CATEGORY:
    MITRE CWE-121: Stack-based Buffer Overflow.

REFERENCE: 
    http://cwe.mitre.org/data/definitions/121.html. 

EXPLANATION:
    The pointer 'p' into the stack-based buffer 'strbuf' is not reset after a
    hex string part has been emitted.

CONSEQUENCES:
    Typically, stacks 'grow' from higher addresses to lower addresses. A
    sufficiently large log request ('len' > 'MAX_BYTES_PER_LOG_LINE') will
    overwrite the stack frames (local variables, return address) of 'logbuf'
    and its calling routines. In the best case, the program just crashes, in
    other cases security- and/or safety-critical data may be overwritten.

BUGFIX:
    The initialization of 'p' needs to be moved to the beginning of the
    while-loop:

    while (remainingBytesToLog > 0) {
        char* p = &strbuf[0];
        size_t bytesToLogForThisLine = (remainingBytesToLog <= MAX_BYTES_PER_LOG_LINE) 
            ? remainingBytesToLog : MAX_BYTES_PER_LOG_LINE;
        ...
    }