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| author | Patrick Steuer <patrick.steuer@de.ibm.com> | 2019-11-03 00:32:04 +0100 |
|---|---|---|
| committer | Patrick Steuer <patrick.steuer@de.ibm.com> | 2019-11-05 13:53:04 +0100 |
| commit | 677c4a012a7e72b5f2dd239639034f01fad850bf (patch) | |
| tree | 092195e1966385aab5aa66297dd2cef0ec911ac3 /crypto | |
| parent | 6376c229c44a355248db17e9f0bb2e4567a16d0d (diff) | |
s390x assembly pack: process x25519 and x448 non-canonical values
...in constant time.
Signed-off-by: Patrick Steuer <patrick.steuer@de.ibm.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10339)
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/ec/ecx_meth.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/crypto/ec/ecx_meth.c b/crypto/ec/ecx_meth.c index 776e88de36..d141fe7b81 100644 --- a/crypto/ec/ecx_meth.c +++ b/crypto/ec/ecx_meth.c @@ -854,6 +854,7 @@ static const EVP_PKEY_METHOD ed448_pkey_meth = { #ifdef S390X_EC_ASM # include "s390x_arch.h" +# include "internal/constant_time.h" static void s390x_x25519_mod_p(unsigned char u[32]) { @@ -867,16 +868,16 @@ static void s390x_x25519_mod_p(unsigned char u[32]) u_red[31] = (unsigned char)c; c >>= 8; - for (i = 30; c > 0 && i >= 0; i--) { + for (i = 30; i >= 0; i--) { c += (unsigned int)u_red[i]; u_red[i] = (unsigned char)c; c >>= 8; } - if (u_red[0] & 0x80) { - u_red[0] &= 0x7f; - memcpy(u, u_red, sizeof(u_red)); - } + c = (u_red[0] & 0x80) >> 7; + u_red[0] &= 0x7f; + constant_time_cond_swap_buff(0 - (unsigned char)c, + u, u_red, sizeof(u_red)); } static void s390x_x448_mod_p(unsigned char u[56]) @@ -901,14 +902,14 @@ static void s390x_x448_mod_p(unsigned char u[56]) u_red[27] = (unsigned char)c; c >>= 8; - for (i = 26; c > 0 && i >= 0; i--) { + for (i = 26; i >= 0; i--) { c += (unsigned int)u_red[i]; u_red[i] = (unsigned char)c; c >>= 8; } - if (c) - memcpy(u, u_red, sizeof(u_red)); + constant_time_cond_swap_buff(0 - (unsigned char)c, + u, u_red, sizeof(u_red)); } static int s390x_x25519_mul(unsigned char u_dst[32], |