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