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 /*
  50  * Lookup AUTH_UNIX creds for current process
  51  */
  52 static struct rpc_cred *
  53 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  54 {
  55         return rpcauth_lookup_credcache(auth, acred, flags);
  56 }
  57
  58 static struct rpc_cred *
  59 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  60 {
  61         struct unx_cred *cred;
  62         unsigned int groups = 0;
  63         unsigned int i;
  64
  65         dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
  66                         from_kuid(&init_user_ns, acred->uid),
  67                         from_kgid(&init_user_ns, acred->gid));
  68
  69         if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
  70                 return ERR_PTR(-ENOMEM);
  71
  72         rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
  73         cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  74
  75         if (acred->group_info != NULL)
  76                 groups = acred->group_info->ngroups;
  77         if (groups > NFS_NGROUPS)
  78                 groups = NFS_NGROUPS;
  79
  80         cred->uc_gid = acred->gid;
  81         for (i = 0; i < groups; i++)
  82                 cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
  83         if (i < NFS_NGROUPS)
  84                 cred->uc_gids[i] = INVALID_GID;
  85
  86         return &cred->uc_base;
  87 }
  88
  89 static void
  90 unx_free_cred(struct unx_cred *unx_cred)
  91 {
  92         dprintk("RPC:       unx_free_cred %p\n", unx_cred);
  93         kfree(unx_cred);
  94 }
  95
  96 static void
  97 unx_free_cred_callback(struct rcu_head *head)
  98 {
  99         struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
 100         unx_free_cred(unx_cred);
 101 }
 102
 103 static void
 104 unx_destroy_cred(struct rpc_cred *cred)
 105 {
 106         call_rcu(&cred->cr_rcu, unx_free_cred_callback);
 107 }
 108
 109 /*
 110  * Match credentials against current process creds.
 111  * The root_override argument takes care of cases where the caller may
 112  * request root creds (e.g. for NFS swapping).
 113  */
 114 static int
 115 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 116 {
 117         struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
 118         unsigned int groups = 0;
 119         unsigned int i;
 120
 121
 122         if (!uid_eq(cred->uc_uid, acred->uid) || !gid_eq(cred->uc_gid, acred->gid))
 123                 return 0;
 124
 125         if (acred->group_info != NULL)
 126                 groups = acred->group_info->ngroups;
 127         if (groups > NFS_NGROUPS)
 128                 groups = NFS_NGROUPS;
 129         for (i = 0; i < groups ; i++)
 130                 if (!gid_eq(cred->uc_gids[i], GROUP_AT(acred->group_info, i)))
 131                         return 0;
 132         if (groups < NFS_NGROUPS && gid_valid(cred->uc_gids[groups]))
 133                 return 0;
 134         return 1;
 135 }
 136
 137 /*
 138  * Marshal credentials.
 139  * Maybe we should keep a cached credential for performance reasons.
 140  */
 141 static __be32 *
 142 unx_marshal(struct rpc_task *task, __be32 *p)
 143 {
 144         struct rpc_clnt *clnt = task->tk_client;
 145         struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
 146         __be32          *base, *hold;
 147         int             i;
 148
 149         *p++ = htonl(RPC_AUTH_UNIX);
 150         base = p++;
 151         *p++ = htonl(jiffies/HZ);
 152
 153         /*
 154          * Copy the UTS nodename captured when the client was created.
 155          */
 156         p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 157
 158         *p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid));
 159         *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid));
 160         hold = p++;
 161         for (i = 0; i < 16 && gid_valid(cred->uc_gids[i]); i++)
 162                 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i]));
 163         *hold = htonl(p - hold - 1);            /* gid array length */
 164         *base = htonl((p - base - 1) << 2);     /* cred length */
 165
 166         *p++ = htonl(RPC_AUTH_NULL);
 167         *p++ = htonl(0);
 168
 169         return p;
 170 }
 171
 172 /*
 173  * Refresh credentials. This is a no-op for AUTH_UNIX
 174  */
 175 static int
 176 unx_refresh(struct rpc_task *task)
 177 {
 178         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
 179         return 0;
 180 }
 181
 182 static __be32 *
 183 unx_validate(struct rpc_task *task, __be32 *p)
 184 {
 185         rpc_authflavor_t        flavor;
 186         u32                     size;
 187
 188         flavor = ntohl(*p++);
 189         if (flavor != RPC_AUTH_NULL &&
 190             flavor != RPC_AUTH_UNIX &&
 191             flavor != RPC_AUTH_SHORT) {
 192                 printk("RPC: bad verf flavor: %u\n", flavor);
 193                 return ERR_PTR(-EIO);
 194         }
 195
 196         size = ntohl(*p++);
 197         if (size > RPC_MAX_AUTH_SIZE) {
 198                 printk("RPC: giant verf size: %u\n", size);
 199                 return ERR_PTR(-EIO);
 200         }
 201         task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
 202         p += (size >> 2);
 203
 204         return p;
 205 }
 206
 207 int __init rpc_init_authunix(void)
 208 {
 209         return rpcauth_init_credcache(&unix_auth);
 210 }
 211
 212 void rpc_destroy_authunix(void)
 213 {
 214         rpcauth_destroy_credcache(&unix_auth);
 215 }
 216
 217 const struct rpc_authops authunix_ops = {
 218         .owner          = THIS_MODULE,
 219         .au_flavor      = RPC_AUTH_UNIX,
 220         .au_name        = "UNIX",
 221         .create         = unx_create,
 222         .destroy        = unx_destroy,
 223         .lookup_cred    = unx_lookup_cred,
 224         .crcreate       = unx_create_cred,
 225 };
 226
 227 static
 228 struct rpc_auth         unix_auth = {
 229         .au_cslack      = UNX_CALLSLACK,
 230         .au_rslack      = NUL_REPLYSLACK,
 231         .au_ops         = &authunix_ops,
 232         .au_flavor      = RPC_AUTH_UNIX,
 233         .au_count       = ATOMIC_INIT(0),
 234 };
 235
 236 static
 237 const struct rpc_credops unix_credops = {
 238         .cr_name        = "AUTH_UNIX",
 239         .crdestroy      = unx_destroy_cred,
 240         .crbind         = rpcauth_generic_bind_cred,
 241         .crmatch        = unx_match,
 242         .crmarshal      = unx_marshal,
 243         .crrefresh      = unx_refresh,
 244         .crvalidate     = unx_validate,
 245 };