net/sunrpc/svcauth.c

   1 /*
   2  * linux/net/sunrpc/svcauth.c
   3  *
   4  * The generic interface for RPC authentication on the server side.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  *
   8  * CHANGES
   9  * 19-Apr-2000 Chris Evans      - Security fix
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/sched.h>
  14 #include <linux/module.h>
  15 #include <linux/sunrpc/types.h>
  16 #include <linux/sunrpc/xdr.h>
  17 #include <linux/sunrpc/svcsock.h>
  18 #include <linux/sunrpc/svcauth.h>
  19 #include <linux/err.h>
  20 #include <linux/hash.h>
  21
  22 #define RPCDBG_FACILITY RPCDBG_AUTH
  23
  24
  25 /*
  26  * Table of authenticators
  27  */
  28 extern struct auth_ops svcauth_null;
  29 extern struct auth_ops svcauth_unix;
  30
  31 static DEFINE_SPINLOCK(authtab_lock);
  32 static struct auth_ops  *authtab[RPC_AUTH_MAXFLAVOR] = {
  33         [0] = &svcauth_null,
  34         [1] = &svcauth_unix,
  35 };
  36
  37 int
  38 svc_authenticate(struct svc_rqst *rqstp, u32 *authp)
  39 {
  40         rpc_authflavor_t        flavor;
  41         struct auth_ops         *aops;
  42
  43         *authp = rpc_auth_ok;
  44
  45         flavor = ntohl(svc_getu32(&rqstp->rq_arg.head[0]));
  46
  47         dprintk("svc: svc_authenticate (%d)\n", flavor);
  48
  49         spin_lock(&authtab_lock);
  50         if (flavor >= RPC_AUTH_MAXFLAVOR || !(aops = authtab[flavor])
  51                         || !try_module_get(aops->owner)) {
  52                 spin_unlock(&authtab_lock);
  53                 *authp = rpc_autherr_badcred;
  54                 return SVC_DENIED;
  55         }
  56         spin_unlock(&authtab_lock);
  57
  58         rqstp->rq_authop = aops;
  59         return aops->accept(rqstp, authp);
  60 }
  61
  62 int svc_set_client(struct svc_rqst *rqstp)
  63 {
  64         return rqstp->rq_authop->set_client(rqstp);
  65 }
  66
  67 /* A request, which was authenticated, has now executed.
  68  * Time to finalise the the credentials and verifier
  69  * and release and resources
  70  */
  71 int svc_authorise(struct svc_rqst *rqstp)
  72 {
  73         struct auth_ops *aops = rqstp->rq_authop;
  74         int rv = 0;
  75
  76         rqstp->rq_authop = NULL;
  77
  78         if (aops) {
  79                 rv = aops->release(rqstp);
  80                 module_put(aops->owner);
  81         }
  82         return rv;
  83 }
  84
  85 int
  86 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
  87 {
  88         int rv = -EINVAL;
  89         spin_lock(&authtab_lock);
  90         if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
  91                 authtab[flavor] = aops;
  92                 rv = 0;
  93         }
  94         spin_unlock(&authtab_lock);
  95         return rv;
  96 }
  97
  98 void
  99 svc_auth_unregister(rpc_authflavor_t flavor)
 100 {
 101         spin_lock(&authtab_lock);
 102         if (flavor < RPC_AUTH_MAXFLAVOR)
 103                 authtab[flavor] = NULL;
 104         spin_unlock(&authtab_lock);
 105 }
 106 EXPORT_SYMBOL(svc_auth_unregister);
 107
 108 /**************************************************
 109  * cache for domain name to auth_domain
 110  * Entries are only added by flavours which will normally
 111  * have a structure that 'inherits' from auth_domain.
 112  * e.g. when an IP -> domainname is given to  auth_unix,
 113  * and the domain name doesn't exist, it will create a
 114  * auth_unix_domain and add it to this hash table.
 115  * If it finds the name does exist, but isn't AUTH_UNIX,
 116  * it will complain.
 117  */
 118
 119 /*
 120  * Auth auth_domain cache is somewhat different to other caches,
 121  * largely because the entries are possibly of different types:
 122  * each auth flavour has it's own type.
 123  * One consequence of this that DefineCacheLookup cannot
 124  * allocate a new structure as it cannot know the size.
 125  * Notice that the "INIT" code fragment is quite different
 126  * from other caches.  When auth_domain_lookup might be
 127  * creating a new domain, the new domain is passed in
 128  * complete and it is used as-is rather than being copied into
 129  * another structure.
 130  */
 131 #define DN_HASHBITS     6
 132 #define DN_HASHMAX      (1<<DN_HASHBITS)
 133 #define DN_HASHMASK     (DN_HASHMAX-1)
 134
 135 static struct cache_head        *auth_domain_table[DN_HASHMAX];
 136
 137 static void auth_domain_drop(struct cache_head *item, struct cache_detail *cd)
 138 {
 139         struct auth_domain *dom = container_of(item, struct auth_domain, h);
 140         if (cache_put(item,cd))
 141                 authtab[dom->flavour]->domain_release(dom);
 142 }
 143
 144
 145 struct cache_detail auth_domain_cache = {
 146         .hash_size      = DN_HASHMAX,
 147         .hash_table     = auth_domain_table,
 148         .name           = "auth.domain",
 149         .cache_put      = auth_domain_drop,
 150 };
 151
 152 void auth_domain_put(struct auth_domain *dom)
 153 {
 154         auth_domain_drop(&dom->h, &auth_domain_cache);
 155 }
 156
 157 static inline int auth_domain_hash(struct auth_domain *item)
 158 {
 159         return hash_str(item->name, DN_HASHBITS);
 160 }
 161 static inline int auth_domain_match(struct auth_domain *tmp, struct auth_domain *item)
 162 {
 163         return strcmp(tmp->name, item->name) == 0;
 164 }
 165
 166 struct auth_domain *
 167 auth_domain_lookup(struct auth_domain *item, int set)
 168 {
 169         struct auth_domain *tmp = NULL;
 170         struct cache_head **hp, **head;
 171         head = &auth_domain_cache.hash_table[auth_domain_hash(item)];
 172
 173         if (set)
 174                 write_lock(&auth_domain_cache.hash_lock);
 175         else
 176                 read_lock(&auth_domain_cache.hash_lock);
 177         for (hp=head; *hp != NULL; hp = &tmp->h.next) {
 178                 tmp = container_of(*hp, struct auth_domain, h);
 179                 if (!auth_domain_match(tmp, item))
 180                         continue;
 181                 if (!set) {
 182                         cache_get(&tmp->h);
 183                         goto out_noset;
 184                 }
 185                 *hp = tmp->h.next;
 186                 tmp->h.next = NULL;
 187                 auth_domain_drop(&tmp->h, &auth_domain_cache);
 188                 goto out_set;
 189         }
 190         /* Didn't find anything */
 191         if (!set)
 192                 goto out_nada;
 193         auth_domain_cache.entries++;
 194 out_set:
 195         item->h.next = *head;
 196         *head = &item->h;
 197         cache_get(&item->h);
 198         write_unlock(&auth_domain_cache.hash_lock);
 199         cache_fresh(&auth_domain_cache, &item->h, item->h.expiry_time);
 200         cache_get(&item->h);
 201         return item;
 202 out_nada:
 203         tmp = NULL;
 204 out_noset:
 205         read_unlock(&auth_domain_cache.hash_lock);
 206         return tmp;
 207 }
 208
 209 struct auth_domain *auth_domain_find(char *name)
 210 {
 211         struct auth_domain *rv, ad;
 212
 213         ad.name = name;
 214         rv = auth_domain_lookup(&ad, 0);
 215         return rv;
 216 }