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Wed, 31 Dec 2025 10:19:30 -0800 (PST) Received: from anonymous ([113.252.77.195]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-34e772ac1basm15823444a91.10.2025.12.31.10.19.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Dec 2025 10:19:30 -0800 (PST) From: Kwok Kin Ming To: jikos@kernel.org, bentiss@kernel.org Cc: Kwok Kin Ming , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] HID: i2c-hid: fix potential buffer overflow in i2c_hid_get_report() Date: Thu, 1 Jan 2026 02:18:26 +0800 Message-ID: <20251231181830.232239-1-kenkinming2002@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" `i2c_hid_xfer` is used to read `recv_len + sizeof(__le16)` bytes of data into `ihid->rawbuf`. The former can come from the userspace in the hidraw driver and is only bounded by HID_MAX_BUFFER_SIZE(16384) by default (unless we also set `max_buffer_size` field of `struct hid_ll_driver` which we do not). The latter has size determined at runtime by the maximum size of different report types you could receive on any particular device and can be a much smaller value. Fix this by truncating `recv_len` to `ihid->bufsize - sizeof(__le16)`. The impact is low since access to hidraw devices requires root. Signed-off-by: Kwok Kin Ming --- drivers/hid/i2c-hid/i2c-hid-core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-h= id-core.c index 63f46a2e5..5a183af3d 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -286,6 +286,7 @@ static int i2c_hid_get_report(struct i2c_hid *ihid, * In addition to report data device will supply data length * in the first 2 bytes of the response, so adjust . */ + recv_len =3D min(recv_len, ihid->bufsize - sizeof(__le16)); error =3D i2c_hid_xfer(ihid, ihid->cmdbuf, length, ihid->rawbuf, recv_len + sizeof(__le16)); if (error) { --=20 2.52.0