Add a SHA256 implementation for platforms that lack it.

(This would be everywhere running OpenSSL 0.9.7x and earlier, including
all current Macintosh users.)

The code is based on Tom St Denis's LibTomCrypt implementation,
modified to be way less general and use Tor's existing facilities.  I
picked this one because it was pretty fast and pretty free, and
because Python uses it too.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/common/crypto.c b/src/common/crypto.c
index 51d4059f3e..dc645b5eda 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -62,6 +62,28 @@
 
 #include <openssl/engine.h>
 
+#if OPENSSL_VERSION_NUMBER < 0x00908000l
+/* On OpenSSL versions before 0.9.8, there is no working SHA256
+ * implementation, so we use Tom St Denis's nice speedy one, slightly adapted
+ * to our needs */
+#define SHA256_CTX sha256_state
+#define SHA256_Init sha256_init
+#define SHA256_Update sha256_process
+#define LTC_ARGCHK(x) tor_assert(x)
+#include "sha256.c"
+#define SHA256_Final(a,b) sha256_done(b,a)
+
+static unsigned char *
+SHA256(const unsigned char *m, size_t len, unsigned char *d)
+{
+  SHA256_CTX ctx;
+  SHA256_Init(&ctx);
+  SHA256_Update(&ctx, m, len);
+  SHA256_Final(d, &ctx);
+  return d;
+}
+#endif
+
 /** Macro: is k a valid RSA public or private key? */
 #define PUBLIC_KEY_OK(k) ((k) && (k)->key && (k)->key->n)
 /** Macro: is k a valid RSA private key? */