[Pkg-bitcoin-commits] [libsecp256k1] 10/22: Restructure nonce clearing

[Jonas Smedegaard]

This is an automated email from the git hooks/post-receive script.

js pushed a commit to branch master
in repository libsecp256k1.

commit 37697832d633ea4debbf5a9d8e9b74ea5ea08a9b
Author: bgorlick <ben at bengorlick.com>
Date:   Fri Oct 21 04:59:32 2016 -0700

    Restructure nonce clearing
    
    Make sure we clear the nonce data even if the nonce function fails (it may have written partial data), and call memset only once in the case we iterate to produce a valid signature.
---
 src/modules/recovery/main_impl.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/modules/recovery/main_impl.h b/src/modules/recovery/main_impl.h
old mode 100644
new mode 100755
index ec42f4b..86f2f0c
--- a/src/modules/recovery/main_impl.h
+++ b/src/modules/recovery/main_impl.h
@@ -138,16 +138,15 @@ int secp256k1_ecdsa_sign_recoverable(const secp256k1_context* ctx, secp256k1_ecd
     secp256k1_scalar_set_b32(&sec, seckey, &overflow);
     /* Fail if the secret key is invalid. */
     if (!overflow && !secp256k1_scalar_is_zero(&sec)) {
+        unsigned char nonce32[32];
         unsigned int count = 0;
         secp256k1_scalar_set_b32(&msg, msg32, NULL);
         while (1) {
-            unsigned char nonce32[32];
             ret = noncefp(nonce32, msg32, seckey, NULL, (void*)noncedata, count);
             if (!ret) {
                 break;
             }
             secp256k1_scalar_set_b32(&non, nonce32, &overflow);
-            memset(nonce32, 0, 32);
             if (!secp256k1_scalar_is_zero(&non) && !overflow) {
                 if (secp256k1_ecdsa_sig_sign(&ctx->ecmult_gen_ctx, &r, &s, &sec, &msg, &non, &recid)) {
                     break;
@@ -155,6 +154,7 @@ int secp256k1_ecdsa_sign_recoverable(const secp256k1_context* ctx, secp256k1_ecd
             }
             count++;
         }
+        memset(nonce32, 0, 32);
         secp256k1_scalar_clear(&msg);
         secp256k1_scalar_clear(&non);
         secp256k1_scalar_clear(&sec);

-- 
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/pkg-bitcoin/libsecp256k1.git