This is the least unacceptable way I've found for declaring the bignum data

and structures as constant without having to cast away const at any point.
There is still plenty of other code that makes gcc's "-Wcast-qual" unhappy,
but crypto/bn/ is now ok. Purists are welcome to suggest alternatives.

diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 686b3b3079fcb5231397d096bebf5f2ad24cc1ff..44ba175247b0bd2ea181ce0e22001de1e6aa7d47 100644 (file)
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -252,6 +252,27 @@ typedef struct bignum_st
        int flags;
        } BIGNUM;
 
        int flags;
        } BIGNUM;
 

+/* Declaring static BIGNUMs as constant is tricky in C; the 'd' data can't be
+ * pre-declared const without having to cast away the const when declaring the
+ * BIGNUM. We use this alternative type for declaring const BIGNUMs. See
+ * bn_nist.c for examples. */
+typedef struct bignum_c_st
+       {
+       const BN_ULONG *d;
+       int top;
+       int dmax;
+       int neg;
+       int flags;
+       } BIGNUM_C;
+#ifdef BN_DEBUG
+/* Use a function to do this so that we can type-check the pointer we're
+ * casting */
+const BIGNUM *BIGNUM_CONST(const BIGNUM_C *bn);
+#else
+/* Use a macro instead */
+#define BIGNUM_CONST(bn)       ((const BIGNUM *)bn)
+#endif
+

 /* Used for temp variables (declaration hidden in bn_lcl.h) */
 typedef struct bignum_ctx BN_CTX;
 
 /* Used for temp variables (declaration hidden in bn_lcl.h) */
 typedef struct bignum_ctx BN_CTX;
 

diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c
index 783881d3a6977964c8993a25a8673d4128c462d1..f63232b9fbc4f7ca0a427231b1da388669165d1a 100644 (file)
--- a/crypto/bn/bn_lib.c
+++ b/crypto/bn/bn_lib.c
@@ -874,3 +874,11 @@ int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
                }
        return bn_cmp_words(a,b,cl);
        }
                }
        return bn_cmp_words(a,b,cl);
        }

+
+/* See the comments surrounding BIGNUM_C in bn.h */
+#ifdef BN_DEBUG
+const BIGNUM *BIGNUM_CONST(const BIGNUM_C *bn)
+       {
+       return (const BIGNUM *)bn;
+       }
+#endif

diff --git a/crypto/bn/bn_nist.c b/crypto/bn/bn_nist.c
index 2ababfbed1ae81f106ad7a91e5a8cb5aadc13b85..ed148d845ce63b553c4dd09bb726764f77a9a82f 100644 (file)
--- a/crypto/bn/bn_nist.c
+++ b/crypto/bn/bn_nist.c
@@ -127,39 +127,40 @@ const static BN_ULONG _nist_p_521[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
        0xFF,0x01};
 #endif
 
        0xFF,0x01};
 #endif
 

+static const BIGNUM_C bn_nist_p_192 =
+       { _nist_p_192, BN_NIST_192_TOP, BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA };
+static const BIGNUM_C bn_nist_p_224 =
+       { _nist_p_224, BN_NIST_224_TOP, BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA };
+static const BIGNUM_C bn_nist_p_256 =
+       { _nist_p_256, BN_NIST_256_TOP, BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA };
+static const BIGNUM_C bn_nist_p_384 =
+       { _nist_p_384, BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };
+static const BIGNUM_C bn_nist_p_521 =
+       { _nist_p_521, BN_NIST_521_TOP, BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA };
+

 const BIGNUM *BN_get0_nist_prime_192(void)
        {
 const BIGNUM *BN_get0_nist_prime_192(void)
        {

-       static BIGNUM const_nist_192={(BN_ULONG *)_nist_p_192,BN_NIST_192_TOP,
-               BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA};
-       return &const_nist_192;
+       return BIGNUM_CONST(&bn_nist_p_192);

        }
 
 const BIGNUM *BN_get0_nist_prime_224(void)
        {
        }
 
 const BIGNUM *BN_get0_nist_prime_224(void)
        {

-       static BIGNUM const_nist_224={(BN_ULONG *)_nist_p_224,BN_NIST_224_TOP,
-               BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA};
-       return &const_nist_224;
+       return BIGNUM_CONST(&bn_nist_p_224);

        }
 
 const BIGNUM *BN_get0_nist_prime_256(void)
        {
        }
 
 const BIGNUM *BN_get0_nist_prime_256(void)
        {

-       static BIGNUM const_nist_256={(BN_ULONG *)_nist_p_256,BN_NIST_256_TOP,
-               BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA};
-       return &const_nist_256;
+       return BIGNUM_CONST(&bn_nist_p_256);

        }
 
 const BIGNUM *BN_get0_nist_prime_384(void)
        {
        }
 
 const BIGNUM *BN_get0_nist_prime_384(void)
        {

-       static BIGNUM const_nist_384={(BN_ULONG *)_nist_p_384,BN_NIST_384_TOP,
-               BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA};
-       return &const_nist_384;
+       return BIGNUM_CONST(&bn_nist_p_384);

        }
 
 const BIGNUM *BN_get0_nist_prime_521(void)
        {
        }
 
 const BIGNUM *BN_get0_nist_prime_521(void)
        {

-       static BIGNUM const_nist_521={(BN_ULONG *)_nist_p_521,BN_NIST_521_TOP,
-               BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA};
-       return &const_nist_521;
+       return BIGNUM_CONST(&bn_nist_p_521);

        }
 
 /* some misc internal functions */
        }
 
 /* some misc internal functions */