Subj : HPT Bug: Corrupted packets not rejected due to missing date validation
To   : All
From : Stephen Walsh
Date : Fri Oct 10 2025 10:38 am



Hi Husky developers,

I've discovered a bug in HPT where packets with corrupted/empty message date
fields are not properly rejected and renamed to .bad as they should be.

PROBLEM DESCRIPTION:
===================
When processing packets, HPT reads the 20-byte datetime field from each
message header (pktread.c:771) and calls parse_ftsc_date() to parse it
(line 777). However, the return value from parse_ftsc_date() is ignored.

The parse_ftsc_date() function returns flag_t values indicating:
- FTSC_BROKEN (2) - field cannot be parsed
- FTSC_FLAWY (1) - field has correctable errors
- FTSC_TS_BROKEN (128) - timestamp broken but date OK

Currently, even when parse_ftsc_date() returns FTSC_BROKEN, the badmsg
counter is not incremented, so the packet is not renamed to .bad and
continues to be processed.

REAL-WORLD IMPACT:
==================
I encountered a packet in the wild (from 2:341/66) that contains:
- Message 3: Empty date field (0 bytes)
- Message 4: Invalid date field (1 byte: '0')

The bad packet can be obtained at: https://vk3heg.net/badpkt.zip

HPT processed this packet instead of rejecting it.

PROPOSED FIX:
=============
After calling parse_ftsc_date(), check if the FTSC_BROKEN flag is set and
increment badmsg accordingly. This ensures corrupted packets are properly
renamed to .bad.

Patch attached below. Please review and consider applying to the codebase.

--- hpt/src/pktread.c.orig      2025-10-09 10:00:00.000000000 +1100
+++ hpt/src/pktread.c   2025-10-09 10:05:00.000000000 +1100
@@ -734,6 +734,7 @@
 {
     s_message * msg;
     size_t len;
+    flag_t date_flags;
     int badmsg = 0;
     struct tm tm;
     long unread;
@@ -774,7 +775,16 @@
     }

     msg->datetime[20] = 0;               /* ensure it's null-terminated */
-    parse_ftsc_date(&tm, (char *)msg->datetime);
+    date_flags = parse_ftsc_date(&tm, (char *)msg->datetime);
+
+    /* Check if the date field is broken and cannot be parsed */
+    if(date_flags & FTSC_BROKEN)
+    {
+        w_log(LL_ERR,
+              "wrong msg header: datetime field is broken ('%s')",
+              msg->datetime);
+        badmsg++;
+    }

     /* val: make_ftsc_date((char*)msg->datetime, &tm); */
     if(globalBuffer == NULL)

TESTING:
========
With this patch applied, packets with broken date fields will be properly
rejected and renamed to .bad instead of being processed.

Be

.