From 2990d731be5155c46ccc71772efd2f35d25ff5ee Mon Sep 17 00:00:00 2001
From: jsing <>
Date: Thu, 12 May 2022 19:33:19 +0000
Subject: Rewrite asn1_enc_save() using CBS.

Rework and clean up other asn1_enc_* related functions while here.

ok tb@
---
 src/lib/libcrypto/asn1/tasn_utl.c | 103 +++++++++++++++++++++++---------------
 1 file changed, 62 insertions(+), 41 deletions(-)

(limited to 'src/lib/libcrypto/asn1/tasn_utl.c')

diff --git a/src/lib/libcrypto/asn1/tasn_utl.c b/src/lib/libcrypto/asn1/tasn_utl.c
index e3b2c9e4dc..1fd061f9f8 100644
--- a/src/lib/libcrypto/asn1/tasn_utl.c
+++ b/src/lib/libcrypto/asn1/tasn_utl.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tasn_utl.c,v 1.15 2022/05/12 19:24:38 jsing Exp $ */
+/* $OpenBSD: tasn_utl.c,v 1.16 2022/05/12 19:33:19 jsing Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2000.
  */
@@ -56,13 +56,17 @@
  *
  */
 
+#include <limits.h>
 #include <stddef.h>
 #include <string.h>
+
 #include <openssl/asn1.h>
 #include <openssl/asn1t.h>
 #include <openssl/objects.h>
 #include <openssl/err.h>
 
+#include "bytestring.h"
+
 /* Utility functions for manipulating fields and offsets */
 
 /* Add 'offset' to 'addr' */
@@ -123,79 +127,96 @@ asn1_do_lock(ASN1_VALUE **pval, int op, const ASN1_ITEM *it)
 static ASN1_ENCODING *
 asn1_get_enc_ptr(ASN1_VALUE **pval, const ASN1_ITEM *it)
 {
-	const ASN1_AUX *aux;
+	const ASN1_AUX *aux = it->funcs;
 
-	if (!pval || !*pval)
+	if (pval == NULL || *pval == NULL)
 		return NULL;
-	aux = it->funcs;
-	if (!aux || !(aux->flags & ASN1_AFLG_ENCODING))
+
+	if (aux == NULL || (aux->flags & ASN1_AFLG_ENCODING) == 0)
 		return NULL;
+
 	return offset2ptr(*pval, aux->enc_offset);
 }
 
 void
 asn1_enc_init(ASN1_VALUE **pval, const ASN1_ITEM *it)
 {
-	ASN1_ENCODING *enc;
+	ASN1_ENCODING *aenc;
 
-	enc = asn1_get_enc_ptr(pval, it);
-	if (enc) {
-		enc->enc = NULL;
-		enc->len = 0;
-		enc->modified = 1;
-	}
+	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
+		return;
+
+	aenc->enc = NULL;
+	aenc->len = 0;
+	aenc->modified = 1;
+}
+
+static void
+asn1_enc_clear(ASN1_ENCODING *aenc)
+{
+	freezero(aenc->enc, aenc->len);
+	aenc->enc = NULL;
+	aenc->len = 0;
+	aenc->modified = 1;
 }
 
 void
 asn1_enc_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
 {
-	ASN1_ENCODING *enc;
-
-	enc = asn1_get_enc_ptr(pval, it);
-	if (enc) {
-		freezero(enc->enc, enc->len);
-		enc->enc = NULL;
-		enc->len = 0;
-		enc->modified = 1;
-	}
+	ASN1_ENCODING *aenc;
+
+	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
+		return;
+
+	asn1_enc_clear(aenc);
 }
 
 int
-asn1_enc_save(ASN1_VALUE **pval, const unsigned char *in, int inlen,
-    const ASN1_ITEM *it)
+asn1_enc_save(ASN1_VALUE **pval, CBS *cbs, const ASN1_ITEM *it)
 {
-	ASN1_ENCODING *enc;
+	ASN1_ENCODING *aenc;
+	uint8_t *data = NULL;
+	size_t data_len = 0;
 
-	enc = asn1_get_enc_ptr(pval, it);
-	if (!enc)
+	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
 		return 1;
 
-	freezero(enc->enc, enc->len);
-	enc->enc = malloc(inlen);
-	if (!enc->enc)
+	asn1_enc_clear(aenc);
+
+	if (!CBS_stow(cbs, &data, &data_len))
+		return 0;
+	if (data_len > LONG_MAX) {
+		freezero(data, data_len);
 		return 0;
-	memcpy(enc->enc, in, inlen);
-	enc->len = inlen;
-	enc->modified = 0;
+	}
+
+	aenc->enc = data;
+	aenc->len = (long)data_len;
+	aenc->modified = 0;
 
 	return 1;
 }
 
 int
-asn1_enc_restore(int *len, unsigned char **out, ASN1_VALUE **pval,
+asn1_enc_restore(int *out_len, unsigned char **out, ASN1_VALUE **pval,
     const ASN1_ITEM *it)
 {
-	ASN1_ENCODING *enc;
+	ASN1_ENCODING *aenc;
+
+	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
+		return 0;
 
-	enc = asn1_get_enc_ptr(pval, it);
-	if (!enc || enc->modified)
+	if (aenc->modified)
 		return 0;
-	if (out) {
-		memcpy(*out, enc->enc, enc->len);
-		*out += enc->len;
+
+	if (out != NULL) {
+		memcpy(*out, aenc->enc, aenc->len);
+		*out += aenc->len;
 	}
-	if (len)
-		*len = enc->len;
+
+	if (out_len != NULL)
+		*out_len = aenc->len;
+
 	return 1;
 }
 
-- 
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