From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Wed, 28 Jan 2015 16:21:00 +0000 (+0000)
Subject: Add base32 decoding routine.
X-Git-Tag: 0.9.0~817^2~13
X-Git-Url: https://source.dussan.org/?a=commitdiff_plain;h=976633feae742845a47aabe70dd93c547ba1876b;p=rspamd.git

Add base32 decoding routine.
---

diff --git a/src/libutil/util.c b/src/libutil/util.c
index 102bfc107..ccec534eb 100644
--- a/src/libutil/util.c
+++ b/src/libutil/util.c
@@ -2117,7 +2117,81 @@ rspamd_encode_base32 (guchar *in, gsize inlen)
 	return out;
 }
 
+static const guchar b32_dec[] = {
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0x12, 0xff, 0x19, 0x1a, 0x1b, 0x1e, 0x1d,
+	0x07, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0x18, 0x01, 0x0c, 0x03, 0x08, 0x05, 0x06,
+	0x1c, 0x15, 0x09, 0x0a, 0xff, 0x0b, 0x02, 0x10,
+	0x0d, 0x0e, 0x04, 0x16, 0x11, 0x13, 0xff, 0x14,
+	0x0f, 0x00, 0x17, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0x18, 0x01, 0x0c, 0x03, 0x08, 0x05, 0x06,
+	0x1c, 0x15, 0x09, 0x0a, 0xff, 0x0b, 0x02, 0x10,
+	0x0d, 0x0e, 0x04, 0x16, 0x11, 0x13, 0xff, 0x14,
+	0x0f, 0x00, 0x17, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
+};
+
+guchar*
+rspamd_decode_base32 (gchar *in, gsize inlen, gsize *outlen)
+{
+	guchar *res, decoded;
+	guchar c;
+	guint acc = 0U;
+	guint processed_bits = 0;
+	gsize olen = 0, i, allocated_len = inlen * 8 / 5 + 1;
+
+	res = g_slice_alloc (allocated_len);
+
+	for (i = 0; i < inlen; i ++) {
+		c = (guchar)in[i];
+
+		if (processed_bits >= 8) {
+			processed_bits -= 8;
+			res[olen++] = acc & 0xFF;
+			acc >>= 8;
+		}
+
+		decoded = b32_dec[c];
+		if (decoded == 0xff) {
+			g_slice_free1 (allocated_len, res);
+			return NULL;
+		}
+
+		acc = (decoded << processed_bits) | acc;
+		processed_bits += 5;
+	}
+
+	if (processed_bits > 0) {
+		res[olen++] = (acc & 0xFF);
+	}
+
+	*outlen = olen;
+
+	return res;
+}
 
+/* Required for tweetnacl */
 void
 randombytes (guchar *buf, guint64 len)
 {
diff --git a/src/libutil/util.h b/src/libutil/util.h
index 62a28d474..23964fc07 100644
--- a/src/libutil/util.h
+++ b/src/libutil/util.h
@@ -426,4 +426,12 @@ void rspamd_ucl_emit_gstring (ucl_object_t *obj,
  */
 gchar * rspamd_encode_base32 (guchar *in, gsize inlen);
 
+/**
+ * Decode string using base32 encoding
+ * @param in input
+ * @param inlen input length
+ * @return freshly allocated base32 decoded value or NULL if input is invalid
+ */
+guchar* rspamd_decode_base32 (gchar *in, gsize inlen, gsize *outlen);
+
 #endif