From 4688f5fa59870b19ec8be08e118c08ca16fb21f8 Mon Sep 17 00:00:00 2001
From: Eric Blankenhorn <eric@wolfssl.com>
Date: Fri, 11 Sep 2020 08:39:34 -0500
Subject: [PATCH] Handle leading zero

---
 wolfcrypt/src/integer.c | 9 ++++++++-
 wolfcrypt/src/tfm.c     | 9 ++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/wolfcrypt/src/integer.c b/wolfcrypt/src/integer.c
index 306d7cef9..ba8777897 100644
--- a/wolfcrypt/src/integer.c
+++ b/wolfcrypt/src/integer.c
@@ -5242,7 +5242,7 @@ int mp_radix_size (mp_int *a, int radix, int *size)
     }
 
     /* digs is the digit count */
-    digs = 1;
+    digs = 0;
 
     /* if it's negative add one for the sign */
     if (a->sign == MP_NEG) {
@@ -5267,6 +5267,13 @@ int mp_radix_size (mp_int *a, int radix, int *size)
     }
     mp_clear (&t);
 
+#ifndef WC_DISABLE_RADIX_ZERO_PAD
+    /* For hexadecimal output, add zero padding when number of digits is odd */
+    if ((digs & 1) && (radix == 16)) {
+        ++digs;
+    }
+#endif
+
     /* return digs + 1, the 1 is for the NULL byte that would be required. */
     *size = digs + 1;
     return MP_OKAY;
diff --git a/wolfcrypt/src/tfm.c b/wolfcrypt/src/tfm.c
index 8b9f3566c..a839bc50c 100644
--- a/wolfcrypt/src/tfm.c
+++ b/wolfcrypt/src/tfm.c
@@ -5451,7 +5451,7 @@ int mp_radix_size (mp_int *a, int radix, int *size)
     }
 
     /* digs is the digit count */
-    digs = 1;
+    digs = 0;
 
     /* if it's negative add one for the sign */
     if (a->sign == FP_NEG) {
@@ -5483,6 +5483,13 @@ int mp_radix_size (mp_int *a, int radix, int *size)
     }
     fp_zero (t);
 
+#ifndef WC_DISABLE_RADIX_ZERO_PAD
+    /* For hexadecimal output, add zero padding when number of digits is odd */
+    if ((digs & 1) && (radix == 16)) {
+        ++digs;
+    }
+#endif
+
     /* return digs + 1, the 1 is for the NULL byte that would be required. */
     *size = digs + 1;
 #ifdef WOLFSSL_SMALL_STACK