eCryptfs: allow userspace messaging to be disabled
When the userspace messaging (for the less common case of userspace key wrap/unwrap via ecryptfsd) is not needed, allow eCryptfs to build with it removed. This saves on kernel code size and reduces potential attack surface by removing the /dev/ecryptfs node. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tyler Hicks <tyhicks@canonical.com>wifi-calibration
Kees Cook
Tyler Hicks
parent
1111eae90f
commit
290502bee2
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@ -12,3 +12,11 @@ config ECRYPT_FS
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To compile this file system support as a module, choose M here: the
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module will be called ecryptfs.
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config ECRYPT_FS_MESSAGING
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bool "Enable notifications for userspace key wrap/unwrap"
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depends on ECRYPT_FS
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help
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Enables the /dev/ecryptfs entry for use by ecryptfsd. This allows
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for userspace to wrap/unwrap file encryption keys by other
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backends, like OpenSSL.
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@ -1,7 +1,10 @@
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#
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# Makefile for the Linux 2.6 eCryptfs
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# Makefile for the Linux eCryptfs
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#
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obj-$(CONFIG_ECRYPT_FS) += ecryptfs.o
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ecryptfs-objs := dentry.o file.o inode.o main.o super.o mmap.o read_write.o crypto.o keystore.o messaging.o miscdev.o kthread.o debug.o
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ecryptfs-y := dentry.o file.o inode.o main.o super.o mmap.o read_write.o \
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crypto.o keystore.o kthread.o debug.o
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ecryptfs-$(CONFIG_ECRYPT_FS_MESSAGING) += messaging.o miscdev.o
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@ -172,6 +172,19 @@ ecryptfs_get_key_payload_data(struct key *key)
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#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE 24
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#define ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN (18 + 1 + 4 + 1 + 32)
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#ifdef CONFIG_ECRYPT_FS_MESSAGING
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# define ECRYPTFS_VERSIONING_MASK_MESSAGING (ECRYPTFS_VERSIONING_DEVMISC \
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| ECRYPTFS_VERSIONING_PUBKEY)
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#else
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# define ECRYPTFS_VERSIONING_MASK_MESSAGING 0
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#endif
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#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
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| ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
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| ECRYPTFS_VERSIONING_XATTR \
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| ECRYPTFS_VERSIONING_MULTKEY \
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| ECRYPTFS_VERSIONING_MASK_MESSAGING \
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| ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION)
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struct ecryptfs_key_sig {
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struct list_head crypt_stat_list;
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char keysig[ECRYPTFS_SIG_SIZE_HEX + 1];
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@ -399,7 +412,9 @@ struct ecryptfs_daemon {
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struct hlist_node euid_chain;
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};
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#ifdef CONFIG_ECRYPT_FS_MESSAGING
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extern struct mutex ecryptfs_daemon_hash_mux;
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#endif
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static inline size_t
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ecryptfs_lower_header_size(struct ecryptfs_crypt_stat *crypt_stat)
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@ -604,6 +619,7 @@ int
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ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
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size_t size, int flags);
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int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode);
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#ifdef CONFIG_ECRYPT_FS_MESSAGING
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int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
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struct ecryptfs_message *msg, u32 seq);
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int ecryptfs_send_message(char *data, int data_len,
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@ -612,6 +628,24 @@ int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
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struct ecryptfs_message **emsg);
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int ecryptfs_init_messaging(void);
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void ecryptfs_release_messaging(void);
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#else
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static inline int ecryptfs_init_messaging(void)
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{
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return 0;
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}
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static inline void ecryptfs_release_messaging(void)
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{ }
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static inline int ecryptfs_send_message(char *data, int data_len,
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struct ecryptfs_msg_ctx **msg_ctx)
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{
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return -ENOTCONN;
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}
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static inline int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
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struct ecryptfs_message **emsg)
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{
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return -ENOMSG;
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}
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#endif
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void
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ecryptfs_write_header_metadata(char *virt,
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@ -649,12 +683,11 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
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size_t offset_in_page, size_t size,
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struct inode *ecryptfs_inode);
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struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index);
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int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon);
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int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon);
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int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
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size_t *length_size);
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int ecryptfs_write_packet_length(char *dest, size_t size,
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size_t *packet_size_length);
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#ifdef CONFIG_ECRYPT_FS_MESSAGING
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int ecryptfs_init_ecryptfs_miscdev(void);
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void ecryptfs_destroy_ecryptfs_miscdev(void);
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int ecryptfs_send_miscdev(char *data, size_t data_size,
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@ -663,6 +696,9 @@ int ecryptfs_send_miscdev(char *data, size_t data_size,
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void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx);
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int
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ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file);
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int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon);
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int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon);
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#endif
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int ecryptfs_init_kthread(void);
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void ecryptfs_destroy_kthread(void);
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int ecryptfs_privileged_open(struct file **lower_file,
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@ -1168,7 +1168,7 @@ decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
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rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error sending message to "
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"ecryptfsd\n");
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"ecryptfsd: %d\n", rc);
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goto out;
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}
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rc = ecryptfs_wait_for_response(msg_ctx, &msg);
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@ -1988,7 +1988,7 @@ pki_encrypt_session_key(struct key *auth_tok_key,
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rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error sending message to "
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"ecryptfsd\n");
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"ecryptfsd: %d\n", rc);
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goto out;
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}
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rc = ecryptfs_wait_for_response(msg_ctx, &msg);
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@ -6,9 +6,8 @@
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#define ECRYPTFS_VERSION_MINOR 0x04
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#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x03
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/* These flags indicate which features are supported by the kernel
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* module; userspace tools such as the mount helper read
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* ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
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* how to behave. */
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* module; userspace tools such as the mount helper read the feature
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* bits from a sysfs handle in order to determine how to behave. */
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#define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001
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#define ECRYPTFS_VERSIONING_PUBKEY 0x00000002
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#define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
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@ -19,13 +18,6 @@
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#define ECRYPTFS_VERSIONING_HMAC 0x00000080
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#define ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION 0x00000100
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#define ECRYPTFS_VERSIONING_GCM 0x00000200
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#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
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| ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
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| ECRYPTFS_VERSIONING_PUBKEY \
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| ECRYPTFS_VERSIONING_XATTR \
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| ECRYPTFS_VERSIONING_MULTKEY \
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| ECRYPTFS_VERSIONING_DEVMISC \
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| ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION)
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#define ECRYPTFS_MAX_PASSWORD_LENGTH 64
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#define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
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#define ECRYPTFS_SALT_SIZE 8
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