frost/secp256k1-zkp
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Split memclear into two versions

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secp256k1_memclear has the side effect of undefining bytes for
valgrind checks. In some cases, we may want to zero bytes
but allow subsequent reads. So we split memclear into
memclear_explicit, which makes no guarantees about the content
of the buffer on return, and memzero_explicit, which guarantees
zero value on return.

Change the memset in partial_sign to use memzero_explicit.
This commit is contained in:
John Moffett
2025-09-08 12:21:48 -04:00
parent 4985ac0f89
commit 399b582a5f
11 changed files with 41 additions and 28 deletions
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10
src/hash_impl.h
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@@ -172,7 +172,7 @@ static void secp256k1_sha256_initialize_tagged(secp256k1_sha256 *hash, const uns
}
static void secp256k1_sha256_clear(secp256k1_sha256 *hash) {
secp256k1_memclear(hash, sizeof(*hash));
secp256k1_memclear_explicit(hash, sizeof(*hash));
}
static void secp256k1_hmac_sha256_initialize(secp256k1_hmac_sha256 *hash, const unsigned char *key, size_t keylen) {
@@ -200,7 +200,7 @@ static void secp256k1_hmac_sha256_initialize(secp256k1_hmac_sha256 *hash, const
rkey[n] ^= 0x5c ^ 0x36;
}
secp256k1_sha256_write(&hash->inner, rkey, sizeof(rkey));
secp256k1_memclear(rkey, sizeof(rkey));
secp256k1_memclear_explicit(rkey, sizeof(rkey));
}
static void secp256k1_hmac_sha256_write(secp256k1_hmac_sha256 *hash, const unsigned char *data, size_t size) {
@@ -211,12 +211,12 @@ static void secp256k1_hmac_sha256_finalize(secp256k1_hmac_sha256 *hash, unsigned
unsigned char temp[32];
secp256k1_sha256_finalize(&hash->inner, temp);
secp256k1_sha256_write(&hash->outer, temp, 32);
secp256k1_memclear(temp, sizeof(temp));
secp256k1_memclear_explicit(temp, sizeof(temp));
secp256k1_sha256_finalize(&hash->outer, out32);
}
static void secp256k1_hmac_sha256_clear(secp256k1_hmac_sha256 *hash) {
secp256k1_memclear(hash, sizeof(*hash));
secp256k1_memclear_explicit(hash, sizeof(*hash));
}
static void secp256k1_rfc6979_hmac_sha256_initialize(secp256k1_rfc6979_hmac_sha256 *rng, const unsigned char *key, size_t keylen) {
@@ -285,7 +285,7 @@ static void secp256k1_rfc6979_hmac_sha256_finalize(secp256k1_rfc6979_hmac_sha256
}
static void secp256k1_rfc6979_hmac_sha256_clear(secp256k1_rfc6979_hmac_sha256 *rng) {
secp256k1_memclear(rng, sizeof(*rng));
secp256k1_memclear_explicit(rng, sizeof(*rng));
}
#undef Round