From cf2ab51a449ce3d92163217c8078f0f625aac7ae Mon Sep 17 00:00:00 2001 From: Vitaly Chikunov Date: Sun, 22 Jul 2018 10:34:03 +0300 Subject: [PATCH] grasshopper: Fix streaming for CTR mode Previously CTR did not continue unfinished block on the next cipher iteration. --- gost_grasshopper_cipher.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/gost_grasshopper_cipher.c b/gost_grasshopper_cipher.c index da68057..d9acd1e 100644 --- a/gost_grasshopper_cipher.c +++ b/gost_grasshopper_cipher.c @@ -209,6 +209,7 @@ GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctr(EVP_CIPHER_CTX* ctx, con gost_grasshopper_cipher_ctx_ctr* c = EVP_CIPHER_CTX_get_cipher_data(ctx); c->c.type = GRASSHOPPER_CIPHER_CTR; + ctx->num = 0; grasshopper_zero128(&c->iv_buffer); grasshopper_zero128(&c->partial_buffer); @@ -306,12 +307,20 @@ int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX* ctx, unsigned char* out, unsigned char* iv = EVP_CIPHER_CTX_iv_noconst(ctx); const unsigned char* current_in = in; unsigned char* current_out = out; - size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE; grasshopper_w128_t* currentInputBlock; grasshopper_w128_t* currentOutputBlock; + unsigned int n = ctx->num; size_t lasted; size_t i; + while (n && inl) { + *(current_out++) = *(current_in++) ^ c->partial_buffer.b[n]; + --inl; + n = (n + 1) % GRASSHOPPER_BLOCK_SIZE; + } + ctx->num = n; + size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE; + memcpy(&c->iv_buffer, iv, 8); // full parts @@ -334,6 +343,7 @@ int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX* ctx, unsigned char* out, for (i = 0; i < lasted; i++) { currentOutputBlock->b[i] = c->partial_buffer.b[i] ^ currentInputBlock->b[i]; } + ctx->num = i; ctr128_inc(c->iv_buffer.b); } -- 2.39.2