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-rw-r--r--Documentation/networking/dns_resolver.txt146
-rw-r--r--fs/afs/Kconfig1
-rw-r--r--fs/afs/cell.c40
-rw-r--r--fs/cifs/Kconfig17
-rw-r--r--fs/cifs/README5
-rw-r--r--fs/cifs/cifs_debug.c25
-rw-r--r--fs/cifs/cifs_dfs_ref.c5
-rw-r--r--fs/cifs/cifs_spnego.c4
-rw-r--r--fs/cifs/cifsfs.c13
-rw-r--r--fs/cifs/cifsproto.h4
-rw-r--r--fs/cifs/connect.c1
-rw-r--r--fs/cifs/dns_resolve.c231
-rw-r--r--fs/cifs/dns_resolve.h2
-rw-r--r--fs/cifs/inode.c43
-rw-r--r--fs/cifs/netmisc.c45
-rw-r--r--include/keys/dns_resolver-type.h23
-rw-r--r--include/linux/dns_resolver.h34
-rw-r--r--net/Kconfig1
-rw-r--r--net/Makefile1
-rw-r--r--net/dns_resolver/Kconfig27
-rw-r--r--net/dns_resolver/Makefile7
-rw-r--r--net/dns_resolver/dns_key.c211
-rw-r--r--net/dns_resolver/dns_query.c160
-rw-r--r--net/dns_resolver/internal.h44
24 files changed, 833 insertions, 257 deletions
diff --git a/Documentation/networking/dns_resolver.txt b/Documentation/networking/dns_resolver.txt
new file mode 100644
index 000000000000..aefd1e681804
--- /dev/null
+++ b/Documentation/networking/dns_resolver.txt
@@ -0,0 +1,146 @@
1 ===================
2 DNS Resolver Module
3 ===================
4
5Contents:
6
7 - Overview.
8 - Compilation.
9 - Setting up.
10 - Usage.
11 - Mechanism.
12 - Debugging.
13
14
15========
16OVERVIEW
17========
18
19The DNS resolver module provides a way for kernel services to make DNS queries
20by way of requesting a key of key type dns_resolver. These queries are
21upcalled to userspace through /sbin/request-key.
22
23These routines must be supported by userspace tools dns.upcall, cifs.upcall and
24request-key. It is under development and does not yet provide the full feature
25set. The features it does support include:
26
27 (*) Implements the dns_resolver key_type to contact userspace.
28
29It does not yet support the following AFS features:
30
31 (*) Dns query support for AFSDB resource record.
32
33This code is extracted from the CIFS filesystem.
34
35
36===========
37COMPILATION
38===========
39
40The module should be enabled by turning on the kernel configuration options:
41
42 CONFIG_DNS_RESOLVER - tristate "DNS Resolver support"
43
44
45==========
46SETTING UP
47==========
48
49To set up this facility, the /etc/request-key.conf file must be altered so that
50/sbin/request-key can appropriately direct the upcalls. For example, to handle
51basic dname to IPv4/IPv6 address resolution, the following line should be
52added:
53
54 #OP TYPE DESC CO-INFO PROGRAM ARG1 ARG2 ARG3 ...
55 #====== ============ ======= ======= ==========================
56 create dns_resolver * * /usr/sbin/cifs.upcall %k
57
58To direct a query for query type 'foo', a line of the following should be added
59before the more general line given above as the first match is the one taken.
60
61 create dns_resolver foo:* * /usr/sbin/dns.foo %k
62
63
64
65=====
66USAGE
67=====
68
69To make use of this facility, one of the following functions that are
70implemented in the module can be called after doing:
71
72 #include <linux/dns_resolver.h>
73
74 (1) int dns_query(const char *type, const char *name, size_t namelen,
75 const char *options, char **_result, time_t *_expiry);
76
77 This is the basic access function. It looks for a cached DNS query and if
78 it doesn't find it, it upcalls to userspace to make a new DNS query, which
79 may then be cached. The key description is constructed as a string of the
80 form:
81
82 [<type>:]<name>
83
84 where <type> optionally specifies the particular upcall program to invoke,
85 and thus the type of query to do, and <name> specifies the string to be
86 looked up. The default query type is a straight hostname to IP address
87 set lookup.
88
89 The name parameter is not required to be a NUL-terminated string, and its
90 length should be given by the namelen argument.
91
92 The options parameter may be NULL or it may be a set of options
93 appropriate to the query type.
94
95 The return value is a string appropriate to the query type. For instance,
96 for the default query type it is just a list of comma-separated IPv4 and
97 IPv6 addresses. The caller must free the result.
98
99 The length of the result string is returned on success, and a negative
100 error code is returned otherwise. -EKEYREJECTED will be returned if the
101 DNS lookup failed.
102
103 If _expiry is non-NULL, the expiry time (TTL) of the result will be
104 returned also.
105
106
107=========
108MECHANISM
109=========
110
111The dnsresolver module registers a key type called "dns_resolver". Keys of
112this type are used to transport and cache DNS lookup results from userspace.
113
114When dns_query() is invoked, it calls request_key() to search the local
115keyrings for a cached DNS result. If that fails to find one, it upcalls to
116userspace to get a new result.
117
118Upcalls to userspace are made through the request_key() upcall vector, and are
119directed by means of configuration lines in /etc/request-key.conf that tell
120/sbin/request-key what program to run to instantiate the key.
121
122The upcall handler program is responsible for querying the DNS, processing the
123result into a form suitable for passing to the keyctl_instantiate_key()
124routine. This then passes the data to dns_resolver_instantiate() which strips
125off and processes any options included in the data, and then attaches the
126remainder of the string to the key as its payload.
127
128The upcall handler program should set the expiry time on the key to that of the
129lowest TTL of all the records it has extracted a result from. This means that
130the key will be discarded and recreated when the data it holds has expired.
131
132dns_query() returns a copy of the value attached to the key, or an error if
133that is indicated instead.
134
135See <file:Documentation/keys-request-key.txt> for further information about
136request-key function.
137
138
139=========
140DEBUGGING
141=========
142
143Debugging messages can be turned on dynamically by writing a 1 into the
144following file:
145
146 /sys/module/dnsresolver/parameters/debug
diff --git a/fs/afs/Kconfig b/fs/afs/Kconfig
index 5c4e61d3c772..8f975f25b486 100644
--- a/fs/afs/Kconfig
+++ b/fs/afs/Kconfig
@@ -2,6 +2,7 @@ config AFS_FS
2 tristate "Andrew File System support (AFS) (EXPERIMENTAL)" 2 tristate "Andrew File System support (AFS) (EXPERIMENTAL)"
3 depends on INET && EXPERIMENTAL 3 depends on INET && EXPERIMENTAL
4 select AF_RXRPC 4 select AF_RXRPC
5 select DNS_RESOLVER
5 help 6 help
6 If you say Y here, you will get an experimental Andrew File System 7 If you say Y here, you will get an experimental Andrew File System
7 driver. It currently only supports unsecured read-only AFS access. 8 driver. It currently only supports unsecured read-only AFS access.
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index e19c13f059ed..ffea35c63879 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -13,6 +13,7 @@
13#include <linux/slab.h> 13#include <linux/slab.h>
14#include <linux/key.h> 14#include <linux/key.h>
15#include <linux/ctype.h> 15#include <linux/ctype.h>
16#include <linux/dns_resolver.h>
16#include <linux/sched.h> 17#include <linux/sched.h>
17#include <keys/rxrpc-type.h> 18#include <keys/rxrpc-type.h>
18#include "internal.h" 19#include "internal.h"
@@ -36,6 +37,8 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
36 struct key *key; 37 struct key *key;
37 size_t namelen; 38 size_t namelen;
38 char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next; 39 char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
40 char *dvllist = NULL, *_vllist = NULL;
41 char delimiter = ':';
39 int ret; 42 int ret;
40 43
41 _enter("%s,%s", name, vllist); 44 _enter("%s,%s", name, vllist);
@@ -43,8 +46,10 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
43 BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */ 46 BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
44 47
45 namelen = strlen(name); 48 namelen = strlen(name);
46 if (namelen > AFS_MAXCELLNAME) 49 if (namelen > AFS_MAXCELLNAME) {
50 _leave(" = -ENAMETOOLONG");
47 return ERR_PTR(-ENAMETOOLONG); 51 return ERR_PTR(-ENAMETOOLONG);
52 }
48 53
49 /* allocate and initialise a cell record */ 54 /* allocate and initialise a cell record */
50 cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL); 55 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)
64 INIT_LIST_HEAD(&cell->vl_list); 69 INIT_LIST_HEAD(&cell->vl_list);
65 spin_lock_init(&cell->vl_lock); 70 spin_lock_init(&cell->vl_lock);
66 71
72 /* if the ip address is invalid, try dns query */
73 if (!vllist || strlen(vllist) < 7) {
74 ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
75 if (ret < 0) {
76 _leave(" = %d", ret);
77 return ERR_PTR(ret);
78 }
79 _vllist = dvllist;
80
81 /* change the delimiter for user-space reply */
82 delimiter = ',';
83
84 } else {
85 _vllist = vllist;
86 }
87
67 /* fill in the VL server list from the rest of the string */ 88 /* fill in the VL server list from the rest of the string */
68 do { 89 do {
69 unsigned a, b, c, d; 90 unsigned a, b, c, d;
70 91
71 next = strchr(vllist, ':'); 92 next = strchr(_vllist, delimiter);
72 if (next) 93 if (next)
73 *next++ = 0; 94 *next++ = 0;
74 95
75 if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) 96 if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
76 goto bad_address; 97 goto bad_address;
77 98
78 if (a > 255 || b > 255 || c > 255 || d > 255) 99 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)
81 cell->vl_addrs[cell->vl_naddrs++].s_addr = 102 cell->vl_addrs[cell->vl_naddrs++].s_addr =
82 htonl((a << 24) | (b << 16) | (c << 8) | d); 103 htonl((a << 24) | (b << 16) | (c << 8) | d);
83 104
84 } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next)); 105 } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next));
85 106
86 /* create a key to represent an anonymous user */ 107 /* create a key to represent an anonymous user */
87 memcpy(keyname, "afs@", 4); 108 memcpy(keyname, "afs@", 4);
@@ -110,6 +131,7 @@ bad_address:
110 ret = -EINVAL; 131 ret = -EINVAL;
111error: 132error:
112 key_put(cell->anonymous_key); 133 key_put(cell->anonymous_key);
134 kfree(dvllist);
113 kfree(cell); 135 kfree(cell);
114 _leave(" = %d", ret); 136 _leave(" = %d", ret);
115 return ERR_PTR(ret); 137 return ERR_PTR(ret);
@@ -201,14 +223,12 @@ int afs_cell_init(char *rootcell)
201 } 223 }
202 224
203 cp = strchr(rootcell, ':'); 225 cp = strchr(rootcell, ':');
204 if (!cp) { 226 if (!cp)
205 printk(KERN_ERR "kAFS: no VL server IP addresses specified\n"); 227 _debug("kAFS: no VL server IP addresses specified");
206 _leave(" = -EINVAL"); 228 else
207 return -EINVAL; 229 *cp++ = 0;
208 }
209 230
210 /* allocate a cell record for the root cell */ 231 /* allocate a cell record for the root cell */
211 *cp++ = 0;
212 new_root = afs_cell_create(rootcell, cp); 232 new_root = afs_cell_create(rootcell, cp);
213 if (IS_ERR(new_root)) { 233 if (IS_ERR(new_root)) {
214 _leave(" = %ld", PTR_ERR(new_root)); 234 _leave(" = %ld", PTR_ERR(new_root));
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index efcb3a78a327..917b7d449bb2 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -70,14 +70,14 @@ config CIFS_WEAK_PW_HASH
70 If unsure, say N. 70 If unsure, say N.
71 71
72config CIFS_UPCALL 72config CIFS_UPCALL
73 bool "Kerberos/SPNEGO advanced session setup" 73 bool "Kerberos/SPNEGO advanced session setup"
74 depends on CIFS && KEYS 74 depends on CIFS && KEYS
75 help 75 select DNS_RESOLVER
76 Enables an upcall mechanism for CIFS which accesses 76 help
77 userspace helper utilities to provide SPNEGO packaged (RFC 4178) 77 Enables an upcall mechanism for CIFS which accesses userspace helper
78 Kerberos tickets which are needed to mount to certain secure servers 78 utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
79 (for which more secure Kerberos authentication is required). If 79 which are needed to mount to certain secure servers (for which more
80 unsure, say N. 80 secure Kerberos authentication is required). If unsure, say N.
81 81
82config CIFS_XATTR 82config CIFS_XATTR
83 bool "CIFS extended attributes" 83 bool "CIFS extended attributes"
@@ -121,6 +121,7 @@ config CIFS_DEBUG2
121config CIFS_DFS_UPCALL 121config CIFS_DFS_UPCALL
122 bool "DFS feature support" 122 bool "DFS feature support"
123 depends on CIFS && KEYS 123 depends on CIFS && KEYS
124 select DNS_RESOLVER
124 help 125 help
125 Distributed File System (DFS) support is used to access shares 126 Distributed File System (DFS) support is used to access shares
126 transparently in an enterprise name space, even if the share 127 transparently in an enterprise name space, even if the share
diff --git a/fs/cifs/README b/fs/cifs/README
index a727b7cb075f..a7081eeeb85d 100644
--- a/fs/cifs/README
+++ b/fs/cifs/README
@@ -568,8 +568,9 @@ module can be displayed via modinfo.
568Misc /proc/fs/cifs Flags and Debug Info 568Misc /proc/fs/cifs Flags and Debug Info
569======================================= 569=======================================
570Informational pseudo-files: 570Informational pseudo-files:
571DebugData Displays information about active CIFS sessions 571DebugData Displays information about active CIFS sessions and
572 and shares, as well as the cifs.ko version. 572 shares, features enabled as well as the cifs.ko
573 version.
573Stats Lists summary resource usage information as well as per 574Stats Lists summary resource usage information as well as per
574 share statistics, if CONFIG_CIFS_STATS in enabled 575 share statistics, if CONFIG_CIFS_STATS in enabled
575 in the kernel configuration. 576 in the kernel configuration.
diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 4fce6e61b34e..eb1ba493489f 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -119,6 +119,31 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
119 "Display Internal CIFS Data Structures for Debugging\n" 119 "Display Internal CIFS Data Structures for Debugging\n"
120 "---------------------------------------------------\n"); 120 "---------------------------------------------------\n");
121 seq_printf(m, "CIFS Version %s\n", CIFS_VERSION); 121 seq_printf(m, "CIFS Version %s\n", CIFS_VERSION);
122 seq_printf(m, "Features: ");
123#ifdef CONFIG_CIFS_DFS_UPCALL
124 seq_printf(m, "dfs");
125 seq_putc(m, ' ');
126#endif
127#ifdef CONFIG_CIFS_FSCACHE
128 seq_printf(m, "fscache");
129 seq_putc(m, ' ');
130#endif
131#ifdef CONFIG_CIFS_WEAK_PW_HASH
132 seq_printf(m, "lanman");
133 seq_putc(m, ' ');
134#endif
135#ifdef CONFIG_CIFS_POSIX
136 seq_printf(m, "posix");
137 seq_putc(m, ' ');
138#endif
139#ifdef CONFIG_CIFS_UPCALL
140 seq_printf(m, "spnego");
141 seq_putc(m, ' ');
142#endif
143#ifdef CONFIG_CIFS_XATTR
144 seq_printf(m, "xattr");
145#endif
146 seq_putc(m, '\n');
122 seq_printf(m, "Active VFS Requests: %d\n", GlobalTotalActiveXid); 147 seq_printf(m, "Active VFS Requests: %d\n", GlobalTotalActiveXid);
123 seq_printf(m, "Servers:"); 148 seq_printf(m, "Servers:");
124 149
diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index dc1ed50ea06e..d6ced7aa23cf 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -141,7 +141,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
141 } 141 }
142 142
143 rc = dns_resolve_server_name_to_ip(*devname, &srvIP); 143 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
144 if (rc != 0) { 144 if (rc < 0) {
145 cERROR(1, "%s: Failed to resolve server part of %s to IP: %d", 145 cERROR(1, "%s: Failed to resolve server part of %s to IP: %d",
146 __func__, *devname, rc); 146 __func__, *devname, rc);
147 goto compose_mount_options_err; 147 goto compose_mount_options_err;
@@ -150,8 +150,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
150 * assuming that we have 'unc=' and 'ip=' in 150 * assuming that we have 'unc=' and 'ip=' in
151 * the original sb_mountdata 151 * the original sb_mountdata
152 */ 152 */
153 md_len = strlen(sb_mountdata) + strlen(srvIP) + 153 md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12;
154 strlen(ref->node_name) + 12;
155 mountdata = kzalloc(md_len+1, GFP_KERNEL); 154 mountdata = kzalloc(md_len+1, GFP_KERNEL);
156 if (mountdata == NULL) { 155 if (mountdata == NULL) {
157 rc = -ENOMEM; 156 rc = -ENOMEM;
diff --git a/fs/cifs/cifs_spnego.c b/fs/cifs/cifs_spnego.c
index 6effccff85a5..87044906cd1f 100644
--- a/fs/cifs/cifs_spnego.c
+++ b/fs/cifs/cifs_spnego.c
@@ -84,6 +84,9 @@ struct key_type cifs_spnego_key_type = {
84/* strlen of ";uid=0x" */ 84/* strlen of ";uid=0x" */
85#define UID_KEY_LEN 7 85#define UID_KEY_LEN 7
86 86
87/* strlen of ";creduid=0x" */
88#define CREDUID_KEY_LEN 11
89
87/* strlen of ";user=" */ 90/* strlen of ";user=" */
88#define USER_KEY_LEN 6 91#define USER_KEY_LEN 6
89 92
@@ -107,6 +110,7 @@ cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
107 IP_KEY_LEN + INET6_ADDRSTRLEN + 110 IP_KEY_LEN + INET6_ADDRSTRLEN +
108 MAX_MECH_STR_LEN + 111 MAX_MECH_STR_LEN +
109 UID_KEY_LEN + (sizeof(uid_t) * 2) + 112 UID_KEY_LEN + (sizeof(uid_t) * 2) +
113 CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
110 USER_KEY_LEN + strlen(sesInfo->userName) + 114 USER_KEY_LEN + strlen(sesInfo->userName) +
111 PID_KEY_LEN + (sizeof(pid_t) * 2) + 1; 115 PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
112 116
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 5ac541a30c1d..a5ed10c9afef 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -45,7 +45,6 @@
45#include "cifs_fs_sb.h" 45#include "cifs_fs_sb.h"
46#include <linux/mm.h> 46#include <linux/mm.h>
47#include <linux/key-type.h> 47#include <linux/key-type.h>
48#include "dns_resolve.h"
49#include "cifs_spnego.h" 48#include "cifs_spnego.h"
50#include "fscache.h" 49#include "fscache.h"
51#define CIFS_MAGIC_NUMBER 0xFF534D42 /* the first four bytes of SMB PDUs */ 50#define CIFS_MAGIC_NUMBER 0xFF534D42 /* the first four bytes of SMB PDUs */
@@ -934,22 +933,13 @@ init_cifs(void)
934 if (rc) 933 if (rc)
935 goto out_unregister_filesystem; 934 goto out_unregister_filesystem;
936#endif 935#endif
937#ifdef CONFIG_CIFS_DFS_UPCALL
938 rc = cifs_init_dns_resolver();
939 if (rc)
940 goto out_unregister_key_type;
941#endif
942 936
943 return 0; 937 return 0;
944 938
945#ifdef CONFIG_CIFS_DFS_UPCALL
946 out_unregister_key_type:
947#endif
948#ifdef CONFIG_CIFS_UPCALL 939#ifdef CONFIG_CIFS_UPCALL
949 unregister_key_type(&cifs_spnego_key_type);
950 out_unregister_filesystem: 940 out_unregister_filesystem:
951#endif
952 unregister_filesystem(&cifs_fs_type); 941 unregister_filesystem(&cifs_fs_type);
942#endif
953 out_destroy_request_bufs: 943 out_destroy_request_bufs:
954 cifs_destroy_request_bufs(); 944 cifs_destroy_request_bufs();
955 out_destroy_mids: 945 out_destroy_mids:
@@ -971,7 +961,6 @@ exit_cifs(void)
971 cifs_fscache_unregister(); 961 cifs_fscache_unregister();
972#ifdef CONFIG_CIFS_DFS_UPCALL 962#ifdef CONFIG_CIFS_DFS_UPCALL
973 cifs_dfs_release_automount_timer(); 963 cifs_dfs_release_automount_timer();
974 cifs_exit_dns_resolver();
975#endif 964#endif
976#ifdef CONFIG_CIFS_UPCALL 965#ifdef CONFIG_CIFS_UPCALL
977 unregister_key_type(&cifs_spnego_key_type); 966 unregister_key_type(&cifs_spnego_key_type);
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 2eaebbd31132..1f5450814087 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -86,8 +86,8 @@ extern unsigned int smbCalcSize(struct smb_hdr *ptr);
86extern unsigned int smbCalcSize_LE(struct smb_hdr *ptr); 86extern unsigned int smbCalcSize_LE(struct smb_hdr *ptr);
87extern int decode_negTokenInit(unsigned char *security_blob, int length, 87extern int decode_negTokenInit(unsigned char *security_blob, int length,
88 struct TCP_Server_Info *server); 88 struct TCP_Server_Info *server);
89extern int cifs_convert_address(struct sockaddr *dst, char *src); 89extern int cifs_convert_address(struct sockaddr *dst, const char *src, int len);
90extern int cifs_fill_sockaddr(struct sockaddr *dst, char *src, 90extern int cifs_fill_sockaddr(struct sockaddr *dst, const char *src, int len,
91 unsigned short int port); 91 unsigned short int port);
92extern int map_smb_to_linux_error(struct smb_hdr *smb, int logErr); 92extern int map_smb_to_linux_error(struct smb_hdr *smb, int logErr);
93extern void header_assemble(struct smb_hdr *, char /* command */ , 93extern void header_assemble(struct smb_hdr *, char /* command */ ,
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 2a43a0aca965..95c2ea67edfb 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1543,6 +1543,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
1543 if (volume_info->UNCip && volume_info->UNC) { 1543 if (volume_info->UNCip && volume_info->UNC) {
1544 rc = cifs_fill_sockaddr((struct sockaddr *)&addr, 1544 rc = cifs_fill_sockaddr((struct sockaddr *)&addr,
1545 volume_info->UNCip, 1545 volume_info->UNCip,
1546 strlen(volume_info->UNCip),
1546 volume_info->port); 1547 volume_info->port);
1547 if (!rc) { 1548 if (!rc) {
1548 /* we failed translating address */ 1549 /* we failed translating address */
diff --git a/fs/cifs/dns_resolve.c b/fs/cifs/dns_resolve.c
index 3ad7f4300c45..0eb87026cad3 100644
--- a/fs/cifs/dns_resolve.c
+++ b/fs/cifs/dns_resolve.c
@@ -4,6 +4,8 @@
4 * Copyright (c) 2007 Igor Mammedov 4 * Copyright (c) 2007 Igor Mammedov
5 * Author(s): Igor Mammedov (niallain@gmail.com) 5 * Author(s): Igor Mammedov (niallain@gmail.com)
6 * Steve French (sfrench@us.ibm.com) 6 * Steve French (sfrench@us.ibm.com)
7 * Wang Lei (wang840925@gmail.com)
8 * David Howells (dhowells@redhat.com)
7 * 9 *
8 * Contains the CIFS DFS upcall routines used for hostname to 10 * Contains the CIFS DFS upcall routines used for hostname to
9 * IP address translation. 11 * IP address translation.
@@ -24,214 +26,73 @@
24 */ 26 */
25 27
26#include <linux/slab.h> 28#include <linux/slab.h>
27#include <linux/keyctl.h> 29#include <linux/dns_resolver.h>
28#include <linux/key-type.h>
29#include <keys/user-type.h>
30#include "dns_resolve.h" 30#include "dns_resolve.h"
31#include "cifsglob.h" 31#include "cifsglob.h"
32#include "cifsproto.h" 32#include "cifsproto.h"
33#include "cifs_debug.h" 33#include "cifs_debug.h"
34 34
35static const struct cred *dns_resolver_cache; 35/**
36 36 * dns_resolve_server_name_to_ip - Resolve UNC server name to ip address.
37/* Checks if supplied name is IP address 37 * @unc: UNC path specifying the server
38 * returns: 38 * @ip_addr: Where to return the IP address.
39 * 1 - name is IP 39 *
40 * 0 - name is not IP 40 * The IP address will be returned in string form, and the caller is
41 */ 41 * responsible for freeing it.
42static int 42 *
43is_ip(char *name) 43 * Returns length of result on success, -ve on error.
44{
45 struct sockaddr_storage ss;
46
47 return cifs_convert_address((struct sockaddr *)&ss, name);
48}
49
50static int
51dns_resolver_instantiate(struct key *key, const void *data,
52 size_t datalen)
53{
54 int rc = 0;
55 char *ip;
56
57 ip = kmalloc(datalen + 1, GFP_KERNEL);
58 if (!ip)
59 return -ENOMEM;
60
61 memcpy(ip, data, datalen);
62 ip[datalen] = '\0';
63
64 /* make sure this looks like an address */
65 if (!is_ip(ip)) {
66 kfree(ip);
67 return -EINVAL;
68 }
69
70 key->type_data.x[0] = datalen;
71 key->payload.data = ip;
72
73 return rc;
74}
75
76static void
77dns_resolver_destroy(struct key *key)
78{
79 kfree(key->payload.data);
80}
81
82struct key_type key_type_dns_resolver = {
83 .name = "dns_resolver",
84 .def_datalen = sizeof(struct in_addr),
85 .describe = user_describe,
86 .instantiate = dns_resolver_instantiate,
87 .destroy = dns_resolver_destroy,
88 .match = user_match,
89};
90
91/* Resolves server name to ip address.
92 * input:
93 * unc - server UNC
94 * output:
95 * *ip_addr - pointer to server ip, caller responcible for freeing it.
96 * return 0 on success
97 */ 44 */
98int 45int
99dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) 46dns_resolve_server_name_to_ip(const char *unc, char **ip_addr)
100{ 47{
101 const struct cred *saved_cred; 48 struct sockaddr_storage ss;
102 int rc = -EAGAIN; 49 const char *hostname, *sep;
103 struct key *rkey = ERR_PTR(-EAGAIN);
104 char *name; 50 char *name;
105 char *data = NULL; 51 int len, rc;
106 int len;
107 52
108 if (!ip_addr || !unc) 53 if (!ip_addr || !unc)
109 return -EINVAL; 54 return -EINVAL;
110 55
111 /* search for server name delimiter */
112 len = strlen(unc); 56 len = strlen(unc);
113 if (len < 3) { 57 if (len < 3) {
114 cFYI(1, "%s: unc is too short: %s", __func__, unc); 58 cFYI(1, "%s: unc is too short: %s", __func__, unc);
115 return -EINVAL; 59 return -EINVAL;
116 } 60 }
117 len -= 2;
118 name = memchr(unc+2, '\\', len);
119 if (!name) {
120 cFYI(1, "%s: probably server name is whole unc: %s",
121 __func__, unc);
122 } else {
123 len = (name - unc) - 2/* leading // */;
124 }
125
126 name = kmalloc(len+1, GFP_KERNEL);
127 if (!name) {
128 rc = -ENOMEM;
129 return rc;
130 }
131 memcpy(name, unc+2, len);
132 name[len] = 0;
133
134 if (is_ip(name)) {
135 cFYI(1, "%s: it is IP, skipping dns upcall: %s",
136 __func__, name);
137 data = name;
138 goto skip_upcall;
139 }
140 61
141 saved_cred = override_creds(dns_resolver_cache); 62 /* Discount leading slashes for cifs */
142 rkey = request_key(&key_type_dns_resolver, name, ""); 63 len -= 2;
143 revert_creds(saved_cred); 64 hostname = unc + 2;
144 if (!IS_ERR(rkey)) {
145 if (!(rkey->perm & KEY_USR_VIEW)) {
146 down_read(&rkey->sem);
147 rkey->perm |= KEY_USR_VIEW;
148 up_read(&rkey->sem);
149 }
150 len = rkey->type_data.x[0];
151 data = rkey->payload.data;
152 } else {
153 cERROR(1, "%s: unable to resolve: %s", __func__, name);
154 goto out;
155 }
156
157skip_upcall:
158 if (data) {
159 *ip_addr = kmalloc(len + 1, GFP_KERNEL);
160 if (*ip_addr) {
161 memcpy(*ip_addr, data, len + 1);
162 if (!IS_ERR(rkey))
163 cFYI(1, "%s: resolved: %s to %s", __func__,
164 name,
165 *ip_addr
166 );
167 rc = 0;
168 } else {
169 rc = -ENOMEM;
170 }
171 if (!IS_ERR(rkey))
172 key_put(rkey);
173 }
174 65
175out: 66 /* Search for server name delimiter */
176 kfree(name); 67 sep = memchr(hostname, '\\', len);
68 if (sep)
69 len = sep - unc;
70 else
71 cFYI(1, "%s: probably server name is whole unc: %s",
72 __func__, unc);
73
74 /* Try to interpret hostname as an IPv4 or IPv6 address */
75 rc = cifs_convert_address((struct sockaddr *)&ss, hostname, len);
76 if (rc > 0)
77 goto name_is_IP_address;
78
79 /* Perform the upcall */
80 rc = dns_query(NULL, hostname, len, NULL, ip_addr, NULL);
81 if (rc < 0)
82 cERROR(1, "%s: unable to resolve: %*.*s",
83 __func__, len, len, hostname);
84 else
85 cFYI(1, "%s: resolved: %*.*s to %s",
86 __func__, len, len, hostname, *ip_addr);
177 return rc; 87 return rc;
178}
179 88
180int __init cifs_init_dns_resolver(void) 89name_is_IP_address:
181{ 90 name = kmalloc(len + 1, GFP_KERNEL);
182 struct cred *cred; 91 if (!name)
183 struct key *keyring;
184 int ret;
185
186 printk(KERN_NOTICE "Registering the %s key type\n",
187 key_type_dns_resolver.name);
188
189 /* create an override credential set with a special thread keyring in
190 * which DNS requests are cached
191 *
192 * this is used to prevent malicious redirections from being installed
193 * with add_key().
194 */
195 cred = prepare_kernel_cred(NULL);
196 if (!cred)
197 return -ENOMEM; 92 return -ENOMEM;
198 93 memcpy(name, hostname, len);
199 keyring = key_alloc(&key_type_keyring, ".dns_resolver", 0, 0, cred, 94 name[len] = 0;
200 (KEY_POS_ALL & ~KEY_POS_SETATTR) | 95 cFYI(1, "%s: unc is IP, skipping dns upcall: %s", __func__, name);
201 KEY_USR_VIEW | KEY_USR_READ, 96 *ip_addr = name;
202 KEY_ALLOC_NOT_IN_QUOTA);
203 if (IS_ERR(keyring)) {
204 ret = PTR_ERR(keyring);
205 goto failed_put_cred;
206 }
207
208 ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
209 if (ret < 0)
210 goto failed_put_key;
211
212 ret = register_key_type(&key_type_dns_resolver);
213 if (ret < 0)
214 goto failed_put_key;
215
216 /* instruct request_key() to use this special keyring as a cache for
217 * the results it looks up */
218 cred->thread_keyring = keyring;
219 cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
220 dns_resolver_cache = cred;
221 return 0; 97 return 0;
222
223failed_put_key:
224 key_put(keyring);
225failed_put_cred:
226 put_cred(cred);
227 return ret;
228}
229
230void cifs_exit_dns_resolver(void)
231{
232 key_revoke(dns_resolver_cache->thread_keyring);
233 unregister_key_type(&key_type_dns_resolver);
234 put_cred(dns_resolver_cache);
235 printk(KERN_NOTICE "Unregistered %s key type\n",
236 key_type_dns_resolver.name);
237} 98}
diff --git a/fs/cifs/dns_resolve.h b/fs/cifs/dns_resolve.h
index 5d7f291df162..d3f5d27f4d06 100644
--- a/fs/cifs/dns_resolve.h
+++ b/fs/cifs/dns_resolve.h
@@ -24,8 +24,6 @@
24#define _DNS_RESOLVE_H 24#define _DNS_RESOLVE_H
25 25
26#ifdef __KERNEL__ 26#ifdef __KERNEL__
27extern int __init cifs_init_dns_resolver(void);
28extern void cifs_exit_dns_resolver(void);
29extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr); 27extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr);
30#endif /* KERNEL */ 28#endif /* KERNEL */
31 29
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index a15b3a9bbff4..dc4c47ab9588 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -732,15 +732,9 @@ cifs_find_inode(struct inode *inode, void *opaque)
732 if ((inode->i_mode & S_IFMT) != (fattr->cf_mode & S_IFMT)) 732 if ((inode->i_mode & S_IFMT) != (fattr->cf_mode & S_IFMT))
733 return 0; 733 return 0;
734 734
735 /* 735 /* if it's not a directory or has no dentries, then flag it */
736 * uh oh -- it's a directory. We can't use it since hardlinked dirs are 736 if (S_ISDIR(inode->i_mode) && !list_empty(&inode->i_dentry))
737 * verboten. Disable serverino and return it as if it were found, the
738 * caller can discard it, generate a uniqueid and retry the find
739 */
740 if (S_ISDIR(inode->i_mode) && !list_empty(&inode->i_dentry)) {
741 fattr->cf_flags |= CIFS_FATTR_INO_COLLISION; 737 fattr->cf_flags |= CIFS_FATTR_INO_COLLISION;
742 cifs_autodisable_serverino(CIFS_SB(inode->i_sb));
743 }
744 738
745 return 1; 739 return 1;
746} 740}
@@ -754,6 +748,27 @@ cifs_init_inode(struct inode *inode, void *opaque)
754 return 0; 748 return 0;
755} 749}
756 750
751/*
752 * walk dentry list for an inode and report whether it has aliases that
753 * are hashed. We use this to determine if a directory inode can actually
754 * be used.
755 */
756static bool
757inode_has_hashed_dentries(struct inode *inode)
758{
759 struct dentry *dentry;
760
761 spin_lock(&dcache_lock);
762 list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
763 if (!d_unhashed(dentry) || IS_ROOT(dentry)) {
764 spin_unlock(&dcache_lock);
765 return true;
766 }
767 }
768 spin_unlock(&dcache_lock);
769 return false;
770}
771
757/* Given fattrs, get a corresponding inode */ 772/* Given fattrs, get a corresponding inode */
758struct inode * 773struct inode *
759cifs_iget(struct super_block *sb, struct cifs_fattr *fattr) 774cifs_iget(struct super_block *sb, struct cifs_fattr *fattr)
@@ -769,12 +784,16 @@ retry_iget5_locked:
769 784
770 inode = iget5_locked(sb, hash, cifs_find_inode, cifs_init_inode, fattr); 785 inode = iget5_locked(sb, hash, cifs_find_inode, cifs_init_inode, fattr);
771 if (inode) { 786 if (inode) {
772 /* was there a problematic inode number collision? */ 787 /* was there a potentially problematic inode collision? */
773 if (fattr->cf_flags & CIFS_FATTR_INO_COLLISION) { 788 if (fattr->cf_flags & CIFS_FATTR_INO_COLLISION) {
774 iput(inode);
775 fattr->cf_uniqueid = iunique(sb, ROOT_I);
776 fattr->cf_flags &= ~CIFS_FATTR_INO_COLLISION; 789 fattr->cf_flags &= ~CIFS_FATTR_INO_COLLISION;
777 goto retry_iget5_locked; 790
791 if (inode_has_hashed_dentries(inode)) {
792 cifs_autodisable_serverino(CIFS_SB(sb));
793 iput(inode);
794 fattr->cf_uniqueid = iunique(sb, ROOT_I);
795 goto retry_iget5_locked;
796 }
778 } 797 }
779 798
780 cifs_fattr_to_inode(inode, fattr); 799 cifs_fattr_to_inode(inode, fattr);
diff --git a/fs/cifs/netmisc.c b/fs/cifs/netmisc.c
index c6721ee26dbc..f97851119e6c 100644
--- a/fs/cifs/netmisc.c
+++ b/fs/cifs/netmisc.c
@@ -140,17 +140,18 @@ static const struct smb_to_posix_error mapping_table_ERRHRD[] = {
140 * Returns 0 on failure. 140 * Returns 0 on failure.
141 */ 141 */
142static int 142static int
143cifs_inet_pton(const int address_family, const char *cp, void *dst) 143cifs_inet_pton(const int address_family, const char *cp, int len, void *dst)
144{ 144{
145 int ret = 0; 145 int ret = 0;
146 146
147 /* calculate length by finding first slash or NULL */ 147 /* calculate length by finding first slash or NULL */
148 if (address_family == AF_INET) 148 if (address_family == AF_INET)
149 ret = in4_pton(cp, -1 /* len */, dst, '\\', NULL); 149 ret = in4_pton(cp, len, dst, '\\', NULL);
150 else if (address_family == AF_INET6) 150 else if (address_family == AF_INET6)
151 ret = in6_pton(cp, -1 /* len */, dst , '\\', NULL); 151 ret = in6_pton(cp, len, dst , '\\', NULL);
152 152
153 cFYI(DBG2, "address conversion returned %d for %s", ret, cp); 153 cFYI(DBG2, "address conversion returned %d for %*.*s",
154 ret, len, len, cp);
154 if (ret > 0) 155 if (ret > 0)
155 ret = 1; 156 ret = 1;
156 return ret; 157 return ret;
@@ -165,37 +166,39 @@ cifs_inet_pton(const int address_family, const char *cp, void *dst)
165 * Returns 0 on failure. 166 * Returns 0 on failure.
166 */ 167 */
167int 168int
168cifs_convert_address(struct sockaddr *dst, char *src) 169cifs_convert_address(struct sockaddr *dst, const char *src, int len)
169{ 170{
170 int rc; 171 int rc, alen, slen;
171 char *pct, *endp; 172 const char *pct;
173 char *endp, scope_id[13];
172 struct sockaddr_in *s4 = (struct sockaddr_in *) dst; 174 struct sockaddr_in *s4 = (struct sockaddr_in *) dst;
173 struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) dst; 175 struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) dst;
174 176
175 /* IPv4 address */ 177 /* IPv4 address */
176 if (cifs_inet_pton(AF_INET, src, &s4->sin_addr.s_addr)) { 178 if (cifs_inet_pton(AF_INET, src, len, &s4->sin_addr.s_addr)) {
177 s4->sin_family = AF_INET; 179 s4->sin_family = AF_INET;
178 return 1; 180 return 1;
179 } 181 }
180 182
181 /* temporarily terminate string */ 183 /* attempt to exclude the scope ID from the address part */
182 pct = strchr(src, '%'); 184 pct = memchr(src, '%', len);
183 if (pct) 185 alen = pct ? pct - src : len;
184 *pct = '\0';
185
186 rc = cifs_inet_pton(AF_INET6, src, &s6->sin6_addr.s6_addr);
187
188 /* repair temp termination (if any) and make pct point to scopeid */
189 if (pct)
190 *pct++ = '%';
191 186
187 rc = cifs_inet_pton(AF_INET6, src, alen, &s6->sin6_addr.s6_addr);
192 if (!rc) 188 if (!rc)
193 return rc; 189 return rc;
194 190
195 s6->sin6_family = AF_INET6; 191 s6->sin6_family = AF_INET6;
196 if (pct) { 192 if (pct) {
193 /* grab the scope ID */
194 slen = len - (alen + 1);
195 if (slen <= 0 || slen > 12)
196 return 0;
197 memcpy(scope_id, pct + 1, slen);
198 scope_id[slen] = '\0';
199
197 s6->sin6_scope_id = (u32) simple_strtoul(pct, &endp, 0); 200 s6->sin6_scope_id = (u32) simple_strtoul(pct, &endp, 0);
198 if (!*pct || *endp) 201 if (endp != scope_id + slen)
199 return 0; 202 return 0;
200 } 203 }
201 204
@@ -203,10 +206,10 @@ cifs_convert_address(struct sockaddr *dst, char *src)
203} 206}
204 207
205int 208int
206cifs_fill_sockaddr(struct sockaddr *dst, char *src, 209cifs_fill_sockaddr(struct sockaddr *dst, const char *src, int len,
207 const unsigned short int port) 210 const unsigned short int port)
208{ 211{
209 if (!cifs_convert_address(dst, src)) 212 if (!cifs_convert_address(dst, src, len))
210 return 0; 213 return 0;
211 214
212 switch (dst->sa_family) { 215 switch (dst->sa_family) {
diff --git a/include/keys/dns_resolver-type.h b/include/keys/dns_resolver-type.h
new file mode 100644
index 000000000000..9284a19393aa
--- /dev/null
+++ b/include/keys/dns_resolver-type.h
@@ -0,0 +1,23 @@
1/* DNS resolver key type
2 *
3 * Copyright (C) 2010 Wang Lei. All Rights Reserved.
4 * Written by Wang Lei (wang840925@gmail.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#ifndef _KEYS_DNS_RESOLVER_TYPE_H
13#define _KEYS_DNS_RESOLVER_TYPE_H
14
15#include <linux/key-type.h>
16
17extern struct key_type key_type_dns_resolver;
18
19extern int request_dns_resolver_key(const char *description,
20 const char *callout_info,
21 char **data);
22
23#endif /* _KEYS_DNS_RESOLVER_TYPE_H */
diff --git a/include/linux/dns_resolver.h b/include/linux/dns_resolver.h
new file mode 100644
index 000000000000..cc92268af89a
--- /dev/null
+++ b/include/linux/dns_resolver.h
@@ -0,0 +1,34 @@
1/*
2 * DNS Resolver upcall management for CIFS DFS and AFS
3 * Handles host name to IP address resolution and DNS query for AFSDB RR.
4 *
5 * Copyright (c) International Business Machines Corp., 2008
6 * Author(s): Steve French (sfrench@us.ibm.com)
7 * Wang Lei (wang840925@gmail.com)
8 *
9 * This library is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as published
11 * by the Free Software Foundation; either version 2.1 of the License, or
12 * (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
17 * the GNU Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public License
20 * along with this library; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 */
23
24#ifndef _LINUX_DNS_RESOLVER_H
25#define _LINUX_DNS_RESOLVER_H
26
27#ifdef __KERNEL__
28
29extern int dns_query(const char *type, const char *name, size_t namelen,
30 const char *options, char **_result, time_t *_expiry);
31
32#endif /* KERNEL */
33
34#endif /* _LINUX_DNS_RESOLVER_H */
diff --git a/net/Kconfig b/net/Kconfig
index e24fa0873f32..e330594d3709 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -213,6 +213,7 @@ source "net/phonet/Kconfig"
213source "net/ieee802154/Kconfig" 213source "net/ieee802154/Kconfig"
214source "net/sched/Kconfig" 214source "net/sched/Kconfig"
215source "net/dcb/Kconfig" 215source "net/dcb/Kconfig"
216source "net/dns_resolver/Kconfig"
216 217
217config RPS 218config RPS
218 boolean 219 boolean
diff --git a/net/Makefile b/net/Makefile
index 41d420070a38..ea60fbce9b1b 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -67,3 +67,4 @@ ifeq ($(CONFIG_NET),y)
67obj-$(CONFIG_SYSCTL) += sysctl_net.o 67obj-$(CONFIG_SYSCTL) += sysctl_net.o
68endif 68endif
69obj-$(CONFIG_WIMAX) += wimax/ 69obj-$(CONFIG_WIMAX) += wimax/
70obj-$(CONFIG_DNS_RESOLVER) += dns_resolver/
diff --git a/net/dns_resolver/Kconfig b/net/dns_resolver/Kconfig
new file mode 100644
index 000000000000..50d49f7e0472
--- /dev/null
+++ b/net/dns_resolver/Kconfig
@@ -0,0 +1,27 @@
1#
2# Configuration for DNS Resolver
3#
4config DNS_RESOLVER
5 tristate "DNS Resolver support"
6 depends on NET && KEYS
7 help
8 Saying Y here will include support for the DNS Resolver key type
9 which can be used to make upcalls to perform DNS lookups in
10 userspace.
11
12 DNS Resolver is used to query DNS server for information. Examples
13 being resolving a UNC hostname element to an IP address for CIFS or
14 performing a DNS query for AFSDB records so that AFS can locate a
15 cell's volume location database servers.
16
17 DNS Resolver is used by the CIFS and AFS modules, and would support
18 SMB2 later. DNS Resolver is supported by the userspace upcall
19 helper "/sbin/dns.resolver" via /etc/request-key.conf.
20
21 See <file:Documentation/networking/dns_resolver.txt> for further
22 information.
23
24 To compile this as a module, choose M here: the module will be called
25 dnsresolver.
26
27 If unsure, say N.
diff --git a/net/dns_resolver/Makefile b/net/dns_resolver/Makefile
new file mode 100644
index 000000000000..c0ef4e71dc49
--- /dev/null
+++ b/net/dns_resolver/Makefile
@@ -0,0 +1,7 @@
1#
2# Makefile for the Linux DNS Resolver.
3#
4
5obj-$(CONFIG_DNS_RESOLVER) += dns_resolver.o
6
7dns_resolver-objs := dns_key.o dns_query.o
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
new file mode 100644
index 000000000000..400a04d5c9a1
--- /dev/null
+++ b/net/dns_resolver/dns_key.c
@@ -0,0 +1,211 @@
1/* Key type used to cache DNS lookups made by the kernel
2 *
3 * See Documentation/networking/dns_resolver.txt
4 *
5 * Copyright (c) 2007 Igor Mammedov
6 * Author(s): Igor Mammedov (niallain@gmail.com)
7 * Steve French (sfrench@us.ibm.com)
8 * Wang Lei (wang840925@gmail.com)
9 * David Howells (dhowells@redhat.com)
10 *
11 * This library is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU Lesser General Public License as published
13 * by the Free Software Foundation; either version 2.1 of the License, or
14 * (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
19 * the GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public License
22 * along with this library; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 */
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/slab.h>
28#include <linux/string.h>
29#include <linux/kernel.h>
30#include <linux/keyctl.h>
31#include <linux/err.h>
32#include <keys/dns_resolver-type.h>
33#include <keys/user-type.h>
34#include "internal.h"
35
36MODULE_DESCRIPTION("DNS Resolver");
37MODULE_AUTHOR("Wang Lei");
38MODULE_LICENSE("GPL");
39
40unsigned dns_resolver_debug;
41module_param_named(debug, dns_resolver_debug, uint, S_IWUSR | S_IRUGO);
42MODULE_PARM_DESC(debug, "DNS Resolver debugging mask");
43
44const struct cred *dns_resolver_cache;
45
46/*
47 * Instantiate a user defined key for dns_resolver.
48 *
49 * The data must be a NUL-terminated string, with the NUL char accounted in
50 * datalen.
51 *
52 * If the data contains a '#' characters, then we take the clause after each
53 * one to be an option of the form 'key=value'. The actual data of interest is
54 * the string leading up to the first '#'. For instance:
55 *
56 * "ip1,ip2,...#foo=bar"
57 */
58static int
59dns_resolver_instantiate(struct key *key, const void *_data, size_t datalen)
60{
61 struct user_key_payload *upayload;
62 int ret;
63 size_t result_len = 0;
64 const char *data = _data, *opt;
65
66 kenter("%%%d,%s,'%s',%zu",
67 key->serial, key->description, data, datalen);
68
69 if (datalen <= 1 || !data || data[datalen - 1] != '\0')
70 return -EINVAL;
71 datalen--;
72
73 /* deal with any options embedded in the data */
74 opt = memchr(data, '#', datalen);
75 if (!opt) {
76 kdebug("no options currently supported");
77 return -EINVAL;
78 }
79
80 result_len = datalen;
81 ret = key_payload_reserve(key, result_len);
82 if (ret < 0)
83 return -EINVAL;
84
85 upayload = kmalloc(sizeof(*upayload) + result_len + 1, GFP_KERNEL);
86 if (!upayload) {
87 kleave(" = -ENOMEM");
88 return -ENOMEM;
89 }
90
91 upayload->datalen = result_len;
92 memcpy(upayload->data, data, result_len);
93 upayload->data[result_len] = '\0';
94 rcu_assign_pointer(key->payload.data, upayload);
95
96 kleave(" = 0");
97 return 0;
98}
99
100/*
101 * The description is of the form "[<type>:]<domain_name>"
102 *
103 * The domain name may be a simple name or an absolute domain name (which
104 * should end with a period). The domain name is case-independent.
105 */
106static int
107dns_resolver_match(const struct key *key, const void *description)
108{
109 int slen, dlen, ret = 0;
110 const char *src = key->description, *dsp = description;
111
112 kenter("%s,%s", src, dsp);
113
114 if (!src || !dsp)
115 goto no_match;
116
117 if (strcasecmp(src, dsp) == 0)
118 goto matched;
119
120 slen = strlen(src);
121 dlen = strlen(dsp);
122 if (slen <= 0 || dlen <= 0)
123 goto no_match;
124 if (src[slen - 1] == '.')
125 slen--;
126 if (dsp[dlen - 1] == '.')
127 dlen--;
128 if (slen != dlen || strncasecmp(src, dsp, slen) != 0)
129 goto no_match;
130
131matched:
132 ret = 1;
133no_match:
134 kleave(" = %d", ret);
135 return ret;
136}
137
138struct key_type key_type_dns_resolver = {
139 .name = "dns_resolver",
140 .instantiate = dns_resolver_instantiate,
141 .match = dns_resolver_match,
142 .revoke = user_revoke,
143 .destroy = user_destroy,
144 .describe = user_describe,
145 .read = user_read,
146};
147
148static int __init init_dns_resolver(void)
149{
150 struct cred *cred;
151 struct key *keyring;
152 int ret;
153
154 printk(KERN_NOTICE "Registering the %s key type\n",
155 key_type_dns_resolver.name);
156
157 /* create an override credential set with a special thread keyring in
158 * which DNS requests are cached
159 *
160 * this is used to prevent malicious redirections from being installed
161 * with add_key().
162 */
163 cred = prepare_kernel_cred(NULL);
164 if (!cred)
165 return -ENOMEM;
166
167 keyring = key_alloc(&key_type_keyring, ".dns_resolver", 0, 0, cred,
168 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
169 KEY_USR_VIEW | KEY_USR_READ,
170 KEY_ALLOC_NOT_IN_QUOTA);
171 if (IS_ERR(keyring)) {
172 ret = PTR_ERR(keyring);
173 goto failed_put_cred;
174 }
175
176 ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
177 if (ret < 0)
178 goto failed_put_key;
179
180 ret = register_key_type(&key_type_dns_resolver);
181 if (ret < 0)
182 goto failed_put_key;
183
184 /* instruct request_key() to use this special keyring as a cache for
185 * the results it looks up */
186 cred->thread_keyring = keyring;
187 cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
188 dns_resolver_cache = cred;
189
190 kdebug("DNS resolver keyring: %d\n", key_serial(keyring));
191 return 0;
192
193failed_put_key:
194 key_put(keyring);
195failed_put_cred:
196 put_cred(cred);
197 return ret;
198}
199
200static void __exit exit_dns_resolver(void)
201{
202 key_revoke(dns_resolver_cache->thread_keyring);
203 unregister_key_type(&key_type_dns_resolver);
204 put_cred(dns_resolver_cache);
205 printk(KERN_NOTICE "Unregistered %s key type\n",
206 key_type_dns_resolver.name);
207}
208
209module_init(init_dns_resolver)
210module_exit(exit_dns_resolver)
211MODULE_LICENSE("GPL");
diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c
new file mode 100644
index 000000000000..03d5255f5cf2
--- /dev/null
+++ b/net/dns_resolver/dns_query.c
@@ -0,0 +1,160 @@
1/* Upcall routine, designed to work as a key type and working through
2 * /sbin/request-key to contact userspace when handling DNS queries.
3 *
4 * See Documentation/networking/dns_resolver.txt
5 *
6 * Copyright (c) 2007 Igor Mammedov
7 * Author(s): Igor Mammedov (niallain@gmail.com)
8 * Steve French (sfrench@us.ibm.com)
9 * Wang Lei (wang840925@gmail.com)
10 * David Howells (dhowells@redhat.com)
11 *
12 * The upcall wrapper used to make an arbitrary DNS query.
13 *
14 * This function requires the appropriate userspace tool dns.upcall to be
15 * installed and something like the following lines should be added to the
16 * /etc/request-key.conf file:
17 *
18 * create dns_resolver * * /sbin/dns.upcall %k
19 *
20 * For example to use this module to query AFSDB RR:
21 *
22 * create dns_resolver afsdb:* * /sbin/dns.afsdb %k
23 *
24 * This library is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU Lesser General Public License as published
26 * by the Free Software Foundation; either version 2.1 of the License, or
27 * (at your option) any later version.
28 *
29 * This library is distributed in the hope that it will be useful,
30 * but WITHOUT ANY WARRANTY; without even the implied warranty of
31 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
32 * the GNU Lesser General Public License for more details.
33 *
34 * You should have received a copy of the GNU Lesser General Public License
35 * along with this library; if not, write to the Free Software
36 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
37 */
38
39#include <linux/module.h>
40#include <linux/slab.h>
41#include <linux/dns_resolver.h>
42#include <linux/err.h>
43#include <keys/dns_resolver-type.h>
44#include <keys/user-type.h>
45
46#include "internal.h"
47
48/**
49 * dns_query - Query the DNS
50 * @type: Query type (or NULL for straight host->IP lookup)
51 * @name: Name to look up
52 * @namelen: Length of name
53 * @options: Request options (or NULL if no options)
54 * @_result: Where to place the returned data.
55 * @_expiry: Where to store the result expiry time (or NULL)
56 *
57 * The data will be returned in the pointer at *result, and the caller is
58 * responsible for freeing it.
59 *
60 * The description should be of the form "[<query_type>:]<domain_name>", and
61 * the options need to be appropriate for the query type requested. If no
62 * query_type is given, then the query is a straight hostname to IP address
63 * lookup.
64 *
65 * The DNS resolution lookup is performed by upcalling to userspace by way of
66 * requesting a key of type dns_resolver.
67 *
68 * Returns the size of the result on success, -ve error code otherwise.
69 */
70int dns_query(const char *type, const char *name, size_t namelen,
71 const char *options, char **_result, time_t *_expiry)
72{
73 struct key *rkey;
74 struct user_key_payload *upayload;
75 const struct cred *saved_cred;
76 size_t typelen, desclen;
77 char *desc, *cp;
78 int ret, len;
79
80 kenter("%s,%*.*s,%zu,%s",
81 type, (int)namelen, (int)namelen, name, namelen, options);
82
83 if (!name || namelen == 0 || !_result)
84 return -EINVAL;
85
86 /* construct the query key description as "[<type>:]<name>" */
87 typelen = 0;
88 desclen = 0;
89 if (type) {
90 typelen = strlen(type);
91 if (typelen < 1)
92 return -EINVAL;
93 desclen += typelen + 1;
94 }
95
96 if (!namelen)
97 namelen = strlen(name);
98 if (namelen < 3)
99 return -EINVAL;
100 desclen += namelen + 1;
101
102 desc = kmalloc(desclen, GFP_KERNEL);
103 if (!desc)
104 return -ENOMEM;
105
106 cp = desc;
107 if (type) {
108 memcpy(cp, type, typelen);
109 cp += typelen;
110 *cp++ = ':';
111 }
112 memcpy(cp, name, namelen);
113 cp += namelen;
114 *cp = '\0';
115
116 if (!options)
117 options = "";
118 kdebug("call request_key(,%s,%s)", desc, options);
119
120 /* make the upcall, using special credentials to prevent the use of
121 * add_key() to preinstall malicious redirections
122 */
123 saved_cred = override_creds(dns_resolver_cache);
124 rkey = request_key(&key_type_dns_resolver, desc, options);
125 revert_creds(saved_cred);
126 kfree(desc);
127 if (IS_ERR(rkey)) {
128 ret = PTR_ERR(rkey);
129 goto out;
130 }
131
132 down_read(&rkey->sem);
133 rkey->perm |= KEY_USR_VIEW;
134
135 ret = key_validate(rkey);
136 if (ret < 0)
137 goto put;
138
139 upayload = rcu_dereference_protected(rkey->payload.data,
140 lockdep_is_held(&rkey->sem));
141 len = upayload->datalen;
142
143 ret = -ENOMEM;
144 *_result = kmalloc(len + 1, GFP_KERNEL);
145 if (!*_result)
146 goto put;
147
148 memcpy(*_result, upayload->data, len + 1);
149 if (_expiry)
150 *_expiry = rkey->expiry;
151
152 ret = len;
153put:
154 up_read(&rkey->sem);
155 key_put(rkey);
156out:
157 kleave(" = %d", ret);
158 return ret;
159}
160EXPORT_SYMBOL(dns_query);
diff --git a/net/dns_resolver/internal.h b/net/dns_resolver/internal.h
new file mode 100644
index 000000000000..189ca9e9b785
--- /dev/null
+++ b/net/dns_resolver/internal.h
@@ -0,0 +1,44 @@
1/*
2 * Copyright (c) 2010 Wang Lei
3 * Author(s): Wang Lei (wang840925@gmail.com). All Rights Reserved.
4 *
5 * Internal DNS Rsolver stuff
6 *
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as published
9 * by the Free Software Foundation; either version 2.1 of the License, or
10 * (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public License
18 * along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/compiler.h>
23#include <linux/kernel.h>
24#include <linux/sched.h>
25
26/*
27 * dns_key.c
28 */
29extern const struct cred *dns_resolver_cache;
30
31/*
32 * debug tracing
33 */
34extern unsigned dns_resolver_debug;
35
36#define kdebug(FMT, ...) \
37do { \
38 if (unlikely(dns_resolver_debug)) \
39 printk(KERN_DEBUG "[%-6.6s] "FMT"\n", \
40 current->comm, ##__VA_ARGS__); \
41} while (0)
42
43#define kenter(FMT, ...) kdebug("==> %s("FMT")", __func__, ##__VA_ARGS__)
44#define kleave(FMT, ...) kdebug("<== %s()"FMT"", __func__, ##__VA_ARGS__)
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-04 16:11:17 -0500