Fix incorrect loop condition in egg_hkdf_perform()

This does not cause a change in behavior (as evidenced by tests,
at least on linux when built with gcc) but is more correct code,
and less likely to be miscompiled.

The condition (i < 256) in the following loop is always false since i
is of type guchar, which is at most 255.

	guchar i;
	...
	for (i = 1; i < 256; ++i) { ... }

This patch changes i to a larger type gint.

Also in the loop we have:

	gcry_md_write (md2, &i, 1);

change it to use gcry_md_putc().

diff --git a/egg/egg-hkdf.c b/egg/egg-hkdf.c
index e79b9d4..bc2919a 100644 (file)
--- a/egg/egg-hkdf.c
+++ b/egg/egg-hkdf.c
@@ -39,7 +39,7 @@ egg_hkdf_perform (const gchar *hash_algo, gconstpointer input, gsize n_input,
        gpointer buffer = NULL;
        gcry_md_hd_t md1, md2;
        guint hash_len;
-       guchar i;
+       gint i;
        gint flags, algo;
        gsize step, n_buffer;
        guchar *at;
@@ -89,7 +89,7 @@ egg_hkdf_perform (const gchar *hash_algo, gconstpointer input, gsize n_input,
                gcry_md_reset (md2);
                gcry_md_write (md2, buffer, n_buffer);
                gcry_md_write (md2, info, n_info);
-               gcry_md_write (md2, &i, 1);
+               gcry_md_putc (md2, i);
 
                n_buffer = hash_len;
                memcpy (buffer, gcry_md_read (md2, algo), n_buffer);