[Pkg-dspam-misc] Bug#722484: Info received (libdspam7-drv-hash segfaults since 3.10.2+dfsg-10)

[Thomas Preud'homme]

Le mercredi 9 octobre 2013 14:56:23, vous avez écrit :
> 
> Yes the bug was introduced between 3.10.2+dfsg-9 and 3.10.2+dfsg-10. As
> I'm running -9 without problems.
> 
> Although the incremental diff from -9 to -10 doesn't look suspicious at
> 
> the first glance:
> > diff --git a/src/hash_drv.c b/src/hash_drv.c
> > index 349b491..daae2e7 100644
> > --- a/src/hash_drv.c
> > +++ b/src/hash_drv.c
> > @@ -1187,32 +1187,36 @@ unsigned long _hash_drv_seek(
> > 
> >    unsigned long fpos;
> >    unsigned long iterations = 0;
> >    
> >    if (offset >= map->file_len)
> >    
> >      return 0;
> >    
> >    fpos = sizeof(struct _hash_drv_header) +
> >    
> >      ((hashcode % header->hash_rec_max) * sizeof(struct
> >      _hash_drv_spam_record));
> 
>         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> According to the backtrace's line number the diff-by-zero should happen
> here. But the modulo, which is IIRC implemented on ARM as
> divide/multiply/difference, was here all the time.
> 
> Was there a compiler change? Maybe some new optimisations brakes the code.

Without having looked at the code, I suspect that hash_rec_max is updated from 
_hash_drv_seek's return value. Since I added a check to detect when the end of 
file is going to be reached, the function returns 0 in case where it was not 
the case before.