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 case -ENOTSUPP: 112 status = -EOPNOTSUPP; 113 default: 114 goto getout; 115 } 116 if ((args.mask & res.mask) != args.mask) { 117 status = -EIO; 118 goto getout; 119 } 120 121 if (res.acl_access != NULL) { 122 if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) || 123 res.acl_access->a_count == 0) { 124 posix_acl_release(res.acl_access); 125 res.acl_access = NULL; 126 } 127 } 128 129 if (res.mask & NFS_ACL) 130 nfs3_complete_get_acl(&inode->i_acl, res.acl_access); 131 else 132 forget_cached_acl(inode, ACL_TYPE_ACCESS); 133 134 if (res.mask & NFS_DFACL) 135 nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default); 136 else 137 forget_cached_acl(inode, ACL_TYPE_DEFAULT); 138 139 nfs_free_fattr(res.fattr); 140 if (type == ACL_TYPE_ACCESS) { 141 posix_acl_release(res.acl_default); 142 return res.acl_access; 143 } else { 144 posix_acl_release(res.acl_access); 145 return res.acl_default; 146 } 147 148 getout: 149 nfs3_abort_get_acl(&inode->i_acl); 150 nfs3_abort_get_acl(&inode->i_default_acl); 151 posix_acl_release(res.acl_access); 152 posix_acl_release(res.acl_default); 153 nfs_free_fattr(res.fattr); 154 return ERR_PTR(status); 155 } 156 157 static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 158 struct posix_acl *dfacl) 159 { 160 struct nfs_server *server = NFS_SERVER(inode); 161 struct nfs_fattr *fattr; 162 struct page *pages[NFSACL_MAXPAGES]; 163 struct nfs3_setaclargs args = { 164 .inode = inode, 165 .mask = NFS_ACL, 166 .acl_access = acl, 167 .pages = pages, 168 }; 169 struct rpc_message msg = { 170 .rpc_argp = &args, 171 .rpc_resp = &fattr, 172 }; 173 int status = 0; 174 175 if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL)) 176 goto out; 177 178 status = -EOPNOTSUPP; 179 if (!nfs_server_capable(inode, NFS_CAP_ACLS)) 180 goto out; 181 182 /* We are doing this here because XDR marshalling does not 183 * return any results, it BUGs. */ 184 status = -ENOSPC; 185 if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES) 186 goto out; 187 if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES) 188 goto out; 189 if (S_ISDIR(inode->i_mode)) { 190 args.mask |= NFS_DFACL; 191 args.acl_default = dfacl; 192 args.len = nfsacl_size(acl, dfacl); 193 } else 194 args.len = nfsacl_size(acl, NULL); 195 196 if (args.len > NFS_ACL_INLINE_BUFSIZE) { 197 unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT); 198 199 status = -ENOMEM; 200 do { 201 args.pages[args.npages] = alloc_page(GFP_KERNEL); 202 if (args.pages[args.npages] == NULL) 203 goto out_freepages; 204 args.npages++; 205 } while (args.npages < npages); 206 } 207 208 dprintk("NFS call setacl\n"); 209 status = -ENOMEM; 210 fattr = nfs_alloc_fattr(); 211 if (fattr == NULL) 212 goto out_freepages; 213 214 msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL]; 215 msg.rpc_resp = fattr; 216 status = rpc_call_sync(server->client_acl, &msg, 0); 217 nfs_access_zap_cache(inode); 218 nfs_zap_acl_cache(inode); 219 dprintk("NFS reply setacl: %d\n", status); 220 221 switch (status) { 222 case 0: 223 status = nfs_refresh_inode(inode, fattr); 224 set_cached_acl(inode, ACL_TYPE_ACCESS, acl); 225 set_cached_acl(inode, ACL_TYPE_DEFAULT, dfacl); 226 break; 227 case -EPFNOSUPPORT: 228 case -EPROTONOSUPPORT: 229 dprintk("NFS_V3_ACL SETACL RPC not supported" 230 "(will not retry)\n"); 231 server->caps &= ~NFS_CAP_ACLS; 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 *alloc = NULL, *dfacl = NULL; 257 int status; 258 259 if (S_ISDIR(inode->i_mode)) { 260 switch(type) { 261 case ACL_TYPE_ACCESS: 262 alloc = dfacl = get_acl(inode, ACL_TYPE_DEFAULT); 263 if (IS_ERR(alloc)) 264 goto fail; 265 break; 266 267 case ACL_TYPE_DEFAULT: 268 dfacl = acl; 269 alloc = acl = get_acl(inode, ACL_TYPE_ACCESS); 270 if (IS_ERR(alloc)) 271 goto fail; 272 break; 273 } 274 } 275 276 if (acl == NULL) { 277 alloc = acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL); 278 if (IS_ERR(alloc)) 279 goto fail; 280 } 281 status = __nfs3_proc_setacls(inode, acl, dfacl); 282 posix_acl_release(alloc); 283 return status; 284 285 fail: 286 return PTR_ERR(alloc); 287 } 288 289 const struct xattr_handler *nfs3_xattr_handlers[] = { 290 &posix_acl_access_xattr_handler, 291 &posix_acl_default_xattr_handler, 292 NULL, 293 }; 294 295 static int 296 nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data, 297 size_t size, ssize_t *result) 298 { 299 struct posix_acl *acl; 300 char *p = data + *result; 301 302 acl = get_acl(inode, type); 303 if (IS_ERR_OR_NULL(acl)) 304 return 0; 305 306 posix_acl_release(acl); 307 308 *result += strlen(name); 309 *result += 1; 310 if (!size) 311 return 0; 312 if (*result > size) 313 return -ERANGE; 314 315 strcpy(p, name); 316 return 0; 317 } 318 319 ssize_t 320 nfs3_listxattr(struct dentry *dentry, char *data, size_t size) 321 { 322 struct inode *inode = d_inode(dentry); 323 ssize_t result = 0; 324 int error; 325 326 error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS, 327 XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result); 328 if (error) 329 return error; 330 331 error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT, 332 XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result); 333 if (error) 334 return error; 335 return result; 336 } 337