From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E13B4248895; Mon, 23 Jun 2025 13:38:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750685916; cv=none; b=geHsVfeLlsCKcucVdxRccRQBXjF/ZgFX3myfDfj3cAVrWQRsEhbp8Z8RC+/+3Zjb1Xl7mKE5sdpHd7uHg6pAIk2WGtvJeDm+y8tFkpKTRrcPjU/dfTAIBi85ut7BslFWJltYSTKS5Oz1CS4JKcSUY4VsF1Uav2+S0iWtmaxx6sw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750685916; c=relaxed/simple; bh=wAqnc522x1zY6TelZkBV6ikwBDQJiKQZcxZlA7On+fU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dhT8YACN+5D4uTgWVN7mVINz7iFtv19udfNJNQIJBPb+c9HDkKjDKagRme6Ef69iDcMlDGiUPGB9v/1ao+50ebcQ8PddbV4PhrxmCTSq/99B+0yxbZQOcVIzUotOolNtSiyuOjpVU44EzDYEGniT1o4NOiFXRFT+r+3b2Qnl6f4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KVJYbaIp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KVJYbaIp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74283C4CEEA; Mon, 23 Jun 2025 13:38:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750685915; bh=wAqnc522x1zY6TelZkBV6ikwBDQJiKQZcxZlA7On+fU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KVJYbaIp7oM5pJTqkl+tx70SNBW3vpysBFshfZj54uUWzMjMMT5AyCL48Ct8Lew4k Ov4gnyXW8KrQgUIR7FQ4tX95FjlrolW4AVfufm5I2P2r661JiL648Qv3Gr4rP/tb+2 5d9pgT3a6rwUloKvBkTnxIE8t1oJCHfdG/aJcxkA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot , Qasim Ijaz , Jakub Kicinski Subject: [PATCH 5.4 127/222] net: ch9200: fix uninitialised access during mii_nway_restart Date: Mon, 23 Jun 2025 15:07:42 +0200 Message-ID: <20250623130615.917827561@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130611.896514667@linuxfoundation.org> References: <20250623130611.896514667@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qasim Ijaz commit 9ad0452c0277b816a435433cca601304cfac7c21 upstream. In mii_nway_restart() the code attempts to call mii->mdio_read which is ch9200_mdio_read(). ch9200_mdio_read() utilises a local buffer called "buff", which is initialised with control_read(). However "buff" is conditionally initialised inside control_read(): if (err == size) { memcpy(data, buf, size); } If the condition of "err == size" is not met, then "buff" remains uninitialised. Once this happens the uninitialised "buff" is accessed and returned during ch9200_mdio_read(): return (buff[0] | buff[1] << 8); The problem stems from the fact that ch9200_mdio_read() ignores the return value of control_read(), leading to uinit-access of "buff". To fix this we should check the return value of control_read() and return early on error. Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=3361c2d6f78a3e0892f9 Tested-by: syzbot Fixes: 4a476bd6d1d9 ("usbnet: New driver for QinHeng CH9200 devices") Cc: stable@vger.kernel.org Signed-off-by: Qasim Ijaz Link: https://patch.msgid.link/20250526183607.66527-1-qasdev00@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/ch9200.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/net/usb/ch9200.c +++ b/drivers/net/usb/ch9200.c @@ -180,6 +180,7 @@ static int ch9200_mdio_read(struct net_d { struct usbnet *dev = netdev_priv(netdev); unsigned char buff[2]; + int ret; netdev_dbg(netdev, "ch9200_mdio_read phy_id:%02x loc:%02x\n", phy_id, loc); @@ -187,8 +188,10 @@ static int ch9200_mdio_read(struct net_d if (phy_id != 0) return -ENODEV; - control_read(dev, REQUEST_READ, 0, loc * 2, buff, 0x02, - CONTROL_TIMEOUT_MS); + ret = control_read(dev, REQUEST_READ, 0, loc * 2, buff, 0x02, + CONTROL_TIMEOUT_MS); + if (ret < 0) + return ret; return (buff[0] | buff[1] << 8); }