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, GFP_NOFS); 56 } 57 58 static struct rpc_cred * 59 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp) 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))) 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 }; 246