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