111 lines
1.8 KiB
Plaintext
111 lines
1.8 KiB
Plaintext
What is it?
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===========
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This is a standalone implementation of fortify source[0]. It provides
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compile time buffer checks. It is libc-agnostic and simply overlays the
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system headers by using the #include_next extension found in GCC. It was
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initially intended to be used on musl[1] based Linux distributions[2].
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Features
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========
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- It is portable, works on *BSD, Linux, Solaris and possibly others.
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- It will only trap non-conformant programs. This means that fortify
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level 2 is treated in the same way as level 1.
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- Avoids making function calls when undefined behaviour has already been
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invoked. This is handled by using __builtin_trap().
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- Support for out-of-bounds read interfaces, such as send(), write(),
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fwrite() etc.
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- No ABI is enforced. All of the fortify check functions are inlined
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into the resulting binary.
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Sample usage
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============
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If you want to quickly test it, you can try something like the following:
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cat > fgets.c <<EOF
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#include <stdio.h>
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int
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main(void)
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{
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char buf[BUFSIZ];
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fgets(buf, sizeof(buf) + 1, stdin);
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return 0;
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}
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EOF
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cc -I<path-to-fortify-include-dir> -D_FORTIFY_SOURCE=1 -O1 fgets.c
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./a.out
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At this point, the program will safely crash.
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Supported interfaces
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====================
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FD_CLR
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FD_SET
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bcopy
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bzero
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confstr
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fgets
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fgetws
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fread
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fwrite
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getcwd
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getdomainname
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getgroups
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gethostname
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getlogin_r
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mbsnrtowcs
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mbsrtowcs
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mbstowcs
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memcpy
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memmove
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mempcpy
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memset
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poll
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ppoll
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pread
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read
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readlink
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readlinkat
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realpath
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recv
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recvfrom
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send
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sendto
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snprintf
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sprintf
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stpcpy
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stpncpy
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strcat
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strcpy
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strlcat
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strlcpy
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strncat
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strncpy
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ttyname_r
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vsnprintf
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vsprintf
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wcrtomb
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wcscat
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wcscpy
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wcsncat
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wcsncpy
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wcsnrtombs
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wcsrtombs
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wcstombs
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wctomb
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wmemcpy
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wmemmove
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wmemset
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write
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[0] http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
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[1] http://www.musl-libc.org/
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[2] http://git.alpinelinux.org/cgit/aports/commit/?id=067a4f28825478911bb62be3b8da758d9722753e
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