[PATCH] Access Control Lists for tmpfs
Add access control lists for tmpfs.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/Makefile b/mm/Makefile
index 60c56c0..6200c6d 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -17,6 +17,7 @@
obj-$(CONFIG_NUMA) += mempolicy.o
obj-$(CONFIG_SPARSEMEM) += sparse.o
obj-$(CONFIG_SHMEM) += shmem.o
+obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_acl.o
obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_SLAB) += slab.o
diff --git a/mm/shmem.c b/mm/shmem.c
index eda907c..b96de69 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -26,6 +26,8 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/generic_acl.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/file.h>
@@ -177,6 +179,7 @@
static struct file_operations shmem_file_operations;
static struct inode_operations shmem_inode_operations;
static struct inode_operations shmem_dir_inode_operations;
+static struct inode_operations shmem_special_inode_operations;
static struct vm_operations_struct shmem_vm_ops;
static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
@@ -637,7 +640,7 @@
struct page *page = NULL;
int error;
- if (attr->ia_valid & ATTR_SIZE) {
+ if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
if (attr->ia_size < inode->i_size) {
/*
* If truncating down to a partial page, then
@@ -670,6 +673,10 @@
error = inode_change_ok(inode, attr);
if (!error)
error = inode_setattr(inode, attr);
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ if (!error && (attr->ia_valid & ATTR_MODE))
+ error = generic_acl_chmod(inode, &shmem_acl_ops);
+#endif
if (page)
page_cache_release(page);
return error;
@@ -1362,6 +1369,7 @@
switch (mode & S_IFMT) {
default:
+ inode->i_op = &shmem_special_inode_operations;
init_special_inode(inode, mode, dev);
break;
case S_IFREG:
@@ -1682,7 +1690,11 @@
iput(inode);
return error;
}
- error = 0;
+ }
+ error = shmem_acl_init(inode, dir);
+ if (error) {
+ iput(inode);
+ return error;
}
if (dir->i_mode & S_ISGID) {
inode->i_gid = dir->i_gid;
@@ -1897,6 +1909,53 @@
.put_link = shmem_put_link,
};
+#ifdef CONFIG_TMPFS_POSIX_ACL
+/**
+ * Superblocks without xattr inode operations will get security.* xattr
+ * support from the VFS "for free". As soon as we have any other xattrs
+ * like ACLs, we also need to implement the security.* handlers at
+ * filesystem level, though.
+ */
+
+static size_t shmem_xattr_security_list(struct inode *inode, char *list,
+ size_t list_len, const char *name,
+ size_t name_len)
+{
+ return security_inode_listsecurity(inode, list, list_len);
+}
+
+static int shmem_xattr_security_get(struct inode *inode, const char *name,
+ void *buffer, size_t size)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return security_inode_getsecurity(inode, name, buffer, size,
+ -EOPNOTSUPP);
+}
+
+static int shmem_xattr_security_set(struct inode *inode, const char *name,
+ const void *value, size_t size, int flags)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return security_inode_setsecurity(inode, name, value, size, flags);
+}
+
+struct xattr_handler shmem_xattr_security_handler = {
+ .prefix = XATTR_SECURITY_PREFIX,
+ .list = shmem_xattr_security_list,
+ .get = shmem_xattr_security_get,
+ .set = shmem_xattr_security_set,
+};
+
+static struct xattr_handler *shmem_xattr_handlers[] = {
+ &shmem_xattr_acl_access_handler,
+ &shmem_xattr_acl_default_handler,
+ &shmem_xattr_security_handler,
+ NULL
+};
+#endif
+
static int shmem_parse_options(char *options, int *mode, uid_t *uid,
gid_t *gid, unsigned long *blocks, unsigned long *inodes,
int *policy, nodemask_t *policy_nodes)
@@ -2094,6 +2153,10 @@
sb->s_magic = TMPFS_MAGIC;
sb->s_op = &shmem_ops;
sb->s_time_gran = 1;
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ sb->s_xattr = shmem_xattr_handlers;
+ sb->s_flags |= MS_POSIXACL;
+#endif
inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
if (!inode)
@@ -2130,6 +2193,7 @@
/* only struct inode is valid if it's an inline symlink */
mpol_free_shared_policy(&SHMEM_I(inode)->policy);
}
+ shmem_acl_destroy_inode(inode);
kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
}
@@ -2141,6 +2205,10 @@
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
inode_init_once(&p->vfs_inode);
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ p->i_acl = NULL;
+ p->i_default_acl = NULL;
+#endif
}
}
@@ -2184,6 +2252,14 @@
.truncate = shmem_truncate,
.setattr = shmem_notify_change,
.truncate_range = shmem_truncate_range,
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+ .permission = shmem_permission,
+#endif
+
};
static struct inode_operations shmem_dir_inode_operations = {
@@ -2198,6 +2274,25 @@
.mknod = shmem_mknod,
.rename = shmem_rename,
#endif
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ .setattr = shmem_notify_change,
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+ .permission = shmem_permission,
+#endif
+};
+
+static struct inode_operations shmem_special_inode_operations = {
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ .setattr = shmem_notify_change,
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+ .permission = shmem_permission,
+#endif
};
static struct super_operations shmem_ops = {
diff --git a/mm/shmem_acl.c b/mm/shmem_acl.c
new file mode 100644
index 0000000..c946bf4
--- /dev/null
+++ b/mm/shmem_acl.c
@@ -0,0 +1,197 @@
+/*
+ * mm/shmem_acl.c
+ *
+ * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/fs.h>
+#include <linux/shmem_fs.h>
+#include <linux/xattr.h>
+#include <linux/generic_acl.h>
+
+/**
+ * shmem_get_acl - generic_acl_operations->getacl() operation
+ */
+static struct posix_acl *
+shmem_get_acl(struct inode *inode, int type)
+{
+ struct posix_acl *acl = NULL;
+
+ spin_lock(&inode->i_lock);
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ acl = posix_acl_dup(SHMEM_I(inode)->i_acl);
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl);
+ break;
+ }
+ spin_unlock(&inode->i_lock);
+
+ return acl;
+}
+
+/**
+ * shmem_get_acl - generic_acl_operations->setacl() operation
+ */
+static void
+shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+ struct posix_acl *free = NULL;
+
+ spin_lock(&inode->i_lock);
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ free = SHMEM_I(inode)->i_acl;
+ SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ free = SHMEM_I(inode)->i_default_acl;
+ SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl);
+ break;
+ }
+ spin_unlock(&inode->i_lock);
+ posix_acl_release(free);
+}
+
+struct generic_acl_operations shmem_acl_ops = {
+ .getacl = shmem_get_acl,
+ .setacl = shmem_set_acl,
+};
+
+/**
+ * shmem_list_acl_access, shmem_get_acl_access, shmem_set_acl_access,
+ * shmem_xattr_acl_access_handler - plumbing code to implement the
+ * system.posix_acl_access xattr using the generic acl functions.
+ */
+
+static size_t
+shmem_list_acl_access(struct inode *inode, char *list, size_t list_size,
+ const char *name, size_t name_len)
+{
+ return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_ACCESS,
+ list, list_size);
+}
+
+static int
+shmem_get_acl_access(struct inode *inode, const char *name, void *buffer,
+ size_t size)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, buffer,
+ size);
+}
+
+static int
+shmem_set_acl_access(struct inode *inode, const char *name, const void *value,
+ size_t size, int flags)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, value,
+ size);
+}
+
+struct xattr_handler shmem_xattr_acl_access_handler = {
+ .prefix = POSIX_ACL_XATTR_ACCESS,
+ .list = shmem_list_acl_access,
+ .get = shmem_get_acl_access,
+ .set = shmem_set_acl_access,
+};
+
+/**
+ * shmem_list_acl_default, shmem_get_acl_default, shmem_set_acl_default,
+ * shmem_xattr_acl_default_handler - plumbing code to implement the
+ * system.posix_acl_default xattr using the generic acl functions.
+ */
+
+static size_t
+shmem_list_acl_default(struct inode *inode, char *list, size_t list_size,
+ const char *name, size_t name_len)
+{
+ return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT,
+ list, list_size);
+}
+
+static int
+shmem_get_acl_default(struct inode *inode, const char *name, void *buffer,
+ size_t size)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, buffer,
+ size);
+}
+
+static int
+shmem_set_acl_default(struct inode *inode, const char *name, const void *value,
+ size_t size, int flags)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, value,
+ size);
+}
+
+struct xattr_handler shmem_xattr_acl_default_handler = {
+ .prefix = POSIX_ACL_XATTR_DEFAULT,
+ .list = shmem_list_acl_default,
+ .get = shmem_get_acl_default,
+ .set = shmem_set_acl_default,
+};
+
+/**
+ * shmem_acl_init - Inizialize the acl(s) of a new inode
+ */
+int
+shmem_acl_init(struct inode *inode, struct inode *dir)
+{
+ return generic_acl_init(inode, dir, &shmem_acl_ops);
+}
+
+/**
+ * shmem_acl_destroy_inode - destroy acls hanging off the in-memory inode
+ *
+ * This is done before destroying the actual inode.
+ */
+
+void
+shmem_acl_destroy_inode(struct inode *inode)
+{
+ if (SHMEM_I(inode)->i_acl)
+ posix_acl_release(SHMEM_I(inode)->i_acl);
+ SHMEM_I(inode)->i_acl = NULL;
+ if (SHMEM_I(inode)->i_default_acl)
+ posix_acl_release(SHMEM_I(inode)->i_default_acl);
+ SHMEM_I(inode)->i_default_acl = NULL;
+}
+
+/**
+ * shmem_check_acl - check_acl() callback for generic_permission()
+ */
+static int
+shmem_check_acl(struct inode *inode, int mask)
+{
+ struct posix_acl *acl = shmem_get_acl(inode, ACL_TYPE_ACCESS);
+
+ if (acl) {
+ int error = posix_acl_permission(inode, acl, mask);
+ posix_acl_release(acl);
+ return error;
+ }
+ return -EAGAIN;
+}
+
+/**
+ * shmem_permission - permission() inode operation
+ */
+int
+shmem_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+ return generic_permission(inode, mask, shmem_check_acl);
+}