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([129.170.197.108]) by smtp.gmail.com with ESMTPSA id af79cd13be357-884a2369a0dsm114261085a.48.2025.10.08.19.57.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Oct 2025 19:57:53 -0700 (PDT) From: pip-izony To: Marcel Holtmann Cc: Seungjin Bae , Kyungtae Kim , Luiz Augusto von Dentz , linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org Subject: [PATCH v3] Bluetooth: bfusb: Fix buffer over-read in rx processing loop Date: Wed, 8 Oct 2025 22:57:01 -0400 Message-ID: <20251009025701.3756598-2-eeodqql09@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <77bde79f-2080-4e40-a013-52b480c0928c@molgen.mpg.de> References: <77bde79f-2080-4e40-a013-52b480c0928c@molgen.mpg.de> 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" From: Seungjin Bae The bfusb_rx_complete() function parses incoming URB data in a while loop. The logic does not sufficiently validate the remaining buffer size(count) across loop iterations, which can lead to a buffer over-read. For example, with 4-bytes remaining buffer, if the first iteration takes the `hdr & 0x4000` branch, 2-bytes are consumed. On the next iteration, only 2-bytes remain, but the else branch is trying to access the third byte(buf[2]). This causes an out-of-bounds read and a potential kernel panic. This patch fixes the vulnerability by adding checks to ensure enough data remains in the buffer before it is accessed. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Seungjin Bae Reviewed-by: Paul Menzel --- v1 -> v2: Fixing the error function name v2 -> v3: Addressing feedback from Paul Menzel drivers/bluetooth/bfusb.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/bluetooth/bfusb.c b/drivers/bluetooth/bfusb.c index 8df310983bf6..90ca5ab2acc3 100644 --- a/drivers/bluetooth/bfusb.c +++ b/drivers/bluetooth/bfusb.c @@ -360,6 +360,12 @@ static void bfusb_rx_complete(struct urb *urb) count -=3D 2; buf +=3D 2; } else { + if (count < 3) { + bt_dev_err(data->hdev, + "block header is too short (count=3D%d, expected=3D3)", + count); + break; + } len =3D (buf[2] =3D=3D 0) ? 256 : buf[2]; count -=3D 3; buf +=3D 3; --=20 2.43.0