NLM: Fix GRANT callback address comparison when IPv6 is enabled

The NFS mount command may pass an AF_INET server address to lockd.  If
lockd happens to be using a PF_INET6 listener, the nlm_cmp_addr() in
nlmclnt_grant() will fail to match requests from that host because they
will all have a mapped IPv4 AF_INET6 address.

Adopt the same solution used in nfs_sockaddr_match_ipaddr() for NFSv4
callbacks: if either address is AF_INET, map it to an AF_INET6 address
before doing the comparison.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 50 insertions, 1 deletions

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 1f3b0fc0d351..aedc47a264c1 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -139,6 +139,55 @@ int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
         return 0;
 }
 
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+static const struct in6_addr *nlmclnt_map_v4addr(const struct sockaddr *sap,
+                                                 struct in6_addr *addr_mapped)
+{
+        const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
+
+        switch (sap->sa_family) {
+        case AF_INET6:
+                return &((const struct sockaddr_in6 *)sap)->sin6_addr;
+        case AF_INET:
+                ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, addr_mapped);
+                return addr_mapped;
+        }
+
+        return NULL;
+}
+
+/*
+ * If lockd is using a PF_INET6 listener, all incoming requests appear
+ * to come from AF_INET6 remotes.  The address of AF_INET remotes are
+ * mapped to AF_INET6 automatically by the network layer.  In case the
+ * user passed an AF_INET server address at mount time, ensure both
+ * addresses are AF_INET6 before comparing them.
+ */
+static int nlmclnt_cmp_addr(const struct nlm_host *host,
+                            const struct sockaddr *sap)
+{
+        const struct in6_addr *addr1;
+        const struct in6_addr *addr2;
+        struct in6_addr addr1_mapped;
+        struct in6_addr addr2_mapped;
+
+        addr1 = nlmclnt_map_v4addr(nlm_addr(host), &addr1_mapped);
+        if (likely(addr1 != NULL)) {
+                addr2 = nlmclnt_map_v4addr(sap, &addr2_mapped);
+                if (likely(addr2 != NULL))
+                        return ipv6_addr_equal(addr1, addr2);
+        }
+
+        return 0;
+}
+#else   /* !(CONFIG_IPV6 || CONFIG_IPV6_MODULE) */
+static int nlmclnt_cmp_addr(const struct nlm_host *host,
+                            const struct sockaddr *sap)
+{
+        return nlm_cmp_addr(nlm_addr(host), sap);
+}
+#endif  /* !(CONFIG_IPV6 || CONFIG_IPV6_MODULE) */
+
 /*
  * The server lockd has called us back to tell us the lock was granted
  */
@@ -166,7 +215,7 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
                  */
                 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
                         continue;
-                if (!nlm_cmp_addr(nlm_addr(block->b_host), addr))
+                if (!nlmclnt_cmp_addr(block->b_host, addr))
                         continue;
                 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0)
                         continue;