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, (unsigned char **)&xfs_acl, &len, 149 ATTR_ALLOC | ATTR_ROOT); 150 if (error) { 151 /* 152 * If the attribute doesn't exist make sure we have a negative 153 * cache entry, for any other error assume it is transient. 154 */ 155 if (error != -ENOATTR) 156 acl = ERR_PTR(error); 157 } else { 158 acl = xfs_acl_from_disk(ip->i_mount, xfs_acl, len, 159 XFS_ACL_MAX_ENTRIES(ip->i_mount)); 160 kmem_free(xfs_acl); 161 } 162 return acl; 163 } 164 165 int 166 __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 167 { 168 struct xfs_inode *ip = XFS_I(inode); 169 unsigned char *ea_name; 170 int error; 171 172 switch (type) { 173 case ACL_TYPE_ACCESS: 174 ea_name = SGI_ACL_FILE; 175 break; 176 case ACL_TYPE_DEFAULT: 177 if (!S_ISDIR(inode->i_mode)) 178 return acl ? -EACCES : 0; 179 ea_name = SGI_ACL_DEFAULT; 180 break; 181 default: 182 return -EINVAL; 183 } 184 185 if (acl) { 186 struct xfs_acl *xfs_acl; 187 int len = XFS_ACL_MAX_SIZE(ip->i_mount); 188 189 xfs_acl = kmem_zalloc_large(len, 0); 190 if (!xfs_acl) 191 return -ENOMEM; 192 193 xfs_acl_to_disk(xfs_acl, acl); 194 195 /* subtract away the unused acl entries */ 196 len -= sizeof(struct xfs_acl_entry) * 197 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count); 198 199 error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl, 200 len, ATTR_ROOT); 201 202 kmem_free(xfs_acl); 203 } else { 204 /* 205 * A NULL ACL argument means we want to remove the ACL. 206 */ 207 error = xfs_attr_remove(ip, ea_name, ATTR_ROOT); 208 209 /* 210 * If the attribute didn't exist to start with that's fine. 211 */ 212 if (error == -ENOATTR) 213 error = 0; 214 } 215 216 if (!error) 217 set_cached_acl(inode, type, acl); 218 return error; 219 } 220 221 static int 222 xfs_set_mode(struct inode *inode, umode_t mode) 223 { 224 int error = 0; 225 226 if (mode != inode->i_mode) { 227 struct iattr iattr; 228 229 iattr.ia_valid = ATTR_MODE | ATTR_CTIME; 230 iattr.ia_mode = mode; 231 iattr.ia_ctime = current_time(inode); 232 233 error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL); 234 } 235 236 return error; 237 } 238 239 int 240 xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 241 { 242 umode_t mode; 243 bool set_mode = false; 244 int error = 0; 245 246 if (!acl) 247 goto set_acl; 248 249 error = -E2BIG; 250 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) 251 return error; 252 253 if (type == ACL_TYPE_ACCESS) { 254 error = posix_acl_update_mode(inode, &mode, &acl); 255 if (error) 256 return error; 257 set_mode = true; 258 } 259 260 set_acl: 261 error = __xfs_set_acl(inode, acl, type); 262 if (error) 263 return error; 264 265 /* 266 * We set the mode after successfully updating the ACL xattr because the 267 * xattr update can fail at ENOSPC and we don't want to change the mode 268 * if the ACL update hasn't been applied. 269 */ 270 if (set_mode) 271 error = xfs_set_mode(inode, mode); 272 273 return error; 274 } 275