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 fallthrough; 112 case -ENOTSUPP: 113 status = -EOPNOTSUPP; 114 goto getout; 115 default: 116 goto getout; 117 } 118 if ((args.mask & res.mask) != args.mask) { 119 status = -EIO; 120 goto getout; 121 } 122 123 if (res.acl_access != NULL) { 124 if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) || 125 res.acl_access->a_count == 0) { 126 posix_acl_release(res.acl_access); 127 res.acl_access = NULL; 128 } 129 } 130 131 if (res.mask & NFS_ACL) 132 nfs3_complete_get_acl(&inode->i_acl, res.acl_access); 133 else 134 forget_cached_acl(inode, ACL_TYPE_ACCESS); 135 136 if (res.mask & NFS_DFACL) 137 nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default); 138 else 139 forget_cached_acl(inode, ACL_TYPE_DEFAULT); 140 141 nfs_free_fattr(res.fattr); 142 if (type == ACL_TYPE_ACCESS) { 143 posix_acl_release(res.acl_default); 144 return res.acl_access; 145 } else { 146 posix_acl_release(res.acl_access); 147 return res.acl_default; 148 } 149 150 getout: 151 nfs3_abort_get_acl(&inode->i_acl); 152 nfs3_abort_get_acl(&inode->i_default_acl); 153 posix_acl_release(res.acl_access); 154 posix_acl_release(res.acl_default); 155 nfs_free_fattr(res.fattr); 156 return ERR_PTR(status); 157 } 158 159 static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 160 struct posix_acl *dfacl) 161 { 162 struct nfs_server *server = NFS_SERVER(inode); 163 struct nfs_fattr *fattr; 164 struct page *pages[NFSACL_MAXPAGES]; 165 struct nfs3_setaclargs args = { 166 .inode = inode, 167 .mask = NFS_ACL, 168 .acl_access = acl, 169 .pages = pages, 170 }; 171 struct rpc_message msg = { 172 .rpc_argp = &args, 173 .rpc_resp = &fattr, 174 }; 175 int status = 0; 176 177 if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL)) 178 goto out; 179 180 status = -EOPNOTSUPP; 181 if (!nfs_server_capable(inode, NFS_CAP_ACLS)) 182 goto out; 183 184 /* We are doing this here because XDR marshalling does not 185 * return any results, it BUGs. */ 186 status = -ENOSPC; 187 if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES) 188 goto out; 189 if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES) 190 goto out; 191 if (S_ISDIR(inode->i_mode)) { 192 args.mask |= NFS_DFACL; 193 args.acl_default = dfacl; 194 args.len = nfsacl_size(acl, dfacl); 195 } else 196 args.len = nfsacl_size(acl, NULL); 197 198 if (args.len > NFS_ACL_INLINE_BUFSIZE) { 199 unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT); 200 201 status = -ENOMEM; 202 do { 203 args.pages[args.npages] = alloc_page(GFP_KERNEL); 204 if (args.pages[args.npages] == NULL) 205 goto out_freepages; 206 args.npages++; 207 } while (args.npages < npages); 208 } 209 210 dprintk("NFS call setacl\n"); 211 status = -ENOMEM; 212 fattr = nfs_alloc_fattr(); 213 if (fattr == NULL) 214 goto out_freepages; 215 216 msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL]; 217 msg.rpc_resp = fattr; 218 status = rpc_call_sync(server->client_acl, &msg, 0); 219 nfs_access_zap_cache(inode); 220 nfs_zap_acl_cache(inode); 221 dprintk("NFS reply setacl: %d\n", status); 222 223 switch (status) { 224 case 0: 225 status = nfs_refresh_inode(inode, fattr); 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 fallthrough; 233 case -ENOTSUPP: 234 status = -EOPNOTSUPP; 235 } 236 nfs_free_fattr(fattr); 237 out_freepages: 238 while (args.npages != 0) { 239 args.npages--; 240 __free_page(args.pages[args.npages]); 241 } 242 out: 243 return status; 244 } 245 246 int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, 247 struct posix_acl *dfacl) 248 { 249 int ret; 250 ret = __nfs3_proc_setacls(inode, acl, dfacl); 251 return (ret == -EOPNOTSUPP) ? 0 : ret; 252 253 } 254 255 int nfs3_set_acl(struct user_namespace *mnt_userns, struct inode *inode, 256 struct posix_acl *acl, int type) 257 { 258 struct posix_acl *orig = acl, *dfacl = NULL, *alloc; 259 int status; 260 261 if (S_ISDIR(inode->i_mode)) { 262 switch(type) { 263 case ACL_TYPE_ACCESS: 264 alloc = get_acl(inode, ACL_TYPE_DEFAULT); 265 if (IS_ERR(alloc)) 266 goto fail; 267 dfacl = alloc; 268 break; 269 270 case ACL_TYPE_DEFAULT: 271 alloc = get_acl(inode, ACL_TYPE_ACCESS); 272 if (IS_ERR(alloc)) 273 goto fail; 274 dfacl = acl; 275 acl = alloc; 276 break; 277 } 278 } 279 280 if (acl == NULL) { 281 alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL); 282 if (IS_ERR(alloc)) 283 goto fail; 284 acl = alloc; 285 } 286 status = __nfs3_proc_setacls(inode, acl, dfacl); 287 out: 288 if (acl != orig) 289 posix_acl_release(acl); 290 if (dfacl != orig) 291 posix_acl_release(dfacl); 292 return status; 293 294 fail: 295 status = PTR_ERR(alloc); 296 goto out; 297 } 298 299 const struct xattr_handler *nfs3_xattr_handlers[] = { 300 &posix_acl_access_xattr_handler, 301 &posix_acl_default_xattr_handler, 302 NULL, 303 }; 304 305 static int 306 nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data, 307 size_t size, ssize_t *result) 308 { 309 struct posix_acl *acl; 310 char *p = data + *result; 311 312 acl = get_acl(inode, type); 313 if (IS_ERR_OR_NULL(acl)) 314 return 0; 315 316 posix_acl_release(acl); 317 318 *result += strlen(name); 319 *result += 1; 320 if (!size) 321 return 0; 322 if (*result > size) 323 return -ERANGE; 324 325 strcpy(p, name); 326 return 0; 327 } 328 329 ssize_t 330 nfs3_listxattr(struct dentry *dentry, char *data, size_t size) 331 { 332 struct inode *inode = d_inode(dentry); 333 ssize_t result = 0; 334 int error; 335 336 error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS, 337 XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result); 338 if (error) 339 return error; 340 341 error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT, 342 XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result); 343 if (error) 344 return error; 345 return result; 346 } 347