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path: root/fs/crypto/Kconfig
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2017-06-24fscrypt: add support for AES-128-CBCDaniel Walter1-0/+1
fscrypt provides facilities to use different encryption algorithms which are selectable by userspace when setting the encryption policy. Currently, only AES-256-XTS for file contents and AES-256-CBC-CTS for file names are implemented. This is a clear case of kernel offers the mechanism and userspace selects a policy. Similar to what dm-crypt and ecryptfs have. This patch adds support for using AES-128-CBC for file contents and AES-128-CBC-CTS for file name encryption. To mitigate watermarking attacks, IVs are generated using the ESSIV algorithm. While AES-CBC is actually slightly less secure than AES-XTS from a security point of view, there is more widespread hardware support. Using AES-CBC gives us the acceptable performance while still providing a moderate level of security for persistent storage. Especially low-powered embedded devices with crypto accelerators such as CAAM or CESA often only support AES-CBC. Since using AES-CBC over AES-XTS is basically thought of a last resort, we use AES-128-CBC over AES-256-CBC since it has less encryption rounds and yields noticeable better performance starting from a file size of just a few kB. Signed-off-by: Daniel Walter <dwalter@sigma-star.at> [david@sigma-star.at: addressed review comments] Signed-off-by: David Gstir <david@sigma-star.at> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-01-02fscrypt: factor out bio specific functionsRichard Weinberger1-1/+0
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>
2016-12-12fscrypto: remove unneeded Kconfig dependenciesEric Biggers1-2/+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>
2016-03-18fs crypto: move per-file encryption from f2fs tree to fs/cryptoJaegeuk Kim1-0/+18
This patch adds the renamed functions moved from the f2fs crypto files. 1. definitions for per-file encryption used by ext4 and f2fs. 2. crypto.c for encrypt/decrypt functions a. IO preparation: - fscrypt_get_ctx / fscrypt_release_ctx b. before IOs: - fscrypt_encrypt_page - fscrypt_decrypt_page - fscrypt_zeroout_range c. after IOs: - fscrypt_decrypt_bio_pages - fscrypt_pullback_bio_page - fscrypt_restore_control_page 3. policy.c supporting context management. a. For ioctls: - fscrypt_process_policy - fscrypt_get_policy b. For context permission - fscrypt_has_permitted_context - fscrypt_inherit_context 4. keyinfo.c to handle permissions - fscrypt_get_encryption_info - fscrypt_free_encryption_info 5. fname.c to support filename encryption a. general wrapper functions - fscrypt_fname_disk_to_usr - fscrypt_fname_usr_to_disk - fscrypt_setup_filename - fscrypt_free_filename b. specific filename handling functions - fscrypt_fname_alloc_buffer - fscrypt_fname_free_buffer 6. Makefile and Kconfig Cc: Al Viro <viro@ftp.linux.org.uk> Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Uday Savagaonkar <savagaon@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>