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Date: Tue, 19 Feb 2013 17:35:50 +0800
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Subject: Re: Possible bug in NFSv4 with krb5p security?
From: =?ISO-8859-1?Q?Elias_M=E5rtenson?= <lokedhs@gmail.com>
To: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>
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Cc: Rick Macklem <rmacklem@uoguelph.ca>, Benjamin Kaduk <kaduk@mit.edu>,
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On 19 February 2013 17:31, Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>wrote:

It can require bigger buffer, since root can get the pw_password field
> in the struct passwd{}.
>
> Since sysconf(_SC_GETPW_R_SIZE_MAX) does not work on FreeBSD, the buffer
> for getpwnam_r() call should have at least (2 * MAXLOGNAME + 2 *
> MAXPATHLEN +
> _PASSWORD_LEN + 1) bytes (it is unclear how much is required for pw_gecos).
>
> This buffer can be dynamically reallocated until getpwnam_r() is not
> return ERANGE error (the following code has not been compiled and
> verified):
>

Is this really a better solution than to aim high right away? A series of
malloc() calls should certainly have much higher overhead than the previous
stack-allocated solution.

A better compromise would be to do the lookup in a separate function, that
allocates the buffer using alloca() instead, yes?

Regards,
Elias