dccp qpolicy: Parameter checking of cmsg qpolicy parameters
Tomasz Grobelny [Thu, 4 Sep 2008 05:30:19 +0000 (07:30 +0200)]
Ensure that cmsg->cmsg_type value is valid for qpolicy
that is currently in use.

Signed-off-by: Tomasz Grobelny <tomasz@grobelny.oswiecenia.net>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

net/dccp/dccp.h
net/dccp/proto.c
net/dccp/qpolicy.c

index ce2dd6f..1585fa2 100644 (file)
@@ -242,6 +242,7 @@ extern bool         dccp_qpolicy_full(struct sock *sk);
 extern void            dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
 extern struct sk_buff  *dccp_qpolicy_top(struct sock *sk);
 extern struct sk_buff  *dccp_qpolicy_pop(struct sock *sk);
+extern bool            dccp_qpolicy_param_ok(struct sock *sk, __be32 param);
 
 /*
  * TX Packet Output and TX Timers
index b56efdd..a3caa11 100644 (file)
@@ -735,6 +735,10 @@ static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
                if (cmsg->cmsg_level != SOL_DCCP)
                        continue;
 
+               if (cmsg->cmsg_type <= DCCP_SCM_QPOLICY_MAX &&
+                   !dccp_qpolicy_param_ok(skb->sk, cmsg->cmsg_type))
+                       return -EINVAL;
+
                switch (cmsg->cmsg_type) {
                case DCCP_SCM_PRIORITY:
                        if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u32)))
index 414696b..27383f8 100644 (file)
@@ -73,17 +73,20 @@ static struct dccp_qpolicy_operations {
        void            (*push) (struct sock *sk, struct sk_buff *skb);
        bool            (*full) (struct sock *sk);
        struct sk_buff* (*top)  (struct sock *sk);
+       __be32          params;
 
 } qpol_table[DCCPQ_POLICY_MAX] = {
        [DCCPQ_POLICY_SIMPLE] = {
-               .push = qpolicy_simple_push,
-               .full = qpolicy_simple_full,
-               .top  = qpolicy_simple_top,
+               .push   = qpolicy_simple_push,
+               .full   = qpolicy_simple_full,
+               .top    = qpolicy_simple_top,
+               .params = 0,
        },
        [DCCPQ_POLICY_PRIO] = {
-               .push = qpolicy_simple_push,
-               .full = qpolicy_prio_full,
-               .top  = qpolicy_prio_best_skb,
+               .push   = qpolicy_simple_push,
+               .full   = qpolicy_prio_full,
+               .top    = qpolicy_prio_best_skb,
+               .params = DCCP_SCM_PRIORITY,
        },
 };
 
@@ -124,3 +127,11 @@ struct sk_buff *dccp_qpolicy_pop(struct sock *sk)
                skb_unlink(skb, &sk->sk_write_queue);
        return skb;
 }
+
+bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param)
+{
+       /* check if exactly one bit is set */
+       if (!param || (param & (param - 1)))
+               return false;
+       return (qpol_table[dccp_sk(sk)->dccps_qpolicy].params & param) == param;
+}