Re: (ITS#5121) IDL cache issue

[ando@sys-net.it]

Howard Chu wrote:
> ando@sys-net.it wrote:
>> To reproduce:
>>
>> - set idlcache
>>
>> - search one entry, so that the idl gets cached
>>
>> - delete that entry, so that the idl gets cleared - but head/tail don't
>>
>> - search another entry so that it gets cached - head/tail are corrupted
>>
>> I've a fix for this about to come (affects 2.4.5 as well, sigh; not sure
>> about re23).
> 
> Coverity shows this patch has introduced a NULL pointer dereference.
> @@ -364,6 +381,9 @@
>                 ee = bdb->bi_idl_lru_tail;
>                 for ( i = 0; i < 10; i++, ee = eprev ) {
>                         eprev = ee->idl_lru_prev;
> +                       if ( eprev == ee ) {
> +                               eprev = NULL;
> +                       }
>                         if ( ee->idl_flags & CACHE_ENTRY_REFERENCED ) {
>                                 ee->idl_flags ^= CACHE_ENTRY_REFERENCED;
>                                 continue;
> 
> What's the purpose of this change

Make sure bi_idl_lru_tail gets set to NULL if purging the cache makes it
empty.  Perhaps it's an overshoot.

> and should you be testing for a NULL
> now in the for loop conditions?

Yes, I realize I should test for ee != NULL in the for loop.

p.



Ing. Pierangelo Masarati
OpenLDAP Core Team

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