From: Andrew Morton <akpm@linux-foundation.org>
To: Vasiliy Kulikov <segooon@gmail.com>
Cc: kernel-janitors@vger.kernel.org,
"André Goddard Rosa" <andre.goddard@gmail.com>,
"Joe Perches" <joe@perches.com>,
"Frederic Weisbecker" <fweisbec@gmail.com>,
"Bjorn Helgaas" <bjorn.helgaas@hp.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lib: vsprintf: fix invalid arg check
Date: Wed, 10 Nov 2010 21:08:34 +0000 [thread overview]
Message-ID: <20101110130834.02496b48.akpm@linux-foundation.org> (raw)
In-Reply-To: <1289421490-23950-1-git-send-email-segooon@gmail.com>
On Wed, 10 Nov 2010 23:38:08 +0300
Vasiliy Kulikov <segooon@gmail.com> wrote:
> "size" is size_t. If we want to check whether it was underflowed
> then we should cast it to ssize_t instead of int. When
> sizeof(size_t) > sizeof(int) the code sees UINT_MAX as underflow,
> but it is not.
>
Does this patch fix any actual observed problem?
> Compile tested.
>
I guess not.
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1290,7 +1290,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
>
> /* Reject out-of-range values early. Large positive sizes are
> used for unknown buffer sizes. */
Thousands of people would find that comment to be utterly mysterious.
I am one.
> - if (WARN_ON_ONCE((int) size < 0))
> + if (WARN_ON_ONCE((ssize_t) size < 0))
> return 0;
>
> str = buf;
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Vasiliy Kulikov <segooon@gmail.com>
Cc: kernel-janitors@vger.kernel.org,
"André Goddard Rosa" <andre.goddard@gmail.com>,
"Joe Perches" <joe@perches.com>,
"Frederic Weisbecker" <fweisbec@gmail.com>,
"Bjorn Helgaas" <bjorn.helgaas@hp.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lib: vsprintf: fix invalid arg check
Date: Wed, 10 Nov 2010 13:08:34 -0800 [thread overview]
Message-ID: <20101110130834.02496b48.akpm@linux-foundation.org> (raw)
In-Reply-To: <1289421490-23950-1-git-send-email-segooon@gmail.com>
On Wed, 10 Nov 2010 23:38:08 +0300
Vasiliy Kulikov <segooon@gmail.com> wrote:
> "size" is size_t. If we want to check whether it was underflowed
> then we should cast it to ssize_t instead of int. When
> sizeof(size_t) > sizeof(int) the code sees UINT_MAX as underflow,
> but it is not.
>
Does this patch fix any actual observed problem?
> Compile tested.
>
I guess not.
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1290,7 +1290,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
>
> /* Reject out-of-range values early. Large positive sizes are
> used for unknown buffer sizes. */
Thousands of people would find that comment to be utterly mysterious.
I am one.
> - if (WARN_ON_ONCE((int) size < 0))
> + if (WARN_ON_ONCE((ssize_t) size < 0))
> return 0;
>
> str = buf;
next prev parent reply other threads:[~2010-11-10 21:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-10 20:38 [PATCH] lib: vsprintf: fix invalid arg check Vasiliy Kulikov
2010-11-10 20:38 ` Vasiliy Kulikov
2010-11-10 21:08 ` Andrew Morton [this message]
2010-11-10 21:08 ` Andrew Morton
2010-11-10 21:38 ` David Rientjes
2010-11-10 21:38 ` David Rientjes
2010-11-11 8:34 ` Vasiliy Kulikov
2010-11-11 8:34 ` Vasiliy Kulikov
2010-11-11 20:38 ` David Rientjes
2010-11-11 20:38 ` David Rientjes
2010-11-11 21:02 ` Vasiliy Kulikov
2010-11-11 21:02 ` Vasiliy Kulikov
2010-11-11 21:34 ` David Rientjes
2010-11-11 21:34 ` David Rientjes
2010-11-12 17:42 ` Vasiliy Kulikov
2010-11-12 17:42 ` Vasiliy Kulikov
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