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From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Dmitry Antipov <dmantipov@yandex.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	David Laight <david.laight.linux@gmail.com>,
	Kees Cook <kees@kernel.org>,
	"Darrick J . Wong" <djwong@kernel.org>,
	linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 2/5] lib: fix memparse() to handle overflow
Date: Thu, 12 Feb 2026 15:36:12 +0200	[thread overview]
Message-ID: <aY3XTDhPmUQB2V4P@smile.fi.intel.com> (raw)
In-Reply-To: <20260212125628.739276-3-dmantipov@yandex.ru>

On Thu, Feb 12, 2026 at 03:56:25PM +0300, Dmitry Antipov wrote:
> Since '_parse_integer_limit()' (and so 'simple_strtoull()') is now
> capable to handle overflow, adjust 'memparse()' to handle overflow
> (denoted by ULLONG_MAX) returned from 'simple_strtoull()'. Also
> use 'check_shl_overflow()' to catch an overflow possibly caused
> by processing size suffix and denote it with ULLONG_MAX as well.

Assuming this is a desired check and you undertake any required
action in case of user breakage, the code wise this version LGTM,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

...

> +	if (shl && likely(ptr != endptr)) {

IIUC the second check is not needed, but harmless as it's basically a shortcut
for a single allowed unit letter.

> +		/* Have valid suffix with preceding number. */
> +		unsigned long long val;
> +
> +		if (unlikely(check_shl_overflow(ret, shl, &val)))
> +			ret = ULLONG_MAX;
> +		else

Id est if we came here with ret == 0, shl == 0, we would get val == 0.

> +			ret = val;
> +		endptr++;
> +	}

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2026-02-12 13:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-12 12:56 [PATCH v7 0/5] lib and lib/cmdline enhancements Dmitry Antipov
2026-02-12 12:56 ` [PATCH v7 1/5] lib: fix _parse_integer_limit() to handle overflow Dmitry Antipov
2026-02-12 13:41   ` Andy Shevchenko
2026-02-12 14:32     ` David Laight
2026-02-12 14:45       ` Andy Shevchenko
2026-02-12 13:51   ` David Laight
2026-02-12 12:56 ` [PATCH v7 2/5] lib: fix memparse() " Dmitry Antipov
2026-02-12 13:36   ` Andy Shevchenko [this message]
2026-02-12 12:56 ` [PATCH v7 3/5] lib: add more string to 64-bit integer conversion overflow tests Dmitry Antipov
2026-02-12 12:56 ` [PATCH v7 4/5] lib/cmdline_kunit: add test case for memparse() Dmitry Antipov
2026-02-12 12:56 ` [PATCH v7 5/5] lib/cmdline: adjust a few comments to fix kernel-doc -Wreturn warnings Dmitry Antipov

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