1 files changed, 48 insertions, 0 deletions
diff --git a/src/util/hash/collisiondetect.c b/src/util/hash/collisiondetect.c
new file mode 100644
index 000000000..c51a402d7
--- /dev/null
+++ b/src/util/hash/collisiondetect.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "collisiondetect.h"
+
+int git_hash_sha1_global_init(void)
+{
+	return 0;
+}
+
+int git_hash_sha1_ctx_init(git_hash_sha1_ctx *ctx)
+{
+	return git_hash_sha1_init(ctx);
+}
+
+void git_hash_sha1_ctx_cleanup(git_hash_sha1_ctx *ctx)
+{
+	GIT_UNUSED(ctx);
+}
+
+int git_hash_sha1_init(git_hash_sha1_ctx *ctx)
+{
+	GIT_ASSERT_ARG(ctx);
+	SHA1DCInit(&ctx->c);
+	return 0;
+}
+
+int git_hash_sha1_update(git_hash_sha1_ctx *ctx, const void *data, size_t len)
+{
+	GIT_ASSERT_ARG(ctx);
+	SHA1DCUpdate(&ctx->c, data, len);
+	return 0;
+}
+
+int git_hash_sha1_final(unsigned char *out, git_hash_sha1_ctx *ctx)
+{
+	GIT_ASSERT_ARG(ctx);
+	if (SHA1DCFinal(out, &ctx->c)) {
+		git_error_set(GIT_ERROR_SHA, "SHA1 collision attack detected");
+		return -1;
+	}
+
+	return 0;
+}