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Jeff King ccdc4819d5 check_stream_sha1(): handle input underflow
This commit fixes an infinite loop when fscking large
truncated loose objects.

The check_stream_sha1() function takes an mmap'd loose
object buffer and streams 4k of output at a time, checking
its sha1. The loop quits when we've output enough bytes (we
know the size from the object header), or when zlib tells us
anything except Z_OK or Z_BUF_ERROR.

The latter is expected because zlib may run out of room in
our 4k buffer, and that is how it tells us to process the
output and loop again.

But Z_BUF_ERROR also covers another case: one in which zlib
cannot make forward progress because it needs more _input_.
This should never happen in this loop, because though we're
streaming the output, we have the entire deflated input
available in the mmap'd buffer. But since we don't check
this case, we'll just loop infinitely if we do see a
truncated object, thinking that zlib is asking for more
output space.

It's tempting to fix this by checking stream->avail_in as
part of the loop condition (and quitting if all of our bytes
have been consumed). But that assumes that once zlib has
consumed the input, there is nothing left to do.  That's not
necessarily the case: it may have read our input into its
internal state, but still have bytes to output.

Instead, let's continue on Z_BUF_ERROR only when we see the
case we're expecting: the previous round filled our output
buffer completely. If it didn't (and we still saw
Z_BUF_ERROR), we know something is wrong and should break
out of the loop.

The bug comes from commit f6371f9210 (sha1_file: add
read_loose_object() function, 2017-01-13), which
reimplemented some of the existing loose object functions.
So it's worth checking if this bug was inherited from any of
those. The answers seems to be no. The two obvious
candidates are both OK:

  1. unpack_sha1_rest(); this doesn't need to loop on
     Z_BUF_ERROR at all, since it allocates the expected
     output buffer in advance (which we can't do since we're
     explicitly streaming here)

  2. check_object_signature(); the streaming path relies on
     the istream interface, which uses read_istream_loose()
     for this case. That function uses a similar "is our
     output buffer full" check with Z_BUF_ERROR (which is
     where I stole it from for this patch!)

Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-31 13:05:26 +09:00
Documentation Git 2.12.5 2017-09-22 14:47:41 +09:00
block-sha1
builtin Merge branch 'rs/update-hook-optim' into maint 2017-03-28 13:52:28 -07:00
ci Travis: also test on 32-bit Linux 2017-03-06 11:19:09 -08:00
compat Merge branch 'js/mingw-isatty' 2017-02-16 14:45:13 -08:00
contrib Merge branch 'rs/strbuf-add-real-path' into maint 2017-03-28 13:52:19 -07:00
ewah Merge branch 'jk/ewah-use-right-type-in-sizeof' into maint 2017-03-21 15:03:24 -07:00
git-gui
gitk-git Merge git://ozlabs.org/~paulus/gitk 2017-01-18 10:27:59 -08:00
gitweb
mergetools Merge branch 'da/mergetool-xxdiff-hotkey' into maint 2017-01-17 15:11:05 -08:00
perl Merge branch 'svn-escape-backslash' of git://bogomips.org/git-svn 2017-02-20 22:01:59 -08:00
po l10n: zh_CN: for git v2.12.0 l10n round 2 2017-02-25 00:19:14 +08:00
ppc
refs Merge branch 'cw/log-updates-for-all-refs-really' 2017-02-03 11:25:19 -08:00
t check_stream_sha1(): handle input underflow 2018-10-31 13:05:26 +09:00
templates
vcs-svn
xdiff
.gitattributes
.gitignore relink: retire the command 2017-01-25 14:42:37 -08:00
.mailmap mailmap: use Michael J Gruber's new address 2017-03-24 12:30:27 -07:00
.travis.yml Travis: also test on 32-bit Linux 2017-03-06 11:19:09 -08:00
COPYING
GIT-VERSION-GEN Git 2.12.5 2017-09-22 14:47:41 +09:00
INSTALL
LGPL-2.1
Makefile Merge branch 'jk/interop-test' into maint 2017-03-28 13:52:20 -07:00
README.md README: create HTTP/HTTPS links from URLs in Markdown 2017-03-01 14:45:45 -08:00
RelNotes Git 2.12.5 2017-09-22 14:47:41 +09:00
abspath.c real_pathdup(): fix callsites that wanted it to die on error 2017-03-08 14:38:41 -08:00
aclocal.m4
advice.c
advice.h
alias.c
alloc.c
apply.c apply: use SWAP macro 2017-01-30 14:07:52 -08:00
apply.h
archive-tar.c
archive-zip.c
archive.c
archive.h
argv-array.c
argv-array.h
attr.c
attr.h
base85.c
bisect.c Merge branch 'mm/two-more-xstrfmt' into maint 2017-03-16 13:56:43 -07:00
bisect.h
blob.c
blob.h
branch.c refs: add option core.logAllRefUpdates = always 2017-01-31 10:01:24 -08:00
branch.h
builtin.h difftool: add a skeleton for the upcoming builtin 2017-01-17 13:32:47 -08:00
bulk-checkin.c
bulk-checkin.h
bundle.c
bundle.h
cache-tree.c
cache-tree.h
cache.h Git 2.11.3 2017-07-30 15:04:22 -07:00
check-builtins.sh
check-racy.c
check_bindir
color.c Merge branch 'nd/log-graph-configurable-colors' 2017-02-02 13:36:58 -08:00
color.h
column.c
column.h
combine-diff.c
command-list.txt relink: retire the command 2017-01-25 14:42:37 -08:00
commit-slab.h
commit.c Merge branch 'rs/commit-parsing-optim' into maint 2017-03-21 15:03:29 -07:00
commit.h
common-main.c
config.c Merge branch 'jk/parse-config-key-cleanup' into maint 2017-03-28 13:52:19 -07:00
config.mak.in
config.mak.uname Merge branch 'rj/remove-unused-mktemp' into maint 2017-03-21 15:03:24 -07:00
configure.ac wrapper.c: remove unused gitmkstemps() function 2017-02-28 11:54:21 -08:00
connect.c Git 2.10.4 2017-07-30 15:01:31 -07:00
connect.h
connected.c
connected.h
convert.c Merge branch 'jc/renormalize-merge-kill-safer-crlf' into maint 2017-01-17 14:49:28 -08:00
convert.h
copy.c
credential-cache--daemon.c
credential-cache.c
credential-store.c
credential.c
credential.h
csum-file.c
csum-file.h
ctype.c
daemon.c
date.c
decorate.c
decorate.h
delta.h
diff-delta.c
diff-lib.c
diff-no-index.c diff: use SWAP macro 2017-01-30 14:23:00 -08:00
diff.c Merge branch 'jc/diff-populate-filespec-size-only-fix' into maint 2017-03-21 15:03:26 -07:00
diff.h
diffcore-break.c
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c Merge branch 'js/regexec-buf' into maint 2017-03-28 13:52:24 -07:00
diffcore-rename.c
diffcore.h
dir-iterator.c
dir-iterator.h
dir.c real_pathdup(): fix callsites that wanted it to die on error 2017-03-08 14:38:41 -08:00
dir.h
editor.c
entry.c
environment.c Merge branch 'jk/pack-name-cleanups' into maint 2017-03-28 13:52:25 -07:00
exec_cmd.c Merge branch 'js/exec-path-coverity-workaround' into maint 2017-01-31 13:32:10 -08:00
exec_cmd.h
fast-import.c replace snprintf with odb_pack_name() 2017-03-16 11:26:18 -07:00
fetch-pack.c fetch-pack: add specific error for fetching an unadvertised object 2017-03-02 11:12:53 -08:00
fetch-pack.h fetch-pack: move code to report unmatched refs to a function 2017-03-02 11:12:53 -08:00
fmt-merge-msg.h
fsck.c fsck: lazily load types under --connectivity-only 2017-01-26 10:51:09 -08:00
fsck.h
generate-cmdlist.sh
gettext.c
gettext.h
git-add--interactive.perl add--interactive: fix missing file prompt for patch mode with "-i" 2017-03-02 10:10:38 -08:00
git-archimport.perl archimport: use safe_pipe_capture for user input 2017-09-12 11:08:15 +09:00
git-bisect.sh
git-compat-util.h Merge branch 'jk/pack-name-cleanups' into maint 2017-03-28 13:52:25 -07:00
git-cvsexportcommit.perl
git-cvsimport.perl cvsimport: shell-quote variable used in backticks 2017-09-12 11:10:22 +09:00
git-cvsserver.perl cvsserver: use safe_pipe_capture for `constant commands` as well 2017-09-11 14:52:29 +09:00
git-difftool--helper.sh
git-filter-branch.sh filter-branch: fix --prune-empty on parentless commits 2017-03-03 12:43:37 -08:00
git-instaweb.sh
git-merge-octopus.sh
git-merge-one-file.sh
git-merge-resolve.sh
git-mergetool--lib.sh
git-mergetool.sh
git-p4.py Merge branch 'ls/p4-path-encoding' 2017-02-16 14:45:12 -08:00
git-parse-remote.sh
git-quiltimport.sh
git-rebase--am.sh
git-rebase--interactive.sh Merge branch 'jk/rebase-i-squash-count-fix' into maint 2017-01-31 13:32:07 -08:00
git-rebase--merge.sh
git-rebase.sh
git-remote-testgit.sh
git-request-pull.sh request-pull: drop old USAGE stuff 2017-01-15 16:23:23 -08:00
git-send-email.perl Merge branch 'jh/send-email-one-cc' into maint 2017-03-21 15:03:30 -07:00
git-sh-i18n.sh
git-sh-setup.sh
git-stash.sh Merge branch 'jk/stash-disable-renames-internally' into maint 2017-01-17 14:49:30 -08:00
git-submodule.sh Merge branch 'sb/submodule-update-initial-runs-custom-script' 2017-02-03 11:25:19 -08:00
git-svn.perl
git-web--browse.sh
git.c Merge branch 'sb/unpack-trees-super-prefix' 2017-02-03 11:25:18 -08:00
git.rc
gpg-interface.c
gpg-interface.h gpg-interface, tag: add GPG_VERIFY_OMIT_STATUS flag 2017-01-17 16:10:22 -08:00
graph.c Merge branch 'rs/swap' 2017-02-15 12:54:19 -08:00
graph.h
grep.c
grep.h
hashmap.c
hashmap.h
help.c help: improve is_executable() on Windows 2017-01-30 09:04:17 -08:00
help.h
hex.c
http-backend.c
http-fetch.c
http-push.c http-push: don't check return value of lookup_unknown_object() 2017-03-18 10:14:07 -07:00
http-walker.c Merge branch 'ew/http-alternates-as-redirects-warning' into maint 2017-03-28 13:52:23 -07:00
http.c Merge branch 'jt/http-base-url-update-upon-redirect' into maint 2017-03-16 13:56:42 -07:00
http.h Merge branch 'jk/http-walker-limit-redirect' into maint 2017-01-17 14:49:29 -08:00
ident.c ident: do not ignore empty config name/email 2017-02-23 12:58:47 -08:00
imap-send.c
iterator.h
khash.h
kwset.c
kwset.h
levenshtein.c
levenshtein.h
line-log.c Merge branch 'vn/line-log-memcpy-size-fix' into maint 2017-03-16 13:56:42 -07:00
line-log.h
line-range.c use SWAP macro 2017-01-30 14:17:00 -08:00
line-range.h
list-objects.c
list-objects.h
list.h
ll-merge.c
ll-merge.h
lockfile.c
lockfile.h
log-tree.c
log-tree.h
mailinfo.c Merge branch 'jt/mailinfo-fold-in-body-headers' into maint 2017-01-17 15:11:06 -08:00
mailinfo.h
mailmap.c
mailmap.h
match-trees.c
merge-blobs.c
merge-blobs.h
merge-recursive.c use SWAP macro 2017-01-30 14:17:00 -08:00
merge-recursive.h
merge.c
mergesort.c
mergesort.h
mru.c
mru.h
name-hash.c
notes-cache.c
notes-cache.h
notes-merge.c
notes-merge.h
notes-utils.c
notes-utils.h
notes.c
notes.h
object.c use SWAP macro 2017-01-30 14:17:00 -08:00
object.h
pack-bitmap-write.c
pack-bitmap.c
pack-bitmap.h
pack-check.c
pack-objects.c
pack-objects.h pack-objects: enforce --depth limit in reused deltas 2017-01-27 16:24:44 -08:00
pack-revindex.c use SWAP macro 2017-01-30 14:17:00 -08:00
pack-revindex.h
pack-write.c
pack.h
pager.c
parse-options-cb.c
parse-options.c
parse-options.h
patch-delta.c
patch-ids.c
patch-ids.h
path.c Git 2.10.4 2017-07-30 15:01:31 -07:00
pathspec.c
pathspec.h
pkt-line.c
pkt-line.h
preload-index.c
pretty.c
prio-queue.c use SWAP macro 2017-01-30 14:17:00 -08:00
prio-queue.h
progress.c stop_progress_msg: convert xsnprintf to xstrfmt 2017-02-16 11:28:02 -08:00
progress.h
prompt.c
prompt.h
quote.c
quote.h
reachable.c
reachable.h
read-cache.c Merge branch 'sb/in-core-index-doc' 2017-01-31 13:14:59 -08:00
ref-filter.c Merge branch 'rs/qsort-s' 2017-01-31 13:15:00 -08:00
ref-filter.h Merge branch 'st/verify-tag' 2017-01-31 13:14:58 -08:00
reflog-walk.c
reflog-walk.h
refs.c Merge branch 'jk/interpret-branch-name' into maint 2017-03-28 13:52:22 -07:00
refs.h refs: add option core.logAllRefUpdates = always 2017-01-31 10:01:24 -08:00
remote-curl.c Merge branch 'dt/smart-http-detect-server-going-away' into maint 2017-01-17 15:19:03 -08:00
remote-testsvn.c
remote.c Merge branch 'jn/remote-helpers-with-git-dir' into maint 2017-03-24 12:57:53 -07:00
remote.h Merge branch 'mm/fetch-show-error-message-on-unadvertised-object' into maint 2017-03-28 13:52:22 -07:00
replace_object.c
rerere.c
rerere.h
resolve-undo.c
resolve-undo.h
revision.c interpret_branch_name: allow callers to restrict expansions 2017-03-02 11:05:04 -08:00
revision.h Merge branch 'rs/path-name-safety-cleanup' into maint 2017-03-28 13:52:27 -07:00
run-command.c Merge branch 'jk/execv-dashed-external' into maint 2017-03-28 13:52:23 -07:00
run-command.h
send-pack.c send-pack: report signal death of pack-objects 2017-03-07 14:58:36 -08:00
send-pack.h
sequencer.c sequencer (rebase -i): write out the final message 2017-01-17 14:06:01 -08:00
sequencer.h
server-info.c
setup.c Merge branch 'rs/strbuf-add-real-path' into maint 2017-03-28 13:52:19 -07:00
sh-i18n--envsubst.c
sha1-array.c
sha1-array.h
sha1-lookup.c
sha1-lookup.h
sha1_file.c check_stream_sha1(): handle input underflow 2018-10-31 13:05:26 +09:00
sha1_name.c strbuf_check_ref_format(): expand only local branches 2017-03-02 11:05:04 -08:00
shallow.c Merge branch 'nd/shallow-fixup' into maint 2017-01-17 15:11:05 -08:00
shell.c shell: drop git-cvsserver support by default 2017-09-12 11:05:58 +09:00
shortlog.h
show-index.c
sideband.c
sideband.h
sigchain.c
sigchain.h
split-index.c
split-index.h
strbuf.c strbuf: add strbuf_add_real_path() 2017-02-27 11:02:06 -08:00
strbuf.h Merge branch 'jk/interpret-branch-name' into maint 2017-03-28 13:52:22 -07:00
streaming.c
streaming.h
string-list.c string-list: use QSORT_S in string_list_sort() 2017-01-23 11:02:38 -08:00
string-list.h
submodule-config.c Merge branch 'sb/submodule-config-parse-ignore-fix' into maint 2017-03-24 12:57:52 -07:00
submodule-config.h Merge branch 'bw/grep-recurse-submodules' 2017-01-18 15:12:11 -08:00
submodule.c real_pathdup(): fix callsites that wanted it to die on error 2017-03-08 14:38:41 -08:00
submodule.h Merge branch 'bw/push-submodule-only' 2017-01-31 13:14:56 -08:00
symlinks.c
tag.c gpg-interface, tag: add GPG_VERIFY_OMIT_STATUS flag 2017-01-17 16:10:22 -08:00
tag.h
tar.h
tempfile.c tempfile: set errno to a known value before calling ferror() 2017-02-17 14:40:29 -08:00
tempfile.h
thread-utils.c
thread-utils.h
tmp-objdir.c
tmp-objdir.h
trace.c
trace.h
trailer.c
trailer.h
transport-helper.c Merge branch 'jn/remote-helpers-with-git-dir' into maint 2017-03-24 12:57:53 -07:00
transport.c Merge branch 'mm/fetch-show-error-message-on-unadvertised-object' into maint 2017-03-28 13:52:22 -07:00
transport.h Merge branch 'bw/push-submodule-only' 2017-01-31 13:14:56 -08:00
tree-diff.c
tree-walk.c
tree-walk.h
tree.c
tree.h
unicode_width.h
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c Merge branch 'sb/unpack-trees-super-prefix' 2017-02-03 11:25:18 -08:00
unpack-trees.h
upload-pack.c upload-pack: report "not our ref" to client 2017-02-23 12:14:40 -08:00
url.c
url.h
urlmatch.c
urlmatch.h
usage.c Merge branch 'jk/vreport-sanitize' 2017-01-31 13:14:56 -08:00
userdiff.c
userdiff.h
utf8.c
utf8.h
varint.c
varint.h
version.c
version.h
versioncmp.c versioncmp: generalize version sort suffix reordering 2017-01-12 12:25:24 -08:00
walker.c
walker.h
wildmatch.c
wildmatch.h
worktree.c Merge branch 'rs/strbuf-add-real-path' into maint 2017-03-28 13:52:19 -07:00
worktree.h
wrap-for-bin.sh
wrapper.c wrapper.c: remove unused gitmkstemps() function 2017-02-28 11:54:21 -08:00
write_or_die.c
ws.c
wt-status.c Merge branch 'sb/wt-status-cleanup' into maint 2017-03-28 13:52:26 -07:00
wt-status.h
xdiff-interface.c
xdiff-interface.h
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 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-.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.

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