diff options
| -rw-r--r-- | fs/crypto/keyring.c | 63 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 7 | ||||
| -rw-r--r-- | include/uapi/linux/fscrypt.h | 15 |
3 files changed, 85 insertions, 0 deletions
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index c3423f0edc70..8c94c2fa0c13 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -11,6 +11,7 @@ * * - FS_IOC_ADD_ENCRYPTION_KEY * - FS_IOC_REMOVE_ENCRYPTION_KEY + * - FS_IOC_GET_ENCRYPTION_KEY_STATUS * * See the "User API" section of Documentation/filesystems/fscrypt.rst for more * information about these ioctls. @@ -538,6 +539,68 @@ int fscrypt_ioctl_remove_key(struct file *filp, void __user *_uarg) } EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key); +/* + * Retrieve the status of an fscrypt master encryption key. + * + * We set ->status to indicate whether the key is absent, present, or + * incompletely removed. "Incompletely removed" means that the master key + * secret has been removed, but some files which had been unlocked with it are + * still in use. This field allows applications to easily determine the state + * of an encrypted directory without using a hack such as trying to open a + * regular file in it (which can confuse the "incompletely removed" state with + * absent or present). + * + * For more details, see the "FS_IOC_GET_ENCRYPTION_KEY_STATUS" section of + * Documentation/filesystems/fscrypt.rst. + */ +int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg) +{ + struct super_block *sb = file_inode(filp)->i_sb; + struct fscrypt_get_key_status_arg arg; + struct key *key; + struct fscrypt_master_key *mk; + int err; + + if (copy_from_user(&arg, uarg, sizeof(arg))) + return -EFAULT; + + if (!valid_key_spec(&arg.key_spec)) + return -EINVAL; + + if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved))) + return -EINVAL; + + memset(arg.__out_reserved, 0, sizeof(arg.__out_reserved)); + + key = fscrypt_find_master_key(sb, &arg.key_spec); + if (IS_ERR(key)) { + if (key != ERR_PTR(-ENOKEY)) + return PTR_ERR(key); + arg.status = FSCRYPT_KEY_STATUS_ABSENT; + err = 0; + goto out; + } + mk = key->payload.data[0]; + down_read(&key->sem); + + if (!is_master_key_secret_present(&mk->mk_secret)) { + arg.status = FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED; + err = 0; + goto out_release_key; + } + + arg.status = FSCRYPT_KEY_STATUS_PRESENT; + err = 0; +out_release_key: + up_read(&key->sem); + key_put(key); +out: + if (!err && copy_to_user(uarg, &arg, sizeof(arg))) + err = -EFAULT; + return err; +} +EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_key_status); + int __init fscrypt_init_keyring(void) { return register_key_type(&key_type_fscrypt); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index b494c5f9c01f..6628d09585bd 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -142,6 +142,7 @@ extern int fscrypt_inherit_context(struct inode *, struct inode *, extern void fscrypt_sb_free(struct super_block *sb); extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); extern int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg); +extern int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg); /* keysetup.c */ extern int fscrypt_get_encryption_info(struct inode *); @@ -388,6 +389,12 @@ static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg) return -EOPNOTSUPP; } +static inline int fscrypt_ioctl_get_key_status(struct file *filp, + void __user *arg) +{ + return -EOPNOTSUPP; +} + /* keysetup.c */ static inline int fscrypt_get_encryption_info(struct inode *inode) { diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index 07f37a27a944..ed5995b15016 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -84,11 +84,26 @@ struct fscrypt_remove_key_arg { __u32 __reserved[5]; }; +/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */ +struct fscrypt_get_key_status_arg { + /* input */ + struct fscrypt_key_specifier key_spec; + __u32 __reserved[6]; + + /* output */ +#define FSCRYPT_KEY_STATUS_ABSENT 1 +#define FSCRYPT_KEY_STATUS_PRESENT 2 +#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3 + __u32 status; + __u32 __out_reserved[15]; +}; + #define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy) #define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16]) #define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy) #define FS_IOC_ADD_ENCRYPTION_KEY _IOWR('f', 23, struct fscrypt_add_key_arg) #define FS_IOC_REMOVE_ENCRYPTION_KEY _IOWR('f', 24, struct fscrypt_remove_key_arg) +#define FS_IOC_GET_ENCRYPTION_KEY_STATUS _IOWR('f', 26, struct fscrypt_get_key_status_arg) /**********************************************************************/ |