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