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 6A1A31AD3FA; Mon, 23 Jun 2025 21:49:09 +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=1750715349; cv=none; b=qQEFFjiMBny3+4lA/ql3/XBaWTdUcPtZgm1e3uaVsyjHNFtiivorHmQGr45dfVBsLPRLPduLG/OKWkIIgpDzljrzNS8WBJPvd877nNNE9boNiJ7rUh6+l7uwF/no0JPlAceExLoKxD5NQUS95A27xjFDuI4s+2jChcmx4ZM6w9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750715349; c=relaxed/simple; bh=ns2+RKVBGXQeGj0Fu1oaupE40/yLYzWtfy4Jpkxzxzo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=T6Xe/QJbH+UmbXFbhOEnKrETHjUL8RHPFU6iILefow3YMMH6JoSqEUrJw9GMg8K2VEQf+99Gb+I+hDT4RmfXkRwZpYHD1jVarQJofVsVHQIz8zCpM/gslG+HNl+OllzwBhH/w3w0WfUbXmmrybnImV564dMTly+3niVigTAwucM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YIv/pEB+; 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="YIv/pEB+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A45C5C4CEEA; Mon, 23 Jun 2025 21:49:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750715349; bh=ns2+RKVBGXQeGj0Fu1oaupE40/yLYzWtfy4Jpkxzxzo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YIv/pEB+vvHMF7wXeVufMqheuGjTM2VUhcHsDUCbbzghTNgVgbJRHkirgXK76CyUV O3nRR0hm38wXXFSLN/bQRRMqY+BPmgyNoan7wshpmOibocsXbhZOHl1eOnDsj0tCIw tKV5iYCDHDzVS4YuAumRhYMpUQcAqY1OXz1KHqpU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot , Qasim Ijaz , Jakub Kicinski Subject: [PATCH 5.15 247/411] net: ch9200: fix uninitialised access during mii_nway_restart Date: Mon, 23 Jun 2025 15:06:31 +0200 Message-ID: <20250623130639.870070565@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130632.993849527@linuxfoundation.org> References: <20250623130632.993849527@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-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 @@ -178,6 +178,7 @@ static int ch9200_mdio_read(struct net_d { struct usbnet *dev = netdev_priv(netdev); unsigned char buff[2]; + int ret; netdev_dbg(netdev, "%s phy_id:%02x loc:%02x\n", __func__, phy_id, loc); @@ -185,8 +186,10 @@ 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); }