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From: Junio C Hamano <gitster@pobox.com>
To: Miriam Rubio <mirucam@gmail.com>
Cc: git@vger.kernel.org, Tanushree Tumane <tanushreetumane@gmail.com>,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	Christian Couder <chriscool@tuxfamily.org>
Subject: Re: [Outreachy] [PATCH v2] bisect--helper: avoid free-after-use
Date: Wed, 11 Dec 2019 09:24:07 -0800	[thread overview]
Message-ID: <xmqqh826pyh4.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <xmqqo8wepyse.fsf@gitster-ct.c.googlers.com> (Junio C. Hamano's message of "Wed, 11 Dec 2019 09:17:21 -0800")

Junio C Hamano <gitster@pobox.com> writes:

> Subject: Re: [Outreachy] [PATCH v2] bisect--helper: avoid free-after-use

It is surprising with multiple mentors, nobody noticed free-after-use
is perfectly fine---it is use-after-free we would want to avoid.

> Miriam Rubio <mirucam@gmail.com> writes:
>
>> From: Tanushree Tumane <tanushreetumane@gmail.com>
>>
>> In 5e82c3dd22a (bisect--helper: `bisect_reset` shell function in C,
>> 2019-01-02), the `git bisect reset` subcommand was ported to C. When the
>> call to `git checkout` failed, an error message was reported to the
>> user.
>>
>> However, this error message used the `strbuf` that had just been
>> released already. Let's switch that around: first use it, then release
>> it.
>>
>> Mentored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
>> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
>> Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com>
>> Signed-off-by: Miriam Rubio <mirucam@gmail.com>
>> ---
>> This patch is a new version of
>> https://public-inbox.org/git/20191208172813.16518-1-mirucam@gmail.com/
>> which itself has been sent previously by Tanushree
>> (https://public-inbox.org/git/64117cde718f0d56ebfa4c30f4d8fe2155f5cf65.1551003074.git.gitgitgadget@gmail.com/).
>>
>>  builtin/bisect--helper.c | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
>> index 1fbe156e67..3055b2bb50 100644
>> --- a/builtin/bisect--helper.c
>> +++ b/builtin/bisect--helper.c
>> @@ -169,11 +169,12 @@ static int bisect_reset(const char *commit)
>>  
>>  		argv_array_pushl(&argv, "checkout", branch.buf, "--", NULL);
>>  		if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
>> +			error(_("could not check out original"
>> +				" HEAD '%s'. Try 'git bisect"
>> +				" reset <commit>'."), branch.buf);
>>  			strbuf_release(&branch);
>>  			argv_array_clear(&argv);
>> -			return error(_("could not check out original"
>> -				       " HEAD '%s'. Try 'git bisect"
>> -				       " reset <commit>'."), branch.buf);
>
> The original obviously was bad X-<.  Will queue.  Thanks.
>
>> +			return -1;
>>  		}
>>  		argv_array_clear(&argv);
>>  	}

  reply	other threads:[~2019-12-11 17:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09 10:39 [Outreachy] [PATCH v2] bisect--helper: avoid free-after-use Miriam Rubio
2019-12-11 17:17 ` Junio C Hamano
2019-12-11 17:24   ` Junio C Hamano [this message]
2019-12-11 19:14     ` Miriam R.
2019-12-12 19:16     ` Johannes Schindelin
  -- strict thread matches above, loose matches on Subject: below --
2019-12-09 10:56 Miriam Rubio

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