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Sat, 23 Nov 2024 23:03:40 -0800 (PST) Received: from google.com ([2601:647:5e00:4acd:8a2a:c45a:2a1f:28b0]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2eb0d048c41sm4837160a91.41.2024.11.23.23.03.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 23 Nov 2024 23:03:39 -0800 (PST) Date: Sun, 24 Nov 2024 07:03:36 +0000 From: Dmitry Torokhov To: Raag Jadav Cc: gregkh@linuxfoundation.org, linus.walleij@linaro.org, mika.westerberg@linux.intel.com, andriy.shevchenko@linux.intel.com, broonie@kernel.org, pierre-louis.bossart@linux.dev, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-sound@vger.kernel.org Subject: Re: [PATCH v1 1/5] devres: Introduce devm_kmemdup_array() Message-ID: References: <20241123200527.7830-1-raag.jadav@intel.com> <20241123200527.7830-2-raag.jadav@intel.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241123200527.7830-2-raag.jadav@intel.com> Hi Raag, On Sun, Nov 24, 2024 at 01:35:23AM +0530, Raag Jadav wrote: > Introduce '_array' variant of devm_kmemdup() for the users which lack > multiplication overflow check. I am not sure that this new helper is needed. Unlike allocators for brand new objects, such as kmalloc_array(), devm_kmemdup() makes a copy of already existing object, which is supposed to be a valid object and therefore will have a reasonable size. So there should be no chance for hitting this overflow unless the caller is completely confused and calls devm_kmemdup() with random arguments (in which case all bets are off). > > Suggested-by: Andy Shevchenko > Signed-off-by: Raag Jadav > --- > include/linux/device.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/include/linux/device.h b/include/linux/device.h > index b4bde8d22697..c31f48d0dde0 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -358,6 +358,16 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc; > const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp); > void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp) > __realloc_size(3); > +static inline void *devm_kmemdup_array(struct device *dev, const void *src, > + size_t n, size_t size, gfp_t flags) > +{ > + size_t bytes; > + > + if (unlikely(check_mul_overflow(n, size, &bytes))) > + return NULL; > + > + return devm_kmemdup(dev, src, bytes, flags); > +} > > unsigned long devm_get_free_pages(struct device *dev, > gfp_t gfp_mask, unsigned int order); > -- > 2.35.3 > Thanks. -- Dmitry