linux/fs/reiserfs/xattr_security.c
Jeff Mahoney 6cb4aff0a7 reiserfs: fix oops while creating privroot with selinux enabled
Commit 57fe60df ("reiserfs: add atomic addition of selinux attributes
during inode creation") contains a bug that will cause it to oops when
mounting a file system that didn't previously contain extended attributes
on a system using security.* xattrs.

The issue is that while creating the privroot during mount
reiserfs_security_init calls reiserfs_xattr_jcreate_nblocks which
dereferences the xattr root.  The xattr root doesn't exist, so we get an
oops.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=15309

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:21 -07:00

119 lines
2.9 KiB
C

#include <linux/reiserfs_fs.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/reiserfs_xattr.h>
#include <linux/security.h>
#include <asm/uaccess.h>
static int
security_get(struct dentry *dentry, const char *name, void *buffer, size_t size,
int handler_flags)
{
if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
return -EINVAL;
if (IS_PRIVATE(dentry->d_inode))
return -EPERM;
return reiserfs_xattr_get(dentry->d_inode, name, buffer, size);
}
static int
security_set(struct dentry *dentry, const char *name, const void *buffer,
size_t size, int flags, int handler_flags)
{
if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
return -EINVAL;
if (IS_PRIVATE(dentry->d_inode))
return -EPERM;
return reiserfs_xattr_set(dentry->d_inode, name, buffer, size, flags);
}
static size_t security_list(struct dentry *dentry, char *list, size_t list_len,
const char *name, size_t namelen, int handler_flags)
{
const size_t len = namelen + 1;
if (IS_PRIVATE(dentry->d_inode))
return 0;
if (list && len <= list_len) {
memcpy(list, name, namelen);
list[namelen] = '\0';
}
return len;
}
/* Initializes the security context for a new inode and returns the number
* of blocks needed for the transaction. If successful, reiserfs_security
* must be released using reiserfs_security_free when the caller is done. */
int reiserfs_security_init(struct inode *dir, struct inode *inode,
struct reiserfs_security_handle *sec)
{
int blocks = 0;
int error;
sec->name = NULL;
/* Don't add selinux attributes on xattrs - they'll never get used */
if (IS_PRIVATE(dir))
return 0;
error = security_inode_init_security(inode, dir, &sec->name,
&sec->value, &sec->length);
if (error) {
if (error == -EOPNOTSUPP)
error = 0;
sec->name = NULL;
sec->value = NULL;
sec->length = 0;
return error;
}
if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
blocks = reiserfs_xattr_jcreate_nblocks(inode) +
reiserfs_xattr_nblocks(inode, sec->length);
/* We don't want to count the directories twice if we have
* a default ACL. */
REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
}
return blocks;
}
int reiserfs_security_write(struct reiserfs_transaction_handle *th,
struct inode *inode,
struct reiserfs_security_handle *sec)
{
int error;
if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
return -EINVAL;
error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
sec->length, XATTR_CREATE);
if (error == -ENODATA || error == -EOPNOTSUPP)
error = 0;
return error;
}
void reiserfs_security_free(struct reiserfs_security_handle *sec)
{
kfree(sec->name);
kfree(sec->value);
sec->name = NULL;
sec->value = NULL;
}
struct xattr_handler reiserfs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.get = security_get,
.set = security_set,
.list = security_list,
};