[patch 14/45] PKT_SCHED: Fix illegal memory dereferences when dumping actions

Greg KH
2006-07-17T16:42:07Z

[-- Attachment #1: pkt_sched-fix-illegal-memory-dereferences-when-dumping-actions.patch --]
[-- Type: text/plain, Size: 1980 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------
From: Thomas Graf <tgraf@suug.ch>

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 <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/sched/act_api.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

--- linux-2.6.17.3.orig/net/sched/act_api.c
+++ linux-2.6.17.3/net/sched/act_api.c
@@ -777,7 +777,7 @@ replay:
return ret;
}

-static char *
+static struct rtattr *
find_dump_kind(struct nlmsghdr *n)
{
struct rtattr *tb1, *tb2[TCA_ACT_MAX+1];
@@ -805,7 +805,7 @@ find_dump_kind(struct nlmsghdr *n)
return NULL;
kind = tb2[TCA_ACT_KIND-1];

- return (char *) RTA_DATA(kind);
+ return kind;
}

static int
@@ -818,16 +818,15 @@ 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;
}

@@ -835,7 +834,7 @@ 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;
}

--