diff mbox series

[v2] bisect--helper: avoid segfault with bad syntax in `start --term-*`

Message ID 20200520232627.30901-1-carenas@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v2] bisect--helper: avoid segfault with bad syntax in `start --term-*` | expand

Commit Message

Carlo Marcelo Arenas Belón May 20, 2020, 11:26 p.m. UTC
06f5608c14 (bisect--helper: `bisect_start` shell function partially in C,
2019-01-02) adds a lax parser for `git bisect start` which could result
in a segfault under a bad syntax call for start with custom terms.

Detect if there are enough arguments left in the command line to use for
--term-{old,good,new,bad} and abort with the same syntax error the original
implementation will show if not.

While at it, remove an unnecessary (and incomplete) check for unknown
arguments and make sure to add a test to avoid regressions.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
---
v2:
* nicer implementation (per Junio) and description (per Eric)
* add test cases

 builtin/bisect--helper.c    | 13 +++++++++----
 t/t6030-bisect-porcelain.sh |  2 ++
 2 files changed, 11 insertions(+), 4 deletions(-)

Comments

Christian Couder May 22, 2020, 3:49 p.m. UTC | #1
On Thu, May 21, 2020 at 1:31 AM Carlo Marcelo Arenas Belón
<carenas@gmail.com> wrote:
>
> 06f5608c14 (bisect--helper: `bisect_start` shell function partially in C,
> 2019-01-02) adds a lax parser for `git bisect start` which could result
> in a segfault under a bad syntax call for start with custom terms.
>
> Detect if there are enough arguments left in the command line to use for
> --term-{old,good,new,bad} and abort with the same syntax error the original
> implementation will show if not.
>
> While at it, remove an unnecessary (and incomplete) check for unknown
> arguments and make sure to add a test to avoid regressions.

This looks good to me!

Thanks,
Christian.
Junio C Hamano May 24, 2020, 4 p.m. UTC | #2
Christian Couder <christian.couder@gmail.com> writes:

> On Thu, May 21, 2020 at 1:31 AM Carlo Marcelo Arenas Belón
> <carenas@gmail.com> wrote:
>>
>> 06f5608c14 (bisect--helper: `bisect_start` shell function partially in C,
>> 2019-01-02) adds a lax parser for `git bisect start` which could result
>> in a segfault under a bad syntax call for start with custom terms.
>>
>> Detect if there are enough arguments left in the command line to use for
>> --term-{old,good,new,bad} and abort with the same syntax error the original
>> implementation will show if not.
>>
>> While at it, remove an unnecessary (and incomplete) check for unknown
>> arguments and make sure to add a test to avoid regressions.
>
> This looks good to me!

Thanks, both.
diff mbox series

Patch

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index c1c40b516d..ec4996282e 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -455,9 +455,12 @@  static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			no_checkout = 1;
 		} else if (!strcmp(arg, "--term-good") ||
 			 !strcmp(arg, "--term-old")) {
+			i++;
+			if (argc <= i)
+				return error(_("'' is not a valid term"));
 			must_write_terms = 1;
 			free((void *) terms->term_good);
-			terms->term_good = xstrdup(argv[++i]);
+			terms->term_good = xstrdup(argv[i]);
 		} else if (skip_prefix(arg, "--term-good=", &arg) ||
 			   skip_prefix(arg, "--term-old=", &arg)) {
 			must_write_terms = 1;
@@ -465,16 +468,18 @@  static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			terms->term_good = xstrdup(arg);
 		} else if (!strcmp(arg, "--term-bad") ||
 			 !strcmp(arg, "--term-new")) {
+			i++;
+			if (argc <= i)
+				return error(_("'' is not a valid term"));
 			must_write_terms = 1;
 			free((void *) terms->term_bad);
-			terms->term_bad = xstrdup(argv[++i]);
+			terms->term_bad = xstrdup(argv[i]);
 		} else if (skip_prefix(arg, "--term-bad=", &arg) ||
 			   skip_prefix(arg, "--term-new=", &arg)) {
 			must_write_terms = 1;
 			free((void *) terms->term_bad);
 			terms->term_bad = xstrdup(arg);
-		} else if (starts_with(arg, "--") &&
-			 !one_of(arg, "--term-good", "--term-bad", NULL)) {
+		} else if (starts_with(arg, "--")) {
 			return error(_("unrecognized option: '%s'"), arg);
 		} else {
 			char *commit_id = xstrfmt("%s^{commit}", arg);
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 821a0c88cf..f7ef15a384 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -859,7 +859,9 @@  test_expect_success 'bisect cannot mix terms' '
 
 test_expect_success 'bisect terms rejects invalid terms' '
 	git bisect reset &&
+	test_must_fail git bisect start --term-good &&
 	test_must_fail git bisect start --term-good invalid..term &&
+	test_must_fail git bisect start --term-bad &&
 	test_must_fail git bisect terms --term-bad invalid..term &&
 	test_must_fail git bisect terms --term-good bad &&
 	test_must_fail git bisect terms --term-good old &&