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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v1 1/1] lib/string_helpers: Don't copy a tail in kstrdup_and_replace() if 'new' is \0
Date: Thu, 14 Sep 2023 21:37:07 +0300	[thread overview]
Message-ID: <ZQNS0qzJVrRRgNLO@smile.fi.intel.com> (raw)
In-Reply-To: <20230913094557.451463-1-andriy.shevchenko@linux.intel.com>

On Wed, Sep 13, 2023 at 12:45:57PM +0300, Andy Shevchenko wrote:
> The kstrdup_and_replace() takes two characters, old and new, to replace
> former with latter after the copying of the original string. But in case
> when new is a NUL, there is no point to copy the rest of the string,
> the contract with the callers is that that the function returns a
> NUL-terminated string and not a buffer of the size filled with a given
> data. With this we can optimize the memory consumption by copying only
> meaningful part of the original string and drop the rest.

Thinking about this more, I self NAK this.
If the caller knows the size of the original message it can be handy to make
a copy and replace all occurrences of old by NUL. This will be an optimized
implementation of strsep(str, "$OLD").

-- 
With Best Regards,
Andy Shevchenko



      reply	other threads:[~2023-09-14 18:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-13  9:45 [PATCH v1 1/1] lib/string_helpers: Don't copy a tail in kstrdup_and_replace() if 'new' is \0 Andy Shevchenko
2023-09-14 18:37 ` Andy Shevchenko [this message]

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