cipso: don't use IPCB() to locate the CIPSO IP option

Using the IPCB() macro to get the IPv4 options is convenient, but
unfortunately NetLabel often needs to examine the CIPSO option outside
of the scope of the IP layer in the stack.  While historically IPCB()
worked above the IP layer, due to the inclusion of the inet_skb_param
struct at the head of the {tcp,udp}_skb_cb structs, recent commit
971f10ec ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
reordered the tcp_skb_cb struct and invalidated this IPCB() trick.

This patch fixes the problem by creating a new function,
cipso_v4_optptr(), which locates the CIPSO option inside the IP header
without calling IPCB().  Unfortunately, this isn't as fast as a simple
lookup so some additional tweaks were made to limit the use of this
new function.

Cc: <stable@vger.kernel.org> # 3.18
Reported-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Tested-by: Casey Schaufler <casey@schaufler-ca.com>

1 files changed, 16 insertions, 9 deletions

diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h
index a6fd939..3ebb168 100644
--- a/include/net/cipso_ipv4.h
+++ b/include/net/cipso_ipv4.h
@@ -121,13 +121,6 @@ extern int cipso_v4_rbm_strictvalid;
 #endif
 
 /*
- * Helper Functions
- */
-
-#define CIPSO_V4_OPTEXIST(x) (IPCB(x)->opt.cipso != 0)
-#define CIPSO_V4_OPTPTR(x) (skb_network_header(x) + IPCB(x)->opt.cipso)
-
-/*
  * DOI List Functions
  */
 
@@ -190,7 +183,7 @@ static inline int cipso_v4_doi_domhsh_remove(struct cipso_v4_doi *doi_def,
 
 #ifdef CONFIG_NETLABEL
 void cipso_v4_cache_invalidate(void);
-int cipso_v4_cache_add(const struct sk_buff *skb,
+int cipso_v4_cache_add(const unsigned char *cipso_ptr,
 		       const struct netlbl_lsm_secattr *secattr);
 #else
 static inline void cipso_v4_cache_invalidate(void)
@@ -198,7 +191,7 @@ static inline void cipso_v4_cache_invalidate(void)
 	return;
 }
 
-static inline int cipso_v4_cache_add(const struct sk_buff *skb,
+static inline int cipso_v4_cache_add(const unsigned char *cipso_ptr,
 				     const struct netlbl_lsm_secattr *secattr)
 {
 	return 0;
@@ -211,6 +204,8 @@ static inline int cipso_v4_cache_add(const struct sk_buff *skb,
 
 #ifdef CONFIG_NETLABEL
 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway);
+int cipso_v4_getattr(const unsigned char *cipso,
+		     struct netlbl_lsm_secattr *secattr);
 int cipso_v4_sock_setattr(struct sock *sk,
 			  const struct cipso_v4_doi *doi_def,
 			  const struct netlbl_lsm_secattr *secattr);
@@ -226,6 +221,7 @@ int cipso_v4_skbuff_setattr(struct sk_buff *skb,
 int cipso_v4_skbuff_delattr(struct sk_buff *skb);
 int cipso_v4_skbuff_getattr(const struct sk_buff *skb,
 			    struct netlbl_lsm_secattr *secattr);
+unsigned char *cipso_v4_optptr(const struct sk_buff *skb);
 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option);
 #else
 static inline void cipso_v4_error(struct sk_buff *skb,
@@ -235,6 +231,12 @@ static inline void cipso_v4_error(struct sk_buff *skb,
 	return;
 }
 
+static inline int cipso_v4_getattr(const unsigned char *cipso,
+				   struct netlbl_lsm_secattr *secattr)
+{
+	return -ENOSYS;
+}
+
 static inline int cipso_v4_sock_setattr(struct sock *sk,
 				      const struct cipso_v4_doi *doi_def,
 				      const struct netlbl_lsm_secattr *secattr)
@@ -282,6 +284,11 @@ static inline int cipso_v4_skbuff_getattr(const struct sk_buff *skb,
 	return -ENOSYS;
 }
 
+static inline unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
+{
+	return NULL;
+}
+
 static inline int cipso_v4_validate(const struct sk_buff *skb,
 				    unsigned char **option)
 {