pki_gcrypt: Fix memory leak

* src/pki_gcrypt.c (_bignum_cmp): Fix memory leak.

Signed-off-by: Justus Winter <justus@g10code.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/pki_gcrypt.c

@@ -1064,6 +1064,7 @@ static int _bignum_cmp(const gcry_sexp_t s1,
     gcry_sexp_t sexp;
     bignum b1;
     bignum b2;
+    int result;
 
     sexp = gcry_sexp_find_token(s1, what, 0);
     if (sexp == NULL) {
@@ -1077,19 +1078,20 @@ static int _bignum_cmp(const gcry_sexp_t s1,
 
     sexp = gcry_sexp_find_token(s2, what, 0);
     if (sexp == NULL) {
+        bignum_free(b1);
         return 1;
     }
     b2 = gcry_sexp_nth_mpi(sexp, 1, GCRYMPI_FMT_USG);
     gcry_sexp_release(sexp);
     if (b2 == NULL) {
+        bignum_free(b1);
         return 1;
     }
 
-    if (bignum_cmp(b1, b2) != 0) {
-        return 1;
-    }
-
-    return 0;
+    result = !! bignum_cmp(b1, b2);
+    bignum_free(b1);
+    bignum_free(b2);
+    return result;
 }
 
 int pki_key_compare(const ssh_key k1,