inet_diag: Make sure we actually run the same bytecode we audited.

We were using nlmsg_find_attr() to look up the bytecode by attribute when
auditing, but then just using the first attribute when actually running
bytecode. So, if we received a message with two attribute elements, where only
the second had type INET_DIAG_REQ_BYTECODE, we would validate and run different
bytecode strings.

Fix this by consistently using nlmsg_find_attr everywhere.

Signed-off-by: Nelson Elhage <nelhage@ksplice.com>
Signed-off-by: Thomas Graf <tgraf@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 11 deletions

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index ba8042665849..2ada17129fce 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -490,9 +490,11 @@ static int inet_csk_diag_dump(struct sock *sk,
 {
         struct inet_diag_req *r = NLMSG_DATA(cb->nlh);
 
-        if (cb->nlh->nlmsg_len > 4 + NLMSG_SPACE(sizeof(*r))) {
+        if (nlmsg_attrlen(cb->nlh, sizeof(*r))) {
                 struct inet_diag_entry entry;
-                struct rtattr *bc = (struct rtattr *)(r + 1);
+                const struct nlattr *bc = nlmsg_find_attr(cb->nlh,
+                                                          sizeof(*r),
+                                                          INET_DIAG_REQ_BYTECODE);
                 struct inet_sock *inet = inet_sk(sk);
 
                 entry.family = sk->sk_family;
@@ -512,7 +514,7 @@ static int inet_csk_diag_dump(struct sock *sk,
                 entry.dport = ntohs(inet->inet_dport);
                 entry.userlocks = sk->sk_userlocks;
 
-                if (!inet_diag_bc_run(RTA_DATA(bc), RTA_PAYLOAD(bc), &entry))
+                if (!inet_diag_bc_run(nla_data(bc), nla_len(bc), &entry))
                         return 0;
         }
 
@@ -527,9 +529,11 @@ static int inet_twsk_diag_dump(struct inet_timewait_sock *tw,
 {
         struct inet_diag_req *r = NLMSG_DATA(cb->nlh);
 
-        if (cb->nlh->nlmsg_len > 4 + NLMSG_SPACE(sizeof(*r))) {
+        if (nlmsg_attrlen(cb->nlh, sizeof(*r))) {
                 struct inet_diag_entry entry;
-                struct rtattr *bc = (struct rtattr *)(r + 1);
+                const struct nlattr *bc = nlmsg_find_attr(cb->nlh,
+                                                          sizeof(*r),
+                                                          INET_DIAG_REQ_BYTECODE);
 
                 entry.family = tw->tw_family;
 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
@@ -548,7 +552,7 @@ static int inet_twsk_diag_dump(struct inet_timewait_sock *tw,
                 entry.dport = ntohs(tw->tw_dport);
                 entry.userlocks = 0;
 
-                if (!inet_diag_bc_run(RTA_DATA(bc), RTA_PAYLOAD(bc), &entry))
+                if (!inet_diag_bc_run(nla_data(bc), nla_len(bc), &entry))
                         return 0;
         }
 
@@ -618,7 +622,7 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
         struct inet_diag_req *r = NLMSG_DATA(cb->nlh);
         struct inet_connection_sock *icsk = inet_csk(sk);
         struct listen_sock *lopt;
-        struct rtattr *bc = NULL;
+        const struct nlattr *bc = NULL;
         struct inet_sock *inet = inet_sk(sk);
         int j, s_j;
         int reqnum, s_reqnum;
@@ -638,8 +642,9 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
         if (!lopt || !lopt->qlen)
                 goto out;
 
-        if (cb->nlh->nlmsg_len > 4 + NLMSG_SPACE(sizeof(*r))) {
-                bc = (struct rtattr *)(r + 1);
+        if (nlmsg_attrlen(cb->nlh, sizeof(*r))) {
+                bc = nlmsg_find_attr(cb->nlh, sizeof(*r),
+                                     INET_DIAG_REQ_BYTECODE);
                 entry.sport = inet->inet_num;
                 entry.userlocks = sk->sk_userlocks;
         }
@@ -672,8 +677,8 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
                                         &ireq->rmt_addr;
                                 entry.dport = ntohs(ireq->rmt_port);
 
-                                if (!inet_diag_bc_run(RTA_DATA(bc),
-                                                    RTA_PAYLOAD(bc), &entry))
+                                if (!inet_diag_bc_run(nla_data(bc),
+                                                      nla_len(bc), &entry))
                                         continue;
                         }