* [PATCH] crypto: ecdh - fix big endian bug in ECC library
@ 2019-10-23 9:50 Ard Biesheuvel
2019-11-01 6:08 ` Herbert Xu
0 siblings, 1 reply; 2+ messages in thread
From: Ard Biesheuvel @ 2019-10-23 9:50 UTC (permalink / raw)
To: linux-crypto; +Cc: herbert, Ard Biesheuvel
The elliptic curve arithmetic library used by the EC-DH KPP implementation
assumes big endian byte order, and unconditionally reverses the byte
and word order of multi-limb quantities. On big endian systems, the byte
reordering is not necessary, while the word ordering needs to be retained.
So replace the __swab64() invocation with a call to be64_to_cpu() which
should do the right thing for both little and big endian builds.
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
crypto/ecc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/crypto/ecc.c b/crypto/ecc.c
index dfe114bc0c4a..8ee787723c5c 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -1284,10 +1284,11 @@ EXPORT_SYMBOL(ecc_point_mult_shamir);
static inline void ecc_swap_digits(const u64 *in, u64 *out,
unsigned int ndigits)
{
+ const __be64 *src = (__force __be64 *)in;
int i;
for (i = 0; i < ndigits; i++)
- out[i] = __swab64(in[ndigits - 1 - i]);
+ out[i] = be64_to_cpu(src[ndigits - 1 - i]);
}
static int __ecc_is_key_valid(const struct ecc_curve *curve,
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] crypto: ecdh - fix big endian bug in ECC library
2019-10-23 9:50 [PATCH] crypto: ecdh - fix big endian bug in ECC library Ard Biesheuvel
@ 2019-11-01 6:08 ` Herbert Xu
0 siblings, 0 replies; 2+ messages in thread
From: Herbert Xu @ 2019-11-01 6:08 UTC (permalink / raw)
To: Ard Biesheuvel; +Cc: linux-crypto
On Wed, Oct 23, 2019 at 11:50:44AM +0200, Ard Biesheuvel wrote:
> The elliptic curve arithmetic library used by the EC-DH KPP implementation
> assumes big endian byte order, and unconditionally reverses the byte
> and word order of multi-limb quantities. On big endian systems, the byte
> reordering is not necessary, while the word ordering needs to be retained.
>
> So replace the __swab64() invocation with a call to be64_to_cpu() which
> should do the right thing for both little and big endian builds.
>
> Cc: <stable@vger.kernel.org> # v4.9+
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> crypto/ecc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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