meta-openembedded/meta-networking/recipes-connectivity/mbedtls/mbedtls/fix-incorrect-EOF-check-in-ssl_context_info.patch

From d696e7d91e42a190d06760279d2e396392143454 Mon Sep 17 00:00:00 2001
From: Nayna Jain <nayna@linux.ibm.com>
Date: Thu, 13 Aug 2020 19:17:53 +0000
Subject: [PATCH] programs/ssl: Fix incorrect EOF check in ssl_context_info.c

In `read_next_b64_code()`, the result of fgetc() is stored into a char,
but later compared against EOF, which is generally -1.  On platforms
where char is unsigned, this generates a compiler warning/error that the
comparison will never be true (causing a build failure).  The value will
never match, with the function ultimately bailing with a "Too many bad
symbols are detected" error.

On platforms with signed char, EOF is detected, but a file containing a
0xFF character will causes a premature end of file exit of the loop.

Fix this by changing the result to an int.

Fixes #3794.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: David Brown <david.brown@linaro.org>
---
 ChangeLog.d/bugfix_3794.txt     | 4 ++++
 programs/ssl/ssl_context_info.c | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)
 create mode 100644 ChangeLog.d/bugfix_3794.txt

diff --git a/ChangeLog.d/bugfix_3794.txt b/ChangeLog.d/bugfix_3794.txt
new file mode 100644
index 0000000000..a483ea76ae
--- /dev/null
+++ b/ChangeLog.d/bugfix_3794.txt
@@ -0,0 +1,4 @@
+Bugfix
+  * Fix handling of EOF against 0xff bytes and on platforms with
+    unsigned chars.  Fixes a build failure on platforms where char is
+    unsigned.  Fixes #3794.
diff --git a/programs/ssl/ssl_context_info.c b/programs/ssl/ssl_context_info.c
index df8819a804..d109c1e6f7 100644
--- a/programs/ssl/ssl_context_info.c
+++ b/programs/ssl/ssl_context_info.c
@@ -377,13 +377,13 @@ size_t read_next_b64_code( uint8_t **b64, size_t *max_len )
     int valid_balance = 0;  /* balance between valid and invalid characters */
     size_t len = 0;
     char pad = 0;
-    char c = 0;
+    int c = 0;
 
     while( EOF != c )
     {
         char c_valid = 0;
 
-        c = (char) fgetc( b64_file );
+        c = fgetc( b64_file );
 
         if( pad > 0 )
         {