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path: root/fs/ecryptfs/ecryptfs_kernel.h
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2008-10-16eCryptfs: remove netlink transportTyler Hicks
The netlink transport code has not worked for a while and the miscdev transport is a simpler solution. This patch removes the netlink code and makes the miscdev transport the only eCryptfs kernel to userspace transport. Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Dustin Kirkland <kirkland@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24eCryptfs: Make all persistent file opens delayedMichael Halcrow
There is no good reason to immediately open the lower file, and that can cause problems with files that the user does not intend to immediately open, such as device nodes. This patch removes the persistent file open from the interpose step and pushes that to the locations where eCryptfs really does need the lower persistent file, such as just before reading or writing the metadata stored in the lower file header. Two functions are jumping to out_dput when they should just be jumping to out on error paths. This patch also fixes these. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24eCryptfs: do not try to open device files on mknodMichael Halcrow
When creating device nodes, eCryptfs needs to delay actually opening the lower persistent file until an application tries to open. Device handles may not be backed by anything when they first come into existence. [Valdis.Kletnieks@vt.edu: build fix] Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: <Valdis.Kletnieks@vt.edu} Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24eCryptfs: Privileged kthread for lower file opensMichael Halcrow
eCryptfs would really like to have read-write access to all files in the lower filesystem. Right now, the persistent lower file may be opened read-only if the attempt to open it read-write fails. One way to keep from having to do that is to have a privileged kthread that can open the lower persistent file on behalf of the user opening the eCryptfs file; this patch implements this functionality. This patch will properly allow a less-privileged user to open the eCryptfs file, followed by a more-privileged user opening the eCryptfs file, with the first user only being able to read and the second user being able to both read and write. eCryptfs currently does this wrong; it will wind up calling vfs_write() on a file that was opened read-only. This is fixed in this patch. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06eCryptfs: remove unnecessary page decrypt callMichael Halcrow
The page decrypt calls in ecryptfs_write() are both pointless and buggy. Pointless because ecryptfs_get_locked_page() has already brought the page up to date, and buggy because prior mmap writes will just be blown away by the decrypt call. This patch also removes the declaration of a now-nonexistent function ecryptfs_write_zeros(). Thanks to Eric Sandeen and David Kleikamp for helping to track this down. Eric said: fsx w/ mmap dies quickly ( < 100 ops) without this, and survives nicely (to millions of ops+) with it in place. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Eric Sandeen <sandeen@redhat.com> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29eCryptfs: make key module subsystem respect namespacesMichael Halcrow
Make eCryptfs key module subsystem respect namespaces. Since I will be removing the netlink interface in a future patch, I just made changes to the netlink.c code so that it will not break the build. With my recent patches, the kernel module currently defaults to the device handle interface rather than the netlink interface. [akpm@linux-foundation.org: export free_user_ns()] Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29eCryptfs: integrate eCryptfs device handle into the module.Michael Halcrow
Update the versioning information. Make the message types generic. Add an outgoing message queue to the daemon struct. Make the functions to parse and write the packet lengths available to the rest of the module. Add functions to create and destroy the daemon structs. Clean up some of the comments and make the code a little more consistent with itself. [akpm@linux-foundation.org: printk fixes] Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29ecryptfs: replace remaining __FUNCTION__ occurrencesHarvey Harrison
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06ecryptfs: check for existing key_tfm at mount timeEric Sandeen
Jeff Moyer pointed out that a mount; umount loop of ecryptfs, with the same cipher & other mount options, created a new ecryptfs_key_tfm_cache item each time, and the cache could grow quite large this way. Looking at this with mhalcrow, we saw that ecryptfs_parse_options() unconditionally called ecryptfs_add_new_key_tfm(), which is what was adding these items. Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a new helper function, ecryptfs_tfm_exists(), which checks for the cipher on the cached key_tfm_list, and sets a pointer to it if it exists. This can then be called from ecryptfs_parse_options(), and new key_tfm's can be added only when a cached one is not found. With list locking changes suggested by akpm. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06eCryptfs: change the type of cipher_code from u16 to u8Trevor Highland
Only the lower byte of cipher_code is ever used, so it makes sense for its type to be u8. Signed-off-by: Trevor Highland <trevor.highland@gmail.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06eCryptfs: set inode key only once per crypto operationTrevor Highland
There is no need to keep re-setting the same key for any given eCryptfs inode. This patch optimizes the use of the crypto API and helps performance a bit. Signed-off-by: Trevor Highland <trevor.highland@gmail.com> Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06eCryptfs: track header bytes rather than extentsMichael Halcrow
Remove internal references to header extents; just keep track of header bytes instead. Headers can easily span multiple pages with the recent persistent file changes. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06fs/ecryptfs/: possible cleanupsAdrian Bunk
- make the following needlessly global code static: - crypto.c:ecryptfs_lower_offset_for_extent() - crypto.c:key_tfm_list - crypto.c:key_tfm_list_mutex - inode.c:ecryptfs_getxattr() - main.c:ecryptfs_init_persistent_file() - remove the no longer used mmap.c:ecryptfs_lower_page_cache - #if 0 the unused read_write.c:ecryptfs_read() Signed-off-by: Adrian Bunk <bunk@kernel.org> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16ecryptfs: clean up page flag handlingMichael Halcrow
The functions that eventually call down to ecryptfs_read_lower(), ecryptfs_decrypt_page(), and ecryptfs_copy_up_encrypted_with_header() should have the responsibility of managing the page Uptodate status. This patch gets rid of some of the ugliness that resulted from trying to push some of the page flag setting too far down the stack. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: remove unused functions and kmem_cacheMichael Halcrow
The switch to read_write.c routines and the persistent file make a number of functions unnecessary. This patch removes them. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: update metadata read/write functionsMichael Halcrow
Update the metadata read/write functions and grow_file() to use the read_write.c routines. Do not open another lower file; use the persistent lower file instead. Provide a separate function for crypto.c::ecryptfs_read_xattr_region() to get to the lower xattr without having to go through the eCryptfs getxattr. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: replace encrypt, decrypt, and inode size writeMichael Halcrow
Replace page encryption and decryption routines and inode size write routine with versions that utilize the read_write.c functions. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: read_write.c routinesMichael Halcrow
Add a set of functions through which all I/O to lower files is consolidated. This patch adds a new inode_info reference to a persistent lower file for each eCryptfs inode; another patch later in this series will set that up. This persistent lower file is what the read_write.c functions use to call vfs_read() and vfs_write() on the lower filesystem, so even when reads and writes come in through aops->readpage and aops->writepage, we can satisfy them without resorting to direct access to the lower inode's address space. Several function declarations are going to be changing with this patchset. For now, in order to keep from breaking the build, I am putting dummy parameters in for those functions. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: remove header_extent_sizeMichael Halcrow
There is no point to keeping a separate header_extent_size and an extent_size. The total size of the header can always be represented as some multiple of the regular data extent size. [randy.dunlap@oracle.com: ecryptfs: fix printk format warning] Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: make needlessly global symbols staticMichael Halcrow
Andrew Morton wrote: > Please check that all the newly-added global symbols do indeed need > to be global. Change symbols in keystore.c and crypto.o to static if they do not need to be global. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: comments for some structsMichael Halcrow
Andrew Morton wrote: > > +struct ecryptfs_global_auth_tok { > > +#define ECRYPTFS_AUTH_TOK_INVALID 0x00000001 > > + u32 flags; > > + struct list_head mount_crypt_stat_list; > > + struct key *global_auth_tok_key; > > + struct ecryptfs_auth_tok *global_auth_tok; > > + unsigned char sig[ECRYPTFS_SIG_SIZE_HEX + 1]; > > +}; > > + > > +struct ecryptfs_key_tfm { > > + struct crypto_blkcipher *key_tfm; > > + size_t key_size; > > + struct mutex key_tfm_mutex; > > + struct list_head key_tfm_list; > > + unsigned char cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; > > +}; > > Please consider commenting your struct fields carefully: it's a > great way to help other to understand your code. Add some comments to the ecryptfs_global_auth_tok and ecryptfs_key_tfm structs to make their functions more easily ascertained. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: grammatical fix (destruct to destroy)Michael Halcrow
Andrew Morton wrote: > > +int ecryptfs_destruct_crypto(void) > > ecryptfs_destroy_crypto would be more grammatically correct ;) Grammatical fix for some function names. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16eCryptfs: add key list structure; search keyringMichael Halcrow
Add support structures for handling multiple keys. The list in crypt_stat contains the key identifiers for all of the keys that should be used for encrypting each file's File Encryption Key (FEK). For now, each inode inherits this list from the mount-wide crypt_stat struct, via the ecryptfs_copy_mount_wide_sigs_to_inode_sigs() function. This patch also removes the global key tfm from the mount-wide crypt_stat struct, instead keeping a list of tfm's meant for dealing with the various inode FEK's. eCryptfs will now search the user's keyring for FEK's parsed from the existing file metadata, so the user can make keys available at any time before or after mounting. Now that multiple FEK packets can be written to the file metadata, we need to be more meticulous about size limits. The updates to the code for writing out packets to the file metadata makes sizes and limits more explicit, uniformly expressed, and (hopefully) easier to follow. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-28eCryptfs: fix write zeros behaviorMichael Halcrow
This patch fixes the processes involved in wiping regions of the data during truncate and write events, fixing a kernel hang in 2.6.22-rc4 while assuring that zero values are written out to the appropriate locations during events in which the i_size will change. The range passed to ecryptfs_truncate() from ecryptfs_prepare_write() includes the page that is the object of ecryptfs_prepare_write(). This leads to a kernel hang as read_cache_page() is executed on the same page in the ecryptfs_truncate() execution path. This patch remedies this by limiting the range passed to ecryptfs_truncate() so as to exclude the page that is the object of ecryptfs_prepare_write(); it also adds code to ecryptfs_prepare_write() to zero out the region of its own page when writing past the i_size position. This patch also modifies ecryptfs_truncate() so that when a file is truncated to a smaller size, eCryptfs will zero out the contents of the new last page from the new size through to the end of the last page. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] eCryptfs: Reduce stack usage in ecryptfs_generate_key_packet_set()Michael Halcrow
eCryptfs is gobbling a lot of stack in ecryptfs_generate_key_packet_set() because it allocates a temporary memory-hungry ecryptfs_key_record struct. This patch introduces a new kmem_cache for that struct and converts ecryptfs_generate_key_packet_set() to use it. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] Mark struct super_operations constJosef 'Jeff' Sipek
This patch is inspired by Arjan's "Patch series to mark struct file_operations and struct inode_operations const". Compile tested with gcc & sparse. Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] mark struct inode_operations const 1Arjan van de Ven
Many struct inode_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: open-code flag checking and manipulationMichael Halcrow
Open-code flag checking and manipulation. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Trevor Highland <tshighla@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: convert kmap() to kmap_atomic()Michael Halcrow
Replace kmap() with kmap_atomic(). Reduce the amount of time that mappings are held. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Trevor Highland <tshighla@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: Encrypted passthroughMichael Halcrow
Provide an option to provide a view of the encrypted files such that the metadata is always in the header of the files, regardless of whether the metadata is actually in the header or in the extended attribute. This mode of operation is useful for applications like incremental backup utilities that do not preserve the extended attributes when directly accessing the lower files. With this option enabled, the files under the eCryptfs mount point will be read-only. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: Generalize metadata read/writeMichael Halcrow
Generalize the metadata reading and writing mechanisms, with two targets for now: metadata in file header and metadata in the user.ecryptfs xattr of the lower file. [akpm@osdl.org: printk warning fix] [bunk@stusta.de: make some needlessly global code static] Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: xattr flags and mount optionsMichael Halcrow
This patch set introduces the ability to store cryptographic metadata into an lower file extended attribute rather than the lower file header region. This patch set implements two new mount options: ecryptfs_xattr_metadata - When set, newly created files will have their cryptographic metadata stored in the extended attribute region of the file rather than the header. When storing the data in the file header, there is a minimum of 8KB reserved for the header information for each file, making each file at least 12KB in size. This can take up a lot of extra disk space if the user creates a lot of small files. By storing the data in the extended attribute, each file will only occupy at least of 4KB of space. As the eCryptfs metadata set becomes larger with new features such as multi-key associations, most popular filesystems will not be able to store all of the information in the xattr region in some cases due to space constraints. However, the majority of users will only ever associate one key per file, so most users will be okay with storing their data in the xattr region. This option should be used with caution. I want to emphasize that the xattr must be maintained under all circumstances, or the file will be rendered permanently unrecoverable. The last thing I want is for a user to forget to set an xattr flag in a backup utility, only to later discover that their backups are worthless. ecryptfs_encrypted_view - When set, this option causes eCryptfs to present applications a view of encrypted files as if the cryptographic metadata were stored in the file header, whether the metadata is actually stored in the header or in the extended attributes. No matter what eCryptfs winds up doing in the lower filesystem, I want to preserve a baseline format compatibility for the encrypted files. As of right now, the metadata may be in the file header or in an xattr. There is no reason why the metadata could not be put in a separate file in future versions. Without the compatibility mode, backup utilities would have to know to back up the metadata file along with the files. The semantics of eCryptfs have always been that the lower files are self-contained units of encrypted data, and the only additional information required to decrypt any given eCryptfs file is the key. That is what has always been emphasized about eCryptfs lower files, and that is what users expect. Providing the encrypted view option will provide a way to userspace applications wherein they can always get to the same old familiar eCryptfs encrypted files, regardless of what eCryptfs winds up doing with the metadata behind the scenes. This patch: Add extended attribute support to version bit vector, flags to indicate when xattr or encrypted view modes are enabled, and support for the new mount options. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: Public key; packet managementMichael Halcrow
Public key support code. This reads and writes packets in the header that contain public key encrypted file keys. It calls the messaging code in the previous patch to send and receive encryption and decryption request packets from the userspace daemon. [akpm@osdl.org: cleab fix] Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] eCryptfs: Public key transport mechanismMichael Halcrow
This is the transport code for public key functionality in eCryptfs. It manages encryption/decryption request queues with a transport mechanism. Currently, netlink is the only implemented transport. Each inode has a unique File Encryption Key (FEK). Under passphrase, a File Encryption Key Encryption Key (FEKEK) is generated from a salt/passphrase combo on mount. This FEKEK encrypts each FEK and writes it into the header of each file using the packet format specified in RFC 2440. This is all symmetric key encryption, so it can all be done via the kernel crypto API. These new patches introduce public key encryption of the FEK. There is no asymmetric key encryption support in the kernel crypto API, so eCryptfs pushes the FEK encryption and decryption out to a userspace daemon. After considering our requirements and determining the complexity of using various transport mechanisms, we settled on netlink for this communication. eCryptfs stores authentication tokens into the kernel keyring. These tokens correlate with individual keys. For passphrase mode of operation, the authentication token contains the symmetric FEKEK. For public key, the authentication token contains a PKI type and an opaque data blob managed by individual PKI modules in userspace. Each user who opens a file under an eCryptfs partition mounted in public key mode must be running a daemon. That daemon has the user's credentials and has access to all of the keys to which the user should have access. The daemon, when started, initializes the pluggable PKI modules available on the system and registers itself with the eCryptfs kernel module. Userspace utilities register public key authentication tokens into the user session keyring. These authentication tokens correlate key signatures with PKI modules and PKI blobs. The PKI blobs contain PKI-specific information necessary for the PKI module to carry out asymmetric key encryption and decryption. When the eCryptfs module parses the header of an existing file and finds a Tag 1 (Public Key) packet (see RFC 2440), it reads in the public key identifier (signature). The asymmetrically encrypted FEK is in the Tag 1 packet; eCryptfs puts together a decrypt request packet containing the signature and the encrypted FEK, then it passes it to the daemon registered for the current->euid via a netlink unicast to the PID of the daemon, which was registered at the time the daemon was started by the user. The daemon actually just makes calls to libecryptfs, which implements request packet parsing and manages PKI modules. libecryptfs grabs the public key authentication token for the given signature from the user session keyring. This auth tok tells libecryptfs which PKI module should receive the request. libecryptfs then makes a decrypt() call to the PKI module, and it passes along the PKI block from the auth tok. The PKI uses the blob to figure out how it should decrypt the data passed to it; it performs the decryption and passes the decrypted data back to libecryptfs. libecryptfs then puts together a reply packet with the decrypted FEK and passes that back to the eCryptfs module. The eCryptfs module manages these request callouts to userspace code via message context structs. The module maintains an array of message context structs and places the elements of the array on two lists: a free and an allocated list. When eCryptfs wants to make a request, it moves a msg ctx from the free list to the allocated list, sets its state to pending, and fires off the message to the user's registered daemon. When eCryptfs receives a netlink message (via the callback), it correlates the msg ctx struct in the alloc list with the data in the message itself. The msg->index contains the offset of the array of msg ctx structs. It verifies that the registered daemon PID is the same as the PID of the process that sent the message. It also validates a sequence number between the received packet and the msg ctx. Then, it copies the contents of the message (the reply packet) into the msg ctx struct, sets the state in the msg ctx to done, and wakes up the process that was sleeping while waiting for the reply. The sleeping process was whatever was performing the sys_open(). This process originally called ecryptfs_send_message(); it is now in ecryptfs_wait_for_response(). When it wakes up and sees that the msg ctx state was set to done, it returns a pointer to the message contents (the reply packet) and returns. If all went well, this packet contains the decrypted FEK, which is then copied into the crypt_stat struct, and life continues as normal. The case for creation of a new file is very similar, only instead of a decrypt request, eCryptfs sends out an encrypt request. > - We have a great clod of key mangement code in-kernel. Why is that > not suitable (or growable) for public key management? eCryptfs uses Howells' keyring to store persistent key data and PKI state information. It defers public key cryptographic transformations to userspace code. The userspace data manipulation request really is orthogonal to key management in and of itself. What eCryptfs basically needs is a secure way to communicate with a particular daemon for a particular task doing a syscall, based on the UID. Nothing running under another UID should be able to access that channel of communication. > - Is it appropriate that new infrastructure for public key > management be private to a particular fs? The messaging.c file contains a lot of code that, perhaps, could be extracted into a separate kernel service. In essence, this would be a sort of request/reply mechanism that would involve a userspace daemon. I am not aware of anything that does quite what eCryptfs does, so I was not aware of any existing tools to do just what we wanted. > What happens if one of these daemons exits without sending a quit > message? There is a stale uid<->pid association in the hash table for that user. When the user registers a new daemon, eCryptfs cleans up the old association and generates a new one. See ecryptfs_process_helo(). > - _why_ does it use netlink? Netlink provides the transport mechanism that would minimize the complexity of the implementation, given that we can have multiple daemons (one per user). I explored the possibility of using relayfs, but that would involve having to introduce control channels and a protocol for creating and tearing down channels for the daemons. We do not have to worry about any of that with netlink. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-07[CRYPTO] api: Remove deprecated interfaceHerbert Xu
This patch removes the old cipher interface and related code. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2006-12-08[PATCH] struct path: make eCryptfs a user of struct pathJosef "Jeff" Sipek
Convert eCryptfs dentry-vfsmount pairs in dentry private data to struct path. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08[PATCH] eCryptfs: Use fsstack's generic copy inode attr functionsJosef "Jeff" Sipek
Replace eCryptfs specific code & calls with the more generic fsstack equivalents and remove the eCryptfs specific functions. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-31[PATCH] eCryptfs: Consolidate lower dentry_open'sMichael Halcrow
Opens on lower dentry objects happen in several places in eCryptfs, and they all involve the same steps (dget, mntget, dentry_open). This patch consolidates the lower open events into a single function call. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-31[PATCH] eCryptfs: Cipher code to new crypto APIMichael Halcrow
Update cipher block encryption code to the new crypto API. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-31[PATCH] eCryptfs: Hash code to new crypto APIMichael Halcrow
Update eCryptfs hash code to the new kernel crypto API. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-31[PATCH] eCryptfs: Clean up crypto initializationMichael Halcrow
Clean up the crypto initialization code; let the crypto API take care of the key size checks. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] ecryptfs: fs/Makefile and fs/KconfigMichael Halcrow
eCryptfs is a stacked cryptographic filesystem for Linux. It is derived from Erez Zadok's Cryptfs, implemented through the FiST framework for generating stacked filesystems. eCryptfs extends Cryptfs to provide advanced key management and policy features. eCryptfs stores cryptographic metadata in the header of each file written, so that encrypted files can be copied between hosts; the file will be decryptable with the proper key, and there is no need to keep track of any additional information aside from what is already in the encrypted file itself. [akpm@osdl.org: updates for ongoing API changes] [bunk@stusta.de: cleanups] [akpm@osdl.org: alpha build fix] [akpm@osdl.org: cleanups] [tytso@mit.edu: inode-diet updates] [pbadari@us.ibm.com: generic_file_*_read/write() interface updates] [rdunlap@xenotime.net: printk format fixes] [akpm@osdl.org: make slab creation and teardown table-driven] Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net> Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>