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 gid_t uc_gid; 22 gid_t uc_gids[NFS_NGROUPS]; 23 }; 24 #define uc_uid uc_base.cr_uid 25 26 #define UNX_WRITESLACK (21 + (UNX_MAXNODENAME >> 2)) 27 28 #ifdef RPC_DEBUG 29 # define RPCDBG_FACILITY RPCDBG_AUTH 30 #endif 31 32 static struct rpc_auth unix_auth; 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 gid_t gid; 84 gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i)); 85 cred->uc_gids[i] = gid; 86 } 87 if (i < NFS_NGROUPS) 88 cred->uc_gids[i] = NOGROUP; 89 90 return &cred->uc_base; 91 } 92 93 static void 94 unx_free_cred(struct unx_cred *unx_cred) 95 { 96 dprintk("RPC: unx_free_cred %p\n", unx_cred); 97 kfree(unx_cred); 98 } 99 100 static void 101 unx_free_cred_callback(struct rcu_head *head) 102 { 103 struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu); 104 unx_free_cred(unx_cred); 105 } 106 107 static void 108 unx_destroy_cred(struct rpc_cred *cred) 109 { 110 call_rcu(&cred->cr_rcu, unx_free_cred_callback); 111 } 112 113 /* 114 * Match credentials against current process creds. 115 * The root_override argument takes care of cases where the caller may 116 * request root creds (e.g. for NFS swapping). 117 */ 118 static int 119 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags) 120 { 121 struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base); 122 unsigned int groups = 0; 123 unsigned int i; 124 125 126 if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid) 127 return 0; 128 129 if (acred->group_info != NULL) 130 groups = acred->group_info->ngroups; 131 if (groups > NFS_NGROUPS) 132 groups = NFS_NGROUPS; 133 for (i = 0; i < groups ; i++) { 134 gid_t gid; 135 gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i)); 136 if (cred->uc_gids[i] != gid) 137 return 0; 138 } 139 if (groups < NFS_NGROUPS && 140 cred->uc_gids[groups] != NOGROUP) 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) cred->uc_uid); 167 *p++ = htonl((u32) cred->uc_gid); 168 hold = p++; 169 for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++) 170 *p++ = htonl((u32) 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 NULL; 202 } 203 204 size = ntohl(*p++); 205 if (size > RPC_MAX_AUTH_SIZE) { 206 printk("RPC: giant verf size: %u\n", size); 207 return NULL; 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 .lookup_cred = unx_lookup_cred, 232 .crcreate = unx_create_cred, 233 }; 234 235 static 236 struct rpc_auth unix_auth = { 237 .au_cslack = UNX_WRITESLACK, 238 .au_rslack = 2, /* assume AUTH_NULL verf */ 239 .au_ops = &authunix_ops, 240 .au_flavor = RPC_AUTH_UNIX, 241 .au_count = ATOMIC_INIT(0), 242 }; 243 244 static 245 const struct rpc_credops unix_credops = { 246 .cr_name = "AUTH_UNIX", 247 .crdestroy = unx_destroy_cred, 248 .crbind = rpcauth_generic_bind_cred, 249 .crmatch = unx_match, 250 .crmarshal = unx_marshal, 251 .crrefresh = unx_refresh, 252 .crvalidate = unx_validate, 253 }; 254