Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964832AbbENQvK (ORCPT ); Thu, 14 May 2015 12:51:10 -0400 Received: from mail.kmu-office.ch ([178.209.48.109]:36137 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932420AbbENQvI (ORCPT ); Thu, 14 May 2015 12:51:08 -0400 From: Stefan Agner To: balbi@ti.com, gregkh@linuxfoundation.org Cc: k.opasiak@samsung.com, andrzej.p@samsung.com, m.szyprowski@samsung.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stefan@agner.ch Subject: [PATCH v3] usb: gadget: ether: Fix MAC address parsing Date: Thu, 14 May 2015 18:50:54 +0200 Message-Id: <1431622254-24758-1-git-send-email-stefan@agner.ch> X-Mailer: git-send-email 2.4.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3680 Lines: 130 MAC addresses can be written without leading zeros. A popular example is libc's ether_ntoa_r function which creates such MAC addresses. Example: 00:14:3d:0f:ff:fe can be written as 0:14:3d:f:ff:fe The function get_ether_addr potentially also parsed past the end of the user provided string. Use the opportunity and fix the function to never parse beyond the end of the string while allowing MAC addresses with and without leading zeros. Also corner cases such as 00:14:3d:0f:ff:0 + new-line character are parsed correctly. Signed-off-by: Stefan Agner --- Changes since v2: - Fix parameter description - Return with error if invalid charaters are part of the string drivers/usb/gadget/function/u_ether.c | 70 ++++++++++++++++++++++++++++------- 1 file changed, 56 insertions(+), 14 deletions(-) diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index f1fd777..c71ab21 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -703,25 +703,62 @@ static int eth_stop(struct net_device *net) /*-------------------------------------------------------------------------*/ +/** + * get_ether_addr - parse ethernet address from string + * @str: string to parse + * @dev_addr: a buffer in which the parsed ethernet address will be + * written + * + * Several common formats are supported: + * 1) 00:14:3d:0f:ff:fe (no skipped 0, semicolons) + * 2) 00.14.3d.0f.ff.fe (no skipped 0, dots) + * 3) 00143d0ffffe (no skipped 0, no separator) + * 4) 0:14:3d:f:ff:fe (skipped leading 0, semicolons) + * 5) 0.14.3d.f.ff.fe (skipped leading 0, dots) + * + * The function will not cross the end of the provided string even + * when the string has the wrong format. + * + * Returns 0 on success, or -EINVAL on error + */ static int get_ether_addr(const char *str, u8 *dev_addr) { - if (str) { - unsigned i; + int num, i; - for (i = 0; i < 6; i++) { - unsigned char num; + for (i = 0; i < ETH_ALEN; i++) { + int j = 0; - if ((*str == '.') || (*str == ':')) + dev_addr[i] = 0; + while (*str) { + char c = *str; + + if (c == '.' || c == ':') { str++; - num = hex_to_bin(*str++) << 4; - num |= hex_to_bin(*str++); - dev_addr [i] = num; + break; + } + + if (j >= 2) + break; + + /* Ignore newline character, e.g. when using echo */ + if (c == '\n') + continue; + + num = hex_to_bin(c); + if (num < 0) + return num; + + dev_addr[i] <<= 4; + dev_addr[i] |= num; + j++; + str++; } - if (is_valid_ether_addr(dev_addr)) - return 0; } - eth_random_addr(dev_addr); - return 1; + + if (!is_valid_ether_addr(dev_addr)) + return -EINVAL; + + return 0; } static int get_ether_addr_str(u8 dev_addr[ETH_ALEN], char *str, int len) @@ -786,12 +823,17 @@ struct eth_dev *gether_setup_name(struct usb_gadget *g, dev->qmult = qmult; snprintf(net->name, sizeof(net->name), "%s%%d", netname); - if (get_ether_addr(dev_addr, net->dev_addr)) + if (get_ether_addr(dev_addr, net->dev_addr)) { + eth_random_addr(net->dev_addr); dev_warn(&g->dev, "using random %s ethernet address\n", "self"); - if (get_ether_addr(host_addr, dev->host_mac)) + } + + if (get_ether_addr(host_addr, dev->host_mac)) { + eth_random_addr(dev->host_mac); dev_warn(&g->dev, "using random %s ethernet address\n", "host"); + } if (ethaddr) memcpy(ethaddr, dev->host_mac, ETH_ALEN); -- 2.4.0 -- 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/