linux-kernel - Adjusting SmPL script “ptr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Sat, 7 Sep 2019 16:54:26 +0200
From:   Markus Elfring <Markus.Elfring@....de>
To:     Coccinelle <cocci@...teme.lip6.fr>, kernel-janitors@...r.kernel.org
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Allison Randal <allison@...utok.net>,
        Enrico Weigelt <lkml@...ux.net>,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nicolas Palix <nicolas.palix@...g.fr>
Subject: Adjusting SmPL script “ptr_ret.cocci”?

Hello,

I have taken another look at a known script for the semantic patch language.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/coccinelle/api/ptr_ret.cocci?id=1e3778cb223e861808ae0daccf353536e7573eed#n3

I got the impression that duplicate SmPL code can be reduced here.
So I tried the following approach out.

…
@depends on patch@
expression ptr;
@@
(
(
- if (IS_ERR(ptr)) return PTR_ERR(ptr); else return 0;
|
- if (IS_ERR(ptr)) return PTR_ERR(ptr); return 0;
)
+ return PTR_ERR_OR_ZERO(ptr);
|
- (IS_ERR(ptr) ? PTR_ERR(ptr) : 0)
+ PTR_ERR_OR_ZERO(ptr)
)
…

Unfortunately, I got the following information then for a test transformation.

elfring@...ne:~/Projekte/Linux/next-patched> spatch -D patch scripts/coccinelle/api/ptr_ret.cocci drivers/spi/spi-gpio.c
…
29: no available token to attach to

It seems that the Coccinelle software “1.0.7-00218-gf284bf36” does not like
the addition of the shown return statement after a nested SmPL disjunction.
But the following SmPL code variant seems to work as expected.

…
@depends on patch@
expression ptr;
@@
(
- if (IS_ERR(ptr)) return PTR_ERR(ptr); else return 0;
+ return PTR_ERR_OR_ZERO(ptr);
|
- if (IS_ERR(ptr)) return PTR_ERR(ptr); return 0;
+ return PTR_ERR_OR_ZERO(ptr);
|
- (IS_ERR(ptr) ? PTR_ERR(ptr) : 0)
+ PTR_ERR_OR_ZERO(ptr)
)
…

How do you think about to reduce subsequent SmPL rules also according to
a possible recombination of affected implementation details?

Regards,
Markus