>On 21 Jul 2001, Dale Southard wrote:
>
>> Sshd should probably be constraining its match to the length of the
>> crypt() output rather than the length of the password file entry. [I
>> say ``probably'' here because some systems (AIX) seem to produce null
>> password file hashes when `passwd` is given a null password. If that
>> behavior is due to the underlying crypt() function, then the
>> ``probably'' suggestion I just made yields remote root on those
>> systems.]
>
>What's wrong with just using `strcmp' (i.e. no constraint at all)? After
>all, what you want to know is just whether the two strings are identical,
>period. And unless crypt() and /etc/shadow are both broken, it will stop
>at the right place. I realize it goes against the reflexive "only strn*
>functions are safe" idea, but that shouldn't substitute for thinking...

It does look a knee-jerk str* is bad, use strn* type of code change.

strcmp() is *never* dangerous. strncmp() is really only useful
for prefix checking and should not be introduced as part of "security fixes".

Casper

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