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