From mboxrd@z Thu Jan 1 00:00:00 1970 From: Masatake YAMATO Subject: [PATCH] Truncate MCAST_GRP_NAME and FAMILY_NAME char arrays as C strings Date: Tue, 19 Mar 2013 21:27:09 +0900 Message-ID: <1363696029-12559-1-git-send-email-yamato@redhat.com> Cc: Masatake YAMATO To: netdev@vger.kernel.org Return-path: Received: from h219-110-095-248.catv01.itscom.jp ([219.110.95.248]:55726 "EHLO localhost.localdomain" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932483Ab3CSR2c (ORCPT ); Tue, 19 Mar 2013 13:28:32 -0400 Sender: netdev-owner@vger.kernel.org List-ID: This is a patch for genl command in iproute2. You will see garbage at the end of line in the output of following command line: $ genl ctrl show | grep thermal_mc_group #1: ID-0x2 name: thermal_mc_group^B The type of structure field for "name" is char[16] in kernel: #define GENL_NAMSIZ 16 /* length of family name */ ... struct genl_multicast_group { ... char name[GENL_NAMSIZ]; ... }; strlen("thermal_mc_group") == 16 is too long for the array size. This patch protects genl process from this kind of bug by putting nul char at the end of array after receiving a message from the kernel. Signed-off-by: Masatake YAMATO --- genl/ctrl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/genl/ctrl.c b/genl/ctrl.c index 7c42578..fd5a50a 100644 --- a/genl/ctrl.c +++ b/genl/ctrl.c @@ -168,6 +168,7 @@ static int print_ctrl_grp(FILE *fp, struct rtattr *arg, __u32 ctrl_ver) } if (tb[1]) { char *name = RTA_DATA(tb[CTRL_ATTR_MCAST_GRP_NAME]); + name[GENL_NAMSIZ - 1] = '\0'; fprintf(fp, " name: %s ", name); } return 0; @@ -214,6 +215,7 @@ static int print_ctrl(const struct sockaddr_nl *who, struct nlmsghdr *n, if (tb[CTRL_ATTR_FAMILY_NAME]) { char *name = RTA_DATA(tb[CTRL_ATTR_FAMILY_NAME]); + name[GENL_NAMSIZ - 1] = '\0'; fprintf(fp, "\nName: %s\n",name); } if (tb[CTRL_ATTR_FAMILY_ID]) { -- 1.7.11.7