[IPV4]: INET_MATCH() annotations

INET_MATCH() and friends depend on an interesting set of kludges:
	* there's a pair of adjacent fields in struct inet_sock - __be16 dport
followed by __u16 num.  We want to search by pair, so we combine the keys into
a single 32bit value and compare with 32bit value read from &...->dport.
	* on 64bit targets we combine comparisons with pair of adjacent __be32
fields in the same way.

Make sure that we don't mix those values with anything else and that pairs
we form them from have correct types.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 26 insertions, 12 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index caca57df0d7d..6dc07ee7702e 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -461,7 +461,7 @@ static inline struct raw6_sock *raw6_sk(const struct sock *sk)
 
 #define INET6_MATCH(__sk, __hash, __saddr, __daddr, __ports, __dif)\
         (((__sk)->sk_hash == (__hash))                          && \
-         ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports))   && \
+         ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports))      && \
          ((__sk)->sk_family             == AF_INET6)            && \
          ipv6_addr_equal(&inet6_sk(__sk)->daddr, (__saddr))     && \
          ipv6_addr_equal(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index b4491c9e2a5a..fb0c09c7090c 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -283,31 +283,45 @@ static inline struct sock *inet_lookup_listener(struct inet_hashinfo *hashinfo,
 }
 
 /* Socket demux engine toys. */
+/* What happens here is ugly; there's a pair of adjacent fields in
+   struct inet_sock; __be16 dport followed by __u16 num.  We want to
+   search by pair, so we combine the keys into a single 32bit value
+   and compare with 32bit value read from &...->dport.  Let's at least
+   make sure that it's not mixed with anything else...
+   On 64bit targets we combine comparisons with pair of adjacent __be32
+   fields in the same way.
+*/
+typedef __u32 __bitwise __portpair;
 #ifdef __BIG_ENDIAN
 #define INET_COMBINED_PORTS(__sport, __dport) \
-        (((__u32)(__sport) << 16) | (__u32)(__dport))
+        ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport)))
 #else /* __LITTLE_ENDIAN */
 #define INET_COMBINED_PORTS(__sport, __dport) \
-        (((__u32)(__dport) << 16) | (__u32)(__sport))
+        ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport)))
 #endif
 
 #if (BITS_PER_LONG == 64)
+typedef __u64 __bitwise __addrpair;
 #ifdef __BIG_ENDIAN
 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
-        const __u64 __name = (((__u64)(__saddr)) << 32) | ((__u64)(__daddr));
+        const __addrpair __name = (__force __addrpair) ( \
+                                   (((__force __u64)(__be32)(__saddr)) << 32) | \
+                                   ((__force __u64)(__be32)(__daddr)));
 #else /* __LITTLE_ENDIAN */
 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
-        const __u64 __name = (((__u64)(__daddr)) << 32) | ((__u64)(__saddr));
+        const __addrpair __name = (__force __addrpair) ( \
+                                   (((__force __u64)(__be32)(__daddr)) << 32) | \
+                                   ((__force __u64)(__be32)(__saddr)));
 #endif /* __BIG_ENDIAN */
 #define INET_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
         (((__sk)->sk_hash == (__hash))                          &&      \
-         ((*((__u64 *)&(inet_sk(__sk)->daddr))) == (__cookie))  &&      \
-         ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports))   &&      \
+         ((*((__addrpair *)&(inet_sk(__sk)->daddr))) == (__cookie))     &&      \
+         ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports))      &&      \
          (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #define INET_TW_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
         (((__sk)->sk_hash == (__hash))                          &&      \
-         ((*((__u64 *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) &&  \
-         ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&   \
+         ((*((__addrpair *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) &&     \
+         ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&      \
          (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #else /* 32-bit arch */
 #define INET_ADDR_COOKIE(__name, __saddr, __daddr)
@@ -315,13 +329,13 @@ static inline struct sock *inet_lookup_listener(struct inet_hashinfo *hashinfo,
         (((__sk)->sk_hash == (__hash))                          &&      \
          (inet_sk(__sk)->daddr          == (__saddr))           &&      \
          (inet_sk(__sk)->rcv_saddr      == (__daddr))           &&      \
-         ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports))   &&      \
+         ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports))      &&      \
          (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #define INET_TW_MATCH(__sk, __hash,__cookie, __saddr, __daddr, __ports, __dif)  \
         (((__sk)->sk_hash == (__hash))                          &&      \
          (inet_twsk(__sk)->tw_daddr     == (__saddr))           &&      \
          (inet_twsk(__sk)->tw_rcv_saddr == (__daddr))           &&      \
-         ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&   \
+         ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&      \
          (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #endif /* 64-bit arch */
 
@@ -338,7 +352,7 @@ static inline struct sock *
                                   const int dif)
 {
         INET_ADDR_COOKIE(acookie, saddr, daddr)
-        const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
+        const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
         struct sock *sk;
         const struct hlist_node *node;
         /* Optimize here for direct hit, only listening connections can