commit 0238eb8f3612515f4374381b593dd79116169330
Author: John Dennis <jdennis@redhat.com>
Date:   Thu Aug 2 16:21:33 2018 -0400

    fix concatkdf failures on big endian architectures
    
    Several of the elements used to compute the digest in ECDH-ES key
    agreement computation are represented in binary form as a 32-bit
    integer length followed by that number of octets.  the length
    field. The 32-bit length integer is represented in big endian
    format (the 8 most significant bits are in the first octet.).
    
    The conversion to a 4 byte big endian integer was being computed
    in a manner that only worked on little endian architectures. The
    function htonl() returns a 32-bit integer whose octet sequence given
    the address of the integer is big endian. There is no need for any
    further manipulation.
    
    The existing code used bit shifting on a 32-bit value. In C bit
    shifting is endian agnostic for multi-octet values, a right shift
    moves most significant bits toward least significant bits. The result
    of a bit shift of a multi-octet value on either big or little
    archictures will always be the same provided you "view" it as the same
    data type (e.g. 32-bit integer). But indexing the octets of that
    mulit-octet value will be different depending on endianness, hence the
    assembled octets differed depending on endianness.
    
    Issue: #77
    Signed-off-by: John Dennis <jdennis@redhat.com>

diff --git a/src/concatkdf.c b/src/concatkdf.c
index ec064ab..59b845a 100644
--- a/src/concatkdf.c
+++ b/src/concatkdf.c
@@ -29,15 +29,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 static uint8_t *_apply_uint32(const uint32_t value, uint8_t *buffer)
 {
-    const uint32_t formatted = htonl(value);
-    const uint8_t data[4] = {
-        (formatted >> 0) & 0xff,
-        (formatted >> 8) & 0xff,
-        (formatted >> 16) & 0xff,
-        (formatted >> 24) & 0xff
-    };
-    memcpy(buffer, data, 4);
+    const uint32_t big_endian_int32 = htonl(value);
 
+    memcpy(buffer, &big_endian_int32, 4);
     return buffer + 4;
 }
 
diff --git a/test/check_concatkdf.c b/test/check_concatkdf.c
index e4325fc..41d0f1c 100644
--- a/test/check_concatkdf.c
+++ b/test/check_concatkdf.c
@@ -60,14 +60,9 @@ _create_otherinfo_header_finish:
 
 static bool _cmp_uint32(uint8_t **actual, uint32_t expected)
 {
-    uint32_t value = htonl(expected);
-    uint8_t expectedData[] = {
-        (value >> 0) & 0xff,
-        (value >> 8) & 0xff,
-        (value >> 16) & 0xff,
-        (value >> 24) & 0xff
-    };
-    bool result = (0 == memcmp(*actual, expectedData, 4));
+    uint32_t big_endian_int32 = htonl(expected);
+
+    bool result = (0 == memcmp(*actual, &big_endian_int32, 4));
     (*actual) += 4;
     return result;
 }