From: Siddhesh Poyarekar <siddhesh@gotplt.org>
To: Alejandro Colomar <alx.manpages@gmail.com>,
Vincent Lefevre <vincent@vinc17.net>,
libc-alpha@sourceware.org
Subject: Re: UB status of snprintf on invalid ptr+size combination?
Date: Mon, 20 Mar 2023 08:29:35 -0400 [thread overview]
Message-ID: <00d00b5a-82ed-0368-7fc2-5d080f01069c@gotplt.org> (raw)
In-Reply-To: <f2da3fc3-62f5-a86a-0429-d0a88f251044@gmail.com>
On 2023-03-20 08:17, Alejandro Colomar wrote:
>>> if (checked)
>>> sprintf (buf, "%s", s);
>>> else
>>> snprintf(buf, n, "%s", s);
>>>
>>> in particular in the cases where the format string is complex.
>
> That pattern looks like _FORTIFY_SOURCE, doesn't it? If so, the correct
> action would be to call sprintf(3) and rely on the compiler to do the
> checks.
Yes the pattern is similar to __sprintf_chk, except that if the result
string is larger, it will result in program abort while in the above
pattern the string will get truncated.
Sid
next prev parent reply other threads:[~2023-03-20 12:29 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-14 19:47 Simon Chopin
2023-03-14 21:39 ` Paul Eggert
2023-03-15 9:22 ` Andreas Schwab
2023-03-15 15:54 ` Siddhesh Poyarekar
2023-03-15 18:34 ` Michael Hudson-Doyle
2023-03-19 14:45 ` manfred
2023-03-19 23:07 ` Vincent Lefevre
2023-03-20 12:05 ` Siddhesh Poyarekar
2023-03-20 12:17 ` Alejandro Colomar
2023-03-20 12:29 ` Siddhesh Poyarekar [this message]
2023-03-20 13:36 ` Vincent Lefevre
2023-03-20 13:50 ` Vincent Lefevre
2023-03-20 16:56 ` Siddhesh Poyarekar
2023-03-20 17:36 ` Vincent Lefevre
2023-03-20 15:09 ` Vincent Lefevre
2023-03-20 16:15 ` Alejandro Colomar
2023-03-20 16:33 ` Vincent Lefevre
2023-03-20 17:00 ` Vincent Lefevre
2023-03-20 17:31 ` Siddhesh Poyarekar
2023-03-20 17:45 ` Vincent Lefevre
2023-03-15 12:39 ` Vincent Lefevre
2023-03-16 10:29 ` Stephan Bergmann
2023-03-18 2:07 ` Vincent Lefevre
2023-03-18 2:30 ` Alejandro Colomar
2023-03-18 10:58 ` Vincent Lefevre
2023-03-18 15:01 ` Andreas Schwab
2023-03-19 22:48 ` Vincent Lefevre
2023-03-19 23:24 ` Andreas Schwab
2023-03-20 4:10 ` Vincent Lefevre
2023-03-20 9:19 ` Andreas Schwab
2023-03-20 10:42 ` Vincent Lefevre
2023-03-20 10:44 ` Andreas Schwab
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