Re: safe strcpy()?

From: Ben Pfaff (blp@cs.stanford.edu)
Date: 01/30/03

  • Next message: Ed Carp: "Re: safe strcpy()?" 
    To: <secprog@securityfocus.com>
From: Ben Pfaff <blp@cs.stanford.edu>
Date: 29 Jan 2003 15:40:16 -0800

    "Michael Howard" <mikehow@microsoft.com> writes:

    > The point I'm making is people seem to think they can write crap code,
    > then bindly replace the calls to strcpy with strncpy and all of a sudden
    > their code is safe. [...]

    The usual reason cited not to use strncpy() is that it doesn't
    necessarily null-terminate its output buffer. But there's at
    least one other reason: using strncpy() into a large buffer can
    be very inefficient. strncpy() always writes to every byte in
    the destination buffer, which can waste a lot of time if the
    destination buffer is much longer than the source string.

    As a result, strncpy() is hardly ever the right function to use.
    strlcpy() from OpenBSD is usually a better choice. 

    -- 
"If a person keeps faithfully busy each hour of the working day, he
 can count on waking up some morning to find himself one of the
 competent ones of his generation."
--William James

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