From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Benjamin Randazzo , NeilBrown , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 001/130] md: use kzalloc() when bitmap is disabled Date: Thu, 27 Aug 2015 15:09:52 -0700 Message-Id: <1440713521-5906-2-git-send-email-kamal@canonical.com> In-Reply-To: <1440713521-5906-1-git-send-email-kamal@canonical.com> References: <1440713521-5906-1-git-send-email-kamal@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.19.8-ckt6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin Randazzo 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 Reference: CVE-2015-5697 Signed-off-by: Kamal Mostafa --- drivers/md/md.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 193feb9..a31e15b 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5443,7 +5443,7 @@ 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; -- 1.9.1