On 5 September 2018 at 21:24, Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
>
> fscrypt doesn't use the CTR mode of operation for anything, so there's
> no need to select CRYPTO_CTR. It was added by commit 71dea01ea2ed
> ("ext4 crypto: require CONFIG_CRYPTO_CTR if ext4 encryption is
> enabled"). But, I've been unable to identify the arm64 crypto bug it
> was supposedly working around.
>
> I suspect the issue was seen only on some old Android device kernel
> (circa 3.10?). So if the fix wasn't mistaken, the real bug is probably
> already fixed. Or maybe it was actually a bug in a non-upstream crypto
> driver.
>
> So, remove the dependency. If it turns out there's actually still a
> bug, we'll fix it properly.
>
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
This may be related to
11e3b725cfc2 crypto: arm64/aes-blk - honour iv_out requirement in CBC
and CTR modes
given that the commit in question mentions CTS. How it actually works
around the issue is unclear to me, though.
> ---
> fs/crypto/Kconfig | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
> index 02b7d91c92310..284b589b4774d 100644
> --- a/fs/crypto/Kconfig
> +++ b/fs/crypto/Kconfig
> @@ -6,7 +6,6 @@ config FS_ENCRYPTION
> select CRYPTO_ECB
> select CRYPTO_XTS
> select CRYPTO_CTS
> - select CRYPTO_CTR
> select CRYPTO_SHA256
> select KEYS
> help
> --
> 2.19.0.rc2.392.g5ba43deb5a-goog
>
