The primary goal of this change is to stop leaking init_db_template_dir.
This leak can happen because:
1. git_init_db_config() allocates new memory into init_db_template_dir
without first freeing the existing value.
2. init_db_template_dir might already contain data, either because:
2.1 git_config() can be invoked twice with this callback in a single
process - at least 2 allocations are likely.
2.2 A single git_config() allocation can invoke the callback multiple
times for a given key (see further explanation in the function
docs) - each of those calls will trigger another leak.
The simplest fix for the leak would be to free(init_db_template_dir)
before overwriting it. Instead we choose to convert to fetching
init.templatedir via git_config_get_value() as that is more explicit,
more efficient, and avoids allocations (the returned result is owned by
the config cache, so we aren't responsible for freeing it).
If we remove init_db_template_dir, git_init_db_config() ends up being
responsible only for forwarding core.* config values to
platform_core_config(). However platform_core_config() already ignores
non-core.* config values, so we can safely remove git_init_db_config()
and invoke git_config() directly with platform_core_config() as the
callback.
The platform_core_config forwarding was originally added in:
287853392a (mingw: respect core.hidedotfiles = false in git-init again, 2019-03-11
And I suspect the potential for a leak existed since the original
implementation of git_init_db_config in:
90b45187ba (Add `init.templatedir` configuration variable., 2010-02-17)
LSAN output from t0001:
Direct leak of 73 byte(s) in 1 object(s) allocated from:
#0 0x49a859 in realloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x9a7276 in xrealloc /home/ahunt/oss-fuzz/git/wrapper.c:126:8
#2 0x9362ad in strbuf_grow /home/ahunt/oss-fuzz/git/strbuf.c:98:2
#3 0x936eaa in strbuf_add /home/ahunt/oss-fuzz/git/strbuf.c:295:2
#4 0x868112 in strbuf_addstr /home/ahunt/oss-fuzz/git/./strbuf.h:304:2
#5 0x86a8ad in expand_user_path /home/ahunt/oss-fuzz/git/path.c:758:2
#6 0x720bb1 in git_config_pathname /home/ahunt/oss-fuzz/git/config.c:1287:10
#7 0x5960e2 in git_init_db_config /home/ahunt/oss-fuzz/git/builtin/init-db.c:161:11
#8 0x7255b8 in configset_iter /home/ahunt/oss-fuzz/git/config.c:1982:7
#9 0x7253fc in repo_config /home/ahunt/oss-fuzz/git/config.c:2311:2
#10 0x725ca7 in git_config /home/ahunt/oss-fuzz/git/config.c:2399:2
#11 0x593e8d in create_default_files /home/ahunt/oss-fuzz/git/builtin/init-db.c:225:2
#12 0x5935c6 in init_db /home/ahunt/oss-fuzz/git/builtin/init-db.c:449:11
#13 0x59588e in cmd_init_db /home/ahunt/oss-fuzz/git/builtin/init-db.c:714:9
#14 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#15 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#16 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#17 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#18 0x69c4de in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#19 0x7f23552d6349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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).
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
e4de4502e6
