Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751213AbdHXBEK (ORCPT ); Wed, 23 Aug 2017 21:04:10 -0400 Received: from mail-pg0-f42.google.com ([74.125.83.42]:37960 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005AbdHXBEI (ORCPT ); Wed, 23 Aug 2017 21:04:08 -0400 From: Bjorn Andersson To: Rob Herring , Frank Rowand Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Rob Herring Subject: [PATCH] of/device: Prevent buffer overflow in of_device_modalias() Date: Wed, 23 Aug 2017 18:04:04 -0700 Message-Id: <20170824010404.9145-1-bjorn.andersson@linaro.org> X-Mailer: git-send-email 2.12.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 989 Lines: 29 As of_device_get_modalias() returns the number of bytes that would have been written to the target string, regardless of how much did fit in the buffer, it's possible that the returned index points beyond the buffer passed to of_device_modalias() - causing memory beyond the buffer to be null terminated. Fixes: 0634c2958927 ("of: Add function for generating a DT modalias with a newline") Cc: Rob Herring Cc: stable@vger.kernel.org Signed-off-by: Bjorn Andersson --- drivers/of/device.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/of/device.c b/drivers/of/device.c index 7cff599a9c6a..b58ca92934cb 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -262,6 +262,8 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len) ssize_t sl = of_device_get_modalias(dev, str, len - 2); if (sl < 0) return sl; + if (sl > len - 2) + return -ENOMEM; str[sl++] = '\n'; str[sl] = 0; -- 2.12.0