From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754887AbbLIJ5M (ORCPT ); Wed, 9 Dec 2015 04:57:12 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45421 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754733AbbLIJlL (ORCPT ); Wed, 9 Dec 2015 04:41:11 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Dan Carpenter , Kalle Valo , Luis Henriques Subject: [PATCH 3.16.y-ckt 089/126] mwifiex: fix mwifiex_rdeeprom_read() Date: Wed, 9 Dec 2015 09:37:39 +0000 Message-Id: <1449653896-5236-90-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1449653896-5236-1-git-send-email-luis.henriques@canonical.com> References: <1449653896-5236-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt21 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter commit 1f9c6e1bc1ba5f8a10fcd6e99d170954d7c6d382 upstream. There were several bugs here. 1) The done label was in the wrong place so we didn't copy any information out when there was no command given. 2) We were using PAGE_SIZE as the size of the buffer instead of "PAGE_SIZE - pos". 3) snprintf() returns the number of characters that would have been printed if there were enough space. If there was not enough space (and we had fixed the memory corruption bug #2) then it would result in an information leak when we do simple_read_from_buffer(). I've changed it to use scnprintf() instead. I also removed the initialization at the start of the function, because I thought it made the code a little more clear. Fixes: 5e6e3a92b9a4 ('wireless: mwifiex: initial commit for Marvell mwifiex driver') Signed-off-by: Dan Carpenter Acked-by: Amitkumar Karwar Signed-off-by: Kalle Valo Signed-off-by: Luis Henriques --- drivers/net/wireless/mwifiex/debugfs.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/wireless/mwifiex/debugfs.c b/drivers/net/wireless/mwifiex/debugfs.c index 7b419bbcd544..147250696181 100644 --- a/drivers/net/wireless/mwifiex/debugfs.c +++ b/drivers/net/wireless/mwifiex/debugfs.c @@ -660,7 +660,7 @@ mwifiex_rdeeprom_read(struct file *file, char __user *ubuf, (struct mwifiex_private *) file->private_data; unsigned long addr = get_zeroed_page(GFP_KERNEL); char *buf = (char *) addr; - int pos = 0, ret = 0, i; + int pos, ret, i; u8 value[MAX_EEPROM_DATA]; if (!buf) @@ -668,7 +668,7 @@ mwifiex_rdeeprom_read(struct file *file, char __user *ubuf, if (saved_offset == -1) { /* No command has been given */ - pos += snprintf(buf, PAGE_SIZE, "0"); + pos = snprintf(buf, PAGE_SIZE, "0"); goto done; } @@ -677,17 +677,17 @@ mwifiex_rdeeprom_read(struct file *file, char __user *ubuf, (u16) saved_bytes, value); if (ret) { ret = -EINVAL; - goto done; + goto out_free; } - pos += snprintf(buf, PAGE_SIZE, "%d %d ", saved_offset, saved_bytes); + pos = snprintf(buf, PAGE_SIZE, "%d %d ", saved_offset, saved_bytes); for (i = 0; i < saved_bytes; i++) - pos += snprintf(buf + strlen(buf), PAGE_SIZE, "%d ", value[i]); - - ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos); + pos += scnprintf(buf + pos, PAGE_SIZE - pos, "%d ", value[i]); done: + ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos); +out_free: free_page(addr); return ret; }