cvs commit: src/usr.sbin/kldxref kldxref.c

[Bruce Evans]

On Sun, 6 Aug 2006, Dag-Erling [iso-8859-1] Smørgrav wrote:

> Marcel Moolenaar <marcel at FreeBSD.org> writes:
>>   Log:
>>   Fix (static) buffer overflow bug. The dest buffer is of size MAXPATHLEN,
>>   so dest[MAXPATHLEN] falls outside the buffer.  This bug corrupted
>>   arenas[0] defined in libc's malloc.c on PowerPC when kldxref is shared,
>>   which triggered a delayed SIGSERV.
>
> MAXPATHLEN should be spelled PATH_MAX.

Actually, MAXPATHLEN is better since it is honestly unportable.  It works
on all [Free]BSD systems, while PATH_MAX only works on POSIX systems that
define it.  The correct spelling of PATH_MAX is {PATH_MAX} or:

#if defined(PATH_MAX) && defined(OPTIMIZE_FOR_COMPILE_TIME_CONST_PATH_MAX)
 	char buf[PATH_MAX];
 	...
#else
 	long path_max;

 	path_max = pathconf(pathname_of_interest, _PC_PATH_MAX);
 	if (path_max == -1)
 		handle_error();
 	assert(path_max > 0 && path_max <= SIZE_MAX)
 	buf = malloc((size_t)path_max);
 	if (buf == NULL)
 		handle_allocation_failure();
 	...
#endif

The correct spelling is too hard to use for simple unportable utilities
like kldxref.

Bruce