diff options
Diffstat (limited to 'fs/ext4/acl.c')
| -rw-r--r-- | fs/ext4/acl.c | 551 |
1 files changed, 551 insertions, 0 deletions
diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c new file mode 100644 index 00000000000..9e882546d91 --- /dev/null +++ b/fs/ext4/acl.c @@ -0,0 +1,551 @@ +/* + * linux/fs/ext4/acl.c + * + * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> + */ + +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/capability.h> +#include <linux/fs.h> +#include <linux/ext4_jbd2.h> +#include <linux/ext4_fs.h> +#include "xattr.h" +#include "acl.h" + +/* + * Convert from filesystem to in-memory representation. + */ +static struct posix_acl * +ext4_acl_from_disk(const void *value, size_t size) +{ + const char *end = (char *)value + size; + int n, count; + struct posix_acl *acl; + + if (!value) + return NULL; + if (size < sizeof(ext4_acl_header)) + return ERR_PTR(-EINVAL); + if (((ext4_acl_header *)value)->a_version != + cpu_to_le32(EXT4_ACL_VERSION)) + return ERR_PTR(-EINVAL); + value = (char *)value + sizeof(ext4_acl_header); + count = ext4_acl_count(size); + if (count < 0) + return ERR_PTR(-EINVAL); + if (count == 0) + return NULL; + acl = posix_acl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + for (n=0; n < count; n++) { + ext4_acl_entry *entry = + (ext4_acl_entry *)value; + if ((char *)value + sizeof(ext4_acl_entry_short) > end) + goto fail; + acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); + acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); + switch(acl->a_entries[n].e_tag) { + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + value = (char *)value + + sizeof(ext4_acl_entry_short); + acl->a_entries[n].e_id = ACL_UNDEFINED_ID; + break; + + case ACL_USER: + case ACL_GROUP: + value = (char *)value + sizeof(ext4_acl_entry); + if ((char *)value > end) + goto fail; + acl->a_entries[n].e_id = + le32_to_cpu(entry->e_id); + break; + + default: + goto fail; + } + } + if (value != end) + goto fail; + return acl; + +fail: + posix_acl_release(acl); + return ERR_PTR(-EINVAL); +} + +/* + * Convert from in-memory to filesystem representation. + */ +static void * +ext4_acl_to_disk(const struct posix_acl *acl, size_t *size) +{ + ext4_acl_header *ext_acl; + char *e; + size_t n; + + *size = ext4_acl_size(acl->a_count); + ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count * + sizeof(ext4_acl_entry), GFP_KERNEL); + if (!ext_acl) + return ERR_PTR(-ENOMEM); + ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION); + e = (char *)ext_acl + sizeof(ext4_acl_header); + for (n=0; n < acl->a_count; n++) { + ext4_acl_entry *entry = (ext4_acl_entry *)e; + entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag); + entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm); + switch(acl->a_entries[n].e_tag) { + case ACL_USER: + case ACL_GROUP: + entry->e_id = + cpu_to_le32(acl->a_entries[n].e_id); + e += sizeof(ext4_acl_entry); + break; + + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + e += sizeof(ext4_acl_entry_short); + break; + + default: + goto fail; + } + } + return (char *)ext_acl; + +fail: + kfree(ext_acl); + return ERR_PTR(-EINVAL); +} + +static inline struct posix_acl * +ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl) +{ + struct posix_acl *acl = EXT4_ACL_NOT_CACHED; + + spin_lock(&inode->i_lock); + if (*i_acl != EXT4_ACL_NOT_CACHED) + acl = posix_acl_dup(*i_acl); + spin_unlock(&inode->i_lock); + + return acl; +} + +static inline void +ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl, + struct posix_acl *acl) +{ + spin_lock(&inode->i_lock); + if (*i_acl != EXT4_ACL_NOT_CACHED) + posix_acl_release(*i_acl); + *i_acl = posix_acl_dup(acl); + spin_unlock(&inode->i_lock); +} + +/* + * Inode operation get_posix_acl(). + * + * inode->i_mutex: don't care + */ +static struct posix_acl * +ext4_get_acl(struct inode *inode, int type) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + int name_index; + char *value = NULL; + struct posix_acl *acl; + int retval; + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return NULL; + + switch(type) { + case ACL_TYPE_ACCESS: + acl = ext4_iget_acl(inode, &ei->i_acl); + if (acl != EXT4_ACL_NOT_CACHED) + return acl; + name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; + break; + + case ACL_TYPE_DEFAULT: + acl = ext4_iget_acl(inode, &ei->i_default_acl); + if (acl != EXT4_ACL_NOT_CACHED) + return acl; + name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; + break; + + default: + return ERR_PTR(-EINVAL); + } + retval = ext4_xattr_get(inode, name_index, "", NULL, 0); + if (retval > 0) { + value = kmalloc(retval, GFP_KERNEL); + if (!value) + return ERR_PTR(-ENOMEM); + retval = ext4_xattr_get(inode, name_index, "", value, retval); + } + if (retval > 0) + acl = ext4_acl_from_disk(value, retval); + else if (retval == -ENODATA || retval == -ENOSYS) + acl = NULL; + else + acl = ERR_PTR(retval); + kfree(value); + + if (!IS_ERR(acl)) { + switch(type) { + case ACL_TYPE_ACCESS: + ext4_iset_acl(inode, &ei->i_acl, acl); + break; + + case ACL_TYPE_DEFAULT: + ext4_iset_acl(inode, &ei->i_default_acl, acl); + break; + } + } + return acl; +} + +/* + * Set the access or default ACL of an inode. + * + * inode->i_mutex: down unless called from ext4_new_inode + */ +static int +ext4_set_acl(handle_t *handle, struct inode *inode, int type, + struct posix_acl *acl) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + int name_index; + void *value = NULL; + size_t size = 0; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + + switch(type) { + case ACL_TYPE_ACCESS: + name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; + if (acl) { + mode_t mode = inode->i_mode; + error = posix_acl_equiv_mode(acl, &mode); + if (error < 0) + return error; + else { + inode->i_mode = mode; + ext4_mark_inode_dirty(handle, inode); + if (error == 0) + acl = NULL; + } + } + break; + + case ACL_TYPE_DEFAULT: + name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; + if (!S_ISDIR(inode->i_mode)) + return acl ? -EACCES : 0; + break; + + default: + return -EINVAL; + } + if (acl) { + value = ext4_acl_to_disk(acl, &size); + if (IS_ERR(value)) + return (int)PTR_ERR(value); + } + + error = ext4_xattr_set_handle(handle, inode, name_index, "", + value, size, 0); + + kfree(value); + if (!error) { + switch(type) { + case ACL_TYPE_ACCESS: + ext4_iset_acl(inode, &ei->i_acl, acl); + break; + + case ACL_TYPE_DEFAULT: + ext4_iset_acl(inode, &ei->i_default_acl, acl); + break; + } + } + return error; +} + +static int +ext4_check_acl(struct inode *inode, int mask) +{ + struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS); + + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + int error = posix_acl_permission(inode, acl, mask); + posix_acl_release(acl); + return error; + } + + return -EAGAIN; +} + +int +ext4_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + return generic_permission(inode, mask, ext4_check_acl); +} + +/* + * Initialize the ACLs of a new inode. Called from ext4_new_inode. + * + * dir->i_mutex: down + * inode->i_mutex: up (access to inode is still exclusive) + */ +int +ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) +{ + struct posix_acl *acl = NULL; + int error = 0; + + if (!S_ISLNK(inode->i_mode)) { + if (test_opt(dir->i_sb, POSIX_ACL)) { + acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT); + if (IS_ERR(acl)) + return PTR_ERR(acl); + } + if (!acl) + inode->i_mode &= ~current->fs->umask; + } + if (test_opt(inode->i_sb, POSIX_ACL) && acl) { + struct posix_acl *clone; + mode_t mode; + + if (S_ISDIR(inode->i_mode)) { + error = ext4_set_acl(handle, inode, + ACL_TYPE_DEFAULT, acl); + if (error) + goto cleanup; + } + clone = posix_acl_clone(acl, GFP_KERNEL); + error = -ENOMEM; + if (!clone) + goto cleanup; + + mode = inode->i_mode; + error = posix_acl_create_masq(clone, &mode); + if (error >= 0) { + inode->i_mode = mode; + if (error > 0) { + /* This is an extended ACL */ + error = ext4_set_acl(handle, inode, + ACL_TYPE_ACCESS, clone); + } + } + posix_acl_release(clone); + } +cleanup: + posix_acl_release(acl); + return error; +} + +/* + * Does chmod for an inode that may have an Access Control List. The + * inode->i_mode field must be updated to the desired value by the caller + * before calling this function. + * Returns 0 on success, or a negative error number. + * + * We change the ACL rather than storing some ACL entries in the file + * mode permission bits (which would be more efficient), because that + * would break once additional permissions (like ACL_APPEND, ACL_DELETE + * for directories) are added. There are no more bits available in the + * file mode. + * + * inode->i_mutex: down + */ +int +ext4_acl_chmod(struct inode *inode) +{ + struct posix_acl *acl, *clone; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + if (!test_opt(inode->i_sb, POSIX_ACL)) + return 0; + acl = ext4_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl) || !acl) + return PTR_ERR(acl); + clone = posix_acl_clone(acl, GFP_KERNEL); + posix_acl_release(acl); + if (!clone) + return -ENOMEM; + error = posix_acl_chmod_masq(clone, inode->i_mode); + if (!error) { + handle_t *handle; + int retries = 0; + + retry: + handle = ext4_journal_start(inode, + EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); + if (IS_ERR(handle)) { + error = PTR_ERR(handle); + ext4_std_error(inode->i_sb, error); + goto out; + } + error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone); + ext4_journal_stop(handle); + if (error == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry; + } +out: + posix_acl_release(clone); + return error; +} + +/* + * Extended attribute handlers + */ +static size_t +ext4_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len, + const char *name, size_t name_len) +{ + const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS); + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return 0; + if (list && size <= list_len) + memcpy(list, POSIX_ACL_XATTR_ACCESS, size); + return size; +} + +static size_t +ext4_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len, + const char *name, size_t name_len) +{ + const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT); + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return 0; + if (list && size <= list_len) + memcpy(list, POSIX_ACL_XATTR_DEFAULT, size); + return size; +} + +static int +ext4_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size) +{ + struct posix_acl *acl; + int error; + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return -EOPNOTSUPP; + + acl = ext4_get_acl(inode, type); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl == NULL) + return -ENODATA; + error = posix_acl_to_xattr(acl, buffer, size); + posix_acl_release(acl); + + return error; +} + +static int +ext4_xattr_get_acl_access(struct inode *inode, const char *name, + void *buffer, size_t size) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size); +} + +static int +ext4_xattr_get_acl_default(struct inode *inode, const char *name, + void *buffer, size_t size) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size); +} + +static int +ext4_xattr_set_acl(struct inode *inode, int type, const void *value, + size_t size) +{ + handle_t *handle; + struct posix_acl *acl; + int error, retries = 0; + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return -EOPNOTSUPP; + if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) + return -EPERM; + + if (value) { + acl = posix_acl_from_xattr(value, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + else if (acl) { + error = posix_acl_valid(acl); + if (error) + goto release_and_out; + } + } else + acl = NULL; + +retry: + handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); + if (IS_ERR(handle)) + return PTR_ERR(handle); + error = ext4_set_acl(handle, inode, type, acl); + ext4_journal_stop(handle); + if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry; + +release_and_out: + posix_acl_release(acl); + return error; +} + +static int +ext4_xattr_set_acl_access(struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size); +} + +static int +ext4_xattr_set_acl_default(struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size); +} + +struct xattr_handler ext4_xattr_acl_access_handler = { + .prefix = POSIX_ACL_XATTR_ACCESS, + .list = ext4_xattr_list_acl_access, + .get = ext4_xattr_get_acl_access, + .set = ext4_xattr_set_acl_access, +}; + +struct xattr_handler ext4_xattr_acl_default_handler = { + .prefix = POSIX_ACL_XATTR_DEFAULT, + .list = ext4_xattr_list_acl_default, + .get = ext4_xattr_get_acl_default, + .set = ext4_xattr_set_acl_default, +}; |