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From: Junio C Hamano <gitster@pobox.com>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: Jinoh Kang <luke1337@theori.io>, Junio C Hamano <junio@pobox.com>,
	git@vger.kernel.org
Subject: Re: [PATCH v5] diff: make diff_free_filespec_data accept NULL
Date: Wed, 11 Nov 2020 11:18:46 -0800	[thread overview]
Message-ID: <xmqqk0ur4s89.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <nycvar.QRO.7.76.6.2011111727090.18437@tvgsbejvaqbjf.bet> (Johannes Schindelin's message of "Wed, 11 Nov 2020 17:27:48 +0100 (CET)")

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> Hi Jinoh,
>
> On Wed, 11 Nov 2020, Jinoh Kang wrote:
>
>> diff_free_filespec_data crashes when passed a NULL fillspec pointer.
>> Commit 3aef54e8b8 ("diff: munmap() file contents before running external
>> diff", 2019-07-11) introduced calls to diff_free_filespec_data in
>> run_external_diff without also checking if the argument is NULL.
>>
>> Git uses NULL filespecs to indicate unmerged files when merge conflict
>> resolution is in progress.  Fortunately, other code paths bail out early
>> even before NULL can reach diff_free_filespec_data(); however, difftool
>> is expected to do a full-blown diff anyway regardless of conflict
>> status.
>>
>> Fix this and prevent any similar bugs in the future by making
>> `diff_free_filespec_data(NULL)` a no-op.
>>
>> Add a test case that confirms that running difftool --cached with
>> unmerged files does not result in a SIGSEGV.
>>
>> Signed-off-by: Jinoh Kang <luke1337@theori.io>
>
> ACK!
>
> The patch looks good to go to me.
>
> Thank you!
> Dscho

Thanks, both.
Will queue.


>
>> ---
>>  diff.c              |  3 +++
>>  t/t7800-difftool.sh | 13 +++++++++++++
>>  2 files changed, 16 insertions(+)
>>
>> diff --git a/diff.c b/diff.c
>> index d24f47df99..ace4a1d387 100644
>> --- a/diff.c
>> +++ b/diff.c
>> @@ -4115,6 +4115,9 @@ void diff_free_filespec_blob(struct diff_filespec *s)
>>
>>  void diff_free_filespec_data(struct diff_filespec *s)
>>  {
>> +	if (!s)
>> +		return;
>> +
>>  	diff_free_filespec_blob(s);
>>  	FREE_AND_NULL(s->cnt_data);
>>  }
>> diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
>> index 524f30f7dc..a578b35761 100755
>> --- a/t/t7800-difftool.sh
>> +++ b/t/t7800-difftool.sh
>> @@ -728,6 +728,19 @@ test_expect_success 'add -N and difftool -d' '
>>  	git difftool --dir-diff --extcmd ls
>>  '
>>
>> +test_expect_success 'difftool --cached with unmerged files' '
>> +	test_when_finished git reset --hard &&
>> +
>> +	test_commit conflicting &&
>> +	test_commit conflict-a conflict.t a &&
>> +	git reset --hard conflicting &&
>> +	test_commit conflict-b conflict.t b &&
>> +	test_must_fail git merge conflict-a &&
>> +
>> +	git difftool --cached --no-prompt >output &&
>> +	test_must_be_empty output
>> +'
>> +
>>  test_expect_success 'outside worktree' '
>>  	echo 1 >1 &&
>>  	echo 2 >2 &&
>> --
>> 2.26.2
>>
>>

  reply	other threads:[~2020-11-11 19:18 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <aeb24944-17af-cf53-93f4-e727f9fe9988@theori.io>
     [not found] ` <xmqq4km4lppy.fsf@gitster.c.googlers.com>
2020-11-06 17:02   ` [PATCH v2] diff: handle NULL filespecs in run_external_diff Jinoh Kang
2020-11-06 17:14     ` [PATCH v3] diff: make diff_free_filespec_data accept NULL Jinoh Kang
2020-11-10 12:08       ` Johannes Schindelin
2020-11-10 13:16         ` Jinoh Kang
2020-11-10 14:21         ` Jinoh Kang
2020-11-10 17:02         ` Junio C Hamano
2020-11-10 14:06       ` [PATCH v4] " Jinoh Kang
2020-11-10 15:38         ` Johannes Schindelin
2020-11-11 12:30           ` Jinoh Kang
2020-11-11 16:28             ` Johannes Schindelin
2020-11-10 19:41         ` Junio C Hamano
2020-11-11 12:15         ` [PATCH v5] " Jinoh Kang
2020-11-11 16:27           ` Johannes Schindelin
2020-11-11 19:18             ` Junio C Hamano [this message]
2020-11-06 19:18     ` [PATCH v2] diff: handle NULL filespecs in run_external_diff Junio C Hamano

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