Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932818AbbHXJKN (ORCPT ); Mon, 24 Aug 2015 05:10:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:58128 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932779AbbHXJKG (ORCPT ); Mon, 24 Aug 2015 05:10:06 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Benjamin Randazzo , NeilBrown , Jiri Slaby Subject: [PATCH 3.12 46/82] md: use kzalloc() when bitmap is disabled Date: Mon, 24 Aug 2015 11:09:06 +0200 Message-Id: <6578b22cd80381c9fbab152e1ababd8bfce8b5d0.1440407339.git.jslaby@suse.cz> X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1831 Lines: 58 From: Benjamin Randazzo 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit b6878d9e03043695dbf3fa1caa6dfc09db225b16 upstream. In drivers/md/md.c get_bitmap_file() uses kmalloc() for creating a mdu_bitmap_file_t called "file". 5769 file = kmalloc(sizeof(*file), GFP_NOIO); 5770 if (!file) 5771 return -ENOMEM; This structure is copied to user space at the end of the function. 5786 if (err == 0 && 5787 copy_to_user(arg, file, sizeof(*file))) 5788 err = -EFAULT But if bitmap is disabled only the first byte of "file" is initialized with zero, so it's possible to read some bytes (up to 4095) of kernel space memory from user space. This is an information leak. 5775 /* bitmap disabled, zero the first byte and copy out */ 5776 if (!mddev->bitmap_info.file) 5777 file->pathname[0] = '\0'; Signed-off-by: Benjamin Randazzo Signed-off-by: NeilBrown Signed-off-by: Jiri Slaby --- drivers/md/md.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 2394b5bbeab9..1c512dc1f17f 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5642,8 +5642,7 @@ static int get_bitmap_file(struct mddev * mddev, void __user * arg) char *ptr, *buf = NULL; int err = -ENOMEM; - file = kmalloc(sizeof(*file), GFP_NOIO); - + file = kzalloc(sizeof(*file), GFP_NOIO); if (!file) goto out; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/