Simplify ec_asn1_group2curve()

Don't try to reuse curve->seed to avoid an allocation. Free it
unconditionally and copy over the group->seed if it's available.
Use asn1_abs_set_unused_bits() instead of inlining it.

ok jsing

1 files changed, 21 insertions, 18 deletions

diff --git a/src/lib/libcrypto/ec/ec_asn1.c b/src/lib/libcrypto/ec/ec_asn1.c
index 4cf0bf5972..6bf7e47d7d 100644
--- a/src/lib/libcrypto/ec/ec_asn1.c
+++ b/src/lib/libcrypto/ec/ec_asn1.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_asn1.c,v 1.36 2022/03/31 13:00:58 tb Exp $ */
+/* $OpenBSD: ec_asn1.c,v 1.37 2022/05/24 20:06:32 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project.
  */
@@ -60,11 +60,13 @@
 
 #include <openssl/opensslconf.h>
 
-#include "ec_lcl.h"
 #include <openssl/err.h>
 #include <openssl/asn1t.h>
 #include <openssl/objects.h>
 
+#include "asn1_locl.h"
+#include "ec_lcl.h"
+
 int 
 EC_GROUP_get_basis_type(const EC_GROUP * group)
 {
@@ -860,24 +862,24 @@ ec_asn1_group2curve(const EC_GROUP * group, X9_62_CURVE * curve)
                 ECerror(ERR_R_ASN1_LIB);
                 goto err;
         }
+
+        ASN1_BIT_STRING_free(curve->seed);
+        curve->seed = NULL;
+
         /* set the seed (optional) */
-        if (group->seed) {
-                if (!curve->seed)
-                        if ((curve->seed = ASN1_BIT_STRING_new()) == NULL) {
-                                ECerror(ERR_R_MALLOC_FAILURE);
-                                goto err;
-                        }
-                curve->seed->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
-                curve->seed->flags |= ASN1_STRING_FLAG_BITS_LEFT;
+        if (group->seed != NULL) {
+                if ((curve->seed = ASN1_BIT_STRING_new()) == NULL) {
+                        ECerror(ERR_R_MALLOC_FAILURE);
+                        goto err;
+                }
                 if (!ASN1_BIT_STRING_set(curve->seed, group->seed,
                         (int) group->seed_len)) {
                         ECerror(ERR_R_ASN1_LIB);
                         goto err;
                 }
-        } else {
-                if (curve->seed) {
-                        ASN1_BIT_STRING_free(curve->seed);
-                        curve->seed = NULL;
+                if (!asn1_abs_set_unused_bits(curve->seed, 0)) {
+                        ECerror(ERR_R_ASN1_LIB);
+                        goto err;
                 }
         }
 
@@ -1481,10 +1483,11 @@ i2d_ECPrivateKey(EC_KEY * a, unsigned char **out)
                         ECerror(ERR_R_EC_LIB);
                         goto err;
                 }
-                priv_key->publicKey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
-                priv_key->publicKey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
-                if (!ASN1_STRING_set(priv_key->publicKey, buffer,
-                        buf_len)) {
+                if (!ASN1_STRING_set(priv_key->publicKey, buffer, buf_len)) {
+                        ECerror(ERR_R_ASN1_LIB);
+                        goto err;
+                }
+                if (!asn1_abs_set_unused_bits(priv_key->publicKey, 0)) {
                         ECerror(ERR_R_ASN1_LIB);
                         goto err;
                 }