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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Trond Myklebust <trond.myklebust@primarydata.com>,
	"J. Bruce Fields" <bfields@fieldses.org>,
	"David S. Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH v3 3/3] lib/string_helpers.c: Change semantics of string_escape_mem
Date: Mon, 23 Feb 2015 14:50:20 +0200	[thread overview]
Message-ID: <1424695820.14897.10.camel@linux.intel.com> (raw)
In-Reply-To: <87oaoo59n2.fsf@rasmusvillemoes.dk>

On Sat, 2015-02-21 at 02:35 +0100, Rasmus Villemoes wrote:
> On Tue, Feb 10 2015, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> >> >> @@ -301,29 +301,26 @@ static __init void test_string_escape(const char *name,
> >> >>  		q_test += len;
> >> >>  	}
> >> >>  
> >> >> -	q_real = string_escape_mem(in, p, &buf, q_real, flags, esc);
> >> >> +	q_real = string_escape_mem(in, p, out_real, out_size, flags, esc);
> >> >>  
> >> >>  	test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
> >> >>  			      q_test);
> >> >> +
> >> >> +	memset(out_real, 'Z', out_size);
> >> >> +	q_real = string_escape_mem(in, p, out_real, 0, flags, esc);
> >> >> +	if (q_real != q_test)
> >> >> +		pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
> >> >> +			name, flags, q_test, q_real);
> >> >> +	if (memchr_inv(out_real, 'Z', out_size))
> >> >> +		pr_warn("Test '%s' failed: osz = 0 but string_escape_mem wrote to the buffer\n",
> >> >> +			name);
> >> >> +
> >> >
> >> > So, why couldn't we split this to separate test case? It seems I already
> >> > pointed this out.
> >> >
> >> 
> >> This actually provides better coverage
> >
> > I do not see much advantage of doing so. You may create a loop with
> > random number for in-size and check. So, I prefer to see separate case
> > for that.
> 
> It's not about the size, it's about exercising all the various escape_*
> helpers, to ensure that they all respect the end of the buffer, while
> still returning the correct would-be output size. For that, one needs to
> call string_escape_mem with various combinations of flags and input
> buffers. The logic for that is already in place in test_string_escape
> and its caller, and I see no point in duplicating all that.

Thanks for clarification.

> If you insist on a separate function for doing the overflow testing,
> I'll just rip it out from my code and let you add such a test later.

What about to make it a separate function *and* call from inside of
test_string_escape? Would it work for you?

> I've updated 2/3 with the early returns you suggested, but I'll wait a
> little before sending out a v4.


-- 
Andy Shevchenko <andriy.shevchenko@intel.com>
Intel Finland Oy


WARNING: multiple messages have this Message-ID
From: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Rasmus Villemoes
	<linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>
Cc: Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Trond Myklebust
	<trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>,
	"J. Bruce Fields"
	<bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v3 3/3] lib/string_helpers.c: Change semantics of string_escape_mem
Date: Mon, 23 Feb 2015 14:50:20 +0200	[thread overview]
Message-ID: <1424695820.14897.10.camel@linux.intel.com> (raw)
In-Reply-To: <87oaoo59n2.fsf-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>

On Sat, 2015-02-21 at 02:35 +0100, Rasmus Villemoes wrote:
> On Tue, Feb 10 2015, Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> wrote:

> >> >> @@ -301,29 +301,26 @@ static __init void test_string_escape(const char *name,
> >> >>  		q_test += len;
> >> >>  	}
> >> >>  
> >> >> -	q_real = string_escape_mem(in, p, &buf, q_real, flags, esc);
> >> >> +	q_real = string_escape_mem(in, p, out_real, out_size, flags, esc);
> >> >>  
> >> >>  	test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
> >> >>  			      q_test);
> >> >> +
> >> >> +	memset(out_real, 'Z', out_size);
> >> >> +	q_real = string_escape_mem(in, p, out_real, 0, flags, esc);
> >> >> +	if (q_real != q_test)
> >> >> +		pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
> >> >> +			name, flags, q_test, q_real);
> >> >> +	if (memchr_inv(out_real, 'Z', out_size))
> >> >> +		pr_warn("Test '%s' failed: osz = 0 but string_escape_mem wrote to the buffer\n",
> >> >> +			name);
> >> >> +
> >> >
> >> > So, why couldn't we split this to separate test case? It seems I already
> >> > pointed this out.
> >> >
> >> 
> >> This actually provides better coverage
> >
> > I do not see much advantage of doing so. You may create a loop with
> > random number for in-size and check. So, I prefer to see separate case
> > for that.
> 
> It's not about the size, it's about exercising all the various escape_*
> helpers, to ensure that they all respect the end of the buffer, while
> still returning the correct would-be output size. For that, one needs to
> call string_escape_mem with various combinations of flags and input
> buffers. The logic for that is already in place in test_string_escape
> and its caller, and I see no point in duplicating all that.

Thanks for clarification.

> If you insist on a separate function for doing the overflow testing,
> I'll just rip it out from my code and let you add such a test later.

What about to make it a separate function *and* call from inside of
test_string_escape? Would it work for you?

> I've updated 2/3 with the early returns you suggested, but I'll wait a
> little before sending out a v4.


-- 
Andy Shevchenko <andriy.shevchenko-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Intel Finland Oy

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  reply	other threads:[~2015-02-23 12:50 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-28 13:25 [PATCH 0/2] Two printf fixes Rasmus Villemoes
2015-01-28 13:25 ` [PATCH 1/2] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-01-28 14:53   ` Andy Shevchenko
2015-01-28 15:49     ` Rasmus Villemoes
2015-01-28 16:43       ` Andy Shevchenko
2015-01-28 13:25 ` [PATCH 2/2] string_helpers: Change semantics of string_escape_mem Rasmus Villemoes
2015-01-28 15:05   ` Andy Shevchenko
2015-01-29 10:03 ` [PATCH v2 0/3] Two printf fixes Rasmus Villemoes
2015-01-29 10:03   ` [PATCH v2 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-01-29 10:43     ` Andy Shevchenko
2015-01-29 10:03   ` [PATCH v2 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-01-29 12:12     ` Andy Shevchenko
2015-01-29 13:10       ` Rasmus Villemoes
2015-01-29 13:37         ` Andy Shevchenko
2015-01-29 19:33           ` Jeff Epler
2015-01-30 10:14             ` Andy Shevchenko
2015-01-29 10:03   ` [PATCH v2 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-01-29 13:29     ` Andy Shevchenko
2015-01-29 14:29       ` Rasmus Villemoes
2015-01-30 10:27         ` Andy Shevchenko
2015-01-30 23:39           ` Rasmus Villemoes
2015-01-30 23:39             ` Rasmus Villemoes
2015-02-02 10:56             ` Andy Shevchenko
2015-02-09 23:44   ` [PATCH v3 0/3] Two printf fixes Rasmus Villemoes
2015-02-09 23:44     ` Rasmus Villemoes
2015-02-09 23:44     ` [PATCH v3 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-02-09 23:44     ` [PATCH v3 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-02-10 12:16       ` Andy Shevchenko
2015-02-09 23:44     ` [PATCH v3 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-02-09 23:44       ` Rasmus Villemoes
2015-02-10 12:32       ` Andy Shevchenko
2015-02-10 12:32         ` Andy Shevchenko
2015-02-10 13:02         ` Rasmus Villemoes
2015-02-10 14:22           ` Andy Shevchenko
2015-02-10 14:22             ` Andy Shevchenko
2015-02-21  1:35             ` Rasmus Villemoes
2015-02-23 12:50               ` Andy Shevchenko [this message]
2015-02-23 12:50                 ` Andy Shevchenko
2015-02-23 22:55                 ` Rasmus Villemoes
2015-02-23 22:55                   ` Rasmus Villemoes
2015-03-02 12:37                   ` Andy Shevchenko
2015-03-02 12:37                     ` Andy Shevchenko
2015-03-02 23:03                     ` Rasmus Villemoes
2015-03-03 10:26                       ` Andy Shevchenko
2015-03-03 10:26                         ` Andy Shevchenko
2015-03-03 23:20     ` [PATCH v4 0/3] Two printf fixes Rasmus Villemoes
2015-03-03 23:20       ` [PATCH v4 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-03-03 23:20       ` [PATCH v4 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-03-04 10:51         ` Andy Shevchenko
2015-03-03 23:20       ` [PATCH v4 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-03-04 11:49         ` Andy Shevchenko
2015-03-04 11:49           ` Andy Shevchenko

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