https://github.com/jvoisin/fortify-headers

Standalone portable header-based implementation of FORTIFY_SOURCE=3
https://github.com/jvoisin/fortify-headers

c fortify-source libc security

Last synced: 2 months ago
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Standalone portable header-based implementation of FORTIFY_SOURCE=3

• Host: GitHub
• URL: https://github.com/jvoisin/fortify-headers
• Owner: jvoisin
• License: 0bsd
• Created: 2023-03-15T20:16:47.000Z (almost 2 years ago)
• Default Branch: master
• Last Pushed: 2024-10-21T13:05:20.000Z (3 months ago)
• Last Synced: 2024-10-21T20:35:12.566Z (3 months ago)
• Topics: c, fortify-source, libc, security
• Language: C
• Homepage:
• Size: 222 KB
• Stars: 17
• Watchers: 8
• Forks: 3
• Open Issues: 15
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# What is it?

This is a [standalone implementation](https://git.2f30.org/fortify-headers/) of

[fortify source]( http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html )

level 3, providing compile time security checks.

It is libc-agnostic and simply overlays the system headers by using the

[`#include_next`](https://gcc.gnu.org/onlinedocs/cpp/Wrapper-Headers.html)

extension found in GCC, and

[black magic](https://github.com/jvoisin/fortify-headers/commit/fe149628eaae9748be08815d726cc56e8e492c73)

on Clang. It was initially intended to be used on

[musl](http://www.musl-libc.org/) based

[Linux distributions](https://git.alpinelinux.org/aports/commit/?id=067a4f28825478911bb62be3b8da758d9722753e).

# Features

- It is portable, works on *BSD, Linux, Solaris and possibly others.

- It will only trap non-conformant programs. This means that fortify

  level 2 is treated in the same way as level 1.

- Avoids making function calls when undefined behaviour has already been

  invoked. This is handled by using `__builtin_trap()`.

- Support for out-of-bounds read interfaces, such as send(), write(), fwrite() etc.

- No ABI is enforced. All of the fortify check functions are inlined

  into the resulting binary.

- It has a [comprehensive suite of

  tests](https://github.com/jvoisin/fortify-headers/tree/master/tests), running

  both on Clang and on GCC for every commit, on C89, C99, C11 and C17, with

  [significant coverage](https://jvoisin.github.io/fortify-headers/)

- Defining `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.

- Defining `FORTIFY_PEDANTIC_CHECKS` will enable pedantic checks, that while technically

  correct, might break some programs relying on widely accepted

  undefined-behaviours.

# Sample usage

If you want to quickly test it, you can try something like the following:

```

cat > fgets.c <

int

main(void)

{

	char buf[BUFSIZ];

	fgets(buf, sizeof(buf) + 1, stdin);

	return 0;

}

EOF

cc -I -D_FORTIFY_SOURCE=3 -O1 fgets.c

./a.out

```

At this point, the program will safely and loudly crash.

# Supported interfaces

- `FD_CLR`

- `FD_SET`

- `asprintf`

- `bcopy`

- `bzero`

- `calloc`

- `confstr`

- `fdopen` 

- `fgets`

- `fgetws`

- `fmemopen` 

- `fopen` 

- `fprintf` 

- `fread`

- `fwrite`

- `getcwd`

- `getdomainname`

- `getgroups`

- `gethostname`

- `getlogin_r`

- `malloc` 

- `mbsnrtowcs`

- `mbsrtowcs`

- `mbstowcs`

- `memchr` 

- `memcpy`

- `memmove`

- `mempcpy`

- `memset`

- `poll`

- `popen` 

- `ppoll`

- `pread`

- `printf` 

- `pwrite` 

- `qsort` 

- `read`

- `readlink`

- `readlinkat`

- `realloc` 

- `reallocarray` 

- `realpath`

- `recv`

- `recvfrom`

- `select` 

- `send`

- `sendto`

- `snprintf`

- `sprintf`

- `stpcpy`

- `stpncpy`

- `strcat`

- `strchr`

- `strcpy`

- `strlcat`

- `strlcpy`

- `strlen`

- `strncat`

- `strncpy`

- `strrchr`

- `tmpfile` 

- `ttyname_r`

- `umask` 

- `vfprintf` 

- `vprintf` 

- `vasprintf`

- `vsnprintf`

- `vsprintf`

- `wcrtomb`

- `wcscat`

- `wcscpy`

- `wcsncat`

- `wcsncpy`

- `wcsnrtombs`

- `wcsrtombs`

- `wcstombs`

- `wctomb`

- `wmemcpy`

- `wmemmove`

- `wmemset`

- `write`