diff options
| -rw-r--r-- | fs/crypto/crypto.c | 10 | ||||
| -rw-r--r-- | fs/crypto/fname.c | 11 | ||||
| -rw-r--r-- | fs/ubifs/ubifs.h | 2 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 12 |
4 files changed, 26 insertions, 9 deletions
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 526a4c1bed99..e78be66bbf01 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -113,7 +113,7 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, if (WARN_ON_ONCE(len <= 0)) return -EINVAL; - if (WARN_ON_ONCE(len % FS_CRYPTO_BLOCK_SIZE != 0)) + if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0)) return -EINVAL; fscrypt_generate_iv(&iv, lblk_num, ci); @@ -213,8 +213,8 @@ EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks); * fscrypt_encrypt_block_inplace() - Encrypt a filesystem block in-place * @inode: The inode to which this block belongs * @page: The page containing the block to encrypt - * @len: Size of block to encrypt. Doesn't need to be a multiple of the - * fs block size, but must be a multiple of FS_CRYPTO_BLOCK_SIZE. + * @len: Size of block to encrypt. This must be a multiple of + * FSCRYPT_CONTENTS_ALIGNMENT. * @offs: Byte offset within @page at which the block to encrypt begins * @lblk_num: Filesystem logical block number of the block, i.e. the 0-based * number of the block within the file @@ -283,8 +283,8 @@ EXPORT_SYMBOL(fscrypt_decrypt_pagecache_blocks); * fscrypt_decrypt_block_inplace() - Decrypt a filesystem block in-place * @inode: The inode to which this block belongs * @page: The page containing the block to decrypt - * @len: Size of block to decrypt. Doesn't need to be a multiple of the - * fs block size, but must be a multiple of FS_CRYPTO_BLOCK_SIZE. + * @len: Size of block to decrypt. This must be a multiple of + * FSCRYPT_CONTENTS_ALIGNMENT. * @offs: Byte offset within @page at which the block to decrypt begins * @lblk_num: Filesystem logical block number of the block, i.e. the 0-based * number of the block within the file diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index a9be4bc74a94..14e0ef5e9a20 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -19,6 +19,13 @@ #include "fscrypt_private.h" /* + * The minimum message length (input and output length), in bytes, for all + * filenames encryption modes. Filenames shorter than this will be zero-padded + * before being encrypted. + */ +#define FSCRYPT_FNAME_MIN_MSG_LEN 16 + +/* * struct fscrypt_nokey_name - identifier for directory entry when key is absent * * When userspace lists an encrypted directory without access to the key, the @@ -267,7 +274,7 @@ bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, if (orig_len > max_len) return false; - encrypted_len = max(orig_len, (u32)FS_CRYPTO_BLOCK_SIZE); + encrypted_len = max_t(u32, orig_len, FSCRYPT_FNAME_MIN_MSG_LEN); encrypted_len = round_up(encrypted_len, padding); *encrypted_len_ret = min(encrypted_len, max_len); return true; @@ -350,7 +357,7 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, return 0; } - if (iname->len < FS_CRYPTO_BLOCK_SIZE) + if (iname->len < FSCRYPT_FNAME_MIN_MSG_LEN) return -EUCLEAN; if (fscrypt_has_encryption_key(inode)) diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index 008fa46ef61e..7d6d2f152e03 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -132,7 +132,7 @@ #define WORST_COMPR_FACTOR 2 #ifdef CONFIG_FS_ENCRYPTION -#define UBIFS_CIPHER_BLOCK_SIZE FS_CRYPTO_BLOCK_SIZE +#define UBIFS_CIPHER_BLOCK_SIZE FSCRYPT_CONTENTS_ALIGNMENT #else #define UBIFS_CIPHER_BLOCK_SIZE 0 #endif diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 50d92d805bd8..efc7f96e5e26 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -18,7 +18,17 @@ #include <linux/slab.h> #include <uapi/linux/fscrypt.h> -#define FS_CRYPTO_BLOCK_SIZE 16 +/* + * The lengths of all file contents blocks must be divisible by this value. + * This is needed to ensure that all contents encryption modes will work, as + * some of the supported modes don't support arbitrarily byte-aligned messages. + * + * Since the needed alignment is 16 bytes, most filesystems will meet this + * requirement naturally, as typical block sizes are powers of 2. However, if a + * filesystem can generate arbitrarily byte-aligned block lengths (e.g., via + * compression), then it will need to pad to this alignment before encryption. + */ +#define FSCRYPT_CONTENTS_ALIGNMENT 16 union fscrypt_policy; struct fscrypt_info; |