From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: [PATCH 1/3] [PKT_SCHED]: Fix illegal memory dereferences when dumping actions Date: Wed, 05 Jul 2006 00:00:01 +0200 Message-ID: <20060704220549.952720000@postel.suug.ch> References: <20060704220504.787776000@postel.suug.ch> Cc: netdev@vger.kernel.org, hadi@cyberus.ca Return-path: Received: from postel.suug.ch ([194.88.212.233]:55749 "EHLO postel.suug.ch") by vger.kernel.org with ESMTP id S932310AbWGDWGp (ORCPT ); Tue, 4 Jul 2006 18:06:45 -0400 To: davem@davemloft.net Content-Disposition: inline; filename=act_fix_dump_null_deref Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org The TCA_ACT_KIND attribute is used without checking its availability when dumping actions therefore leading to a value of 0x4 being dereferenced. The use of strcmp() in tc_lookup_action_n() isn't safe when fed with string from an attribute without enforcing proper NUL termination. Both bugs can be triggered with malformed netlink message and don't require any privileges. Signed-off-by: Thomas Graf Index: net-2.6.git/net/sched/act_api.c =================================================================== --- net-2.6.git.orig/net/sched/act_api.c +++ net-2.6.git/net/sched/act_api.c @@ -776,7 +776,7 @@ replay: return ret; } -static char * +static struct rtattr * find_dump_kind(struct nlmsghdr *n) { struct rtattr *tb1, *tb2[TCA_ACT_MAX+1]; @@ -804,7 +804,7 @@ find_dump_kind(struct nlmsghdr *n) return NULL; kind = tb2[TCA_ACT_KIND-1]; - return (char *) RTA_DATA(kind); + return kind; } static int @@ -817,16 +817,15 @@ tc_dump_action(struct sk_buff *skb, stru struct tc_action a; int ret = 0; struct tcamsg *t = (struct tcamsg *) NLMSG_DATA(cb->nlh); - char *kind = find_dump_kind(cb->nlh); + struct rtattr *kind = find_dump_kind(cb->nlh); if (kind == NULL) { printk("tc_dump_action: action bad kind\n"); return 0; } - a_o = tc_lookup_action_n(kind); + a_o = tc_lookup_action(kind); if (a_o == NULL) { - printk("failed to find %s\n", kind); return 0; } @@ -834,7 +833,7 @@ tc_dump_action(struct sk_buff *skb, stru a.ops = a_o; if (a_o->walk == NULL) { - printk("tc_dump_action: %s !capable of dumping table\n", kind); + printk("tc_dump_action: %s !capable of dumping table\n", a_o->kind); goto rtattr_failure; } --