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Wed, 07 Jan 2026 08:08:26 -0800 (PST) Received: from anonymous ([113.252.77.195]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a3e3c4796asm55507165ad.34.2026.01.07.08.08.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Jan 2026 08:08:25 -0800 (PST) Date: Thu, 8 Jan 2026 00:08:22 +0800 From: kenkinming2002@gmail.com To: Benjamin Tissoires Cc: jikos@kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] HID: i2c-hid: fix potential buffer overflow in i2c_hid_get_report() Message-ID: References: <20251231181830.232239-1-kenkinming2002@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@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: On Wed, Jan 07, 2026 at 03:20:13PM +0100, Benjamin Tissoires wrote: > It makes sense to put this min call here, but it's already present at > line 304 a few lines after. Could you remove that second check (and > unnecessary one after your change). The min call at line 304 uses ret_count which comes from the first 2 bytes in the device response and indicates the actual size of the returned report descriptor. Notice that importantly ret_count can be strictly smaller than ihid->bufsize because persumably not all reports have the same size. The behavior will change if the caller provides a larger buffer than is necessary. With the min call at line 304, we will return the actual size of the report descriptor (without the 2 bytes length header). Without the min call at 304, we will instead return the size of supplied buffer. Yours sincerely, Ken Kwok