Re: [PATCH v1] imap/auth_cram.c: Don't use strfcpy() where we don't want to generate a C string

"Kevin J. McCarthy" <[email protected]> Mon, 20 Apr 2026 07:04:02 +0800

Newsgroups	gmane.mail.mutt.devel
Message-ID	<aeVfYi8_cr8w1_IQ@qinghai>

On Sun, Apr 19, 2026 at 08:24:01PM +0200, Alejandro Colomar via Mutt-dev wrote:
>strfcpy() ensures it creates a string.  But that's not what we want.
>Here, we just want raw bytes in the output.  It's only the input which
>is a string (password).
>
>strncpy(3) is quite appropriate for this specific use.  It's a function
>that takes a C string as input, and fills a fixed-size buffer with bytes
>from it, zeroing the unused remainder part of the buffer.
>
>Because of this use of strncpy(3), we can remove the memset(3) calls.
>They're now entirely redundant.  (The other branch fills the entire
>buffer, so it was only meaningful in the branch we're touching.)

It's early and my brain isn't fully awake.  But I believe this is 
incorrect.  The other branch only fills to MD5_DIGEST_LEN.  Removing the 
memset() in that case, and copying the entire secret buffer, instead of 
secret_len, would break the algorithm.

-- 
Kevin J. McCarthy
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