Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  [DNS RESOLVER] Minor typo correction
  DNS: Fixes for the DNS query module
  cifs: Include linux/err.h for IS_ERR and PTR_ERR
  DNS: Make AFS go to the DNS for AFSDB records for unknown cells
  DNS: Separate out CIFS DNS Resolver code
  cifs: account for new creduid=0x%x parameter in spnego upcall string
  cifs: reduce false positives with inode aliasing serverino autodisable
  CIFS: Make cifs_convert_address() take a const src pointer and a length
  cifs: show features compiled in as part of DebugData
  cifs: update README

Fix up trivial conflicts in fs/cifs/cifsfs.c due to workqueue changes

Documentation/networking/dns_resolver.txt

@@ -0,0 +1,146 @@
+			     ===================
+			     DNS Resolver Module
+			     ===================
+
+Contents:
+
+ - Overview.
+ - Compilation.
+ - Setting up.
+ - Usage.
+ - Mechanism.
+ - Debugging.
+
+
+========
+OVERVIEW
+========
+
+The DNS resolver module provides a way for kernel services to make DNS queries
+by way of requesting a key of key type dns_resolver.  These queries are
+upcalled to userspace through /sbin/request-key.
+
+These routines must be supported by userspace tools dns.upcall, cifs.upcall and
+request-key.  It is under development and does not yet provide the full feature
+set.  The features it does support include:
+
+ (*) Implements the dns_resolver key_type to contact userspace.
+
+It does not yet support the following AFS features:
+
+ (*) Dns query support for AFSDB resource record.
+
+This code is extracted from the CIFS filesystem.
+
+
+===========
+COMPILATION
+===========
+
+The module should be enabled by turning on the kernel configuration options:
+
+	CONFIG_DNS_RESOLVER	- tristate "DNS Resolver support"
+
+
+==========
+SETTING UP
+==========
+
+To set up this facility, the /etc/request-key.conf file must be altered so that
+/sbin/request-key can appropriately direct the upcalls.  For example, to handle
+basic dname to IPv4/IPv6 address resolution, the following line should be
+added:
+
+	#OP	TYPE		DESC	CO-INFO	PROGRAM ARG1 ARG2 ARG3 ...
+	#======	============	=======	=======	==========================
+	create	dns_resolver  	*	*	/usr/sbin/cifs.upcall %k
+
+To direct a query for query type 'foo', a line of the following should be added
+before the more general line given above as the first match is the one taken.
+
+	create	dns_resolver  	foo:*	*	/usr/sbin/dns.foo %k
+
+
+
+=====
+USAGE
+=====
+
+To make use of this facility, one of the following functions that are
+implemented in the module can be called after doing:
+
+	#include <linux/dns_resolver.h>
+
+ (1) int dns_query(const char *type, const char *name, size_t namelen,
+		   const char *options, char **_result, time_t *_expiry);
+
+     This is the basic access function.  It looks for a cached DNS query and if
+     it doesn't find it, it upcalls to userspace to make a new DNS query, which
+     may then be cached.  The key description is constructed as a string of the
+     form:
+
+		[<type>:]<name>
+
+     where <type> optionally specifies the particular upcall program to invoke,
+     and thus the type of query to do, and <name> specifies the string to be
+     looked up.  The default query type is a straight hostname to IP address
+     set lookup.
+
+     The name parameter is not required to be a NUL-terminated string, and its
+     length should be given by the namelen argument.
+
+     The options parameter may be NULL or it may be a set of options
+     appropriate to the query type.
+
+     The return value is a string appropriate to the query type.  For instance,
+     for the default query type it is just a list of comma-separated IPv4 and
+     IPv6 addresses.  The caller must free the result.
+
+     The length of the result string is returned on success, and a negative
+     error code is returned otherwise.  -EKEYREJECTED will be returned if the
+     DNS lookup failed.
+
+     If _expiry is non-NULL, the expiry time (TTL) of the result will be
+     returned also.
+
+
+=========
+MECHANISM
+=========
+
+The dnsresolver module registers a key type called "dns_resolver".  Keys of
+this type are used to transport and cache DNS lookup results from userspace.
+
+When dns_query() is invoked, it calls request_key() to search the local
+keyrings for a cached DNS result.  If that fails to find one, it upcalls to
+userspace to get a new result.
+
+Upcalls to userspace are made through the request_key() upcall vector, and are
+directed by means of configuration lines in /etc/request-key.conf that tell
+/sbin/request-key what program to run to instantiate the key.
+
+The upcall handler program is responsible for querying the DNS, processing the
+result into a form suitable for passing to the keyctl_instantiate_key()
+routine.  This then passes the data to dns_resolver_instantiate() which strips
+off and processes any options included in the data, and then attaches the
+remainder of the string to the key as its payload.
+
+The upcall handler program should set the expiry time on the key to that of the
+lowest TTL of all the records it has extracted a result from.  This means that
+the key will be discarded and recreated when the data it holds has expired.
+
+dns_query() returns a copy of the value attached to the key, or an error if
+that is indicated instead.
+
+See <file:Documentation/keys-request-key.txt> for further information about
+request-key function.
+
+
+=========
+DEBUGGING
+=========
+
+Debugging messages can be turned on dynamically by writing a 1 into the
+following file:
+
+        /sys/module/dnsresolver/parameters/debug

fs/afs/Kconfig

@@ -2,6 +2,7 @@ config AFS_FS
 	tristate "Andrew File System support (AFS) (EXPERIMENTAL)"
 	depends on INET && EXPERIMENTAL
 	select AF_RXRPC
+	select DNS_RESOLVER
 	help
 	  If you say Y here, you will get an experimental Andrew File System
 	  driver. It currently only supports unsecured read-only AFS access.

fs/afs/cell.c

@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/key.h>
 #include <linux/ctype.h>
+#include <linux/dns_resolver.h>
 #include <linux/sched.h>
 #include <keys/rxrpc-type.h>
 #include "internal.h"
@@ -36,15 +37,19 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
 	struct key *key;
 	size_t namelen;
 	char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
+	char  *dvllist = NULL, *_vllist = NULL;
+	char  delimiter = ':';
 	int ret;
 
 	_enter("%s,%s", name, vllist);
 
 	BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
 
 	namelen = strlen(name);
-	if (namelen > AFS_MAXCELLNAME)
+	if (namelen > AFS_MAXCELLNAME) {
+		_leave(" = -ENAMETOOLONG");
 		return ERR_PTR(-ENAMETOOLONG);
+	}
 
 	/* allocate and initialise a cell record */
 	cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
@@ -64,15 +69,31 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
 	INIT_LIST_HEAD(&cell->vl_list);
 	spin_lock_init(&cell->vl_lock);
 
+	/* if the ip address is invalid, try dns query */
+	if (!vllist || strlen(vllist) < 7) {
+		ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
+		if (ret < 0) {
+			_leave(" = %d", ret);
+			return ERR_PTR(ret);
+		}
+		_vllist = dvllist;
+
+		/* change the delimiter for user-space reply */
+		delimiter = ',';
+
+	} else {
+		_vllist = vllist;
+	}
+
 	/* fill in the VL server list from the rest of the string */
 	do {
 		unsigned a, b, c, d;
 
-		next = strchr(vllist, ':');
+		next = strchr(_vllist, delimiter);
 		if (next)
 			*next++ = 0;
 
-		if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
+		if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
 			goto bad_address;
 
 		if (a > 255 || b > 255 || c > 255 || d > 255)
@@ -81,7 +102,7 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
 		cell->vl_addrs[cell->vl_naddrs++].s_addr =
 			htonl((a << 24) | (b << 16) | (c << 8) | d);
 
-	} while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next));
+	} while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next));
 
 	/* create a key to represent an anonymous user */
 	memcpy(keyname, "afs@", 4);
@@ -110,6 +131,7 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
 	ret = -EINVAL;
 error:
 	key_put(cell->anonymous_key);
+	kfree(dvllist);
 	kfree(cell);
 	_leave(" = %d", ret);
 	return ERR_PTR(ret);
@@ -201,14 +223,12 @@ int afs_cell_init(char *rootcell)
 	}
 
 	cp = strchr(rootcell, ':');
-	if (!cp) {
-		printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
-		_leave(" = -EINVAL");
-		return -EINVAL;
-	}
+	if (!cp)
+		_debug("kAFS: no VL server IP addresses specified");
+	else
+		*cp++ = 0;
 
 	/* allocate a cell record for the root cell */
-	*cp++ = 0;
 	new_root = afs_cell_create(rootcell, cp);
 	if (IS_ERR(new_root)) {
 		_leave(" = %ld", PTR_ERR(new_root));

fs/cifs/Kconfig

@@ -70,14 +70,14 @@ config CIFS_WEAK_PW_HASH
 	  If unsure, say N.
 
 config CIFS_UPCALL
-	  bool "Kerberos/SPNEGO advanced session setup"
-	  depends on CIFS && KEYS
-	  help
-	    Enables an upcall mechanism for CIFS which accesses
-	    userspace helper utilities to provide SPNEGO packaged (RFC 4178)
-	    Kerberos tickets which are needed to mount to certain secure servers
-	    (for which more secure Kerberos authentication is required). If
-	    unsure, say N.
+	bool "Kerberos/SPNEGO advanced session setup"
+	depends on CIFS && KEYS
+	select DNS_RESOLVER
+	help
+	  Enables an upcall mechanism for CIFS which accesses userspace helper
+	  utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
+	  which are needed to mount to certain secure servers (for which more
+	  secure Kerberos authentication is required). If unsure, say N.
 
 config CIFS_XATTR
         bool "CIFS extended attributes"
@@ -121,6 +121,7 @@ config CIFS_DEBUG2
 config CIFS_DFS_UPCALL
 	  bool "DFS feature support"
 	  depends on CIFS && KEYS
+	  select DNS_RESOLVER
 	  help
 	    Distributed File System (DFS) support is used to access shares
 	    transparently in an enterprise name space, even if the share

fs/cifs/README

@@ -568,8 +568,9 @@ module can be displayed via modinfo.
 Misc /proc/fs/cifs Flags and Debug Info
 =======================================
 Informational pseudo-files:
-DebugData		Displays information about active CIFS sessions
-			and shares, as well as the cifs.ko version.
+DebugData		Displays information about active CIFS sessions and
+			shares, features enabled as well as the cifs.ko
+			version.
 Stats			Lists summary resource usage information as well as per
 			share statistics, if CONFIG_CIFS_STATS in enabled
 			in the kernel configuration.

fs/cifs/cifs_debug.c

@@ -119,6 +119,31 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 		    "Display Internal CIFS Data Structures for Debugging\n"
 		    "---------------------------------------------------\n");
 	seq_printf(m, "CIFS Version %s\n", CIFS_VERSION);
+	seq_printf(m, "Features: ");
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	seq_printf(m, "dfs");
+	seq_putc(m, ' ');
+#endif
+#ifdef CONFIG_CIFS_FSCACHE
+	seq_printf(m, "fscache");
+	seq_putc(m, ' ');
+#endif
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+	seq_printf(m, "lanman");
+	seq_putc(m, ' ');
+#endif
+#ifdef CONFIG_CIFS_POSIX
+	seq_printf(m, "posix");
+	seq_putc(m, ' ');
+#endif
+#ifdef CONFIG_CIFS_UPCALL
+	seq_printf(m, "spnego");
+	seq_putc(m, ' ');
+#endif
+#ifdef CONFIG_CIFS_XATTR
+	seq_printf(m, "xattr");
+#endif
+	seq_putc(m, '\n');
 	seq_printf(m, "Active VFS Requests: %d\n", GlobalTotalActiveXid);
 	seq_printf(m, "Servers:");
 

fs/cifs/cifs_dfs_ref.c

@@ -141,7 +141,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
 	}
 
 	rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
-	if (rc != 0) {
+	if (rc < 0) {
 		cERROR(1, "%s: Failed to resolve server part of %s to IP: %d",
 			  __func__, *devname, rc);
 		goto compose_mount_options_err;
@@ -150,8 +150,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
 	 * assuming that we have 'unc=' and 'ip=' in
 	 * the original sb_mountdata
 	 */
-	md_len = strlen(sb_mountdata) + strlen(srvIP) +
-		strlen(ref->node_name) + 12;
+	md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12;
 	mountdata = kzalloc(md_len+1, GFP_KERNEL);
 	if (mountdata == NULL) {
 		rc = -ENOMEM;

fs/cifs/cifs_spnego.c

@@ -84,6 +84,9 @@ struct key_type cifs_spnego_key_type = {
 /* strlen of ";uid=0x" */
 #define UID_KEY_LEN		7
 
+/* strlen of ";creduid=0x" */
+#define CREDUID_KEY_LEN		11
+
 /* strlen of ";user=" */
 #define USER_KEY_LEN		6
 
@@ -107,6 +110,7 @@ cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
 		   IP_KEY_LEN + INET6_ADDRSTRLEN +
 		   MAX_MECH_STR_LEN +
 		   UID_KEY_LEN + (sizeof(uid_t) * 2) +
+		   CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
 		   USER_KEY_LEN + strlen(sesInfo->userName) +
 		   PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;