libressl/0082-ssl-fix-CMAC-support.patch

From a5ef2b157731e3bd2f9c0dbba4caf361195fa5c8 Mon Sep 17 00:00:00 2001
From: Dmitry Baryshkov <dbaryshkov@gmail.com>
Date: Wed, 1 Apr 2020 22:43:37 +0300
Subject: [PATCH 82/87] ssl: fix CMAC support

For CMAC EVP_MD_CTX_md is NULL. Thus tls1_mac() will not be called.
Store read/write mac_size in the context to make it work.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
---
 src/lib/libssl/ssl.h      |  1 +
 src/lib/libssl/ssl_lib.c  |  2 ++
 src/lib/libssl/ssl_locl.h |  1 +
 src/lib/libssl/ssl_pkt.c  | 11 ++++-------
 src/lib/libssl/t1_enc.c   | 23 ++++++++++++-----------
 5 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/lib/libssl/ssl.h b/src/lib/libssl/ssl.h
index b11216b1e..1f9095feb 100644
--- a/src/lib/libssl/ssl.h
+++ b/src/lib/libssl/ssl.h
@@ -872,6 +872,7 @@ struct ssl_st {
 	 */
 	EVP_CIPHER_CTX *enc_read_ctx;		/* cryptographic state */
 	EVP_MD_CTX *read_hash;			/* used for mac generation */
+	int read_mac_size;
 
 	struct ssl_internal_st *internal;
 };
diff --git a/src/lib/libssl/ssl_lib.c b/src/lib/libssl/ssl_lib.c
index 5495a74ad..c989d802c 100644
--- a/src/lib/libssl/ssl_lib.c
+++ b/src/lib/libssl/ssl_lib.c
@@ -2538,6 +2538,7 @@ ssl_clear_cipher_read_state(SSL *s)
 	s->enc_read_ctx = NULL;
 	EVP_MD_CTX_free(s->read_hash);
 	s->read_hash = NULL;
+	s->read_mac_size = 0;
 
 	if (s->internal->aead_read_ctx != NULL) {
 		EVP_AEAD_CTX_cleanup(&s->internal->aead_read_ctx->ctx);
@@ -2553,6 +2554,7 @@ ssl_clear_cipher_write_state(SSL *s)
 	s->internal->enc_write_ctx = NULL;
 	EVP_MD_CTX_free(s->internal->write_hash);
 	s->internal->write_hash = NULL;
+	s->internal->write_mac_size = 0;
 
 	if (s->internal->aead_write_ctx != NULL) {
 		EVP_AEAD_CTX_cleanup(&s->internal->aead_write_ctx->ctx);
diff --git a/src/lib/libssl/ssl_locl.h b/src/lib/libssl/ssl_locl.h
index f522abf96..858010b87 100644
--- a/src/lib/libssl/ssl_locl.h
+++ b/src/lib/libssl/ssl_locl.h
@@ -737,6 +737,7 @@ typedef struct ssl_internal_st {
 
 	EVP_CIPHER_CTX *enc_write_ctx;		/* cryptographic state */
 	EVP_MD_CTX *write_hash;			/* used for mac generation */
+	int write_mac_size;
 
 	/* session info */
 
diff --git a/src/lib/libssl/ssl_pkt.c b/src/lib/libssl/ssl_pkt.c
index d4aebebe9..23a5509c3 100644
--- a/src/lib/libssl/ssl_pkt.c
+++ b/src/lib/libssl/ssl_pkt.c
@@ -443,12 +443,12 @@ ssl3_get_record(SSL *s)
 
 	/* r->length is now the compressed data plus mac */
 	if ((sess != NULL) && (s->enc_read_ctx != NULL) &&
-	    (EVP_MD_CTX_md(s->read_hash) != NULL)) {
+	    (s->read_mac_size != 0)) {
 		/* s->read_hash != NULL => mac_size != -1 */
 		unsigned char *mac = NULL;
 		unsigned char mac_tmp[EVP_MAX_MD_SIZE];
 
-		mac_size = EVP_MD_CTX_size(s->read_hash);
+		mac_size = s->read_mac_size;
 		OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
 
 		orig_len = rr->length + rr->padding_length;
@@ -628,13 +628,10 @@ ssl3_create_record(SSL *s, unsigned char *p, int type, const unsigned char *buf,
 
 	memset(&cbb, 0, sizeof(cbb));
 
-	if ((sess == NULL) || (s->internal->enc_write_ctx == NULL) ||
-	    (EVP_MD_CTX_md(s->internal->write_hash) == NULL)) {
+	if ((sess == NULL) || (s->internal->enc_write_ctx == NULL)) {
 		mac_size = 0;
 	} else {
-		mac_size = EVP_MD_CTX_size(s->internal->write_hash);
-		if (mac_size < 0)
-			goto err;
+		mac_size = s->internal->write_mac_size;
 	}
 
 	/*
diff --git a/src/lib/libssl/t1_enc.c b/src/lib/libssl/t1_enc.c
index 7e9422b51..363447b52 100644
--- a/src/lib/libssl/t1_enc.c
+++ b/src/lib/libssl/t1_enc.c
@@ -407,6 +407,7 @@ tls1_change_cipher_state_cipher(SSL *s, char is_read,
 	const EVP_CIPHER *cipher;
 	EVP_MD_CTX *mac_ctx;
 	EVP_PKEY *mac_key;
+	int mac_size;
 	const EVP_MD *mac;
 	const EVP_CIPHER *mac_cipher;
 	int mac_type;
@@ -459,14 +460,20 @@ tls1_change_cipher_state_cipher(SSL *s, char is_read,
 	if (mac_type == EVP_PKEY_CMAC) {
 		mac_key = EVP_PKEY_new_CMAC_key(NULL, mac_secret,
 				mac_secret_size, mac_cipher);
+		mac_size = EVP_CIPHER_block_size(mac_cipher);
 	} else {
 		mac_key = EVP_PKEY_new_mac_key(mac_type, NULL, mac_secret,
 				mac_secret_size);
+		mac_size = EVP_MD_size(mac);
 	}
 	if (mac_key  == NULL)
 		goto err;
 	EVP_DigestSignInit(mac_ctx, NULL, mac, NULL, mac_key);
 	EVP_PKEY_free(mac_key);
+	if (is_read)
+		s->read_mac_size = mac_size;
+	else
+		s->internal->write_mac_size = mac_size;
 
 	if (S3I(s)->hs.new_cipher->algorithm_enc == SSL_eGOST2814789CNT) {
 		int nid;
@@ -846,10 +853,7 @@ tls1_enc(SSL *s, int send)
 	}
 
 	if (send) {
-		if (EVP_MD_CTX_md(s->internal->write_hash)) {
-			int n = EVP_MD_CTX_size(s->internal->write_hash);
-			OPENSSL_assert(n >= 0);
-		}
+		OPENSSL_assert(s->internal->write_mac_size >= 0);
 		ds = s->internal->enc_write_ctx;
 		if (s->internal->enc_write_ctx == NULL)
 			enc = NULL;
@@ -874,10 +878,7 @@ tls1_enc(SSL *s, int send)
 			}
 		}
 	} else {
-		if (EVP_MD_CTX_md(s->read_hash)) {
-			int n = EVP_MD_CTX_size(s->read_hash);
-			OPENSSL_assert(n >= 0);
-		}
+		OPENSSL_assert(s->read_mac_size >= 0);
 		ds = s->enc_read_ctx;
 		if (s->enc_read_ctx == NULL)
 			enc = NULL;
@@ -917,8 +918,7 @@ tls1_enc(SSL *s, int send)
 			return -1;	/* AEAD can fail to verify MAC */
 
 		ret = 1;
-		if (EVP_MD_CTX_md(s->read_hash) != NULL)
-			mac_size = EVP_MD_CTX_size(s->read_hash);
+		mac_size = s->read_mac_size;
 		if ((bs != 1) && !send)
 			ret = tls1_cbc_remove_padding(s, rec, bs, mac_size);
 	}
@@ -970,13 +970,14 @@ tls1_mac(SSL *ssl, unsigned char *md, int send)
 		rec = &(ssl->s3->internal->wrec);
 		seq = &(ssl->s3->internal->write_sequence[0]);
 		hash = ssl->internal->write_hash;
+		t = ssl->internal->write_mac_size;
 	} else {
 		rec = &(ssl->s3->internal->rrec);
 		seq = &(ssl->s3->internal->read_sequence[0]);
 		hash = ssl->read_hash;
+		t = ssl->read_mac_size;
 	}
 
-	t = EVP_MD_CTX_size(hash);
 	OPENSSL_assert(t >= 0);
 	md_size = t;
 
-- 
2.17.1