linux-stable/fs/cifs/cifsfs.h
David Disseldorp 1e144b6820 cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL
commit 179a88a855 upstream.

When compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount
is NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to
S_AUTOMOUNT and corresponding dentry flags is retained regardless of
CONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in
VFS follow_automount() when traversing a DFS referral link:
  BUG: kernel NULL pointer dereference, address: 0000000000000000
  ...
  Call Trace:
   <TASK>
   __traverse_mounts+0xb5/0x220
   ? cifs_revalidate_mapping+0x65/0xc0 [cifs]
   step_into+0x195/0x610
   ? lookup_fast+0xe2/0xf0
   path_lookupat+0x64/0x140
   filename_lookup+0xc2/0x140
   ? __create_object+0x299/0x380
   ? kmem_cache_alloc+0x119/0x220
   ? user_path_at_empty+0x31/0x50
   user_path_at_empty+0x31/0x50
   __x64_sys_chdir+0x2a/0xd0
   ? exit_to_user_mode_prepare+0xca/0x100
   do_syscall_64+0x42/0x90
   entry_SYSCALL_64_after_hwframe+0x72/0xdc

This fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler
when CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to
avoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This
approach was chosen as it provides more control over the error path.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Cc: stable@vger.kernel.org
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:12:41 +02:00

161 lines
6.4 KiB
C

/* SPDX-License-Identifier: LGPL-2.1 */
/*
*
* Copyright (c) International Business Machines Corp., 2002, 2007
* Author(s): Steve French (sfrench@us.ibm.com)
*
*/
#ifndef _CIFSFS_H
#define _CIFSFS_H
#include <linux/hash.h>
#define ROOT_I 2
/*
* ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
* so that it will fit. We use hash_64 to convert the value to 31 bits, and
* then add 1, to ensure that we don't end up with a 0 as the value.
*/
static inline ino_t
cifs_uniqueid_to_ino_t(u64 fileid)
{
if ((sizeof(ino_t)) < (sizeof(u64)))
return (ino_t)hash_64(fileid, (sizeof(ino_t) * 8) - 1) + 1;
return (ino_t)fileid;
}
static inline void cifs_set_time(struct dentry *dentry, unsigned long time)
{
dentry->d_fsdata = (void *) time;
}
static inline unsigned long cifs_get_time(struct dentry *dentry)
{
return (unsigned long) dentry->d_fsdata;
}
extern struct file_system_type cifs_fs_type, smb3_fs_type;
extern const struct address_space_operations cifs_addr_ops;
extern const struct address_space_operations cifs_addr_ops_smallbuf;
/* Functions related to super block operations */
extern void cifs_sb_active(struct super_block *sb);
extern void cifs_sb_deactive(struct super_block *sb);
/* Functions related to inodes */
extern const struct inode_operations cifs_dir_inode_ops;
extern struct inode *cifs_root_iget(struct super_block *);
extern int cifs_create(struct user_namespace *, struct inode *,
struct dentry *, umode_t, bool excl);
extern int cifs_atomic_open(struct inode *, struct dentry *,
struct file *, unsigned, umode_t);
extern struct dentry *cifs_lookup(struct inode *, struct dentry *,
unsigned int);
extern int cifs_unlink(struct inode *dir, struct dentry *dentry);
extern int cifs_hardlink(struct dentry *, struct inode *, struct dentry *);
extern int cifs_mknod(struct user_namespace *, struct inode *, struct dentry *,
umode_t, dev_t);
extern int cifs_mkdir(struct user_namespace *, struct inode *, struct dentry *,
umode_t);
extern int cifs_rmdir(struct inode *, struct dentry *);
extern int cifs_rename2(struct user_namespace *, struct inode *,
struct dentry *, struct inode *, struct dentry *,
unsigned int);
extern int cifs_revalidate_file_attr(struct file *filp);
extern int cifs_revalidate_dentry_attr(struct dentry *);
extern int cifs_revalidate_file(struct file *filp);
extern int cifs_revalidate_dentry(struct dentry *);
extern int cifs_invalidate_mapping(struct inode *inode);
extern int cifs_revalidate_mapping(struct inode *inode);
extern int cifs_zap_mapping(struct inode *inode);
extern int cifs_getattr(struct user_namespace *, const struct path *,
struct kstat *, u32, unsigned int);
extern int cifs_setattr(struct user_namespace *, struct dentry *,
struct iattr *);
extern int cifs_fiemap(struct inode *, struct fiemap_extent_info *, u64 start,
u64 len);
extern const struct inode_operations cifs_file_inode_ops;
extern const struct inode_operations cifs_symlink_inode_ops;
extern const struct inode_operations cifs_dfs_referral_inode_operations;
/* Functions related to files and directories */
extern const struct file_operations cifs_file_ops;
extern const struct file_operations cifs_file_direct_ops; /* if directio mnt */
extern const struct file_operations cifs_file_strict_ops; /* if strictio mnt */
extern const struct file_operations cifs_file_nobrl_ops; /* no brlocks */
extern const struct file_operations cifs_file_direct_nobrl_ops;
extern const struct file_operations cifs_file_strict_nobrl_ops;
extern int cifs_open(struct inode *inode, struct file *file);
extern int cifs_close(struct inode *inode, struct file *file);
extern int cifs_closedir(struct inode *inode, struct file *file);
extern ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to);
extern ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to);
extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to);
extern ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from);
extern ssize_t cifs_direct_writev(struct kiocb *iocb, struct iov_iter *from);
extern ssize_t cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from);
extern int cifs_flock(struct file *pfile, int cmd, struct file_lock *plock);
extern int cifs_lock(struct file *, int, struct file_lock *);
extern int cifs_fsync(struct file *, loff_t, loff_t, int);
extern int cifs_strict_fsync(struct file *, loff_t, loff_t, int);
extern int cifs_flush(struct file *, fl_owner_t id);
extern int cifs_file_mmap(struct file *file, struct vm_area_struct *vma);
extern int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma);
extern const struct file_operations cifs_dir_ops;
extern int cifs_dir_open(struct inode *inode, struct file *file);
extern int cifs_readdir(struct file *file, struct dir_context *ctx);
/* Functions related to dir entries */
extern const struct dentry_operations cifs_dentry_ops;
extern const struct dentry_operations cifs_ci_dentry_ops;
#ifdef CONFIG_CIFS_DFS_UPCALL
extern struct vfsmount *cifs_dfs_d_automount(struct path *path);
#else
static inline struct vfsmount *cifs_dfs_d_automount(struct path *path)
{
return ERR_PTR(-EREMOTE);
}
#endif
/* Functions related to symlinks */
extern const char *cifs_get_link(struct dentry *, struct inode *,
struct delayed_call *);
extern int cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
struct dentry *direntry, const char *symname);
#ifdef CONFIG_CIFS_XATTR
extern const struct xattr_handler *cifs_xattr_handlers[];
extern ssize_t cifs_listxattr(struct dentry *, char *, size_t);
#else
# define cifs_xattr_handlers NULL
# define cifs_listxattr NULL
#endif
extern ssize_t cifs_file_copychunk_range(unsigned int xid,
struct file *src_file, loff_t off,
struct file *dst_file, loff_t destoff,
size_t len, unsigned int flags);
extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
extern void cifs_setsize(struct inode *inode, loff_t offset);
extern int cifs_truncate_page(struct address_space *mapping, loff_t from);
struct smb3_fs_context;
extern struct dentry *cifs_smb3_do_mount(struct file_system_type *fs_type,
int flags, struct smb3_fs_context *ctx);
#ifdef CONFIG_CIFS_NFSD_EXPORT
extern const struct export_operations cifs_export_ops;
#endif /* CONFIG_CIFS_NFSD_EXPORT */
/* when changing internal version - update following two lines at same time */
#define SMB3_PRODUCT_BUILD 41
#define CIFS_VERSION "2.41"
#endif /* _CIFSFS_H */