We experienced a crash when running the latest master with a simplified decoded backtrace of:

free (cursorname) on line 72 of fw1-cursor.c
open_fw1_cursorfile()
main()

Raw:
*** glibc detected *** /usr/local/bin/fw1-loggrabber: free(): invalid next size (fast): 0x08494768 ***
======= Backtrace: =========
/lib/libc.so.6(+0x70bb1)[0xf742abb1]
/lib/libc.so.6(+0x73611)[0xf742d611]
/usr/local/bin/fw1-loggrabber[0x804e098]
/usr/local/bin/fw1-loggrabber[0x804f432]
/lib/libc.so.6(__libc_start_main+0xe6)[0xf73d0d26]
/usr/local/bin/fw1-loggrabber[0x804d361]

From a review of how cursorname is constructed in get_fw1_cursorname(), it appears that the malloc is one byte too small since ".cursor" is 7 bytes and the NULL terminator is 1 byte. Therefore, it should be:

char *cursorname =
(char *) malloc (strlen (LogfileName) + 8);

instead of:

char *cursorname =
(char *) malloc (strlen (LogfileName) + 7);

The fix provided attempts to do the +8 in a more maintainable way by preventing needing to actually count the bytes in ".cursor".