libcrypto refactoring: introduce and use ossl_asn1_string_set_bits_left()

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/18668)

5 files changed, 13 insertions, 11 deletions

diff --git a/crypto/asn1/a_bitstr.c b/crypto/asn1/a_bitstr.c
index f8938ad107..7b3991a071 100644
--- a/crypto/asn1/a_bitstr.c
+++ b/crypto/asn1/a_bitstr.c
@@ -110,8 +110,7 @@ ASN1_BIT_STRING *ossl_c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
      * We do this to preserve the settings.  If we modify the settings, via
      * the _set_bit function, we will recalculate on output
      */
-    ret->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear */
-    ret->flags |= (ASN1_STRING_FLAG_BITS_LEFT | i); /* set */
+    ossl_asn1_string_set_bits_left(ret, i);
 
     if (len-- > 1) {            /* using one because of the bits left byte */
         s = OPENSSL_malloc((int)len);
diff --git a/crypto/asn1/a_sign.c b/crypto/asn1/a_sign.c
index fc3f15007e..a1e2719e64 100644
--- a/crypto/asn1/a_sign.c
+++ b/crypto/asn1/a_sign.c
@@ -102,8 +102,7 @@ int ASN1_sign(i2d_of_void *i2d, X509_ALGOR *algor1, X509_ALGOR *algor2,
      * In the interests of compatibility, I'll make sure that the bit string
      * has a 'not-used bits' value of 0
      */
-    signature->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
-    signature->flags |= ASN1_STRING_FLAG_BITS_LEFT;
+    ossl_asn1_string_set_bits_left(signature, 0);
  err:
     EVP_MD_CTX_free(ctx);
     OPENSSL_clear_free((char *)buf_in, inll);
@@ -286,8 +285,7 @@ int ASN1_item_sign_ctx(const ASN1_ITEM *it, X509_ALGOR *algor1,
      * In the interests of compatibility, I'll make sure that the bit string
      * has a 'not-used bits' value of 0
      */
-    signature->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
-    signature->flags |= ASN1_STRING_FLAG_BITS_LEFT;
+    ossl_asn1_string_set_bits_left(signature, 0);
  err:
     OPENSSL_clear_free((char *)buf_in, inl);
     OPENSSL_clear_free((char *)buf_out, outll);
diff --git a/crypto/asn1/asn1_gen.c b/crypto/asn1/asn1_gen.c
index 5b5a469fa9..c590c62fc2 100644
--- a/crypto/asn1/asn1_gen.c
+++ b/crypto/asn1/asn1_gen.c
@@ -714,11 +714,8 @@ static ASN1_TYPE *asn1_str2type(const char *str, int format, int utype)
             goto bad_form;
         }
 
-        if ((utype == V_ASN1_BIT_STRING) && no_unused) {
-            atmp->value.asn1_string->flags
-                &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
-            atmp->value.asn1_string->flags |= ASN1_STRING_FLAG_BITS_LEFT;
-        }
+        if ((utype == V_ASN1_BIT_STRING) && no_unused)
+            ossl_asn1_string_set_bits_left(atmp->value.asn1_string, 0);
 
         break;
 
diff --git a/crypto/asn1/asn1_lib.c b/crypto/asn1/asn1_lib.c
index 5359cbc117..55e3ddbafd 100644
--- a/crypto/asn1/asn1_lib.c
+++ b/crypto/asn1/asn1_lib.c
@@ -248,6 +248,12 @@ int ASN1_object_size(int constructed, int length, int tag)
     return ret + length;
 }
 
+void ossl_asn1_string_set_bits_left(ASN1_STRING *str, unsigned int num)
+{
+    str->flags &= ~0x07;
+    str->flags |= ASN1_STRING_FLAG_BITS_LEFT | (num & 0x07);
+}
+
 int ASN1_STRING_copy(ASN1_STRING *dst, const ASN1_STRING *str)
 {
     if (str == NULL)
diff --git a/crypto/asn1/asn1_local.h b/crypto/asn1/asn1_local.h
index f73bd8fc6a..10e9fcb7de 100644
--- a/crypto/asn1/asn1_local.h
+++ b/crypto/asn1/asn1_local.h
@@ -9,6 +9,8 @@
 
 /* Internal ASN1 structures and functions: not for application use */
 
+#include "crypto/asn1.h"
+
 typedef const ASN1_VALUE const_ASN1_VALUE;
 SKM_DEFINE_STACK_OF(const_ASN1_VALUE, const ASN1_VALUE, ASN1_VALUE)