net/sunrpc/auth_unix.c

   1 /*
   2  * linux/net/sunrpc/auth_unix.c
   3  *
   4  * UNIX-style authentication; no AUTH_SHORT support
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/types.h>
  11 #include <linux/sched.h>
  12 #include <linux/module.h>
  13 #include <linux/sunrpc/clnt.h>
  14 #include <linux/sunrpc/auth.h>
  15 #include <linux/user_namespace.h>
  16
  17 #define NFS_NGROUPS     16
  18
  19 struct unx_cred {
  20         struct rpc_cred         uc_base;
  21         kgid_t                  uc_gid;
  22         kgid_t                  uc_gids[NFS_NGROUPS];
  23 };
  24 #define uc_uid                  uc_base.cr_uid
  25
  26 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  27 # define RPCDBG_FACILITY        RPCDBG_AUTH
  28 #endif
  29
  30 static struct rpc_auth          unix_auth;
  31 static const struct rpc_credops unix_credops;
  32
  33 static struct rpc_auth *
  34 unx_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
  35 {
  36         dprintk("RPC:       creating UNIX authenticator for client %p\n",
  37                         clnt);
  38         atomic_inc(&unix_auth.au_count);
  39         return &unix_auth;
  40 }
  41
  42 static void
  43 unx_destroy(struct rpc_auth *auth)
  44 {
  45         dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
  46         rpcauth_clear_credcache(auth->au_credcache);
  47 }
  48
  49 static int
  50 unx_hash_cred(struct auth_cred *acred, unsigned int hashbits)
  51 {
  52         return hash_64(from_kgid(&init_user_ns, acred->gid) |
  53                 ((u64)from_kuid(&init_user_ns, acred->uid) <<
  54                         (sizeof(gid_t) * 8)), hashbits);
  55 }
  56
  57 /*
  58  * Lookup AUTH_UNIX creds for current process
  59  */
  60 static struct rpc_cred *
  61 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  62 {
  63         return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
  64 }
  65
  66 static struct rpc_cred *
  67 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
  68 {
  69         struct unx_cred *cred;
  70         unsigned int groups = 0;
  71         unsigned int i;
  72
  73         dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
  74                         from_kuid(&init_user_ns, acred->uid),
  75                         from_kgid(&init_user_ns, acred->gid));
  76
  77         if (!(cred = kmalloc(sizeof(*cred), gfp)))
  78                 return ERR_PTR(-ENOMEM);
  79
  80         rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
  81         cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  82
  83         if (acred->group_info != NULL)
  84                 groups = acred->group_info->ngroups;
  85         if (groups > NFS_NGROUPS)
  86                 groups = NFS_NGROUPS;
  87
  88         cred->uc_gid = acred->gid;
  89         for (i = 0; i < groups; i++)
  90                 cred->uc_gids[i] = acred->group_info->gid[i];
  91         if (i < NFS_NGROUPS)
  92                 cred->uc_gids[i] = INVALID_GID;
  93
  94         return &cred->uc_base;
  95 }
  96
  97 static void
  98 unx_free_cred(struct unx_cred *unx_cred)
  99 {
 100         dprintk("RPC:       unx_free_cred %p\n", unx_cred);
 101         kfree(unx_cred);
 102 }
 103
 104 static void
 105 unx_free_cred_callback(struct rcu_head *head)
 106 {
 107         struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
 108         unx_free_cred(unx_cred);
 109 }
 110
 111 static void
 112 unx_destroy_cred(struct rpc_cred *cred)
 113 {
 114         call_rcu(&cred->cr_rcu, unx_free_cred_callback);
 115 }
 116
 117 /*
 118  * Match credentials against current process creds.
 119  * The root_override argument takes care of cases where the caller may
 120  * request root creds (e.g. for NFS swapping).
 121  */
 122 static int
 123 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 124 {
 125         struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
 126         unsigned int groups = 0;
 127         unsigned int i;
 128
 129
 130         if (!uid_eq(cred->uc_uid, acred->uid) || !gid_eq(cred->uc_gid, acred->gid))
 131                 return 0;
 132
 133         if (acred->group_info != NULL)
 134                 groups = acred->group_info->ngroups;
 135         if (groups > NFS_NGROUPS)
 136                 groups = NFS_NGROUPS;
 137         for (i = 0; i < groups ; i++)
 138                 if (!gid_eq(cred->uc_gids[i], acred->group_info->gid[i]))
 139                         return 0;
 140         if (groups < NFS_NGROUPS && gid_valid(cred->uc_gids[groups]))
 141                 return 0;
 142         return 1;
 143 }
 144
 145 /*
 146  * Marshal credentials.
 147  * Maybe we should keep a cached credential for performance reasons.
 148  */
 149 static __be32 *
 150 unx_marshal(struct rpc_task *task, __be32 *p)
 151 {
 152         struct rpc_clnt *clnt = task->tk_client;
 153         struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
 154         __be32          *base, *hold;
 155         int             i;
 156
 157         *p++ = htonl(RPC_AUTH_UNIX);
 158         base = p++;
 159         *p++ = htonl(jiffies/HZ);
 160
 161         /*
 162          * Copy the UTS nodename captured when the client was created.
 163          */
 164         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 165
 166         *p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid));
 167         *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid));
 168         hold = p++;
 169         for (i = 0; i < 16 && gid_valid(cred->uc_gids[i]); i++)
 170                 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i]));
 171         *hold = htonl(p - hold - 1);            /* gid array length */
 172         *base = htonl((p - base - 1) << 2);     /* cred length */
 173
 174         *p++ = htonl(RPC_AUTH_NULL);
 175         *p++ = htonl(0);
 176
 177         return p;
 178 }
 179
 180 /*
 181  * Refresh credentials. This is a no-op for AUTH_UNIX
 182  */
 183 static int
 184 unx_refresh(struct rpc_task *task)
 185 {
 186         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
 187         return 0;
 188 }
 189
 190 static __be32 *
 191 unx_validate(struct rpc_task *task, __be32 *p)
 192 {
 193         rpc_authflavor_t        flavor;
 194         u32                     size;
 195
 196         flavor = ntohl(*p++);
 197         if (flavor != RPC_AUTH_NULL &&
 198             flavor != RPC_AUTH_UNIX &&
 199             flavor != RPC_AUTH_SHORT) {
 200                 printk("RPC: bad verf flavor: %u\n", flavor);
 201                 return ERR_PTR(-EIO);
 202         }
 203
 204         size = ntohl(*p++);
 205         if (size > RPC_MAX_AUTH_SIZE) {
 206                 printk("RPC: giant verf size: %u\n", size);
 207                 return ERR_PTR(-EIO);
 208         }
 209         task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
 210         p += (size >> 2);
 211
 212         return p;
 213 }
 214
 215 int __init rpc_init_authunix(void)
 216 {
 217         return rpcauth_init_credcache(&unix_auth);
 218 }
 219
 220 void rpc_destroy_authunix(void)
 221 {
 222         rpcauth_destroy_credcache(&unix_auth);
 223 }
 224
 225 const struct rpc_authops authunix_ops = {
 226         .owner          = THIS_MODULE,
 227         .au_flavor      = RPC_AUTH_UNIX,
 228         .au_name        = "UNIX",
 229         .create         = unx_create,
 230         .destroy        = unx_destroy,
 231         .hash_cred      = unx_hash_cred,
 232         .lookup_cred    = unx_lookup_cred,
 233         .crcreate       = unx_create_cred,
 234 };
 235
 236 static
 237 struct rpc_auth         unix_auth = {
 238         .au_cslack      = UNX_CALLSLACK,
 239         .au_rslack      = NUL_REPLYSLACK,
 240         .au_flags       = RPCAUTH_AUTH_NO_CRKEY_TIMEOUT,
 241         .au_ops         = &authunix_ops,
 242         .au_flavor      = RPC_AUTH_UNIX,
 243         .au_count       = ATOMIC_INIT(0),
 244 };
 245
 246 static
 247 const struct rpc_credops unix_credops = {
 248         .cr_name        = "AUTH_UNIX",
 249         .crdestroy      = unx_destroy_cred,
 250         .crbind         = rpcauth_generic_bind_cred,
 251         .crmatch        = unx_match,
 252         .crmarshal      = unx_marshal,
 253         .crrefresh      = unx_refresh,
 254         .crvalidate     = unx_validate,
 255 };