From: Fabian Stelzer <fs@gigacodes.de>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: git@vger.kernel.org, Pedro Martelletto <pedro@yubico.com>,
Junio C Hamano <gitster@pobox.com>, Jeff King <peff@peff.net>,
Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: Re: [PATCH v3] gpg-interface: trim CR from ssh-keygen
Date: Mon, 10 Jan 2022 13:59:01 +0100 [thread overview]
Message-ID: <20220110125901.apxqy7tzrc3edjwa@fs> (raw)
In-Reply-To: <YdtVrT4gBvnXfNr6@flurp.local>
On 09.01.2022 16:37, Eric Sunshine wrote:
>On Fri, Jan 07, 2022 at 10:07:35AM +0100, Fabian Stelzer wrote:
>> We need to trim \r from the output of 'ssh-keygen -Y find-principals' on
>> Windows, or we end up calling 'ssh-keygen -Y verify' with a bogus signer
>> identity. ssh-keygen.c:2841 contains a call to puts(3), which confirms
>> this hypothesis. Signature verification passes with the fix.
>>
>> Helped-by: Pedro Martelletto <pedro@yubico.com>
>> Signed-off-by: Fabian Stelzer <fs@gigacodes.de>
>
>Should this also have a "Helped-by: Junio" since this code was heavily
>inspired by his suggestion[1]?
Yeah, this should have a "Written-by: Junio" ^^
I'm never sure when to add these headers (except the signed-off).
>
>[1]: https://lore.kernel.org/git/xmqqo84rcn3j.fsf@gitster.g/
>
>> ---
>> diff --git a/gpg-interface.c b/gpg-interface.c
>> @@ -502,15 +501,30 @@ static int verify_ssh_signed_buffer(struct signature_check *sigc,
>> + const char *next;
>> + for (line = ssh_principals_out.buf;
>> + *line;
>> + line = next) {
>> + const char *end_of_text;
>> +
>> + next = end_of_text = strchrnul(line, '\n');
>> +
>> + /* Did we find a LF, and did we have CR before it? */
>> + if (*end_of_text &&
>> + line < end_of_text &&
>> + end_of_text[-1] == '\r')
>> + end_of_text--;
>> +
>> + /* Unless we hit NUL, skip over the LF we found */
>> + if (*next)
>> + next++;
>> +
>> + /* Not all lines are data. Skip empty ones */
>> + if (line == end_of_text)
>> + continue;
>> +
>> + /* We now know we have an non-empty line. Process it */
>> + principal = xmemdupz(line, end_of_text - line);
>
>Considering that this code makes a copy of the line _anyhow_ which it
>assigns to `principal`, it still seems like it would be simpler and
>far easier to understand at-a-glance to instead take advantage of one
>of the existing string-splitting functions. For instance, something
>like this:
>
> struct strbuf **line, **to_free;
> line = to_free = strbuf_split(&ssh_principals_out, '\n');
> for (; *line; line++) {
> strbuf_trim_trailing_newline(*line);
> if (!(*line)->len)
> continue;
> principal = (*line)->buf;
>
>keeping in mind that strbuf_trim_trailing_newline() takes care of
>CR/LF, and with appropriate cleanup at the end of the loop:
>
> strbuf_list_free(to_free);
>
>(and removal of `FREE_AND_NULL(principal)` which is no longer needed).
>
>Something similar can be done with string_list_split(), as well.
I agree that this is the most readable of the variants (and it works just as
well). Since in most cases there even will only ever be a single line of
output the extra work/allocation we might be doing with it is quite minimal.
I have done something quite similar in get_default_ssh_signing_key() and got
a bit of negative feedback for it (being overkill for retrieving a single
line) but ended up using it anyway.
next prev parent reply other threads:[~2022-01-10 13:00 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-03 13:31 [PATCH] gpg-interface: trim CR from ssh-keygen -Y find-principals Johannes Schindelin via GitGitGadget
2021-12-03 14:18 ` Fabian Stelzer
2021-12-03 15:58 ` Jeff King
2021-12-04 13:11 ` Fabian Stelzer
2021-12-05 5:50 ` Junio C Hamano
[not found] ` <CABPYr=y+sDDko9zPxQTOM6Tz4E7CafH7hJc6oB1zv7XYA9KH1A@mail.gmail.com>
2021-12-09 16:33 ` Fabian Stelzer
[not found] ` <CABPYr=xfotWvTQK9k1eKHa0kP4SsB=TKKuM0d8cpMb5BtuUZLA@mail.gmail.com>
2021-12-09 17:20 ` Fabian Stelzer
2021-12-30 10:25 ` Fabian Stelzer
2021-12-05 23:06 ` Damien Miller
2021-12-06 8:39 ` Fabian Stelzer
2022-01-03 9:53 ` [PATCH v2] gpg-interface: trim CR from ssh-keygen Fabian Stelzer
2022-01-03 17:17 ` Eric Sunshine
2022-01-03 23:34 ` Junio C Hamano
2022-01-04 0:41 ` Eric Sunshine
2022-01-04 1:19 ` Junio C Hamano
2022-01-04 3:06 ` Eric Sunshine
2022-01-04 12:55 ` Fabian Stelzer
2022-01-04 19:33 ` Junio C Hamano
2022-01-05 7:09 ` Eric Sunshine
2022-01-05 10:36 ` Fabian Stelzer
2022-01-05 20:40 ` Junio C Hamano
2022-01-06 10:26 ` Fabian Stelzer
2022-01-06 17:50 ` Junio C Hamano
2022-01-09 20:49 ` Eric Sunshine
2022-01-10 12:28 ` Fabian Stelzer
2022-01-07 9:07 ` [PATCH v3] " Fabian Stelzer
2022-01-09 21:37 ` Eric Sunshine
2022-01-10 12:59 ` Fabian Stelzer [this message]
2022-01-10 17:51 ` Junio C Hamano
2022-01-10 17:03 ` Junio C Hamano
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