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 #define UNX_WRITESLACK (21 + XDR_QUADLEN(UNX_MAXNODENAME)) 27 28 #if IS_ENABLED(CONFIG_SUNRPC_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_auth_create_args *args, struct rpc_clnt *clnt) 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 from_kuid(&init_user_ns, acred->uid), 69 from_kgid(&init_user_ns, acred->gid)); 70 71 if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS))) 72 return ERR_PTR(-ENOMEM); 73 74 rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops); 75 cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE; 76 77 if (acred->group_info != NULL) 78 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] = INVALID_GID; 87 88 return &cred->uc_base; 89 } 90 91 static void 92 unx_free_cred(struct unx_cred *unx_cred) 93 { 94 dprintk("RPC: unx_free_cred %p\n", unx_cred); 95 kfree(unx_cred); 96 } 97 98 static void 99 unx_free_cred_callback(struct rcu_head *head) 100 { 101 struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu); 102 unx_free_cred(unx_cred); 103 } 104 105 static void 106 unx_destroy_cred(struct rpc_cred *cred) 107 { 108 call_rcu(&cred->cr_rcu, unx_free_cred_callback); 109 } 110 111 /* 112 * Match credentials against current process creds. 113 * The root_override argument takes care of cases where the caller may 114 * request root creds (e.g. for NFS swapping). 115 */ 116 static int 117 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags) 118 { 119 struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base); 120 unsigned int groups = 0; 121 unsigned int i; 122 123 124 if (!uid_eq(cred->uc_uid, acred->uid) || !gid_eq(cred->uc_gid, acred->gid)) 125 return 0; 126 127 if (acred->group_info != NULL) 128 groups = acred->group_info->ngroups; 129 if (groups > NFS_NGROUPS) 130 groups = NFS_NGROUPS; 131 for (i = 0; i < groups ; i++) 132 if (!gid_eq(cred->uc_gids[i], GROUP_AT(acred->group_info, i))) 133 return 0; 134 if (groups < NFS_NGROUPS && gid_valid(cred->uc_gids[groups])) 135 return 0; 136 return 1; 137 } 138 139 /* 140 * Marshal credentials. 141 * Maybe we should keep a cached credential for performance reasons. 142 */ 143 static __be32 * 144 unx_marshal(struct rpc_task *task, __be32 *p) 145 { 146 struct rpc_clnt *clnt = task->tk_client; 147 struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base); 148 __be32 *base, *hold; 149 int i; 150 151 *p++ = htonl(RPC_AUTH_UNIX); 152 base = p++; 153 *p++ = htonl(jiffies/HZ); 154 155 /* 156 * Copy the UTS nodename captured when the client was created. 157 */ 158 p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen); 159 160 *p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid)); 161 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid)); 162 hold = p++; 163 for (i = 0; i < 16 && gid_valid(cred->uc_gids[i]); i++) 164 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i])); 165 *hold = htonl(p - hold - 1); /* gid array length */ 166 *base = htonl((p - base - 1) << 2); /* cred length */ 167 168 *p++ = htonl(RPC_AUTH_NULL); 169 *p++ = htonl(0); 170 171 return p; 172 } 173 174 /* 175 * Refresh credentials. This is a no-op for AUTH_UNIX 176 */ 177 static int 178 unx_refresh(struct rpc_task *task) 179 { 180 set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags); 181 return 0; 182 } 183 184 static __be32 * 185 unx_validate(struct rpc_task *task, __be32 *p) 186 { 187 rpc_authflavor_t flavor; 188 u32 size; 189 190 flavor = ntohl(*p++); 191 if (flavor != RPC_AUTH_NULL && 192 flavor != RPC_AUTH_UNIX && 193 flavor != RPC_AUTH_SHORT) { 194 printk("RPC: bad verf flavor: %u\n", flavor); 195 return ERR_PTR(-EIO); 196 } 197 198 size = ntohl(*p++); 199 if (size > RPC_MAX_AUTH_SIZE) { 200 printk("RPC: giant verf size: %u\n", size); 201 return ERR_PTR(-EIO); 202 } 203 task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2; 204 p += (size >> 2); 205 206 return p; 207 } 208 209 int __init rpc_init_authunix(void) 210 { 211 return rpcauth_init_credcache(&unix_auth); 212 } 213 214 void rpc_destroy_authunix(void) 215 { 216 rpcauth_destroy_credcache(&unix_auth); 217 } 218 219 const struct rpc_authops authunix_ops = { 220 .owner = THIS_MODULE, 221 .au_flavor = RPC_AUTH_UNIX, 222 .au_name = "UNIX", 223 .create = unx_create, 224 .destroy = unx_destroy, 225 .lookup_cred = unx_lookup_cred, 226 .crcreate = unx_create_cred, 227 }; 228 229 static 230 struct rpc_auth unix_auth = { 231 .au_cslack = UNX_WRITESLACK, 232 .au_rslack = 2, /* assume AUTH_NULL verf */ 233 .au_ops = &authunix_ops, 234 .au_flavor = RPC_AUTH_UNIX, 235 .au_count = ATOMIC_INIT(0), 236 }; 237 238 static 239 const struct rpc_credops unix_credops = { 240 .cr_name = "AUTH_UNIX", 241 .crdestroy = unx_destroy_cred, 242 .crbind = rpcauth_generic_bind_cred, 243 .crmatch = unx_match, 244 .crmarshal = unx_marshal, 245 .crrefresh = unx_refresh, 246 .crvalidate = unx_validate, 247 }; 248