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From: Julia Lawall <julia.lawall@inria.fr>
To: Denis Efremov <efremov@linux.com>
Cc: linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
	cocci@systeme.lip6.fr
Subject: Re: [Cocci] [PATCH] coccinelle: misc: add array_size_dup script to detect missed overlow checks
Date: Wed, 17 Jun 2020 22:08:19 +0200 (CEST)
Message-ID: <alpine.DEB.2.22.394.2006172154040.3083@hadrien> (raw)
In-Reply-To: <e34b7e26-6f07-19b6-39ad-e3bc939551fc@linux.com>



On Wed, 17 Jun 2020, Denis Efremov wrote:

>
> >
> > Awesome! I'll take a look into this. :)
> >
> Here is another script for your #83 ticket.
> Currently, it issues 598 warnings.
>
> // SPDX-License-Identifier: GPL-2.0-only
> ///
> /// Check for missing overflow checks in allocation functions.
> /// Low confidence because it's pointless to check for overflow
> /// relatively small allocations.
> ///
> // Confidence: Low
> // Copyright: (C) 2020 Denis Efremov ISPRAS
> // Options: --no-includes --include-headers
>
> virtual patch
> virtual context
> virtual org
> virtual report
>
> @depends on patch@
> expression E1, E2, E3, E4, size;
> @@
>
> (
> - size = E1 * E2;
> + size = array_size(E1, E2);
> |
> - size = E1 * E2 * E3;
> + size = array3_size(E1, E2, E3);
> |
> - size = E1 * E2 + E3;
> + size = struct_size(E1, E2, E3);

Should the arguments be checked to see if they have something to do with
arrays and structures?

> )
>   ... when != size = E4
>       when != size += E4
>       when != size -= E4
>       when != size *= E4

Here you can have a metavariable

assignment operator aop;

and then say size aop E4

It doesn't really look like an assignment any more, but it could be a
little safer.

julia

>       when != &size
>   \(kmalloc\|krealloc\|kzalloc\|kzalloc_node\|
>     vmalloc\|vzalloc\|vzalloc_node\|
>     kvmalloc\|kvzalloc\|kvzalloc_node\|
>     sock_kmalloc\|
>     f2fs_kmalloc\|f2fs_kzalloc\|f2fs_kvmalloc\|f2fs_kvzalloc\|
>     devm_kmalloc\|devm_kzalloc\)
>   (..., size, ...)
>
> @r depends on !patch@
> expression E1, E2, E3, E4, size;
> position p;
> @@
>
> (
> * size = E1 * E2;@p
> |
> * size = E1 * E2 * E3;@p
> |
> * size = E1 * E2 + E3;@p
> )
>   ... when != size = E4
>       when != size += E4
>       when != size -= E4
>       when != size *= E4
>       when != &size
> * \(kmalloc\|krealloc\|kzalloc\|kzalloc_node\|
>     vmalloc\|vzalloc\|vzalloc_node\|
>     kvmalloc\|kvzalloc\|kvzalloc_node\|
>     sock_kmalloc\|
>     f2fs_kmalloc\|f2fs_kzalloc\|f2fs_kvmalloc\|f2fs_kvzalloc\|
>     devm_kmalloc\|devm_kzalloc\)
>   (..., size, ...)
>
> @script:python depends on report@
> p << r.p;
> @@
>
> coccilib.report.print_report(p[0], "WARNING: missing overflow check")
>
> @script:python depends on org@
> p << r.p;
> @@
>
> coccilib.org.print_todo(p[0], "WARNING: missing overflow check")
> _______________________________________________
> Cocci mailing list
> Cocci@systeme.lip6.fr
> https://systeme.lip6.fr/mailman/listinfo/cocci
>
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  reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15 10:20 Denis Efremov
2020-06-15 18:23 ` Kees Cook
2020-06-15 18:35   ` Denis Efremov
2020-06-15 18:46     ` Gustavo A. R. Silva
2020-06-17  9:32       ` Denis Efremov
2020-06-17 10:55       ` Denis Efremov
2020-06-17 20:08         ` Julia Lawall [this message]
2020-06-17 20:15           ` Julia Lawall
2020-06-17 18:15 ` Kees Cook
2020-06-17 18:54   ` Julia Lawall
2020-06-18 19:52     ` Kees Cook
2020-06-18 19:56       ` Julia Lawall
2020-06-18 20:48         ` Kees Cook
2020-06-18 21:08           ` Julia Lawall
2020-06-17 20:30 ` Julia Lawall
2020-06-17 20:50   ` Denis Efremov
2020-06-17 20:52     ` Julia Lawall
2020-06-18 10:23 ` [Cocci] [PATCH v2] " Denis Efremov
2020-06-19 13:13 ` [Cocci] [PATCH v3] coccinelle: misc: add array_size_dup script to detect missed overflow checks Denis Efremov
2020-06-21 20:53   ` Julia Lawall
2020-06-21 20:56   ` Julia Lawall
2020-06-22 12:12     ` Denis Efremov
2020-06-22 12:16     ` Denis Efremov
2020-06-22 12:19       ` Julia Lawall
2020-06-22 22:10 ` [Cocci] [PATCH v4] " Denis Efremov
2020-06-24 19:42   ` Julia Lawall

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