[Unbound-users] Segfault on user not found with 1.5.3

[W.C.A. Wijngaards]

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Hi Maciej,

On 03/23/2015 09:41 PM, Maciej Soltysiak wrote:
> Hi Wouter,
> 
> On Mon, Mar 23, 2015 at 9:21 PM, W.C.A. Wijngaards
> <wouter at nlnetlabs.nl <mailto:wouter at nlnetlabs.nl>> wrote:
> 
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> 
> Hi Maciej,
> 
> On 03/23/2015 06:04 PM, Maciej Soltysiak wrote:
>> Hi,
>> 
>> I just took the latest 1.5.3, compiled it and ran the executable 
>> without doing any config. Just to see what happens.
>> 
>> It segfaulted after saying user unbound not found.
>> 
>> The issue is in util/config_file.c in function 
>> config_lookup_uid().
>> 
>> getpwnam() can return NULL and so subsequent referrences to
>> pw_uid and pw_gid are invalid.
>> 
>> This patch corrects the code path to assign uid and gid only if 
>> getpwnam() is successful.
>> 
>> It also removes the log_err() call, because perform_setup() in 
>> daemon/unbound.c would print it anyway in fatal_exit()
>> 
>> I know it's a tiny buglet, but I couldn't resist fixing a
>> segfault :-)
> 
> Thank you for the report, applied it by setting checks on the
> success of that lookup and continuing with the error printed.
> 
> Thanks for reviewing and applying.
> 
> What you applied to SVN is exactly what I've done initially. That
> however made it first display "user 'unbound' does not exist."
> twice. First from util/config_file.c. That allows the code run
> further, until it encounters a getpwnam() call in perform_setup()
> of unbound.c where it has fatal_exit() with the same message.
> 
> Confirmed with gdb.
> 
> That's why I removed the duplication to allow the latter error
> message to show up.
> 
> I think you might want to look at it again; or maybe point me where
> I'm making a mistake.
> 

Yes you are right, and I re-fixed it like your commit,

Best regards,
   Wouter


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