1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/fs.h> 3 #include <linux/gfp.h> 4 #include <linux/nfs.h> 5 #include <linux/nfs3.h> 6 #include <linux/nfs_fs.h> 7 #include <linux/posix_acl_xattr.h> 8 #include <linux/nfsacl.h> 9 10 #include "internal.h" 11 #include "nfs3_fs.h" 12 13 #define NFSDBG_FACILITY NFSDBG_PROC 14 15 /* 16 * nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for 17 * caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl() 18 * for explanations. 19 */ 20 static void nfs3_prepare_get_acl(struct posix_acl **p) 21 { 22 struct posix_acl *sentinel = uncached_acl_sentinel(current); 23 24 if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) { 25 /* Not the first reader or sentinel already in place. */ 26 } 27 } 28 29 static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl) 30 { 31 struct posix_acl *sentinel = uncached_acl_sentinel(current); 32 33 /* Only cache the ACL if our sentinel is still in place. */ 34 posix_acl_dup(acl); 35 if (cmpxchg(p, sentinel, acl) != sentinel) 36 posix_acl_release(acl); 37 } 38 39 static void nfs3_abort_get_acl(struct posix_acl **p) 40 { 41 struct posix_acl *sentinel = uncached_acl_sentinel(current); 42 43 /* Remove our sentinel upon failure. */ 44 cmpxchg(p, sentinel, ACL_NOT_CACHED); 45 } 46 47 struct posix_acl *nfs3_get_acl(struct inode *inode, int type, bool rcu) 48 { 49 struct nfs_server *server = NFS_SERVER(inode); 50 struct page *pages[NFSACL_MAXPAGES] = { }; 51 struct nfs3_getaclargs args = { 52 .fh = NFS_FH(inode), 53 /* The xdr layer may allocate pages here. */ 54 .pages = pages, 55 }; 56 struct nfs3_getaclres res = { 57 NULL, 58 }; 59 struct rpc_message msg = { 60 .rpc_argp = &args, 61 .rpc_resp = &res, 62 }; 63 int status, count; 64 65 if (rcu) 66 return ERR_PTR(-ECHILD); 67 68 if (!nfs_server_capable(inode, NFS_CAP_ACLS)) 69 return ERR_PTR(-EOPNOTSUPP); 70 71 status = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE); 72 if (status < 0) 73 return ERR_PTR(status); 74 75 /* 76 * Only get the access acl when explicitly requested: We don't 77 * need it for access decisions, and only some applications use 78 * it. Applications which request the access acl first are not 79 * penalized from this optimization. 80 */ 81 if (type == ACL_TYPE_ACCESS) 82 args.mask |= NFS_ACLCNT|NFS_ACL; 83 if (S_ISDIR(inode->i_mode)) 84 args.mask |= NFS_DFACLCNT|NFS_DFACL; 85 if (args.mask == 0) 86 return NULL; 87 88 dprintk("NFS call getacl\n"); 89 msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL]; 90 res.fattr = nfs_alloc_fattr(); 91 if (res.fattr == NULL) 92 return ERR_PTR(-ENOMEM); 93 94 if (args.mask & NFS_ACL) 95 nfs3_prepare_get_acl(&inode->i_acl); 96 if (args.mask & NFS_DFACL) 97 nfs3_prepare_get_acl(&inode->i_default_acl); 98 99 status = rpc_call_sync(server->client_acl, &msg, 0); 100 dprintk("NFS reply getacl: %d\n", status); 101 102 /* pages may have been allocated at the xdr layer. */ 103 for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++) 104 __free_page(args.pages[count]); 105 106 switch (status) { 107 case 0: 108 status = nfs_refresh_inode(inode, res.fattr); 109 break; 110 case -EPFNOSUPPORT: 111 case -EPROTONOSUPPORT: 112 dprintk("NFS_V3_ACL extension not supported; disabling\n"); 113 server->caps &= ~NFS_CAP_ACLS; 114 fallthrough; 115 case -ENOTSUPP: 116 status = -EOPNOTSUPP; 117 goto getout; 118 default: 119 goto getout; 120 } 121 if ((args.mask & res.mask) != args.mask) { 122 status = -EIO; 123 goto getout; 124 } 125 126 if (res.acl_access != NULL) { 127 if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) || 128 res.acl_access->a_count == 0) { 129 posix_acl_release(res.acl_access); 130 res.acl_access = NULL; 131 } 132 } 133 134 if (res.mask & NFS_ACL) 135 nfs3_complete_get_acl(&inode->i_acl, res.acl_access); 136 else 137 forget_cached_acl(inode, ACL_TYPE_ACCESS); 138 139 if (res.mask & NFS_DFACL) 140 nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default); 141 else 142 forget_cached_acl(inode, ACL_TYPE_DEFAULT); 143 144 nfs_free_fattr(res.fattr); 145 if (type == ACL_TYPE_ACCESS) { 146 posix_acl_release(res.acl_default); 147 return res.acl_access; 148 } else { 149 posix_acl_release(res.acl_access); 150 return res.acl_default; 151 } 152 153 getout: 154 nfs3_abort_get_acl(&inode->i_acl); 155 nfs3_abort_get_acl(&inode->i_default_acl); 156 posix_acl_release(res.acl_access); 157 posix_acl_release(res.acl_default); 158 nfs_free_fattr(res.fattr); 159 return ERR_PTR(status); 160 } 161 162 static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 163 struct posix_acl *dfacl) 164 { 165 struct nfs_server *server = NFS_SERVER(inode); 166 struct nfs_fattr *fattr; 167 struct page *pages[NFSACL_MAXPAGES]; 168 struct nfs3_setaclargs args = { 169 .inode = inode, 170 .mask = NFS_ACL, 171 .acl_access = acl, 172 .pages = pages, 173 }; 174 struct rpc_message msg = { 175 .rpc_argp = &args, 176 .rpc_resp = &fattr, 177 }; 178 int status = 0; 179 180 if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL)) 181 goto out; 182 183 status = -EOPNOTSUPP; 184 if (!nfs_server_capable(inode, NFS_CAP_ACLS)) 185 goto out; 186 187 /* We are doing this here because XDR marshalling does not 188 * return any results, it BUGs. */ 189 status = -ENOSPC; 190 if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES) 191 goto out; 192 if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES) 193 goto out; 194 if (S_ISDIR(inode->i_mode)) { 195 args.mask |= NFS_DFACL; 196 args.acl_default = dfacl; 197 args.len = nfsacl_size(acl, dfacl); 198 } else 199 args.len = nfsacl_size(acl, NULL); 200 201 if (args.len > NFS_ACL_INLINE_BUFSIZE) { 202 unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT); 203 204 status = -ENOMEM; 205 do { 206 args.pages[args.npages] = alloc_page(GFP_KERNEL); 207 if (args.pages[args.npages] == NULL) 208 goto out_freepages; 209 args.npages++; 210 } while (args.npages < npages); 211 } 212 213 dprintk("NFS call setacl\n"); 214 status = -ENOMEM; 215 fattr = nfs_alloc_fattr(); 216 if (fattr == NULL) 217 goto out_freepages; 218 219 msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL]; 220 msg.rpc_resp = fattr; 221 status = rpc_call_sync(server->client_acl, &msg, 0); 222 nfs_access_zap_cache(inode); 223 nfs_zap_acl_cache(inode); 224 dprintk("NFS reply setacl: %d\n", status); 225 226 switch (status) { 227 case 0: 228 status = nfs_refresh_inode(inode, fattr); 229 break; 230 case -EPFNOSUPPORT: 231 case -EPROTONOSUPPORT: 232 dprintk("NFS_V3_ACL SETACL RPC not supported" 233 "(will not retry)\n"); 234 server->caps &= ~NFS_CAP_ACLS; 235 fallthrough; 236 case -ENOTSUPP: 237 status = -EOPNOTSUPP; 238 } 239 nfs_free_fattr(fattr); 240 out_freepages: 241 while (args.npages != 0) { 242 args.npages--; 243 __free_page(args.pages[args.npages]); 244 } 245 out: 246 return status; 247 } 248 249 int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 250 struct posix_acl *dfacl) 251 { 252 int ret; 253 ret = __nfs3_proc_setacls(inode, acl, dfacl); 254 return (ret == -EOPNOTSUPP) ? 0 : ret; 255 256 } 257 258 int nfs3_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, 259 struct posix_acl *acl, int type) 260 { 261 struct posix_acl *orig = acl, *dfacl = NULL, *alloc; 262 struct inode *inode = d_inode(dentry); 263 int status; 264 265 if (S_ISDIR(inode->i_mode)) { 266 switch(type) { 267 case ACL_TYPE_ACCESS: 268 alloc = get_inode_acl(inode, ACL_TYPE_DEFAULT); 269 if (IS_ERR(alloc)) 270 goto fail; 271 dfacl = alloc; 272 break; 273 274 case ACL_TYPE_DEFAULT: 275 alloc = get_inode_acl(inode, ACL_TYPE_ACCESS); 276 if (IS_ERR(alloc)) 277 goto fail; 278 dfacl = acl; 279 acl = alloc; 280 break; 281 } 282 } 283 284 if (acl == NULL) { 285 alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL); 286 if (IS_ERR(alloc)) 287 goto fail; 288 acl = alloc; 289 } 290 status = __nfs3_proc_setacls(inode, acl, dfacl); 291 out: 292 if (acl != orig) 293 posix_acl_release(acl); 294 if (dfacl != orig) 295 posix_acl_release(dfacl); 296 return status; 297 298 fail: 299 status = PTR_ERR(alloc); 300 goto out; 301 } 302 303 const struct xattr_handler *nfs3_xattr_handlers[] = { 304 &posix_acl_access_xattr_handler, 305 &posix_acl_default_xattr_handler, 306 NULL, 307 }; 308 309 static int 310 nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data, 311 size_t size, ssize_t *result) 312 { 313 struct posix_acl *acl; 314 char *p = data + *result; 315 316 acl = get_inode_acl(inode, type); 317 if (IS_ERR_OR_NULL(acl)) 318 return 0; 319 320 posix_acl_release(acl); 321 322 *result += strlen(name); 323 *result += 1; 324 if (!size) 325 return 0; 326 if (*result > size) 327 return -ERANGE; 328 329 strcpy(p, name); 330 return 0; 331 } 332 333 ssize_t 334 nfs3_listxattr(struct dentry *dentry, char *data, size_t size) 335 { 336 struct inode *inode = d_inode(dentry); 337 ssize_t result = 0; 338 int error; 339 340 error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS, 341 XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result); 342 if (error) 343 return error; 344 345 error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT, 346 XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result); 347 if (error) 348 return error; 349 return result; 350 } 351