Commit 39f0247d authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Linus Torvalds

[PATCH] Access Control Lists for tmpfs

Add access control lists for tmpfs.
Signed-off-by: default avatarAndreas Gruenbacher <agruen@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f0c8bd16
......@@ -881,6 +881,19 @@ config TMPFS
See <file:Documentation/filesystems/tmpfs.txt> for details.
config TMPFS_POSIX_ACL
bool "Tmpfs POSIX Access Control Lists"
depends on TMPFS
select GENERIC_ACL
help
POSIX Access Control Lists (ACLs) support permissions for users and
groups beyond the owner/group/world scheme.
To learn more about Access Control Lists, visit the POSIX ACLs for
Linux website <http://acl.bestbits.at/>.
If you don't know what Access Control Lists are, say N.
config HUGETLBFS
bool "HugeTLB file system support"
depends X86 || IA64 || PPC64 || SPARC64 || SUPERH || BROKEN
......
......@@ -19,6 +19,10 @@ struct shmem_inode_info {
swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
struct list_head swaplist; /* chain of maybes on swap */
struct inode vfs_inode;
#ifdef CONFIG_TMPFS_POSIX_ACL
struct posix_acl *i_acl;
struct posix_acl *i_default_acl;
#endif
};
struct shmem_sb_info {
......@@ -36,4 +40,24 @@ static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
return container_of(inode, struct shmem_inode_info, vfs_inode);
}
#ifdef CONFIG_TMPFS_POSIX_ACL
int shmem_permission(struct inode *, int, struct nameidata *);
int shmem_acl_init(struct inode *, struct inode *);
void shmem_acl_destroy_inode(struct inode *);
extern struct xattr_handler shmem_xattr_acl_access_handler;
extern struct xattr_handler shmem_xattr_acl_default_handler;
extern struct generic_acl_operations shmem_acl_ops;
#else
static inline int shmem_acl_init(struct inode *inode, struct inode *dir)
{
return 0;
}
static inline void shmem_acl_destroy_inode(struct inode *inode)
{
}
#endif /* CONFIG_TMPFS_POSIX_ACL */
#endif
......@@ -17,6 +17,7 @@ obj-$(CONFIG_HUGETLBFS) += hugetlb.o
obj-$(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
......
......@@ -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 const struct address_space_operations shmem_aops;
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 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
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 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
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 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
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 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
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 @@ static struct inode_operations shmem_symlink_inode_operations = {
.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 @@ static int shmem_fill_super(struct super_block *sb,
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 @@ static void shmem_destroy_inode(struct inode *inode)
/* 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 @@ static void init_once(void *foo, struct kmem_cache *cachep,
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 @@ static struct inode_operations shmem_inode_operations = {
.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 @@ static struct inode_operations shmem_dir_inode_operations = {
.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 = {
......
/*
* 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);
}
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