Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754192AbcJLMfR (ORCPT ); Wed, 12 Oct 2016 08:35:17 -0400 Received: from mail.kernel.org ([198.145.29.136]:42458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752653AbcJLMfF (ORCPT ); Wed, 12 Oct 2016 08:35:05 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Dan Carpenter , Kalle Valo , Zefan Li Subject: [PATCH 3.4 003/125] mwifiex: fix mwifiex_rdeeprom_read() Date: Wed, 12 Oct 2016 20:31:59 +0800 Message-Id: <1476275641-4697-3-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1476275600-4626-1-git-send-email-lizf@kernel.org> References: <1476275600-4626-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2741 Lines: 82 From: Dan Carpenter 3.4.113-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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: Zefan Li --- 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 1a84507..e24ef9a 100644 --- a/drivers/net/wireless/mwifiex/debugfs.c +++ b/drivers/net/wireless/mwifiex/debugfs.c @@ -621,7 +621,7 @@ 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) @@ -629,7 +629,7 @@ 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; } @@ -638,17 +638,17 @@ 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; } -- 1.9.1