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2020-03-19README.md: improve documentation for PAM configuration (#204)Eric Biggers
2020-02-22Makefile: clean up installation commands (#201)Eric Biggers
Improve the documentation for the installation-related Makefile variables, and update the commands to remove the forward slash after $(DESTDIR) in order to remove a duplicate forward slash and match the recommended usage.
2020-02-18Use DESTDIR for install prefix (#200)Anatol Pomozov
DESTDIR has a well established purpose https://www.gnu.org/prep/standards/html_node/DESTDIR.html It is a suffix for all the files to be installed. And it is used by package managers who installs the files into some $tmpdir before creating a package. Change the build commands to follow this convention. Add BINDIR that does the same what previous did $DESTDIR.
2020-02-10Release version v0.2.6 (#198)v0.2.6Joseph Richey
* Release version v0.2.6 Fixes #195 Also, update the encrypted API key. My person access token had expired, this one should work now. Signed-off-by: Joe Richey <joerichey@google.com>
2020-01-29cmd/fscrypt/commands: allow disabling recovery passphrase (#193)Eric Biggers
While it's important to generate a recovery passphrase in the linked protector case to avoid data loss if the system is reinstalled, some people really don't want it (even though it can be safely ignored as it almost certainly has far more entropy than the login passphrase). As a compromise, prompt for y/n before generating it, with default y. Also, to allow disabling the recovery passphrase during noninteractive use, add a --no-recovery command-line option. Update https://github.com/google/fscrypt/issues/186
2020-01-29Merge pull request #192 from ebiggers/cleanup-on-errorEric Biggers
Clean up policies and protectors on error
2020-01-28actions/policy: revert new protector links on failureEric Biggers
Ensure that when an encryption policy is reverted (e.g. due to encryptPath() failing after the policy was created), we also delete any new protector links that were created for the policy, as this is not handled by the logic that reverts new protectors.
2020-01-28filesystem: don't overwrite existing protector linksEric Biggers
When adding a protector to a policy, don't unconditionally overwrite the protector link, because it may already exist. Instead, if it already exists and points to the mount, just use it. If it already exists and points to the wrong place, return an error. Also add a bool to the return value of AddLinkedProtector() so that callers can check whether the link was newly created or not.
2020-01-28cmd/fscrypt/commands: clean up properly when encryptPath() failsEric Biggers
Move the deferred locking and deletion of the policy on failure to the correct places, so that it's done in all failure cases, including in the case where adding the recovery protector fails. Also make the recovery protector be locked and deleted on failure. Finally, put all the code to do deferred deprovisioning of the policy in the same place: right after it's provisioned.
2020-01-28actions/recovery: revert protector if it can't be added to policyEric Biggers
Ensure that a failed AddRecoveryPassphrase() doesn't leave around an unneeded protector file.
2020-01-28cmd/fscrypt/errors: explicitly mark error messages as errors (#191)Eric Biggers
When an fscrypt command fails and prints an error message, in some cases it isn't clear that the message is actually an error, e.g.: fscrypt encrypt: login protectors do not need a name Make it clear by always prefixing the message with "[ERROR] ", e.g. [ERROR] fscrypt encrypt: login protectors do not need a name Update https://github.com/google/fscrypt/issues/186
2020-01-28cmd/fscrypt/setup: don't prompt to create /etc/fscrypt.conf (#190)Eric Biggers
When 'fscrypt setup' sees that /etc/fscrypt.conf doesn't exist, don't ask for confirmation before creating it. Just do it. This is the normal use, and there's not a good reason to ask the user to confirm it.
2020-01-27actions/recovery: ensure recovery passphrase is really custom_passphraseEric Biggers
If the login protector was just created by the same 'fscrypt encrypt' command, then policy.Context.Config.Source will be pam_passphrase. This needs to be overridden to custom_passphrase when creating the protector for the recovery passphrase. This fixes the following error: fscrypt encrypt: login protectors do not need a name Resolves https://github.com/google/fscrypt/issues/187 Update https://github.com/google/fscrypt/issues/186
2020-01-23Document how to check for kernel config options (#183)ebiggers
Resolves https://github.com/google/fscrypt/issues/181
2020-01-23privileges.go: remove a stale comment (#184)ebiggers
The workaround for Go versions before 1.10 was already removed by commit 3022c1603d96 ("Ensure setting user privileges is reversible").
2020-01-23filesystem: remove canonicalizePath() (#185)ebiggers
canonicalizePath() is now only used by an error path in getMountFromLink(), which we can make use getDeviceName() instead.
2020-01-22Merge pull request #167 from ebiggers/recovery-passphraseebiggers
Automatically generate recovery passphrase when useful
2020-01-22Automatically generate recovery passphrase when usefulEric Biggers
If a user re-installs their system (or otherwise loses the /.fscrypt directory on the root filesystem) they also lose access to any login passphrase-protected directories on other filesystems, unless additional protectors were manually added. This can be unexpected, as it may be expected that the old login passphrase would still work. We can't really fix this by storing a login protector on every filesystem because: - If a user were to have N login protectors, it would take them N times longer to log in, as every login protector would need to be unlocked. - If a user were to change their login passphrase while any external volumes were unmounted, login protectors would get out of sync. - It's preferable that an external volume isn't unlockable by itself using only a login passphrase, as login passphrases are often weak. Instead, generate a recovery passphrase when creating a login passphrase-protected directory on a non-root filesystem. The recovery passphrase is added as a custom_passphrase protector, thus giving the policy two protectors: one pam_passphrase and one custom_passphrase. Then this passphrase is written to a file in the new encrypted directory. Writing the passphrase to a file here is okay since it's encrypted, but it's obviously useless by itself; it's up to the user to store this passphrase somewhere else if they need it. Use a recovery passphrase instead of a "recovery code" that encodes the policy key directly because a passphrase is more user-friendly: it can safely be made much shorter than a key, and it works just like any other fscrypt protector. Also, it's not as critical to allow recovery when the .fscrypt directory on the *same* filesystem is deleted. Resolves https://github.com/google/fscrypt/issues/164
2020-01-22Merge pull request #148 from ebiggers/fscrypt-key-mgmt-improvementsebiggers
Filesystem keyring and v2 encryption policy support
2020-01-05README.md: document new settings and troubleshooting key accessEric Biggers
Document the new /etc/fscrypt.conf settings for the filesystem keyring and v2 encryption policies, and add a new subsection for troubleshooting key access problems.
2020-01-05cmd/fscrypt, keyring: add --all-users option to 'fscrypt lock'Eric Biggers
Allow root to provide the --all-users option to 'fscrypt lock' to force an encryption key to be removed from the filesystem (i.e., force an encrypted directory to be locked), even if other users have added it. To implement this option, we just need to use the FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctl rather than FS_IOC_REMOVE_ENCRYPTION_KEY. In theory this option could be implemented for the user keyrings case too, but it would be difficult and the user keyrings are being deprecated for fscrypt, so don't bother.
2020-01-05Keyring support for v2 encryption policiesEric Biggers
Implement adding/removing v2 encryption policy keys to/from the kernel. The kernel requires that the new ioctls FS_IOC_ADD_ENCRYPTION_KEY and FS_IOC_REMOVE_ENCRYPTION_KEY be used for this. Root is not required. However, non-root support brings an extra complication: the kernel keeps track of which users have called FS_IOC_ADD_ENCRYPTION_KEY for the same key. FS_IOC_REMOVE_ENCRYPTION_KEY only works as one of these users, and it only removes the calling user's claim to the key; the key is only truly removed when the last claim is removed. Implement the following behavior: - 'fscrypt unlock' and pam_fscrypt add the key for the user, even if other user(s) have it added already. This behavior is needed so that another user can't remove the key out from under the user. - 'fscrypt lock' and pam_fscrypt remove the key for the user. However, if the key wasn't truly removed because other users still have it added, 'fscrypt lock' prints a warning. - 'fscrypt status' shows whether the directory is unlocked for anyone.
2020-01-05Metadata support for v2 encryption policiesEric Biggers
Linux v5.4 and later supports v2 encryption policies. These have several advantages over v1 encryption policies: - Their encryption keys can be added/removed to/from the filesystem by non-root users, thus gaining the benefits of the filesystem keyring while also retaining support for non-root use. - They use a more standard, secure, and flexible key derivation function. Because of this, some future kernel-level fscrypt features will be implemented for v2 policies only. - They prevent a denial-of-service attack where a user could associate the wrong key with another user's encrypted files. Prepare the fscrypt tool to support v2 encryption policies by: - Adding a policy_version field to the EncryptionOptions, i.e. to the config file and to the policy metadata files. - Using the kernel-specified algorithm to compute the key descriptor for v2 policies. - Handling setting and getting v2 policies. Actually adding/removing the keys for v2 policies to/from the kernel is left for the next patch.
2020-01-05pam_fscrypt: update to handle filesystem keyringEric Biggers
FS_IOC_ADD_ENCRYPTION_KEY and FS_IOC_REMOVE_ENCRYPTION_KEY require root for v1 policy keys, so update the PAM module to re-acquire root privileges while provisioning/deprovisioning policies that need this. Also, only set up the user keyring if it will actually be used.
2020-01-05cmd/fscrypt: adjust user and keyring validation and preparationEric Biggers
Don't force the user to provide a --user argument when running fscrypt as root if they're doing something where the TargetUser isn't actually needed, such as provisioning/deprovisioning a v1 encryption policy to/from the filesystem keyring, or creating a non-login protector. Also don't set up the user keyring (or check for it being set up) if it won't actually be used. Finally, if we'll be provisioning/deprovisioning a v1 encryption policy to/from the filesystem keyring, make sure the command is running as root, since the kernel requires this.
2020-01-05cmd/fscrypt: add 'fscrypt lock' commandEric Biggers
Add support for 'fscrypt lock'. This command "locks" a directory, undoing 'fscrypt unlock'. When the filesystem keyring is used, 'fscrypt lock' also detects when a directory wasn't fully locked due to some files still being in-use. It can then be run again later to try to finish locking the files.
2020-01-05keyring: support filesystem keyring with v1 encryption policiesEric Biggers
Linux v5.4 and later allows fscrypt keys to be added/removed directly to/from the filesystem via the new ioctls FS_IOC_ADD_ENCRYPTION_KEY and FS_IOC_REMOVE_ENCRYPTION_KEY. Among other benefits, these fix the key visibility problems that many users have been running into, where system services and containers can't access encrypted files. Allow the user to opt-in to using these new ioctls for their existing encrypted directories by setting in their /etc/fscrypt.conf: "use_fs_keyring_for_v1_policies": true Note that it can't really be on by default, since for v1 policies the ioctls require root, whereas user keyrings don't. I.e., setting this to true means that users will need to use 'sudo fscrypt unlock', not 'fscrypt unlock'. v2 policies won't have this restriction.
2020-01-05Add keyring packageEric Biggers
In preparation for introducing support for the new filesystem-level keyrings, move the existing user keyring management code from security/keyring.go and crypto/crypto.go into a new package, 'keyring'. This package provides functions AddEncryptionKey, RemoveEncryptionKey, and GetEncryptionKeyStatus which delegate to either the filesystem keyring (added by a later patch) or to the user keyring. This provides a common interface to both types of keyrings, to the extent possible.
2020-01-05README.md: document /etc/fscrypt.confEric Biggers
2019-12-15keyring: fix permission denied accessing user keyring (#177)ebiggers
When userKeyringIDLookup() looks up a user keyring, it links it into the process keyring to ensure that the process retains the "possessor privileges" over the user keyring, then caches the user keyring's ID. Unfortunately, this use of the process keyring randomly fails because Go creates threads before even init() and main() are run, and then can run code on them later. Since the kernel doesn't create the process keyring until userspace requests it and the process keyring is actually a per-thread property that's only inherited by new threads, different threads in a Go process may see different process keyrings. Fix this by removing the user keyring cache, switching from the process keyring to the thread keyring, and using LockOSThread() to pin the goroutine to an OS thread while needed to perform a keyring operation. Resolves https://github.com/google/fscrypt/issues/176
2019-11-28README.md: update output to match realityEric Biggers
Update the example output in the README to match reality. Also make a few other updates to the examples to take into account that 'fscrypt purge' now drops caches by default, and that the root filesystem doesn't need to support encryption if the encrypted directories are being created on a different filesystem. Resolves https://github.com/google/fscrypt/issues/62
2019-11-28Merge pull request #172 from ebiggers/login-passphrase-doc-fixJoseph Richey
README.md: remove obsolete warning about changing login passphrase
2019-11-27README.md: remove obsolete warning about changing login passphraseEric Biggers
For some time now, fscrypt actually does re-wrap a user's login protector when their login passphrase changes, provided that the PAM configuration is correct. Remove the obsolete paragraph. Update https://github.com/google/fscrypt/issues/51
2019-11-27cmd/fscrypt: preserve paragraphs in wrapText()Eric Biggers
Preserve empty lines rather than squashing them into a single space. This allows having command descriptions that contain multiple paragraphs. This also eliminates the need to have a special case for ordered lists.
2019-11-27Rename some variables from 'target' to 'targetUser'Eric Biggers
Refer to the target User as 'targetUser' rather than simply 'target'. This will help avoid confusion when we add support for the filesystem keyring, since then the Mount will also be a "target".
2019-11-27Use latest fscrypt declarations from sys/unixEric Biggers
Use the new name for fscrypt constants and structures which have been given a new name. Also use the named constant for the DIRECT_KEY fscrypt policy flag. No change in behavior. This is just preparing for future work.
2019-11-27Upgrade to latest golang.org/x/sys moduleEric Biggers
Upgrade to get the new fscrypt declarations from Linux v5.4.
2019-11-27cmd/fscrypt: adjust message when listing protector sourcesEric Biggers
Saying "Your data can be protected with one of the following sources" is ambiguous because it could be interpreted to mean that an encrypted directory can only have one type of protector. In fact, an encrypted directory can have multiple protectors, and they can be of any type. Update https://github.com/google/fscrypt/issues/164
2019-11-27Allow filesystem links to contain leading/trailing whitespaceEric Biggers
To make manually editing linked protectors slightly more user-friendly, automatically strip any leading or trailing whitespace. E.g. treat "UUID=3a6d9a76-47f0-4f13-81bf-3332fbe984fb\n" the same as "UUID=3a6d9a76-47f0-4f13-81bf-3332fbe984fb". Update https://github.com/google/fscrypt/issues/115
2019-11-26travis: set GO111MODULE=on for 'go get'Eric Biggers
Ensure that the environmental variable GO111MODULE is set to "on" when running 'go get'. This fixes a CI failure with Go 1.11 and 1.12.
2019-11-08Merge pull request #162 from josephlr/masterJoseph Richey
Add Code of Conduct
2019-11-05Add Code of ConductJoe Richey
This project has always been under a CoC, but I forgot to incude the file when creating the repo. See also: https://opensource.google/conduct/ Signed-off-by: Joe Richey <joerichey@google.com>
2019-10-30Merge pull request #154 from ebiggers/bind-mountsJoseph Richey
Store fscrypt metadata in only one place per filesystem, so that bind mounts don't get their own metadata directories (which was ambiguous, as the same file may be accessible via multiple mounts). Also correctly set the source device for root filesystems mounted via the kernel command line, and fix creating linked protectors to such filesystems.
2019-10-30filesystem: add unit tests for loadMountInfo()Eric Biggers
Add a version of loadMountInfo() that takes an io.Reader parameter to allow injecting a custom mountinfo file, then add some unit tests.
2019-10-30filesystem: handle bind mounts properlyEric Biggers
Currently, fscrypt treats bind mounts as separate filesystems. This is broken because fscrypt will look for a directory's encryption policy in different places depending on which mount it's accessed through. This forces users to create an fscrypt metadata directory at every bind mount, and to copy fscrypt metadata around between mounts. Fix this by storing fscrypt metadata only at the root of the filesystem. To accomplish this: - Make mountsByDevice store only a single Mount per filesystem, rather than multiple. For this Mount, choose a mount of the full filesystem if available, preferably a read-write mount. If the filesystem has only bind mounts, store a nil entry in mountsByDevice so we can show a proper error message later. - Change FindMount() and GetMount() to look up the Mount by device number rather than by path, so that they don't return different Mounts depending on which path is used. - Change AllFilesystems() to not return bind mounts. - Due to the above changes, the mountsByPath map is no longer needed outside of loadMountInfo(). So make it a local variable there. Resolves https://github.com/google/fscrypt/issues/59
2019-10-30filesystem: make link handling more robustEric Biggers
The previous patch fixed making linked protectors to /dev/root, by setting Mount.Device to the real device node rather than /dev/root. That's good, but it also hints that the linked protector handling is unnecessarily fragile, as it relies on the device node name matching exactly. The Linux kernel allows the same device to have multiple device nodes, and path comparisons are slow and error-prone in general. Change it to compare the device number instead.
2019-10-30filesystem: get correct device for kernel-mounted rootfsEric Biggers
A root filesystem mounted via the kernel command line always has a source of "/dev/root", which isn't a real device node. This makes fscrypt think this filesystem doesn't have a source device, which breaks creating login passphrase-protected directories on other filesystems: fscrypt encrypt: filesystem /: no device for mount "/": system error: cannot create filesystem link This also makes 'fscrypt status' show a blank source device: MOUNTPOINT DEVICE FILESYSTEM ENCRYPTION FSCRYPT / ext4 supported Yes To fix this case, update loadMountInfo() to map the device number to the device name via sysfs rather than use the mount source field.
2019-10-30filesystem: add device number utilitiesEric Biggers
Add a utility type and functions for handling device numbers.
2019-10-30filesystem: skip unnecessary mountpoint canonicalizationEric Biggers
The kernel always shows mountpoints as absolute paths without symlinks, so there's no need to canonicalize them in userspace.
2019-10-30filesystem: switch to using /proc/self/mountinfoEric Biggers
Change loadMountInfo() to load the mounts directly from /proc/self/mountinfo, rather than use the mntent.h C library calls. This is needed for correct handling of bind mounts and of "/dev/root", since /proc/self/mountinfo has extra fields which show the mounted subtree and the filesystem's device number. /proc/mounts lacks these fields, and the C library calls can't provide them. To start, this patch just switches to using /proc/self/mountinfo, without doing anything with the extra fields yet. As a bonus, this eliminates all C code in mountpoint.go.