linux/fs/reiserfs/xattr_security.c
Tetsuo Handa d031f4e8b4 reiserfs: Initialize sec->length in reiserfs_security_init().
syzbot is reporting that sec->length is not initialized.

Since security_inode_init_security() returns 0 when initxattrs is provided
but call_int_hook(inode_init_security) returned -EOPNOTSUPP, control will
reach to "if (sec->length && ...) {" without initializing sec->length.

Reported-by: syzbot <syzbot+00a3779539a23cbee38c@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=00a3779539a23cbee38c
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 52ca4b6435 ("reiserfs: Switch to security_inode_init_security()")
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-05-25 17:44:44 -04:00

128 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "reiserfs.h"
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/slab.h>
#include "xattr.h"
#include <linux/security.h>
#include <linux/uaccess.h>
static int
security_get(const struct xattr_handler *handler, struct dentry *unused,
struct inode *inode, const char *name, void *buffer, size_t size)
{
if (IS_PRIVATE(inode))
return -EPERM;
return reiserfs_xattr_get(inode, xattr_full_name(handler, name),
buffer, size);
}
static int
security_set(const struct xattr_handler *handler,
struct mnt_idmap *idmap, struct dentry *unused,
struct inode *inode, const char *name, const void *buffer,
size_t size, int flags)
{
if (IS_PRIVATE(inode))
return -EPERM;
return reiserfs_xattr_set(inode,
xattr_full_name(handler, name),
buffer, size, flags);
}
static bool security_list(struct dentry *dentry)
{
return !IS_PRIVATE(d_inode(dentry));
}
static int
reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
void *fs_info)
{
struct reiserfs_security_handle *sec = fs_info;
sec->value = kmemdup(xattr_array->value, xattr_array->value_len,
GFP_KERNEL);
if (!sec->value)
return -ENOMEM;
sec->name = xattr_array->name;
sec->length = xattr_array->value_len;
return 0;
}
/* 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,
const struct qstr *qstr,
struct reiserfs_security_handle *sec)
{
int blocks = 0;
int error;
sec->name = NULL;
sec->value = NULL;
sec->length = 0;
/* 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, qstr,
&reiserfs_initxattrs, sec);
if (error) {
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)
{
char xattr_name[XATTR_NAME_MAX + 1] = XATTR_SECURITY_PREFIX;
int error;
if (XATTR_SECURITY_PREFIX_LEN + strlen(sec->name) > XATTR_NAME_MAX)
return -EINVAL;
strlcat(xattr_name, sec->name, sizeof(xattr_name));
error = reiserfs_xattr_set_handle(th, inode, xattr_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->value);
sec->name = NULL;
sec->value = NULL;
}
const struct xattr_handler reiserfs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.get = security_get,
.set = security_set,
.list = security_list,
};