This is a standalone implementation of
fortify source
level 3, providing compile time security checks.
It is libc-agnostic and simply overlays the system headers by using the
#include_next
extension found in GCC, and
black magic
on Clang. It was initially intended to be used on
musl based
Linux distributions.
__builtin_trap().FORTIFY_USE_NATIVE_CHK will make use of compiler-provided builtin _chk
functions, which might be a bit better in term of diagnostics,
but won't necessarily provide the same amount of security checks.FORTIFY_PEDANTIC_CHECKS will enable pedantic checks, that while technically
correct, might break some programs relying on widely accepted
undefined-behaviours.If you want to quickly test it, you can try something like the following:
cat > fgets.c <<EOF
#include <stdio.h>
int
main(void)
{
char buf[BUFSIZ];
fgets(buf, sizeof(buf) + 1, stdin);
return 0;
}
EOF
cc -I<path-to-fortify-include-dir> -D_FORTIFY_SOURCE=3 -O1 fgets.c
./a.outAt this point, the program will safely and loudly crash.
FD_CLRFD_SETasprintfbcopybzerocallocconfstrfdopen fgetsfgetwsfmemopen fopen fprintf freadfwritegetcwdgetdomainnamegetgroupsgethostnamegetlogin_rmalloc mbsnrtowcsmbsrtowcsmbstowcsmemchr memcpymemmovemempcpymemsetpollpopen ppollpreadprintf pwrite qsort readreadlinkreadlinkatrealloc reallocarray realpathrecvrecvfromselect sendsendtosnprintfsprintfstpcpystpncpystrcatstrchrstrcpystrlcatstrlcpystrlenstrncatstrncpystrrchrtmpfile ttyname_rumask vfprintf vprintf vasprintfvsnprintfvsprintfwcrtombwcscatwcscpywcsncatwcsncpywcsnrtombswcsrtombswcstombswctombwmemcpywmemmovewmemsetwrite