From: Junio C Hamano <gitster@pobox•com>
To: Stefan Beller <sbeller@google•com>
Cc: sahlberg@google•com, jrnieder@gmail•com, git@vger•kernel.org
Subject: Re: [PATCH] refs.c: add a function to append a reflog entry to a fd
Date: Wed, 19 Nov 2014 17:34:44 -0800 [thread overview]
Message-ID: <xmqqvbma4pu3.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <xmqqzjbm4qe5.fsf@gitster.dls.corp.google.com> (Junio C. Hamano's message of "Wed, 19 Nov 2014 17:22:42 -0800")
Junio C Hamano <gitster@pobox•com> writes:
> Stefan Beller <sbeller@google•com> writes:
>
>> Compared to the last send of this patch[1], there was one change in the print
>> function. Replaced sprintf by snprintf for security reasons.
>
> Careful. I despise people who blindly think strlcpy() and
> snprintf() are good solutions for for security. They are by
> themselves not.
> ...
> So use of snprintf() is not really buying you much here, not in the
> current code certainly, but not as a future-proofing measure,
> either.
Don't get me wrong. I am not saying that using snprintf() here is
bad per-se. There should be no difference.
But I do not want to see people getting in the habit of thinking "I
now use snprintf/strlcpy instead of sprintf/strcpy, and made my code
more secure." Often they are not doing that.
The only case snprintf/strlcpy is useful is when your data does not
matter in its detail. E.g. when you are preparing human-readble
data whose first part is sufficient to convey the information you
want to convey, you would be perfectly happy if the result is
truncated. In such a case, counting to allocate enough to hold
everything and running sprintf() only to chop the result later is
not necessary --- it still is not wrong, though --- and allocating
enough to satisify the eventual chop length and using snprintf()
is easier way to achieve the same result.
But I do not think this codepath falls into such an "I am willing to
lose data" case.
next prev parent reply other threads:[~2014-11-20 1:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-20 0:42 [PATCH] refs.c: add a function to append a reflog entry to a fd Stefan Beller
2014-11-20 1:22 ` Junio C Hamano
2014-11-20 1:34 ` Junio C Hamano [this message]
2014-11-20 2:05 ` Stefan Beller
2014-11-20 2:36 ` Jonathan Nieder
2014-11-20 16:57 ` Junio C Hamano
2014-11-20 18:37 ` [PATCH v3] " Stefan Beller
2014-11-20 21:20 ` Jonathan Nieder
2014-11-20 21:24 ` Stefan Beller
2014-11-20 21:31 ` Jonathan Nieder
2014-11-20 21:42 ` Junio C Hamano
2014-11-20 21:58 ` Stefan Beller
2014-11-20 22:05 ` Jonathan Nieder
2014-11-20 22:11 ` Junio C Hamano
2014-11-20 21:59 ` [PATCH v4] " Stefan Beller
2014-11-20 22:11 ` Jonathan Nieder
2014-11-20 22:29 ` Junio C Hamano
2014-11-20 1:42 ` [PATCH] " Jonathan Nieder
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