  447. zlib.c
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). 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 https://public-inbox.org/git/, http://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