mailing list archives
Re: Smashing the Stack: prevention?
From: snar () CARRIER KIEV UA (Alexander Snarskii)
Date: Mon, 28 Apr 1997 22:29:17 +0300
1. 'you gotta change the code'
This one is obvious; people must change their SUID programs'
source code to avoid nasty things like gets() sprintf() strcat() and
strcpy() using things like fgets() strncat() strncpy() as substitutes.
Just one more way: replace ususal strcpy/sprintf/strcat
in libc to check stack integrity before exit, and generate
kill(SIGSEGV,getpid()) in case of violations.
That is a 'bad thing' from the performance point of view,
but not so bad (about 1% more time with stack
level 10); and that is not portable - because
stack checker must be written in assembler.
Sometimes ago i propagated such patches to FreeBSD team,
they did'nt commit it. If anyone interested:
the source code is included.
- vulnerabilities in kerberos, (continued)