Re: replace strtok() - Mailing list pgsql-hackers

On 10.10.24 14:59, Ranier Vilela wrote:
>     Please look at the SCRAM secret, which breaks parse_scram_secret(),
>     perhaps because strsep() doesn't return NULL where strtok() did:
>
>     CREATE ROLE r PASSWORD
>     'SCRAM-
>     SHA-256$4096:hpFyHTUsSWcR7O9P$LgZFIt6Oqdo27ZFKbZ2nV+=vtnYM995pDh9ca6WSi120qVV5NeluNfUPkwm7Vqat25RjSPLkGeoZBQs6wVv+um4=';
>
>     Core was generated by `postgres: law regression [local] CREATE
>     ROLE                                  '.
>     Program terminated with signal SIGSEGV, Segmentation fault.
>
>     #0  __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:74
>     (gdb) bt
>     #0  __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:74
>     #1  0x0000563625e9e5b0 in parse_scram_secret (...) at auth-scram.c:655
>
> Thanks for the report.
>
> It seems to me that it could be due to incorrect use of the strsep function.
> See:
> https://man7.org/linux/man-pages/man3/strsep.3.html <https://man7.org/
> linux/man-pages/man3/strsep.3.html>
> "
>
> In case no delimiter was found, the token
>         is taken to be the entire string/*stringp/, and/*stringp/ is made
>         NULL.
>
> "
> So, it is necessary to check the *stringp* against NULL too.

Thanks for the analysis.  I think moreover we *only* need to check the
"stringp" for NULL, not the return value of strsep(), which would never
be NULL in our case.  So I propose the attached patch as a variant of yours.