Backport r8651: SHA256 consistancy fix.

git-svn-id: http://svn.inspircd.org/repository/branches/1_1_stable@8652 e03df62e-2008-0410-955e-edbf42e46eb7

1 files changed, 19 insertions, 1 deletions

diff --git a/src/modules/m_sha256.cpp b/src/modules/m_sha256.cpp
index 547e7655c..c15799ea1 100644
--- a/src/modules/m_sha256.cpp
+++ b/src/modules/m_sha256.cpp
@@ -189,7 +189,25 @@ class ModuleSHA256 : public Module
 	
 	void SHA256Update(SHA256Context *ctx, unsigned char *message, unsigned int len)
 	{
-		unsigned int rem_len = SHA256_BLOCK_SIZE - ctx->len;
+		/*
+		 * XXX here be dragons!
+		 * After many hours of pouring over this, I think I've found the problem.
+		 * When Special created our module from the reference one, he used:
+		 *
+		 * unsigned int rem_len = SHA256_BLOCK_SIZE - ctx->len;
+		 *
+		 * instead of the reference's version of:
+		 *
+		 * unsigned int tmp_len = SHA256_BLOCK_SIZE - ctx->len;
+		 * unsigned int rem_len = len < tmp_len ? len : tmp_len;
+		 *
+		 * I've changed back to the reference version of this code, and it seems to work with no errors.
+		 * So I'm inclined to believe this was the problem..
+		 * -- w00t (January 06, 2008)
+		 */
+		unsigned int tmp_len = SHA256_BLOCK_SIZE - ctx->len;
+		unsigned int rem_len = len < tmp_len ? len : tmp_len;
+
 		memcpy(&ctx->block[ctx->len], message, rem_len);
 		if (ctx->len + len < SHA256_BLOCK_SIZE)
 		{