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) 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 (!nfs_server_capable(inode, NFS_CAP_ACLS)) 66 return ERR_PTR(-EOPNOTSUPP); 67 68 status = nfs_revalidate_inode(server, inode); 69 if (status < 0) 70 return ERR_PTR(status); 71 72 /* 73 * Only get the access acl when explicitly requested: We don't 74 * need it for access decisions, and only some applications use 75 * it. Applications which request the access acl first are not 76 * penalized from this optimization. 77 */ 78 if (type == ACL_TYPE_ACCESS) 79 args.mask |= NFS_ACLCNT|NFS_ACL; 80 if (S_ISDIR(inode->i_mode)) 81 args.mask |= NFS_DFACLCNT|NFS_DFACL; 82 if (args.mask == 0) 83 return NULL; 84 85 dprintk("NFS call getacl\n"); 86 msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL]; 87 res.fattr = nfs_alloc_fattr(); 88 if (res.fattr == NULL) 89 return ERR_PTR(-ENOMEM); 90 91 if (args.mask & NFS_ACL) 92 nfs3_prepare_get_acl(&inode->i_acl); 93 if (args.mask & NFS_DFACL) 94 nfs3_prepare_get_acl(&inode->i_default_acl); 95 96 status = rpc_call_sync(server->client_acl, &msg, 0); 97 dprintk("NFS reply getacl: %d\n", status); 98 99 /* pages may have been allocated at the xdr layer. */ 100 for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++) 101 __free_page(args.pages[count]); 102 103 switch (status) { 104 case 0: 105 status = nfs_refresh_inode(inode, res.fattr); 106 break; 107 case -EPFNOSUPPORT: 108 case -EPROTONOSUPPORT: 109 dprintk("NFS_V3_ACL extension not supported; disabling\n"); 110 server->caps &= ~NFS_CAP_ACLS; 111 /* fall through */ 112 case -ENOTSUPP: 113 status = -EOPNOTSUPP; 114 default: 115 goto getout; 116 } 117 if ((args.mask & res.mask) != args.mask) { 118 status = -EIO; 119 goto getout; 120 } 121 122 if (res.acl_access != NULL) { 123 if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) || 124 res.acl_access->a_count == 0) { 125 posix_acl_release(res.acl_access); 126 res.acl_access = NULL; 127 } 128 } 129 130 if (res.mask & NFS_ACL) 131 nfs3_complete_get_acl(&inode->i_acl, res.acl_access); 132 else 133 forget_cached_acl(inode, ACL_TYPE_ACCESS); 134 135 if (res.mask & NFS_DFACL) 136 nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default); 137 else 138 forget_cached_acl(inode, ACL_TYPE_DEFAULT); 139 140 nfs_free_fattr(res.fattr); 141 if (type == ACL_TYPE_ACCESS) { 142 posix_acl_release(res.acl_default); 143 return res.acl_access; 144 } else { 145 posix_acl_release(res.acl_access); 146 return res.acl_default; 147 } 148 149 getout: 150 nfs3_abort_get_acl(&inode->i_acl); 151 nfs3_abort_get_acl(&inode->i_default_acl); 152 posix_acl_release(res.acl_access); 153 posix_acl_release(res.acl_default); 154 nfs_free_fattr(res.fattr); 155 return ERR_PTR(status); 156 } 157 158 static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 159 struct posix_acl *dfacl) 160 { 161 struct nfs_server *server = NFS_SERVER(inode); 162 struct nfs_fattr *fattr; 163 struct page *pages[NFSACL_MAXPAGES]; 164 struct nfs3_setaclargs args = { 165 .inode = inode, 166 .mask = NFS_ACL, 167 .acl_access = acl, 168 .pages = pages, 169 }; 170 struct rpc_message msg = { 171 .rpc_argp = &args, 172 .rpc_resp = &fattr, 173 }; 174 int status = 0; 175 176 if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL)) 177 goto out; 178 179 status = -EOPNOTSUPP; 180 if (!nfs_server_capable(inode, NFS_CAP_ACLS)) 181 goto out; 182 183 /* We are doing this here because XDR marshalling does not 184 * return any results, it BUGs. */ 185 status = -ENOSPC; 186 if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES) 187 goto out; 188 if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES) 189 goto out; 190 if (S_ISDIR(inode->i_mode)) { 191 args.mask |= NFS_DFACL; 192 args.acl_default = dfacl; 193 args.len = nfsacl_size(acl, dfacl); 194 } else 195 args.len = nfsacl_size(acl, NULL); 196 197 if (args.len > NFS_ACL_INLINE_BUFSIZE) { 198 unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT); 199 200 status = -ENOMEM; 201 do { 202 args.pages[args.npages] = alloc_page(GFP_KERNEL); 203 if (args.pages[args.npages] == NULL) 204 goto out_freepages; 205 args.npages++; 206 } while (args.npages < npages); 207 } 208 209 dprintk("NFS call setacl\n"); 210 status = -ENOMEM; 211 fattr = nfs_alloc_fattr(); 212 if (fattr == NULL) 213 goto out_freepages; 214 215 msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL]; 216 msg.rpc_resp = fattr; 217 status = rpc_call_sync(server->client_acl, &msg, 0); 218 nfs_access_zap_cache(inode); 219 nfs_zap_acl_cache(inode); 220 dprintk("NFS reply setacl: %d\n", status); 221 222 switch (status) { 223 case 0: 224 status = nfs_refresh_inode(inode, fattr); 225 break; 226 case -EPFNOSUPPORT: 227 case -EPROTONOSUPPORT: 228 dprintk("NFS_V3_ACL SETACL RPC not supported" 229 "(will not retry)\n"); 230 server->caps &= ~NFS_CAP_ACLS; 231 /* fall through */ 232 case -ENOTSUPP: 233 status = -EOPNOTSUPP; 234 } 235 nfs_free_fattr(fattr); 236 out_freepages: 237 while (args.npages != 0) { 238 args.npages--; 239 __free_page(args.pages[args.npages]); 240 } 241 out: 242 return status; 243 } 244 245 int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 246 struct posix_acl *dfacl) 247 { 248 int ret; 249 ret = __nfs3_proc_setacls(inode, acl, dfacl); 250 return (ret == -EOPNOTSUPP) ? 0 : ret; 251 252 } 253 254 int nfs3_set_acl(struct inode *inode, struct posix_acl *acl, int type) 255 { 256 struct posix_acl *orig = acl, *dfacl = NULL, *alloc; 257 int status; 258 259 if (S_ISDIR(inode->i_mode)) { 260 switch(type) { 261 case ACL_TYPE_ACCESS: 262 alloc = get_acl(inode, ACL_TYPE_DEFAULT); 263 if (IS_ERR(alloc)) 264 goto fail; 265 dfacl = alloc; 266 break; 267 268 case ACL_TYPE_DEFAULT: 269 alloc = get_acl(inode, ACL_TYPE_ACCESS); 270 if (IS_ERR(alloc)) 271 goto fail; 272 dfacl = acl; 273 acl = alloc; 274 break; 275 } 276 } 277 278 if (acl == NULL) { 279 alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL); 280 if (IS_ERR(alloc)) 281 goto fail; 282 acl = alloc; 283 } 284 status = __nfs3_proc_setacls(inode, acl, dfacl); 285 out: 286 if (acl != orig) 287 posix_acl_release(acl); 288 if (dfacl != orig) 289 posix_acl_release(dfacl); 290 return status; 291 292 fail: 293 status = PTR_ERR(alloc); 294 goto out; 295 } 296 297 const struct xattr_handler *nfs3_xattr_handlers[] = { 298 &posix_acl_access_xattr_handler, 299 &posix_acl_default_xattr_handler, 300 NULL, 301 }; 302 303 static int 304 nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data, 305 size_t size, ssize_t *result) 306 { 307 struct posix_acl *acl; 308 char *p = data + *result; 309 310 acl = get_acl(inode, type); 311 if (IS_ERR_OR_NULL(acl)) 312 return 0; 313 314 posix_acl_release(acl); 315 316 *result += strlen(name); 317 *result += 1; 318 if (!size) 319 return 0; 320 if (*result > size) 321 return -ERANGE; 322 323 strcpy(p, name); 324 return 0; 325 } 326 327 ssize_t 328 nfs3_listxattr(struct dentry *dentry, char *data, size_t size) 329 { 330 struct inode *inode = d_inode(dentry); 331 ssize_t result = 0; 332 int error; 333 334 error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS, 335 XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result); 336 if (error) 337 return error; 338 339 error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT, 340 XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result); 341 if (error) 342 return error; 343 return result; 344 } 345