2018-02-12 16:55:05

by Jinbum Park

Subject: [PATCH] crypto: arm/aes-cipher - move S-box to .rodata section

Move the AES inverse S-box to the .rodata section
where it is safe from abuse by speculation.

Signed-off-by: Jinbum Park <[email protected]>
---
arch/arm/crypto/aes-cipher-core.S | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/arm/crypto/aes-cipher-core.S b/arch/arm/crypto/aes-cipher-core.S
index 54b3840..184d6c2 100644
--- a/arch/arm/crypto/aes-cipher-core.S
+++ b/arch/arm/crypto/aes-cipher-core.S
@@ -174,6 +174,16 @@
.ltorg
.endm

+ENTRY(__aes_arm_encrypt)
+ do_crypt fround, crypto_ft_tab, crypto_ft_tab + 1, 2
+ENDPROC(__aes_arm_encrypt)
+
+ .align 5
+ENTRY(__aes_arm_decrypt)
+ do_crypt iround, crypto_it_tab, __aes_arm_inverse_sbox, 0
+ENDPROC(__aes_arm_decrypt)
+
+ .section ".rodata", "a"
.align L1_CACHE_SHIFT
.type __aes_arm_inverse_sbox, %object
__aes_arm_inverse_sbox:
@@ -210,12 +220,3 @@ __aes_arm_inverse_sbox:
.byte 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26
.byte 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
.size __aes_arm_inverse_sbox, . - __aes_arm_inverse_sbox
-
-ENTRY(__aes_arm_encrypt)
- do_crypt fround, crypto_ft_tab, crypto_ft_tab + 1, 2
-ENDPROC(__aes_arm_encrypt)
-
- .align 5
-ENTRY(__aes_arm_decrypt)
- do_crypt iround, crypto_it_tab, __aes_arm_inverse_sbox, 0
-ENDPROC(__aes_arm_decrypt)
--
1.9.1

2018-02-13 10:58:43

by Ard Biesheuvel

Subject: Re: [PATCH] crypto: arm/aes-cipher - move S-box to .rodata section

On 12 February 2018 at 13:52, Jinbum Park <[email protected]> wrote:
> Move the AES inverse S-box to the .rodata section
> where it is safe from abuse by speculation.
>
> Signed-off-by: Jinbum Park <[email protected]>

Acked-by: Ard Biesheuvel <[email protected]>

> ---
> arch/arm/crypto/aes-cipher-core.S | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/crypto/aes-cipher-core.S b/arch/arm/crypto/aes-cipher-core.S
> index 54b3840..184d6c2 100644
> --- a/arch/arm/crypto/aes-cipher-core.S
> +++ b/arch/arm/crypto/aes-cipher-core.S
> @@ -174,6 +174,16 @@
> .ltorg
> .endm
>
> +ENTRY(__aes_arm_encrypt)
> + do_crypt fround, crypto_ft_tab, crypto_ft_tab + 1, 2
> +ENDPROC(__aes_arm_encrypt)
> +
> + .align 5
> +ENTRY(__aes_arm_decrypt)
> + do_crypt iround, crypto_it_tab, __aes_arm_inverse_sbox, 0
> +ENDPROC(__aes_arm_decrypt)
> +
> + .section ".rodata", "a"
> .align L1_CACHE_SHIFT
> .type __aes_arm_inverse_sbox, %object
> __aes_arm_inverse_sbox:
> @@ -210,12 +220,3 @@ __aes_arm_inverse_sbox:
> .byte 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26
> .byte 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
> .size __aes_arm_inverse_sbox, . - __aes_arm_inverse_sbox
> -
> -ENTRY(__aes_arm_encrypt)
> - do_crypt fround, crypto_ft_tab, crypto_ft_tab + 1, 2
> -ENDPROC(__aes_arm_encrypt)
> -
> - .align 5
> -ENTRY(__aes_arm_decrypt)
> - do_crypt iround, crypto_it_tab, __aes_arm_inverse_sbox, 0
> -ENDPROC(__aes_arm_decrypt)
> --
> 1.9.1
>

2018-02-22 15:14:22

by Herbert Xu

Subject: Re: [PATCH] crypto: arm/aes-cipher - move S-box to .rodata section

On Mon, Feb 12, 2018 at 10:52:37PM +0900, Jinbum Park wrote:
> Move the AES inverse S-box to the .rodata section
> where it is safe from abuse by speculation.
>
> Signed-off-by: Jinbum Park <[email protected]>

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt