| 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_da_format.h" |
| 14 | #include "xfs_da_btree.h" |
| 15 | #include "xfs_attr.h" |
| 16 | #include "xfs_trace.h" |
| 17 | #include "xfs_error.h" |
| 18 | #include "xfs_acl.h" |
| 19 | #include "xfs_trans.h" |
| 20 | #include "xfs_xattr.h" |
| 21 | |
| 22 | #include <linux/posix_acl_xattr.h> |
| 23 | |
| 24 | /* |
| 25 | * Locking scheme: |
| 26 | * - all ACL updates are protected by inode->i_mutex, which is taken before |
| 27 | * calling into this file. |
| 28 | */ |
| 29 | |
| 30 | STATIC struct posix_acl * |
| 31 | xfs_acl_from_disk( |
| 32 | struct xfs_mount *mp, |
| 33 | const struct xfs_acl *aclp, |
| 34 | int len, |
| 35 | int max_entries) |
| 36 | { |
| 37 | struct posix_acl_entry *acl_e; |
| 38 | struct posix_acl *acl; |
| 39 | const struct xfs_acl_entry *ace; |
| 40 | unsigned int count, i; |
| 41 | |
| 42 | if (len < sizeof(*aclp)) { |
| 43 | XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp, |
| 44 | len); |
| 45 | return ERR_PTR(-EFSCORRUPTED); |
| 46 | } |
| 47 | |
| 48 | count = be32_to_cpu(aclp->acl_cnt); |
| 49 | if (count > max_entries || XFS_ACL_SIZE(count) != len) { |
| 50 | XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp, |
| 51 | len); |
| 52 | return ERR_PTR(-EFSCORRUPTED); |
| 53 | } |
| 54 | |
| 55 | acl = posix_acl_alloc(count, GFP_KERNEL); |
| 56 | if (!acl) |
| 57 | return ERR_PTR(-ENOMEM); |
| 58 | |
| 59 | for (i = 0; i < count; i++) { |
| 60 | acl_e = &acl->a_entries[i]; |
| 61 | ace = &aclp->acl_entry[i]; |
| 62 | |
| 63 | /* |
| 64 | * The tag is 32 bits on disk and 16 bits in core. |
| 65 | * |
| 66 | * Because every access to it goes through the core |
| 67 | * format first this is not a problem. |
| 68 | */ |
| 69 | acl_e->e_tag = be32_to_cpu(ace->ae_tag); |
| 70 | acl_e->e_perm = be16_to_cpu(ace->ae_perm); |
| 71 | |
| 72 | switch (acl_e->e_tag) { |
| 73 | case ACL_USER: |
| 74 | acl_e->e_uid = make_kuid(&init_user_ns, |
| 75 | be32_to_cpu(ace->ae_id)); |
| 76 | break; |
| 77 | case ACL_GROUP: |
| 78 | acl_e->e_gid = make_kgid(&init_user_ns, |
| 79 | be32_to_cpu(ace->ae_id)); |
| 80 | break; |
| 81 | case ACL_USER_OBJ: |
| 82 | case ACL_GROUP_OBJ: |
| 83 | case ACL_MASK: |
| 84 | case ACL_OTHER: |
| 85 | break; |
| 86 | default: |
| 87 | goto fail; |
| 88 | } |
| 89 | } |
| 90 | return acl; |
| 91 | |
| 92 | fail: |
| 93 | posix_acl_release(acl); |
| 94 | return ERR_PTR(-EINVAL); |
| 95 | } |
| 96 | |
| 97 | STATIC void |
| 98 | xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) |
| 99 | { |
| 100 | const struct posix_acl_entry *acl_e; |
| 101 | struct xfs_acl_entry *ace; |
| 102 | int i; |
| 103 | |
| 104 | aclp->acl_cnt = cpu_to_be32(acl->a_count); |
| 105 | for (i = 0; i < acl->a_count; i++) { |
| 106 | ace = &aclp->acl_entry[i]; |
| 107 | acl_e = &acl->a_entries[i]; |
| 108 | |
| 109 | ace->ae_tag = cpu_to_be32(acl_e->e_tag); |
| 110 | switch (acl_e->e_tag) { |
| 111 | case ACL_USER: |
| 112 | ace->ae_id = cpu_to_be32( |
| 113 | from_kuid(&init_user_ns, acl_e->e_uid)); |
| 114 | break; |
| 115 | case ACL_GROUP: |
| 116 | ace->ae_id = cpu_to_be32( |
| 117 | from_kgid(&init_user_ns, acl_e->e_gid)); |
| 118 | break; |
| 119 | default: |
| 120 | ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID); |
| 121 | break; |
| 122 | } |
| 123 | |
| 124 | ace->ae_perm = cpu_to_be16(acl_e->e_perm); |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | struct posix_acl * |
| 129 | xfs_get_acl(struct inode *inode, int type, bool rcu) |
| 130 | { |
| 131 | struct xfs_inode *ip = XFS_I(inode); |
| 132 | struct xfs_mount *mp = ip->i_mount; |
| 133 | struct posix_acl *acl = NULL; |
| 134 | struct xfs_da_args args = { |
| 135 | .dp = ip, |
| 136 | .attr_filter = XFS_ATTR_ROOT, |
| 137 | .valuelen = XFS_ACL_MAX_SIZE(mp), |
| 138 | }; |
| 139 | int error; |
| 140 | |
| 141 | if (rcu) |
| 142 | return ERR_PTR(-ECHILD); |
| 143 | |
| 144 | trace_xfs_get_acl(ip); |
| 145 | |
| 146 | switch (type) { |
| 147 | case ACL_TYPE_ACCESS: |
| 148 | args.name = SGI_ACL_FILE; |
| 149 | break; |
| 150 | case ACL_TYPE_DEFAULT: |
| 151 | args.name = SGI_ACL_DEFAULT; |
| 152 | break; |
| 153 | default: |
| 154 | BUG(); |
| 155 | } |
| 156 | args.namelen = strlen(args.name); |
| 157 | |
| 158 | /* |
| 159 | * If the attribute doesn't exist make sure we have a negative cache |
| 160 | * entry, for any other error assume it is transient. |
| 161 | */ |
| 162 | error = xfs_attr_get(&args); |
| 163 | if (!error) { |
| 164 | acl = xfs_acl_from_disk(mp, args.value, args.valuelen, |
| 165 | XFS_ACL_MAX_ENTRIES(mp)); |
| 166 | } else if (error != -ENOATTR) { |
| 167 | acl = ERR_PTR(error); |
| 168 | } |
| 169 | |
| 170 | kvfree(args.value); |
| 171 | return acl; |
| 172 | } |
| 173 | |
| 174 | int |
| 175 | __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) |
| 176 | { |
| 177 | struct xfs_inode *ip = XFS_I(inode); |
| 178 | struct xfs_da_args args = { |
| 179 | .dp = ip, |
| 180 | .attr_filter = XFS_ATTR_ROOT, |
| 181 | }; |
| 182 | int error; |
| 183 | |
| 184 | switch (type) { |
| 185 | case ACL_TYPE_ACCESS: |
| 186 | args.name = SGI_ACL_FILE; |
| 187 | break; |
| 188 | case ACL_TYPE_DEFAULT: |
| 189 | if (!S_ISDIR(inode->i_mode)) |
| 190 | return acl ? -EACCES : 0; |
| 191 | args.name = SGI_ACL_DEFAULT; |
| 192 | break; |
| 193 | default: |
| 194 | return -EINVAL; |
| 195 | } |
| 196 | args.namelen = strlen(args.name); |
| 197 | |
| 198 | if (acl) { |
| 199 | args.valuelen = XFS_ACL_SIZE(acl->a_count); |
| 200 | args.value = kvzalloc(args.valuelen, GFP_KERNEL); |
| 201 | if (!args.value) |
| 202 | return -ENOMEM; |
| 203 | xfs_acl_to_disk(args.value, acl); |
| 204 | error = xfs_attr_change(&args, XFS_ATTRUPDATE_UPSERT); |
| 205 | kvfree(args.value); |
| 206 | } else { |
| 207 | error = xfs_attr_change(&args, XFS_ATTRUPDATE_REMOVE); |
| 208 | /* |
| 209 | * If the attribute didn't exist to start with that's fine. |
| 210 | */ |
| 211 | if (error == -ENOATTR) |
| 212 | error = 0; |
| 213 | } |
| 214 | |
| 215 | if (!error) |
| 216 | set_cached_acl(inode, type, acl); |
| 217 | return error; |
| 218 | } |
| 219 | |
| 220 | static int |
| 221 | xfs_acl_set_mode( |
| 222 | struct inode *inode, |
| 223 | umode_t mode) |
| 224 | { |
| 225 | struct xfs_inode *ip = XFS_I(inode); |
| 226 | struct xfs_mount *mp = ip->i_mount; |
| 227 | struct xfs_trans *tp; |
| 228 | int error; |
| 229 | |
| 230 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); |
| 231 | if (error) |
| 232 | return error; |
| 233 | |
| 234 | xfs_ilock(ip, XFS_ILOCK_EXCL); |
| 235 | xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); |
| 236 | inode->i_mode = mode; |
| 237 | inode_set_ctime_current(inode); |
| 238 | xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
| 239 | |
| 240 | if (xfs_has_wsync(mp)) |
| 241 | xfs_trans_set_sync(tp); |
| 242 | return xfs_trans_commit(tp); |
| 243 | } |
| 244 | |
| 245 | int |
| 246 | xfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, |
| 247 | struct posix_acl *acl, int type) |
| 248 | { |
| 249 | umode_t mode; |
| 250 | bool set_mode = false; |
| 251 | int error = 0; |
| 252 | struct inode *inode = d_inode(dentry); |
| 253 | |
| 254 | if (!acl) |
| 255 | goto set_acl; |
| 256 | |
| 257 | error = -E2BIG; |
| 258 | if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) |
| 259 | return error; |
| 260 | |
| 261 | if (type == ACL_TYPE_ACCESS) { |
| 262 | error = posix_acl_update_mode(idmap, inode, &mode, &acl); |
| 263 | if (error) |
| 264 | return error; |
| 265 | set_mode = true; |
| 266 | } |
| 267 | |
| 268 | set_acl: |
| 269 | /* |
| 270 | * We set the mode after successfully updating the ACL xattr because the |
| 271 | * xattr update can fail at ENOSPC and we don't want to change the mode |
| 272 | * if the ACL update hasn't been applied. |
| 273 | */ |
| 274 | error = __xfs_set_acl(inode, acl, type); |
| 275 | if (!error && set_mode && mode != inode->i_mode) |
| 276 | error = xfs_acl_set_mode(inode, mode); |
| 277 | return error; |
| 278 | } |
| 279 | |
| 280 | /* |
| 281 | * Invalidate any cached ACLs if the user has bypassed the ACL interface. |
| 282 | * We don't validate the content whatsoever so it is caller responsibility to |
| 283 | * provide data in valid format and ensure i_mode is consistent. |
| 284 | */ |
| 285 | void |
| 286 | xfs_forget_acl( |
| 287 | struct inode *inode, |
| 288 | const char *name) |
| 289 | { |
| 290 | if (!strcmp(name, SGI_ACL_FILE)) |
| 291 | forget_cached_acl(inode, ACL_TYPE_ACCESS); |
| 292 | else if (!strcmp(name, SGI_ACL_DEFAULT)) |
| 293 | forget_cached_acl(inode, ACL_TYPE_DEFAULT); |
| 294 | } |