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