ECDSA_SIG: add simple getters for commonly used struct members

Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6290)

crypto/ec/ec_asn1.c

@@ -1183,6 +1183,16 @@ void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps)
         *ps = sig->s;
 }
 
+const BIGNUM *ECDSA_SIG_get0_r(const ECDSA_SIG *sig)
+{
+    return sig->r;
+}
+
+const BIGNUM *ECDSA_SIG_get0_s(const ECDSA_SIG *sig)
+{
+    return sig->s;
+}
+
 int ECDSA_SIG_set0(ECDSA_SIG *sig, BIGNUM *r, BIGNUM *s)
 {
     if (r == NULL || s == NULL)

doc/man3/ECDSA_SIG_new.pod

@@ -2,7 +2,7 @@
 
 =head1 NAME
 
-ECDSA_SIG_get0, ECDSA_SIG_set0,
+ECDSA_SIG_get0, ECDSA_SIG_get0_r, ECDSA_SIG_get0_s, ECDSA_SIG_set0,
 ECDSA_SIG_new, ECDSA_SIG_free, i2d_ECDSA_SIG, d2i_ECDSA_SIG, ECDSA_size,
 ECDSA_sign, ECDSA_do_sign, ECDSA_verify, ECDSA_do_verify, ECDSA_sign_setup,
 ECDSA_sign_ex, ECDSA_do_sign_ex - low level elliptic curve digital signature
@@ -15,6 +15,8 @@ algorithm (ECDSA) functions
  ECDSA_SIG *ECDSA_SIG_new(void);
  void ECDSA_SIG_free(ECDSA_SIG *sig);
  void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps);
+ const BIGNUM *ECDSA_SIG_get0_r(const ECDSA_SIG *sig);
+ const BIGNUM *ECDSA_SIG_get0_s(const ECDSA_SIG *sig);
  int ECDSA_SIG_set0(ECDSA_SIG *sig, BIGNUM *r, BIGNUM *s);
  int i2d_ECDSA_SIG(const ECDSA_SIG *sig, unsigned char **pp);
  ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **sig, const unsigned char **pp, long len);
@@ -53,7 +55,12 @@ OpenSSL 1.1.0 the: the B<r> and B<s> components were initialised.
 ECDSA_SIG_free() frees the B<ECDSA_SIG> structure B<sig>.
 
 ECDSA_SIG_get0() returns internal pointers the B<r> and B<s> values contained
-in B<sig>.
+in B<sig> and stores them in B<*pr> and B<*ps>, respectively.
+The pointer B<pr> or B<ps> can be NULL, in which case the corresponding value
+is not returned.
+
+The values B<r>, B<s> can also be retrieved separately by the corresponding
+function ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s(), respectively.
 
 The B<r> and B<s> values can be set by calling ECDSA_SIG_set0() and passing the
 new values for B<r> and B<s> as parameters to the function. Calling this
@@ -116,6 +123,9 @@ returned as a newly allocated B<ECDSA_SIG> structure (or NULL on error).
 
 ECDSA_SIG_set0() returns 1 on success or 0 on failure.
 
+ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s() return the corresponding value,
+or NULL if it is unset.
+
 ECDSA_size() returns the maximum length signature or 0 on error.
 
 ECDSA_sign(), ECDSA_sign_ex() and ECDSA_sign_setup() return 1 if successful

include/openssl/ec.h

@@ -1060,16 +1060,24 @@ int i2d_ECDSA_SIG(const ECDSA_SIG *sig, unsigned char **pp);
 ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **sig, const unsigned char **pp, long len);
 
 /** Accessor for r and s fields of ECDSA_SIG
- *  \param  sig  pointer to ECDSA_SIG pointer
+ *  \param  sig  pointer to ECDSA_SIG structure
  *  \param  pr   pointer to BIGNUM pointer for r (may be NULL)
  *  \param  ps   pointer to BIGNUM pointer for s (may be NULL)
  */
 void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps);
 
+/** Accessor for r field of ECDSA_SIG
+ *  \param  sig  pointer to ECDSA_SIG structure
+ */
+const BIGNUM *ECDSA_SIG_get0_r(const ECDSA_SIG *sig);
+
+/** Accessor for s field of ECDSA_SIG
+ *  \param  sig  pointer to ECDSA_SIG structure
+ */
+const BIGNUM *ECDSA_SIG_get0_s(const ECDSA_SIG *sig);
+
 /** Setter for r and s fields of ECDSA_SIG
- *  \param  sig  pointer to ECDSA_SIG pointer
- *  \param  r    pointer to BIGNUM for r (may be NULL)
- *  \param  s    pointer to BIGNUM for s (may be NULL)
+ *  \param  sig  pointer to ECDSA_SIG structure
  */
 int ECDSA_SIG_set0(ECDSA_SIG *sig, BIGNUM *r, BIGNUM *s);
 

util/libcrypto.num

@@ -4546,3 +4546,5 @@ RSA_get0_e                              4487	1_1_1	EXIST::FUNCTION:RSA
 RSA_get0_q                              4488	1_1_1	EXIST::FUNCTION:RSA
 RSA_get0_p                              4489	1_1_1	EXIST::FUNCTION:RSA
 RSA_get0_iqmp                           4490	1_1_1	EXIST::FUNCTION:RSA
+ECDSA_SIG_get0_r                        4491	1_1_1	EXIST::FUNCTION:EC
+ECDSA_SIG_get0_s                        4492	1_1_1	EXIST::FUNCTION:EC