Re: [tpop3d-discuss]Some conditions may lead getpwuid to fail

[Giampaolo Tomassoni]

No reply to this? Not even a "Blah!". :(

giampaolo


> Dears,
> 
> I see that in many auth_ modules in tpop3d (at least auth_pgsql) 
> user authentication involves the invoking of parse_uid() from 
> util.c, followed by a getpwuid() to obtain the user's struct passwd.
> 
> The purpose seems to me to obtain the struct passwd by allowing 
> the user database back-ends to return either a username or a uid.
> 
> Unfortunately, this causes some troubles to me. When it is 
> difficult to assign a unique id to each user, mailbox users are 
> often given a single uid and the user itself is identified only 
> by its name, not by its uid. So, the chain parse_uid() -> 
> getpwuid() may give wrong results and should be avoided. Also, it 
> is inefficient when a username is involved, since basicly 
> parse_uid() must already obtain the passwd structure in order to 
> convert the username to its uid.
> 
> The basic idea for a fix which doesn't impact on other cases, 
> would be to use getpwuid() only when the user field contains 
> numbers, while relaying on getpwnam() when a username is instead involved.
> 
> A attach a small patch which fixes this for the auth_pgsql 
> module, since this is the only one I can actually test. The patch 
> adds the new function get_pw_by_name_or_uid() to util.c, which 
> basicly mimes the work of parse_uid(), but gives back a struct 
> passwd* by mean of getpwuid() or getpwnam(). In auth_pgsql.c, a 
> call to this function replaces the parse_uid() -> getpwuid() chain.
> 
> I hope to see it in the main branch soon or later: it really 
> seems to fix my problem.
> 
> Regards,
> 
> -----------------------------------
> Giampaolo Tomassoni - IT Consultant
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