linux-hardened/fs/ext4/xattr_security.c
Andreas Gruenbacher 98e9cb5711 vfs: Distinguish between full xattr names and proper prefixes
Add an additional "name" field to struct xattr_handler.  When the name
is set, the handler matches attributes with exactly that name.  When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-06 21:33:52 -05:00

81 lines
2 KiB
C

/*
* linux/fs/ext4/xattr_security.c
* Handler for storing security labels as extended attributes.
*/
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/slab.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
static size_t
ext4_xattr_security_list(const struct xattr_handler *handler,
struct dentry *dentry, char *list, size_t list_size,
const char *name, size_t name_len)
{
const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
const size_t total_len = prefix_len + name_len + 1;
if (list && total_len <= list_size) {
memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
memcpy(list+prefix_len, name, name_len);
list[prefix_len + name_len] = '\0';
}
return total_len;
}
static int
ext4_xattr_security_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
name, buffer, size);
}
static int
ext4_xattr_security_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
name, value, size, flags);
}
static int
ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
void *fs_info)
{
const struct xattr *xattr;
handle_t *handle = fs_info;
int err = 0;
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
err = ext4_xattr_set_handle(handle, inode,
EXT4_XATTR_INDEX_SECURITY,
xattr->name, xattr->value,
xattr->value_len, 0);
if (err < 0)
break;
}
return err;
}
int
ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
const struct qstr *qstr)
{
return security_inode_init_security(inode, dir, qstr,
&ext4_initxattrs, handle);
}
const struct xattr_handler ext4_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.list = ext4_xattr_security_list,
.get = ext4_xattr_security_get,
.set = ext4_xattr_security_set,
};