From 33287ae1340ea4a6225dc9e2016b91bf115214f2 Mon Sep 17 00:00:00 2001
From: Dave Rodgman <dave.rodgman@arm.com>
Date: Mon, 11 Sep 2023 17:03:22 +0100
Subject: [PATCH] Tidy up mbedtls_asn1_write_len

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
---
 library/asn1write.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/library/asn1write.c b/library/asn1write.c
index 4887f1551..7d533491f 100644
--- a/library/asn1write.c
+++ b/library/asn1write.c
@@ -37,9 +37,8 @@ int mbedtls_asn1_write_len(unsigned char **p, const unsigned char *start, size_t
 #endif
 
     int required = 1;
-    if (len < 0x80) {
-        required = 1;
-    } else {
+
+    if (len >= 0x80) {
         for (size_t l = len; l != 0; l >>= 8) {
             required++;
         }
@@ -55,7 +54,7 @@ int mbedtls_asn1_write_len(unsigned char **p, const unsigned char *start, size_t
     } while (len);
 
     if (required > 1) {
-        *--(*p) = (unsigned char) (required + 0x7f);
+        *--(*p) = (unsigned char) (0x80 + required - 1);
     }
 
     return required;