mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-17 03:48:11 +07:00
32c3cf028e
Introduce a helper function which prepares to look up the given dentry in the given directory. If the directory is encrypted, it handles loading the directory's encryption key, setting the dentry's ->d_op to fscrypt_d_ops, and setting DCACHE_ENCRYPTED_WITH_KEY if the directory's encryption key is available. Note: once all filesystems switch over to this, we'll be able to move fscrypt_d_ops and fscrypt_set_encrypted_dentry() to fscrypt_private.h. Acked-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/*
|
|
* fs/crypto/hooks.c
|
|
*
|
|
* Encryption hooks for higher-level filesystem operations.
|
|
*/
|
|
|
|
#include <linux/ratelimit.h>
|
|
#include "fscrypt_private.h"
|
|
|
|
/**
|
|
* fscrypt_file_open - prepare to open a possibly-encrypted regular file
|
|
* @inode: the inode being opened
|
|
* @filp: the struct file being set up
|
|
*
|
|
* Currently, an encrypted regular file can only be opened if its encryption key
|
|
* is available; access to the raw encrypted contents is not supported.
|
|
* Therefore, we first set up the inode's encryption key (if not already done)
|
|
* and return an error if it's unavailable.
|
|
*
|
|
* We also verify that if the parent directory (from the path via which the file
|
|
* is being opened) is encrypted, then the inode being opened uses the same
|
|
* encryption policy. This is needed as part of the enforcement that all files
|
|
* in an encrypted directory tree use the same encryption policy, as a
|
|
* protection against certain types of offline attacks. Note that this check is
|
|
* needed even when opening an *unencrypted* file, since it's forbidden to have
|
|
* an unencrypted file in an encrypted directory.
|
|
*
|
|
* Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
|
|
*/
|
|
int fscrypt_file_open(struct inode *inode, struct file *filp)
|
|
{
|
|
int err;
|
|
struct dentry *dir;
|
|
|
|
err = fscrypt_require_key(inode);
|
|
if (err)
|
|
return err;
|
|
|
|
dir = dget_parent(file_dentry(filp));
|
|
if (IS_ENCRYPTED(d_inode(dir)) &&
|
|
!fscrypt_has_permitted_context(d_inode(dir), inode)) {
|
|
pr_warn_ratelimited("fscrypt: inconsistent encryption contexts: %lu/%lu",
|
|
d_inode(dir)->i_ino, inode->i_ino);
|
|
err = -EPERM;
|
|
}
|
|
dput(dir);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(fscrypt_file_open);
|
|
|
|
int __fscrypt_prepare_link(struct inode *inode, struct inode *dir)
|
|
{
|
|
int err;
|
|
|
|
err = fscrypt_require_key(dir);
|
|
if (err)
|
|
return err;
|
|
|
|
if (!fscrypt_has_permitted_context(dir, inode))
|
|
return -EPERM;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__fscrypt_prepare_link);
|
|
|
|
int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
|
|
struct inode *new_dir, struct dentry *new_dentry,
|
|
unsigned int flags)
|
|
{
|
|
int err;
|
|
|
|
err = fscrypt_require_key(old_dir);
|
|
if (err)
|
|
return err;
|
|
|
|
err = fscrypt_require_key(new_dir);
|
|
if (err)
|
|
return err;
|
|
|
|
if (old_dir != new_dir) {
|
|
if (IS_ENCRYPTED(new_dir) &&
|
|
!fscrypt_has_permitted_context(new_dir,
|
|
d_inode(old_dentry)))
|
|
return -EPERM;
|
|
|
|
if ((flags & RENAME_EXCHANGE) &&
|
|
IS_ENCRYPTED(old_dir) &&
|
|
!fscrypt_has_permitted_context(old_dir,
|
|
d_inode(new_dentry)))
|
|
return -EPERM;
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__fscrypt_prepare_rename);
|
|
|
|
int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
int err = fscrypt_get_encryption_info(dir);
|
|
|
|
if (err)
|
|
return err;
|
|
|
|
if (fscrypt_has_encryption_key(dir)) {
|
|
spin_lock(&dentry->d_lock);
|
|
dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY;
|
|
spin_unlock(&dentry->d_lock);
|
|
}
|
|
|
|
d_set_d_op(dentry, &fscrypt_d_ops);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
|