@matheusbsbs / matheus-bagliano / commits / d8d77153ea

config: allow specifying config entries via envvar pairs

While we currently have the `GIT_CONFIG_PARAMETERS` environment variable which can be used to pass runtime configuration data to git processes, it's an internal implementation detail and not supposed to be used by end users. Next to being for internal use only, this way of passing config entries has a major downside: the config keys need to be parsed as they contain both key and value in a single variable. As such, it is left to the user to escape any potentially harmful characters in the value, which is quite hard to do if values are controlled by a third party. This commit thus adds a new way of adding config entries via the environment which gets rid of this shortcoming. If the user passes the `GIT_CONFIG_COUNT=$n` environment variable, Git will parse environment variable pairs `GIT_CONFIG_KEY_$i` and `GIT_CONFIG_VALUE_$i` for each `i` in `[0,n)`. While the same can be achieved with `git -c <name>=<value>`, one may wish to not do so for potentially sensitive information. E.g. if one wants to set `http.extraHeader` to contain an authentication token, doing so via `-c` would trivially leak those credentials via e.g. ps(1), which typically also shows command arguments. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Patrick Steinhardt committed Jan 12, 2021 at 13:27 UTC d8d77153eafdb0fc334e827976f09e4bdff26b58
5 files changed +191 -9
Documentation/git-config.txt
+16
@@ -337,6 +337,22 @@ GIT_CONFIG_NOSYSTEM::
337
338 See also <<FILES>>.
339
340 +GIT_CONFIG_COUNT::
341 +GIT_CONFIG_KEY_<n>::
342 +GIT_CONFIG_VALUE_<n>::
343 + If GIT_CONFIG_COUNT is set to a positive number, all environment pairs
344 + GIT_CONFIG_KEY_<n> and GIT_CONFIG_VALUE_<n> up to that number will be
345 + added to the process's runtime configuration. The config pairs are
346 + zero-indexed. Any missing key or value is treated as an error. An empty
347 + GIT_CONFIG_COUNT is treated the same as GIT_CONFIG_COUNT=0, namely no
348 + pairs are processed. These environment variables will override values
349 + in configuration files, but will be overridden by any explicit options
350 + passed via `git -c`.
351 ++
352 +This is useful for cases where you want to spawn multiple git commands
353 +with a common configuration but cannot depend on a configuration file,
354 +for example when writing scripts.
355 +
356
357 [[EXAMPLES]]
358 EXAMPLES
cache.h
+1
@@ -472,6 +472,7 @@ static inline enum object_type object_type(unsigned int mode)
472 #define TEMPLATE_DIR_ENVIRONMENT "GIT_TEMPLATE_DIR"
473 #define CONFIG_ENVIRONMENT "GIT_CONFIG"
474 #define CONFIG_DATA_ENVIRONMENT "GIT_CONFIG_PARAMETERS"
475 +#define CONFIG_COUNT_ENVIRONMENT "GIT_CONFIG_COUNT"
476 #define EXEC_PATH_ENVIRONMENT "GIT_EXEC_PATH"
477 #define CEILING_DIRECTORIES_ENVIRONMENT "GIT_CEILING_DIRECTORIES"
478 #define NO_REPLACE_OBJECTS_ENVIRONMENT "GIT_NO_REPLACE_OBJECTS"
config.c
+59 -8
@@ -8,6 +8,7 @@
8 #include "cache.h"
9 #include "branch.h"
10 #include "config.h"
11 +#include "environment.h"
12 #include "repository.h"
13 #include "lockfile.h"
14 #include "exec-cmd.h"
@@ -598,23 +599,73 @@ static int parse_config_env_list(char *env, config_fn_t fn, void *data)
599
600 int git_config_from_parameters(config_fn_t fn, void *data)
601 {
601 - const char *env = getenv(CONFIG_DATA_ENVIRONMENT);
602 + const char *env;
603 + struct strbuf envvar = STRBUF_INIT;
604 + struct strvec to_free = STRVEC_INIT;
605 int ret = 0;
603 - char *envw;
606 + char *envw = NULL;
607 struct config_source source;
608
606 - if (!env)
607 - return 0;
608 -
609 memset(&source, 0, sizeof(source));
610 source.prev = cf;
611 source.origin_type = CONFIG_ORIGIN_CMDLINE;
612 cf = &source;
613
614 - /* sq_dequote will write over it */
615 - envw = xstrdup(env);
616 - ret = parse_config_env_list(envw, fn, data);
614 + env = getenv(CONFIG_COUNT_ENVIRONMENT);
615 + if (env) {
616 + unsigned long count;
617 + char *endp;
618 + int i;
619
620 + count = strtoul(env, &endp, 10);
621 + if (*endp) {
622 + ret = error(_("bogus count in %s"), CONFIG_COUNT_ENVIRONMENT);
623 + goto out;
624 + }
625 + if (count > INT_MAX) {
626 + ret = error(_("too many entries in %s"), CONFIG_COUNT_ENVIRONMENT);
627 + goto out;
628 + }
629 +
630 + for (i = 0; i < count; i++) {
631 + const char *key, *value;
632 +
633 + strbuf_addf(&envvar, "GIT_CONFIG_KEY_%d", i);
634 + key = getenv_safe(&to_free, envvar.buf);
635 + if (!key) {
636 + ret = error(_("missing config key %s"), envvar.buf);
637 + goto out;
638 + }
639 + strbuf_reset(&envvar);
640 +
641 + strbuf_addf(&envvar, "GIT_CONFIG_VALUE_%d", i);
642 + value = getenv_safe(&to_free, envvar.buf);
643 + if (!value) {
644 + ret = error(_("missing config value %s"), envvar.buf);
645 + goto out;
646 + }
647 + strbuf_reset(&envvar);
648 +
649 + if (config_parse_pair(key, value, fn, data) < 0) {
650 + ret = -1;
651 + goto out;
652 + }
653 + }
654 + }
655 +
656 + env = getenv(CONFIG_DATA_ENVIRONMENT);
657 + if (env) {
658 + /* sq_dequote will write over it */
659 + envw = xstrdup(env);
660 + if (parse_config_env_list(envw, fn, data) < 0) {
661 + ret = -1;
662 + goto out;
663 + }
664 + }
665 +
666 +out:
667 + strbuf_release(&envvar);
668 + strvec_clear(&to_free);
669 free(envw);
670 cf = source.prev;
671 return ret;
environment.c
+1
@@ -117,6 +117,7 @@ const char * const local_repo_env[] = {
117 ALTERNATE_DB_ENVIRONMENT,
118 CONFIG_ENVIRONMENT,
119 CONFIG_DATA_ENVIRONMENT,
120 + CONFIG_COUNT_ENVIRONMENT,
121 DB_ENVIRONMENT,
122 GIT_DIR_ENVIRONMENT,
123 GIT_WORK_TREE_ENVIRONMENT,
t/t1300-config.sh
+114 -1
@@ -1424,6 +1424,117 @@ test_expect_success '--config-env handles keys with equals' '
1424 test_cmp expect actual
1425 '
1426
1427 +test_expect_success 'git config handles environment config pairs' '
1428 + GIT_CONFIG_COUNT=2 \
1429 + GIT_CONFIG_KEY_0="pair.one" GIT_CONFIG_VALUE_0="foo" \
1430 + GIT_CONFIG_KEY_1="pair.two" GIT_CONFIG_VALUE_1="bar" \
1431 + git config --get-regexp "pair.*" >actual &&
1432 + cat >expect <<-EOF &&
1433 + pair.one foo
1434 + pair.two bar
1435 + EOF
1436 + test_cmp expect actual
1437 +'
1438 +
1439 +test_expect_success 'git config ignores pairs without count' '
1440 + test_must_fail env GIT_CONFIG_KEY_0="pair.one" GIT_CONFIG_VALUE_0="value" \
1441 + git config pair.one 2>error &&
1442 + test_must_be_empty error
1443 +'
1444 +
1445 +test_expect_success 'git config ignores pairs with zero count' '
1446 + test_must_fail env \
1447 + GIT_CONFIG_COUNT=0 \
1448 + GIT_CONFIG_KEY_0="pair.one" GIT_CONFIG_VALUE_0="value" \
1449 + git config pair.one
1450 +'
1451 +
1452 +test_expect_success 'git config ignores pairs exceeding count' '
1453 + GIT_CONFIG_COUNT=1 \
1454 + GIT_CONFIG_KEY_0="pair.one" GIT_CONFIG_VALUE_0="value" \
1455 + GIT_CONFIG_KEY_1="pair.two" GIT_CONFIG_VALUE_1="value" \
1456 + git config --get-regexp "pair.*" >actual &&
1457 + cat >expect <<-EOF &&
1458 + pair.one value
1459 + EOF
1460 + test_cmp expect actual
1461 +'
1462 +
1463 +test_expect_success 'git config ignores pairs with zero count' '
1464 + test_must_fail env \
1465 + GIT_CONFIG_COUNT=0 GIT_CONFIG_KEY_0="pair.one" GIT_CONFIG_VALUE_0="value" \
1466 + git config pair.one >error &&
1467 + test_must_be_empty error
1468 +'
1469 +
1470 +test_expect_success 'git config ignores pairs with empty count' '
1471 + test_must_fail env \
1472 + GIT_CONFIG_COUNT= GIT_CONFIG_KEY_0="pair.one" GIT_CONFIG_VALUE_0="value" \
1473 + git config pair.one >error &&
1474 + test_must_be_empty error
1475 +'
1476 +
1477 +test_expect_success 'git config fails with invalid count' '
1478 + test_must_fail env GIT_CONFIG_COUNT=10a git config --list 2>error &&
1479 + test_i18ngrep "bogus count" error &&
1480 + test_must_fail env GIT_CONFIG_COUNT=9999999999999999 git config --list 2>error &&
1481 + test_i18ngrep "too many entries" error
1482 +'
1483 +
1484 +test_expect_success 'git config fails with missing config key' '
1485 + test_must_fail env GIT_CONFIG_COUNT=1 GIT_CONFIG_VALUE_0="value" \
1486 + git config --list 2>error &&
1487 + test_i18ngrep "missing config key" error
1488 +'
1489 +
1490 +test_expect_success 'git config fails with missing config value' '
1491 + test_must_fail env GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0="pair.one" \
1492 + git config --list 2>error &&
1493 + test_i18ngrep "missing config value" error
1494 +'
1495 +
1496 +test_expect_success 'git config fails with invalid config pair key' '
1497 + test_must_fail env GIT_CONFIG_COUNT=1 \
1498 + GIT_CONFIG_KEY_0= GIT_CONFIG_VALUE_0=value \
1499 + git config --list &&
1500 + test_must_fail env GIT_CONFIG_COUNT=1 \
1501 + GIT_CONFIG_KEY_0=missing-section GIT_CONFIG_VALUE_0=value \
1502 + git config --list
1503 +'
1504 +
1505 +test_expect_success 'environment overrides config file' '
1506 + test_when_finished "rm -f .git/config" &&
1507 + cat >.git/config <<-EOF &&
1508 + [pair]
1509 + one = value
1510 + EOF
1511 + GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=pair.one GIT_CONFIG_VALUE_0=override \
1512 + git config pair.one >actual &&
1513 + cat >expect <<-EOF &&
1514 + override
1515 + EOF
1516 + test_cmp expect actual
1517 +'
1518 +
1519 +test_expect_success 'GIT_CONFIG_PARAMETERS overrides environment config' '
1520 + GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=pair.one GIT_CONFIG_VALUE_0=value \
1521 + GIT_CONFIG_PARAMETERS="${SQ}pair.one=override${SQ}" \
1522 + git config pair.one >actual &&
1523 + cat >expect <<-EOF &&
1524 + override
1525 + EOF
1526 + test_cmp expect actual
1527 +'
1528 +
1529 +test_expect_success 'command line overrides environment config' '
1530 + GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=pair.one GIT_CONFIG_VALUE_0=value \
1531 + git -c pair.one=override config pair.one >actual &&
1532 + cat >expect <<-EOF &&
1533 + override
1534 + EOF
1535 + test_cmp expect actual
1536 +'
1537 +
1538 test_expect_success 'git config --edit works' '
1539 git config -f tmp test.value no &&
1540 echo test.value=yes >expect &&
@@ -1769,9 +1880,11 @@ test_expect_success '--show-origin with --list' '
1880 file:.git/config user.override=local
1881 file:.git/config include.path=../include/relative.include
1882 file:.git/../include/relative.include user.relative=include
1883 + command line: user.environ=true
1884 command line: user.cmdline=true
1885 EOF
1774 - git -c user.cmdline=true config --list --show-origin >output &&
1886 + GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=user.environ GIT_CONFIG_VALUE_0=true\
1887 + git -c user.cmdline=true config --list --show-origin >output &&
1888 test_cmp expect output
1889 '
1890