From aa4d978448c314470d55b4086fd9984b77421e7f Mon Sep 17 00:00:00 2001
From: Dirk Ziegelmeier <dirk@ziegelmeier.net>
Date: Wed, 26 Jul 2017 09:28:07 +0200
Subject: [PATCH] Fix [bug #51520] Big endian bug in apps/snmp/snmp_asn1.c
 Apply patch from Art Heers that does not need endianess checks

---
 src/apps/snmp/snmp_asn1.c | 36 +++++-------------------------------
 1 file changed, 5 insertions(+), 31 deletions(-)

diff --git a/src/apps/snmp/snmp_asn1.c b/src/apps/snmp/snmp_asn1.c
index 71aad9ce..92c1188d 100644
--- a/src/apps/snmp/snmp_asn1.c
+++ b/src/apps/snmp/snmp_asn1.c
@@ -579,51 +579,25 @@ snmp_asn1_dec_u64t(struct snmp_pbuf_stream *pbuf_stream, u16_t len, u32_t *value
 err_t
 snmp_asn1_dec_s32t(struct snmp_pbuf_stream *pbuf_stream, u16_t len, s32_t *value)
 {
-#if BYTE_ORDER == LITTLE_ENDIAN
-  u8_t *lsb_ptr = (u8_t*)value;
-#endif
-#if BYTE_ORDER == BIG_ENDIAN
-  u8_t *lsb_ptr = (u8_t*)value + sizeof(s32_t) - 1;
-#endif
-  u8_t sign;
   u8_t data;
 
   if ((len > 0) && (len < 5)) {
     PBUF_OP_EXEC(snmp_pbuf_stream_read(pbuf_stream, &data));
-    len--;
 
     if (data & 0x80) {
       /* negative, start from -1 */
-      *value = -1;
-      sign = 1;
-      *lsb_ptr &= data;
+      *value = (-1 << 8) | data;
     } else {
       /* positive, start from 0 */
-      *value = 0;
-      sign = 0;
-      *lsb_ptr |= data;
+      *value = data;
     }
-
-    /* OR/AND octets with value */
+    len--;
+    /* shift in the remaining value */
     while (len > 0) {
       PBUF_OP_EXEC(snmp_pbuf_stream_read(pbuf_stream, &data));
+      *value = (*value << 8) | data;
       len--;
-
-#if BYTE_ORDER == LITTLE_ENDIAN
-      *value <<= 8;
-#endif
-#if BYTE_ORDER == BIG_ENDIAN
-      *value >>= 8;
-#endif
-
-      if (sign) {
-        *lsb_ptr |= 255;
-        *lsb_ptr &= data;
-      } else {
-        *lsb_ptr |= data;
-      }
     }
-
     return ERR_OK;
   }