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References: <20210310072726.288252-1-ebiggers@kernel.org>
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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Wed, 10 Mar 2021 09:55:35 +0100
Message-ID: <CAMj1kXF_9jdynzL3Dy=s4Bp21LoUMnqPi+hG1OnjJg7S6+uHpQ@mail.gmail.com>
Subject: Re: [PATCH] crypto: arm/blake2s - fix for big endian
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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On Wed, 10 Mar 2021 at 08:29, Eric Biggers <ebiggers@kernel.org> wrote:
>
> From: Eric Biggers <ebiggers@google.com>
>
> The new ARM BLAKE2s code doesn't work correctly (fails the self-tests)
> in big endian kernel builds because it doesn't swap the endianness of
> the message words when loading them.  Fix this.
>
> Fixes: 5172d322d34c ("crypto: arm/blake2s - add ARM scalar optimized BLAKE2s")
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  arch/arm/crypto/blake2s-core.S | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/arch/arm/crypto/blake2s-core.S b/arch/arm/crypto/blake2s-core.S
> index bed897e9a181a..86345751bbf3a 100644
> --- a/arch/arm/crypto/blake2s-core.S
> +++ b/arch/arm/crypto/blake2s-core.S
> @@ -8,6 +8,7 @@
>   */
>
>  #include <linux/linkage.h>
> +#include <asm/assembler.h>
>
>         // Registers used to hold message words temporarily.  There aren't
>         // enough ARM registers to hold the whole message block, so we have to
> @@ -38,6 +39,23 @@
>  #endif
>  .endm
>
> +.macro _le32_bswap     a, tmp
> +#ifdef __ARMEB__
> +       rev_l           \a, \tmp
> +#endif
> +.endm
> +
> +.macro _le32_bswap_8x  a, b, c, d, e, f, g, h,  tmp
> +       _le32_bswap     \a, \tmp
> +       _le32_bswap     \b, \tmp
> +       _le32_bswap     \c, \tmp
> +       _le32_bswap     \d, \tmp
> +       _le32_bswap     \e, \tmp
> +       _le32_bswap     \f, \tmp
> +       _le32_bswap     \g, \tmp
> +       _le32_bswap     \h, \tmp
> +.endm
> +
>  // Execute a quarter-round of BLAKE2s by mixing two columns or two diagonals.
>  // (a0, b0, c0, d0) and (a1, b1, c1, d1) give the registers containing the two
>  // columns/diagonals.  s0-s1 are the word offsets to the message words the first
> @@ -180,8 +198,10 @@ ENTRY(blake2s_compress_arch)
>         tst             r1, #3
>         bne             .Lcopy_block_misaligned
>         ldmia           r1!, {r2-r9}
> +       _le32_bswap_8x  r2, r3, r4, r5, r6, r7, r8, r9,  r14
>         stmia           r12!, {r2-r9}
>         ldmia           r1!, {r2-r9}
> +       _le32_bswap_8x  r2, r3, r4, r5, r6, r7, r8, r9,  r14
>         stmia           r12, {r2-r9}
>  .Lcopy_block_done:
>         str             r1, [sp, #68]           // Update message pointer
> @@ -268,6 +288,7 @@ ENTRY(blake2s_compress_arch)
>  1:
>  #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
>         ldr             r3, [r1], #4
> +       _le32_bswap     r3, r4
>  #else
>         ldrb            r3, [r1, #0]
>         ldrb            r4, [r1, #1]
> --
> 2.30.1
>