1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/net/sunrpc/auth_unix.c 4 * 5 * UNIX-style authentication; no AUTH_SHORT support 6 * 7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 8 */ 9 10 #include <linux/slab.h> 11 #include <linux/types.h> 12 #include <linux/sched.h> 13 #include <linux/module.h> 14 #include <linux/sunrpc/clnt.h> 15 #include <linux/sunrpc/auth.h> 16 #include <linux/user_namespace.h> 17 18 struct unx_cred { 19 struct rpc_cred uc_base; 20 kgid_t uc_gid; 21 kgid_t uc_gids[UNX_NGROUPS]; 22 }; 23 #define uc_uid uc_base.cr_uid 24 25 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) 26 # define RPCDBG_FACILITY RPCDBG_AUTH 27 #endif 28 29 static struct rpc_auth unix_auth; 30 static const struct rpc_credops unix_credops; 31 32 static struct rpc_auth * 33 unx_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt) 34 { 35 dprintk("RPC: creating UNIX authenticator for client %p\n", 36 clnt); 37 refcount_inc(&unix_auth.au_count); 38 return &unix_auth; 39 } 40 41 static void 42 unx_destroy(struct rpc_auth *auth) 43 { 44 dprintk("RPC: destroying UNIX authenticator %p\n", auth); 45 rpcauth_clear_credcache(auth->au_credcache); 46 } 47 48 static int 49 unx_hash_cred(struct auth_cred *acred, unsigned int hashbits) 50 { 51 return hash_64(from_kgid(&init_user_ns, acred->cred->fsgid) | 52 ((u64)from_kuid(&init_user_ns, acred->cred->fsuid) << 53 (sizeof(gid_t) * 8)), hashbits); 54 } 55 56 /* 57 * Lookup AUTH_UNIX creds for current process 58 */ 59 static struct rpc_cred * 60 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags) 61 { 62 return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS); 63 } 64 65 static struct rpc_cred * 66 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp) 67 { 68 struct unx_cred *cred; 69 unsigned int groups = 0; 70 unsigned int i; 71 72 dprintk("RPC: allocating UNIX cred for uid %d gid %d\n", 73 from_kuid(&init_user_ns, acred->cred->fsuid), 74 from_kgid(&init_user_ns, acred->cred->fsgid)); 75 76 if (!(cred = kmalloc(sizeof(*cred), gfp))) 77 return ERR_PTR(-ENOMEM); 78 79 rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops); 80 cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE; 81 82 if (acred->cred && acred->cred->group_info != NULL) 83 groups = acred->cred->group_info->ngroups; 84 if (groups > UNX_NGROUPS) 85 groups = UNX_NGROUPS; 86 87 cred->uc_gid = acred->cred->fsgid; 88 for (i = 0; i < groups; i++) 89 cred->uc_gids[i] = acred->cred->group_info->gid[i]; 90 if (i < UNX_NGROUPS) 91 cred->uc_gids[i] = INVALID_GID; 92 93 return &cred->uc_base; 94 } 95 96 static void 97 unx_free_cred(struct unx_cred *unx_cred) 98 { 99 dprintk("RPC: unx_free_cred %p\n", unx_cred); 100 put_cred(unx_cred->uc_base.cr_cred); 101 kfree(unx_cred); 102 } 103 104 static void 105 unx_free_cred_callback(struct rcu_head *head) 106 { 107 struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu); 108 unx_free_cred(unx_cred); 109 } 110 111 static void 112 unx_destroy_cred(struct rpc_cred *cred) 113 { 114 call_rcu(&cred->cr_rcu, unx_free_cred_callback); 115 } 116 117 /* 118 * Match credentials against current process creds. 119 * The root_override argument takes care of cases where the caller may 120 * request root creds (e.g. for NFS swapping). 121 */ 122 static int 123 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags) 124 { 125 struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base); 126 unsigned int groups = 0; 127 unsigned int i; 128 129 130 if (!uid_eq(cred->uc_uid, acred->cred->fsuid) || !gid_eq(cred->uc_gid, acred->cred->fsgid)) 131 return 0; 132 133 if (acred->cred && acred->cred->group_info != NULL) 134 groups = acred->cred->group_info->ngroups; 135 if (groups > UNX_NGROUPS) 136 groups = UNX_NGROUPS; 137 for (i = 0; i < groups ; i++) 138 if (!gid_eq(cred->uc_gids[i], acred->cred->group_info->gid[i])) 139 return 0; 140 if (groups < UNX_NGROUPS && gid_valid(cred->uc_gids[groups])) 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) from_kuid(&init_user_ns, cred->uc_uid)); 167 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid)); 168 hold = p++; 169 for (i = 0; i < UNX_NGROUPS && gid_valid(cred->uc_gids[i]); i++) 170 *p++ = htonl((u32) from_kgid(&init_user_ns, 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 ERR_PTR(-EIO); 202 } 203 204 size = ntohl(*p++); 205 if (size > RPC_MAX_AUTH_SIZE) { 206 printk("RPC: giant verf size: %u\n", size); 207 return ERR_PTR(-EIO); 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 .hash_cred = unx_hash_cred, 232 .lookup_cred = unx_lookup_cred, 233 .crcreate = unx_create_cred, 234 }; 235 236 static 237 struct rpc_auth unix_auth = { 238 .au_cslack = UNX_CALLSLACK, 239 .au_rslack = NUL_REPLYSLACK, 240 .au_ops = &authunix_ops, 241 .au_flavor = RPC_AUTH_UNIX, 242 .au_count = REFCOUNT_INIT(1), 243 }; 244 245 static 246 const struct rpc_credops unix_credops = { 247 .cr_name = "AUTH_UNIX", 248 .crdestroy = unx_destroy_cred, 249 .crmatch = unx_match, 250 .crmarshal = unx_marshal, 251 .crrefresh = unx_refresh, 252 .crvalidate = unx_validate, 253 }; 254