1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2008, Christoph Hellwig 4 * All Rights Reserved. 5 */ 6 #include "xfs.h" 7 #include "xfs_shared.h" 8 #include "xfs_format.h" 9 #include "xfs_log_format.h" 10 #include "xfs_trans_resv.h" 11 #include "xfs_mount.h" 12 #include "xfs_inode.h" 13 #include "xfs_attr.h" 14 #include "xfs_trace.h" 15 #include "xfs_error.h" 16 #include "xfs_acl.h" 17 18 #include <linux/posix_acl_xattr.h> 19 20 /* 21 * Locking scheme: 22 * - all ACL updates are protected by inode->i_mutex, which is taken before 23 * calling into this file. 24 */ 25 26 STATIC struct posix_acl * 27 xfs_acl_from_disk( 28 struct xfs_mount *mp, 29 const struct xfs_acl *aclp, 30 int len, 31 int max_entries) 32 { 33 struct posix_acl_entry *acl_e; 34 struct posix_acl *acl; 35 const struct xfs_acl_entry *ace; 36 unsigned int count, i; 37 38 if (len < sizeof(*aclp)) { 39 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp, 40 len); 41 return ERR_PTR(-EFSCORRUPTED); 42 } 43 44 count = be32_to_cpu(aclp->acl_cnt); 45 if (count > max_entries || XFS_ACL_SIZE(count) != len) { 46 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp, 47 len); 48 return ERR_PTR(-EFSCORRUPTED); 49 } 50 51 acl = posix_acl_alloc(count, GFP_KERNEL); 52 if (!acl) 53 return ERR_PTR(-ENOMEM); 54 55 for (i = 0; i < count; i++) { 56 acl_e = &acl->a_entries[i]; 57 ace = &aclp->acl_entry[i]; 58 59 /* 60 * The tag is 32 bits on disk and 16 bits in core. 61 * 62 * Because every access to it goes through the core 63 * format first this is not a problem. 64 */ 65 acl_e->e_tag = be32_to_cpu(ace->ae_tag); 66 acl_e->e_perm = be16_to_cpu(ace->ae_perm); 67 68 switch (acl_e->e_tag) { 69 case ACL_USER: 70 acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id)); 71 break; 72 case ACL_GROUP: 73 acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id)); 74 break; 75 case ACL_USER_OBJ: 76 case ACL_GROUP_OBJ: 77 case ACL_MASK: 78 case ACL_OTHER: 79 break; 80 default: 81 goto fail; 82 } 83 } 84 return acl; 85 86 fail: 87 posix_acl_release(acl); 88 return ERR_PTR(-EINVAL); 89 } 90 91 STATIC void 92 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) 93 { 94 const struct posix_acl_entry *acl_e; 95 struct xfs_acl_entry *ace; 96 int i; 97 98 aclp->acl_cnt = cpu_to_be32(acl->a_count); 99 for (i = 0; i < acl->a_count; i++) { 100 ace = &aclp->acl_entry[i]; 101 acl_e = &acl->a_entries[i]; 102 103 ace->ae_tag = cpu_to_be32(acl_e->e_tag); 104 switch (acl_e->e_tag) { 105 case ACL_USER: 106 ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid)); 107 break; 108 case ACL_GROUP: 109 ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid)); 110 break; 111 default: 112 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID); 113 break; 114 } 115 116 ace->ae_perm = cpu_to_be16(acl_e->e_perm); 117 } 118 } 119 120 struct posix_acl * 121 xfs_get_acl(struct inode *inode, int type) 122 { 123 struct xfs_inode *ip = XFS_I(inode); 124 struct posix_acl *acl = NULL; 125 struct xfs_acl *xfs_acl = NULL; 126 unsigned char *ea_name; 127 int error; 128 int len; 129 130 trace_xfs_get_acl(ip); 131 132 switch (type) { 133 case ACL_TYPE_ACCESS: 134 ea_name = SGI_ACL_FILE; 135 break; 136 case ACL_TYPE_DEFAULT: 137 ea_name = SGI_ACL_DEFAULT; 138 break; 139 default: 140 BUG(); 141 } 142 143 /* 144 * If we have a cached ACLs value just return it, not need to 145 * go out to the disk. 146 */ 147 len = XFS_ACL_MAX_SIZE(ip->i_mount); 148 error = xfs_attr_get(ip, ea_name, strlen(ea_name), 149 (unsigned char **)&xfs_acl, &len, 150 ATTR_ALLOC | ATTR_ROOT); 151 if (error) { 152 /* 153 * If the attribute doesn't exist make sure we have a negative 154 * cache entry, for any other error assume it is transient. 155 */ 156 if (error != -ENOATTR) 157 acl = ERR_PTR(error); 158 } else { 159 acl = xfs_acl_from_disk(ip->i_mount, xfs_acl, len, 160 XFS_ACL_MAX_ENTRIES(ip->i_mount)); 161 kmem_free(xfs_acl); 162 } 163 return acl; 164 } 165 166 int 167 __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 168 { 169 struct xfs_inode *ip = XFS_I(inode); 170 unsigned char *ea_name; 171 int error; 172 173 switch (type) { 174 case ACL_TYPE_ACCESS: 175 ea_name = SGI_ACL_FILE; 176 break; 177 case ACL_TYPE_DEFAULT: 178 if (!S_ISDIR(inode->i_mode)) 179 return acl ? -EACCES : 0; 180 ea_name = SGI_ACL_DEFAULT; 181 break; 182 default: 183 return -EINVAL; 184 } 185 186 if (acl) { 187 struct xfs_acl *xfs_acl; 188 int len = XFS_ACL_MAX_SIZE(ip->i_mount); 189 190 xfs_acl = kmem_zalloc_large(len, 0); 191 if (!xfs_acl) 192 return -ENOMEM; 193 194 xfs_acl_to_disk(xfs_acl, acl); 195 196 /* subtract away the unused acl entries */ 197 len -= sizeof(struct xfs_acl_entry) * 198 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count); 199 200 error = xfs_attr_set(ip, ea_name, strlen(ea_name), 201 (unsigned char *)xfs_acl, len, ATTR_ROOT); 202 203 kmem_free(xfs_acl); 204 } else { 205 /* 206 * A NULL ACL argument means we want to remove the ACL. 207 */ 208 error = xfs_attr_remove(ip, ea_name, 209 strlen(ea_name), 210 ATTR_ROOT); 211 212 /* 213 * If the attribute didn't exist to start with that's fine. 214 */ 215 if (error == -ENOATTR) 216 error = 0; 217 } 218 219 if (!error) 220 set_cached_acl(inode, type, acl); 221 return error; 222 } 223 224 static int 225 xfs_set_mode(struct inode *inode, umode_t mode) 226 { 227 int error = 0; 228 229 if (mode != inode->i_mode) { 230 struct iattr iattr; 231 232 iattr.ia_valid = ATTR_MODE | ATTR_CTIME; 233 iattr.ia_mode = mode; 234 iattr.ia_ctime = current_time(inode); 235 236 error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL); 237 } 238 239 return error; 240 } 241 242 int 243 xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 244 { 245 umode_t mode; 246 bool set_mode = false; 247 int error = 0; 248 249 if (!acl) 250 goto set_acl; 251 252 error = -E2BIG; 253 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) 254 return error; 255 256 if (type == ACL_TYPE_ACCESS) { 257 error = posix_acl_update_mode(inode, &mode, &acl); 258 if (error) 259 return error; 260 set_mode = true; 261 } 262 263 set_acl: 264 error = __xfs_set_acl(inode, acl, type); 265 if (error) 266 return error; 267 268 /* 269 * We set the mode after successfully updating the ACL xattr because the 270 * xattr update can fail at ENOSPC and we don't want to change the mode 271 * if the ACL update hasn't been applied. 272 */ 273 if (set_mode) 274 error = xfs_set_mode(inode, mode); 275 276 return error; 277 } 278