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* fscrypt: introduce helper function for filename matchingEric Biggers2017-05-042-22/+70
| | | | | | | | | Introduce a helper function fscrypt_match_name() which tests whether a fscrypt_name matches a directory entry. Also clean up the magic numbers and document things properly. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: avoid collisions when presenting long encrypted filenamesEric Biggers2017-05-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When accessing an encrypted directory without the key, userspace must operate on filenames derived from the ciphertext names, which contain arbitrary bytes. Since we must support filenames as long as NAME_MAX, we can't always just base64-encode the ciphertext, since that may make it too long. Currently, this is solved by presenting long names in an abbreviated form containing any needed filesystem-specific hashes (e.g. to identify a directory block), then the last 16 bytes of ciphertext. This needs to be sufficient to identify the actual name on lookup. However, there is a bug. It seems to have been assumed that due to the use of a CBC (ciphertext block chaining)-based encryption mode, the last 16 bytes (i.e. the AES block size) of ciphertext would depend on the full plaintext, preventing collisions. However, we actually use CBC with ciphertext stealing (CTS), which handles the last two blocks specially, causing them to appear "flipped". Thus, it's actually the second-to-last block which depends on the full plaintext. This caused long filenames that differ only near the end of their plaintexts to, when observed without the key, point to the wrong inode and be undeletable. For example, with ext4: # echo pass | e4crypt add_key -p 16 edir/ # seq -f "edir/abcdefghijklmnopqrstuvwxyz012345%.0f" 100000 | xargs touch # find edir/ -type f | xargs stat -c %i | sort | uniq | wc -l 100000 # sync # echo 3 > /proc/sys/vm/drop_caches # keyctl new_session # find edir/ -type f | xargs stat -c %i | sort | uniq | wc -l 2004 # rm -rf edir/ rm: cannot remove 'edir/_A7nNFi3rhkEQlJ6P,hdzluhODKOeWx5V': Structure needs cleaning ... To fix this, when presenting long encrypted filenames, encode the second-to-last block of ciphertext rather than the last 16 bytes. Although it would be nice to solve this without depending on a specific encryption mode, that would mean doing a cryptographic hash like SHA-256 which would be much less efficient. This way is sufficient for now, and it's still compatible with encryption modes like HEH which are strong pseudorandom permutations. Also, changing the presented names is still allowed at any time because they are only provided to allow applications to do things like delete encrypted directories. They're not designed to be used to persistently identify files --- which would be hard to do anyway, given that they're encrypted after all. For ease of backports, this patch only makes the minimal fix to both ext4 and f2fs. It leaves ubifs as-is, since ubifs doesn't compare the ciphertext block yet. Follow-on patches will clean things up properly and make the filesystems use a shared helper function. Fixes: 5de0b4d0cd15 ("ext4 crypto: simplify and speed up filename encryption") Reported-by: Gwendal Grignou <gwendal@chromium.org> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: fix context consistency check when key(s) unavailableEric Biggers2017-05-041-19/+68
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To mitigate some types of offline attacks, filesystem encryption is designed to enforce that all files in an encrypted directory tree use the same encryption policy (i.e. the same encryption context excluding the nonce). However, the fscrypt_has_permitted_context() function which enforces this relies on comparing struct fscrypt_info's, which are only available when we have the encryption keys. This can cause two incorrect behaviors: 1. If we have the parent directory's key but not the child's key, or vice versa, then fscrypt_has_permitted_context() returned false, causing applications to see EPERM or ENOKEY. This is incorrect if the encryption contexts are in fact consistent. Although we'd normally have either both keys or neither key in that case since the master_key_descriptors would be the same, this is not guaranteed because keys can be added or removed from keyrings at any time. 2. If we have neither the parent's key nor the child's key, then fscrypt_has_permitted_context() returned true, causing applications to see no error (or else an error for some other reason). This is incorrect if the encryption contexts are in fact inconsistent, since in that case we should deny access. To fix this, retrieve and compare the fscrypt_contexts if we are unable to set up both fscrypt_infos. While this slightly hurts performance when accessing an encrypted directory tree without the key, this isn't a case we really need to be optimizing for; access *with* the key is much more important. Furthermore, the performance hit is barely noticeable given that we are already retrieving the fscrypt_context and doing two keyring searches in fscrypt_get_encryption_info(). If we ever actually wanted to optimize this case we might start by caching the fscrypt_contexts. Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Move key structure and constants to uapiJoe Richey2017-04-301-11/+0
| | | | | | | | | | | | | | | | | | | This commit exposes the necessary constants and structures for a userspace program to pass filesystem encryption keys into the keyring. The fscrypt_key structure was already part of the kernel ABI, this change just makes it so programs no longer have to redeclare these structures (like e4crypt in e2fsprogs currently does). Note that we do not expose the other FS_*_KEY_SIZE constants as they are not necessary. Only XTS is supported for contents_encryption_mode, so currently FS_MAX_KEY_SIZE bytes of key material must always be passed to the kernel. This commit also removes __packed from fscrypt_key as it does not contain any implicit padding and does not refer to an on-disk structure. Signed-off-by: Joe Richey <joerichey@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: remove unnecessary checks for NULL operationsEric Biggers2017-04-302-13/+1
| | | | | | | | | | | | | | The functions in fs/crypto/*.c are only called by filesystems configured with encryption support. Since the ->get_context(), ->set_context(), and ->empty_dir() operations are always provided in that case (and must be, otherwise there would be no way to get/set encryption policies, or in the case of ->get_context() even access encrypted files at all), there is no need to check for these operations being NULL and we can remove these unneeded checks. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* Merge tag 'fscrypt-for-linus_stable' of ↵Linus Torvalds2017-03-255-64/+11
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt Pull fscrypto fixes from Ted Ts'o: "A code cleanup and bugfix for fs/crypto" * tag 'fscrypt-for-linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt: fscrypt: eliminate ->prepare_context() operation fscrypt: remove broken support for detecting keyring key revocation
| * fscrypt: eliminate ->prepare_context() operationEric Biggers2017-03-151-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | The only use of the ->prepare_context() fscrypt operation was to allow ext4 to evict inline data from the inode before ->set_context(). However, there is no reason why this cannot be done as simply the first step in ->set_context(), and in fact it makes more sense to do it that way because then the policy modes and flags get validated before any real work is done. Therefore, merge ext4_prepare_context() into ext4_set_context(), and remove ->prepare_context(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * fscrypt: remove broken support for detecting keyring key revocationEric Biggers2017-03-154-57/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Filesystem encryption ostensibly supported revoking a keyring key that had been used to "unlock" encrypted files, causing those files to become "locked" again. This was, however, buggy for several reasons, the most severe of which was that when key revocation happened to be detected for an inode, its fscrypt_info was immediately freed, even while other threads could be using it for encryption or decryption concurrently. This could be exploited to crash the kernel or worse. This patch fixes the use-after-free by removing the code which detects the keyring key having been revoked, invalidated, or expired. Instead, an encrypted inode that is "unlocked" now simply remains unlocked until it is evicted from memory. Note that this is no worse than the case for block device-level encryption, e.g. dm-crypt, and it still remains possible for a privileged user to evict unused pages, inodes, and dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by simply unmounting the filesystem. In fact, one of those actions was already needed anyway for key revocation to work even somewhat sanely. This change is not expected to break any applications. In the future I'd like to implement a real API for fscrypt key revocation that interacts sanely with ongoing filesystem operations --- waiting for existing operations to complete and blocking new operations, and invalidating and sanitizing key material and plaintext from the VFS caches. But this is a hard problem, and for now this bug must be fixed. This bug affected almost all versions of ext4, f2fs, and ubifs encryption, and it was potentially reachable in any kernel configured with encryption support (CONFIG_EXT4_ENCRYPTION=y, CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or CONFIG_UBIFS_FS_ENCRYPTION=y). Note that older kernels did not use the shared fs/crypto/ code, but due to the potential security implications of this bug, it may still be worthwhile to backport this fix to them. Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode") Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: Michael Halcrow <mhalcrow@google.com>
* | KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()David Howells2017-03-021-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rcu_dereference_key() and user_key_payload() are currently being used in two different, incompatible ways: (1) As a wrapper to rcu_dereference() - when only the RCU read lock used to protect the key. (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is used to protect the key and the may be being modified. Fix this by splitting both of the key wrappers to produce: (1) RCU accessors for keys when caller has the key semaphore locked: dereference_key_locked() user_key_payload_locked() (2) RCU accessors for keys when caller holds the RCU read lock: dereference_key_rcu() user_key_payload_rcu() This should fix following warning in the NFS idmapper =============================== [ INFO: suspicious RCU usage. ] 4.10.0 #1 Tainted: G W ------------------------------- ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 1 lock held by mount.nfs/5987: #0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4] stack backtrace: CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1 Call Trace: dump_stack+0xe8/0x154 (unreliable) lockdep_rcu_suspicious+0x140/0x190 nfs_idmap_get_key+0x380/0x420 [nfsv4] nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4] decode_getfattr_attrs+0xfac/0x16b0 [nfsv4] decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4] nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4] rpcauth_unwrap_resp+0xe8/0x140 [sunrpc] call_decode+0x29c/0x910 [sunrpc] __rpc_execute+0x140/0x8f0 [sunrpc] rpc_run_task+0x170/0x200 [sunrpc] nfs4_call_sync_sequence+0x68/0xa0 [nfsv4] _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4] nfs4_lookup_root+0xe0/0x350 [nfsv4] nfs4_lookup_root_sec+0x70/0xa0 [nfsv4] nfs4_find_root_sec+0xc4/0x100 [nfsv4] nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4] nfs4_get_rootfh+0x6c/0x190 [nfsv4] nfs4_server_common_setup+0xc4/0x260 [nfsv4] nfs4_create_server+0x278/0x3c0 [nfsv4] nfs4_remote_mount+0x50/0xb0 [nfsv4] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 nfs_do_root_mount+0xb0/0x140 [nfsv4] nfs4_try_mount+0x60/0x100 [nfsv4] nfs_fs_mount+0x5ec/0xda0 [nfs] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 do_mount+0x254/0xf70 SyS_mount+0x94/0x100 system_call+0x38/0xe0 Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* fscrypt: properly declare on-stack completionRichard Weinberger2017-02-061-1/+1
| | | | | | | | | | When a completion is declared on-stack we have to use COMPLETION_INITIALIZER_ONSTACK(). Fixes: 0b81d07790726 ("fs crypto: move per-file encryption from f2fs tree to fs/crypto") Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: split supp and notsupp declarations into their own headersEric Biggers2017-02-061-1/+1
| | | | | | | | | | | | | | | | Previously, each filesystem configured without encryption support would define all the public fscrypt functions to their notsupp_* stubs. This list of #defines had to be updated in every filesystem whenever a change was made to the public fscrypt functions. To make things more maintainable now that we have three filesystems using fscrypt, split the old header fscrypto.h into several new headers. fscrypt_supp.h contains the real declarations and is included by filesystems when configured with encryption support, whereas fscrypt_notsupp.h contains the inline stubs and is included by filesystems when configured without encryption support. fscrypt_common.h contains common declarations needed by both. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: remove redundant assignment of resColin Ian King2017-02-061-1/+0
| | | | | | | | | | | res is assigned to sizeof(ctx), however, this is unused and res is updated later on without that assigned value to res ever being used. Remove this redundant assignment. Fixes CoverityScan CID#1395546 "Unused value" Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: make fscrypt_operations.key_prefix a stringEric Biggers2017-01-081-20/+11
| | | | | | | | | | | | | There was an unnecessary amount of complexity around requesting the filesystem-specific key prefix. It was unclear why; perhaps it was envisioned that different instances of the same filesystem type could use different key prefixes, or that key prefixes could be binary. However, neither of those things were implemented or really make sense at all. So simplify the code by making key_prefix a const char *. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: make test_dummy_encryption require a keyring keyTheodore Ts'o2017-01-022-24/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the test_dummy_encryption ext4 mount option, which exists only to test encrypted I/O paths with xfstests, overrides all per-inode encryption keys with a fixed key. This change minimizes test_dummy_encryption-specific code path changes by supplying a fake context for directories which are not encrypted for use when creating new directories, files, or symlinks. This allows us to properly exercise the keyring lookup, derivation, and context inheritance code paths. Before mounting a file system using test_dummy_encryption, userspace must execute the following shell commands: mode='\x00\x00\x00\x00' raw="$(printf ""\\\\x%02x"" $(seq 0 63))" if lscpu | grep "Byte Order" | grep -q Little ; then size='\x40\x00\x00\x00' else size='\x00\x00\x00\x40' fi key="${mode}${raw}${size}" keyctl new_session echo -n -e "${key}" | keyctl padd logon fscrypt:4242424242424242 @s Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: factor out bio specific functionsRichard Weinberger2017-01-015-143/+177
| | | | | | | | | | | | | That way we can get rid of the direct dependency on CONFIG_BLOCK. Fixes: d475a507457b ("ubifs: Add skeleton for fscrypto") Reported-by: Arnd Bergmann <arnd@arndb.de> Reported-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Gstir <david@sigma-star.at> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: pass up error codes from ->get_context()Eric Biggers2016-12-311-31/+23
| | | | | | | | | | | | | It was possible for the ->get_context() operation to fail with a specific error code, which was then not returned to the caller of FS_IOC_SET_ENCRYPTION_POLICY or FS_IOC_GET_ENCRYPTION_POLICY. Make sure to pass through these error codes. Also reorganize the code so that ->get_context() only needs to be called one time when setting an encryption policy, and handle contexts of unrecognized sizes more appropriately. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: remove user-triggerable warning messagesEric Biggers2016-12-311-13/+2
| | | | | | | | | | Several warning messages were not rate limited and were user-triggerable from FS_IOC_SET_ENCRYPTION_POLICY. These shouldn't really have been there in the first place, but either way they aren't as useful now that the error codes have been improved. So just remove them. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: use EEXIST when file already uses different policyEric Biggers2016-12-311-1/+1
| | | | | | | | | | | | | | | As part of an effort to clean up fscrypt-related error codes, make FS_IOC_SET_ENCRYPTION_POLICY fail with EEXIST when the file already uses a different encryption policy. This is more descriptive than EINVAL, which was ambiguous with some of the other error cases. I am not aware of any users who might be relying on the previous error code of EINVAL, which was never documented anywhere. This failure case will be exercised by an xfstest. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: use ENOTDIR when setting encryption policy on nondirectoryEric Biggers2016-12-311-1/+1
| | | | | | | | | | | | | | | | As part of an effort to clean up fscrypt-related error codes, make FS_IOC_SET_ENCRYPTION_POLICY fail with ENOTDIR when the file descriptor does not refer to a directory. This is more descriptive than EINVAL, which was ambiguous with some of the other error cases. I am not aware of any users who might be relying on the previous error code of EINVAL, which was never documented anywhere, and in some buggy kernels did not exist at all as the S_ISDIR() check was missing. This failure case will be exercised by an xfstest. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: use ENOKEY when file cannot be created w/o keyEric Biggers2016-12-311-2/+2
| | | | | | | | | | | | | | | | | | | As part of an effort to clean up fscrypt-related error codes, make attempting to create a file in an encrypted directory that hasn't been "unlocked" fail with ENOKEY. Previously, several error codes were used for this case, including ENOENT, EACCES, and EPERM, and they were not consistent between and within filesystems. ENOKEY is a better choice because it expresses that the failure is due to lacking the encryption key. It also matches the error code returned when trying to open an encrypted regular file without the key. I am not aware of any users who might be relying on the previous inconsistent error codes, which were never documented anywhere. This failure case will be exercised by an xfstest. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: fix renaming and linking special filesEric Biggers2016-12-311-0/+5
| | | | | | | | | | | | | | | | | | | | Attempting to link a device node, named pipe, or socket file into an encrypted directory through rename(2) or link(2) always failed with EPERM. This happened because fscrypt_has_permitted_context() saw that the file was unencrypted and forbid creating the link. This behavior was unexpected because such files are never encrypted; only regular files, directories, and symlinks can be encrypted. To fix this, make fscrypt_has_permitted_context() always return true on special files. This will be covered by a test in my encryption xfstests patchset. Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support") Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Richard Weinberger <richard@nod.at> Cc: stable@vger.kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: fix the test_dummy_encryption mount optionTheodore Ts'o2016-12-271-1/+2
| | | | | | | | | | | | | | | | | Commit f1c131b45410a: "crypto: xts - Convert to skcipher" now fails the setkey operation if the AES key is the same as the tweak key. Previously this check was only done if FIPS mode is enabled. Now this check is also done if weak key checking was requested. This is reasonable, but since we were using the dummy key which was a constant series of 0x42 bytes, it now caused dummy encrpyption test mode to fail. Fix this by using 0x42... and 0x24... for the two keys, so they are different. Fixes: f1c131b45410a202eb45cc55980a7a9e4e4b4f40 Cc: stable@vger.kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Rename FS_WRITE_PATH_FL to FS_CTX_HAS_BOUNCE_BUFFER_FLDavid Gstir2016-12-112-4/+4
| | | | | | | | ... to better explain its purpose after introducing in-place encryption without bounce buffer. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Delay bounce page pool allocation until neededDavid Gstir2016-12-113-4/+9
| | | | | | | | | | Since fscrypt users can now indicated if fscrypt_encrypt_page() should use a bounce page, we can delay the bounce page pool initialization util it is really needed. That is until fscrypt_operations has no FS_CFLG_OWN_PAGES flag set. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Cleanup page locking requirements for fscrypt_{decrypt,encrypt}_page()David Gstir2016-12-111-3/+8
| | | | | | | | | | Rename the FS_CFLG_INPLACE_ENCRYPTION flag to FS_CFLG_OWN_PAGES which, when set, indicates that the fs uses pages under its own control as opposed to writeback pages which require locking and a bounce buffer for encryption. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Cleanup fscrypt_{decrypt,encrypt}_page()David Gstir2016-12-111-41/+52
| | | | | | | | | | - Improve documentation - Add BUG_ON(len == 0) to avoid accidental switch of offs and len parameters - Improve variable names for readability Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Never allocate fscrypt_ctx on in-place encryptionDavid Gstir2016-12-111-11/+19
| | | | | | | | | | | In case of in-place encryption fscrypt_ctx was allocated but never released. Since we don't need it for in-place encryption, we skip allocating it. Fixes: 1c7dcf69eea3 ("fscrypt: Add in-place encryption mode") Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Use correct index in decrypt path.David Gstir2016-12-111-1/+1
| | | | | | | | | | Actually use the fs-provided index instead of always using page->index which is only set for page-cache pages. Fixes: 9c4bb8a3a9b4 ("fscrypt: Let fs select encryption index/tweak") Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: move non-public structures and constants to fscrypt_private.hTheodore Ts'o2016-12-113-2/+73
| | | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Eric Biggers <ebiggers@google.com>
* fscrypt: unexport fscrypt_initialize()Theodore Ts'o2016-12-112-1/+3
| | | | | | | | The fscrypt_initalize() function isn't used outside fs/crypto, so there's no point making it be an exported symbol. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Eric Biggers <ebiggers@google.com>
* fscrypt: rename get_crypt_info() to fscrypt_get_crypt_info()Theodore Ts'o2016-12-113-5/+24
| | | | | | | | | | To avoid namespace collisions, rename get_crypt_info() to fscrypt_get_crypt_info(). The function is only used inside the fs/crypto directory, so declare it in the new header file, fscrypt_private.h. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Eric Biggers <ebiggers@google.com>
* fscrypto: move ioctl processing more fully into common codeEric Biggers2016-12-111-13/+21
| | | | | | | | | | | | Multiple bugs were recently fixed in the "set encryption policy" ioctl. To make it clear that fscrypt_process_policy() and fscrypt_get_policy() implement ioctls and therefore their implementations must take standard security and correctness precautions, rename them to fscrypt_ioctl_set_policy() and fscrypt_ioctl_get_policy(). Make the latter take in a struct file * to make it consistent with the former. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypto: remove unneeded Kconfig dependenciesEric Biggers2016-12-111-2/+0
| | | | | | | | | | | | SHA256 and ENCRYPTED_KEYS are not needed. CTR shouldn't be needed either, but I left it for now because it was intentionally added by commit 71dea01ea2ed ("ext4 crypto: require CONFIG_CRYPTO_CTR if ext4 encryption is enabled"). So it sounds like there may be a dependency problem elsewhere, which I have not been able to identify specifically, that must be solved before CTR can be removed. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypto: don't use on-stack buffer for key derivationEric Biggers2016-11-131-3/+13
| | | | | | | | | | | | | | | | With the new (in 4.9) option to use a virtually-mapped stack (CONFIG_VMAP_STACK), stack buffers cannot be used as input/output for the scatterlist crypto API because they may not be directly mappable to struct page. get_crypt_info() was using a stack buffer to hold the output from the encryption operation used to derive the per-file key. Fix it by using a heap buffer. This bug could most easily be observed in a CONFIG_DEBUG_SG kernel because this allowed the BUG in sg_set_buf() to be triggered. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypto: don't use on-stack buffer for filename encryptionEric Biggers2016-11-131-32/+21
| | | | | | | | | | | | | | | | | With the new (in 4.9) option to use a virtually-mapped stack (CONFIG_VMAP_STACK), stack buffers cannot be used as input/output for the scatterlist crypto API because they may not be directly mappable to struct page. For short filenames, fname_encrypt() was encrypting a stack buffer holding the padded filename. Fix it by encrypting the filename in-place in the output buffer, thereby making the temporary buffer unnecessary. This bug could most easily be observed in a CONFIG_DEBUG_SG kernel because this allowed the BUG in sg_set_buf() to be triggered. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Let fs select encryption index/tweakDavid Gstir2016-11-131-4/+7
| | | | | | | | | | | Avoid re-use of page index as tweak for AES-XTS when multiple parts of same page are encrypted. This will happen on multiple (partial) calls of fscrypt_encrypt_page on same page. page->index is only valid for writeback pages. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Constify struct inode pointerDavid Gstir2016-11-132-7/+7
| | | | | | | | | Some filesystems, such as UBIFS, maintain a const pointer for struct inode. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Enable partial page encryptionDavid Gstir2016-11-131-16/+26
| | | | | | | | | Not all filesystems work on full pages, thus we should allow them to hand partial pages to fscrypt for en/decryption. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Allow fscrypt_decrypt_page() to function with non-writeback pagesDavid Gstir2016-11-131-5/+6
| | | | | | | | | | Some filesystem might pass pages which do not have page->mapping->host set to the encrypted inode. We want the caller to explicitly pass the corresponding inode. Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypt: Add in-place encryption modeDavid Gstir2016-11-131-10/+15
| | | | | | | | | | | ext4 and f2fs require a bounce page when encrypting pages. However, not all filesystems will need that (eg. UBIFS). This is handled via a flag on fscrypt_operations where a fs implementation can select in-place encryption over using a bounce page (which is the default). Signed-off-by: David Gstir <david@sigma-star.at> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fscrypto: lock inode while setting encryption policyEric Biggers2016-10-151-0/+4
| | | | | | | | | | | | | i_rwsem needs to be acquired while setting an encryption policy so that concurrent calls to FS_IOC_SET_ENCRYPTION_POLICY are correctly serialized (especially the ->get_context() + ->set_context() pair), and so that new files cannot be created in the directory during or after the ->empty_dir() check. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Richard Weinberger <richard@nod.at> Cc: stable@vger.kernel.org
* fscrypto: make XTS tweak initialization endian-independentEric Biggers2016-10-121-7/+8
| | | | | | | | | | | | | | | | | The XTS tweak (or IV) was initialized differently on little endian and big endian systems. Because the ciphertext depends on the XTS tweak, it was not possible to use an encrypted filesystem created by a little endian system on a big endian system and vice versa, even if they shared the same PAGE_SIZE. Fix this by always using little endian. This will break hypothetical big endian users of ext4 or f2fs encryption. However, all users we are aware of are little endian, and it's believed that "real" big endian users are unlikely to exist yet. So this might as well be fixed now before it's too late. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
* Merge tag 'ext4_for_linus' of ↵Linus Torvalds2016-10-073-74/+93
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Lots of bug fixes and cleanups" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (40 commits) ext4: remove unused variable ext4: use journal inode to determine journal overhead ext4: create function to read journal inode ext4: unmap metadata when zeroing blocks ext4: remove plugging from ext4_file_write_iter() ext4: allow unlocked direct IO when pages are cached ext4: require encryption feature for EXT4_IOC_SET_ENCRYPTION_POLICY fscrypto: use standard macros to compute length of fname ciphertext ext4: do not unnecessarily null-terminate encrypted symlink data ext4: release bh in make_indexed_dir ext4: Allow parallel DIO reads ext4: allow DAX writeback for hole punch jbd2: fix lockdep annotation in add_transaction_credits() blockgroup_lock.h: simplify definition of NR_BG_LOCKS blockgroup_lock.h: remove debris from bgl_lock_ptr() conversion fscrypto: make filename crypto functions return 0 on success fscrypto: rename completion callbacks to reflect usage fscrypto: remove unnecessary includes fscrypto: improved validation when loading inode encryption metadata ext4: fix memory leak when symlink decryption fails ...
| * fscrypto: use standard macros to compute length of fname ciphertextEric Biggers2016-09-301-12/+5
| | | | | | | | | | Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * fscrypto: make filename crypto functions return 0 on successEric Biggers2016-09-151-24/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Several filename crypto functions: fname_decrypt(), fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned the output length on success or -errno on failure. However, the output length was redundant with the value written to 'oname->len'. It is also potentially error-prone to make callers have to check for '< 0' instead of '!= 0'. Therefore, make these functions return 0 instead of a length, and make the callers who cared about the return value being a length use 'oname->len' instead. For consistency also make other callers check for a nonzero result rather than a negative result. This change also fixes the inconsistency of fname_encrypt() actually already returning 0 on success, not a length like the other filename crypto functions and as documented in its function comment. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
| * fscrypto: rename completion callbacks to reflect usageEric Biggers2016-09-152-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | fscrypt_complete() was used only for data pages, not for all encryption/decryption. Rename it to page_crypt_complete(). dir_crypt_complete() was used for filename encryption/decryption for both directory entries and symbolic links. Rename it to fname_crypt_complete(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * fscrypto: remove unnecessary includesEric Biggers2016-09-153-6/+0
| | | | | | | | | | | | | | | | | | This patch removes some #includes that are clearly not needed, such as a reference to ecryptfs, which is unrelated to the new filesystem encryption code. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * fscrypto: improved validation when loading inode encryption metadataEric Biggers2016-09-151-23/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Validate fscrypt_context.format and fscrypt_context.flags. If unrecognized values are set, then the kernel may not know how to interpret the encrypted file, so it should fail the operation. - Validate that AES_256_XTS is used for contents and that AES_256_CTS is used for filenames. It was previously possible for the kernel to accept these reversed, though it would have taken manual editing of the block device. This was not intended. - Fail cleanly rather than BUG()-ing if a file has an unexpected type. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | fscrypto: require write access to mount to set encryption policyEric Biggers2016-09-101-13/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Since setting an encryption policy requires writing metadata to the filesystem, it should be guarded by mnt_want_write/mnt_drop_write. Otherwise, a user could cause a write to a frozen or readonly filesystem. This was handled correctly by f2fs but not by ext4. Make fscrypt_process_policy() handle it rather than relying on the filesystem to get it right. Signed-off-by: Eric Biggers <ebiggers@google.com> Cc: stable@vger.kernel.org # 4.1+; check fs/{ext4,f2fs} Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
* | fscrypto: only allow setting encryption policy on directoriesEric Biggers2016-09-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The FS_IOC_SET_ENCRYPTION_POLICY ioctl allowed setting an encryption policy on nondirectory files. This was unintentional, and in the case of nonempty regular files did not behave as expected because existing data was not actually encrypted by the ioctl. In the case of ext4, the user could also trigger filesystem errors in ->empty_dir(), e.g. due to mismatched "directory" checksums when the kernel incorrectly tried to interpret a regular file as a directory. This bug affected ext4 with kernels v4.8-rc1 or later and f2fs with kernels v4.6 and later. It appears that older kernels only permitted directories and that the check was accidentally lost during the refactoring to share the file encryption code between ext4 and f2fs. This patch restores the !S_ISDIR() check that was present in older kernels. Signed-off-by: Eric Biggers <ebiggers@google.com> Cc: stable@vger.kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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