From b5a7aef1ef436ec005fef0efe31a676ec5f4ab31 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 4 May 2016 22:05:01 -0700 Subject: fscrypto/f2fs: allow fs-specific key prefix for fs encryption This patch allows fscrypto to handle a second key prefix given by filesystem. The main reason is to provide backward compatibility, since previously f2fs used "f2fs:" as a crypto prefix instead of "fscrypt:". Later, ext4 should also provide key_prefix() to give "ext4:". One concern decribed by Ted would be kinda double check overhead of prefixes. In x86, for example, validate_user_key consumes 8 ms after boot-up, which turns out derive_key_aes() consumed most of the time to load specific crypto module. After such the cold miss, it shows almost zero latencies, which treats as a negligible overhead. Note that request_key() detects wrong prefix in prior to derive_key_aes() even. Cc: Ted Tso Cc: stable@vger.kernel.org # v4.6 Signed-off-by: Jaegeuk Kim --- include/linux/fscrypto.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h index 6027f6bbb061..cfa6cde25f8e 100644 --- a/include/linux/fscrypto.h +++ b/include/linux/fscrypto.h @@ -175,6 +175,7 @@ struct fscrypt_name { */ struct fscrypt_operations { int (*get_context)(struct inode *, void *, size_t); + int (*key_prefix)(struct inode *, u8 **); int (*prepare_context)(struct inode *); int (*set_context)(struct inode *, const void *, size_t, void *); int (*dummy_context)(struct inode *); -- cgit v1.2.3