Commit 26dab893 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

[PKT_SCHED]: Fix illegal memory dereferences when dumping actions

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: default avatarThomas Graf <>
Signed-off-by: default avatarDavid S. Miller <>
parent e340221a
......@@ -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, struct netlink_callback *cb)
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, struct netlink_callback *cb)
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;
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