cosmopolitan/libc/str/path.h
Justine Tunney 98254a7c1f Make pledge() and unveil() work amazingly
This change reconciles our pledge() implementation with the OpenBSD
kernel source code. We now a polyfill that's much closer to OpenBSD's
behavior. For example, it was discovered that "stdio" permits threads.
There were a bunch of Linux system calls that needed to be added, like
sched_yield(). The exec / execnative category division is now dropped.
We're instead using OpenBSD's "prot_exec" promise for launching APE
binaries and dynamic shared objects. We also now filter clone() flags.

The pledge.com command has been greatly improved. It now does unveiling
by default when Landlock is available. It's now smart enough to unveil a
superset of paths that OpenBSD automatically unveils with pledge(), such
as /etc/localtime. pledge.com also now checks if the executable being
launched is a dynamic shared object, in which case it unveils libraries.

These changes now make it possible to pledge curl on ubuntu 20.04 glibc:

    pledge.com -p 'stdio rpath prot_exec inet dns tty sendfd recvfd' \
        curl -s https://justine.lol/hello.txt

Here's what pledging curl on Alpine 3.16 with Musl Libc looks like:

    pledge.com -p 'stdio rpath prot_exec dns inet' \
        curl -s https://justine.lol/hello.txt

Here's what pledging curl.com w/ ape loader looks like:

    pledge.com -p 'stdio rpath prot_exec dns inet' \
        o//examples/curl.com https://justine.lol/hello.txt

The most secure sandbox, is curl.com converted to static ELF:

    o//tool/build/assimilate.com o//examples/curl.com
    pledge.com -p 'stdio rpath dns inet' \
        o//examples/curl.com https://justine.lol/hello.txt

A weird corner case needed to be handled when resolving symbolic links
during the unveiling process, that's arguably a Landlock bug. It's not
surprising since Musl and Glibc are also inconsistent here too.
2022-07-19 21:33:49 -07:00

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C

#ifndef COSMOPOLITAN_LIBC_STR_PATH_H_
#define COSMOPOLITAN_LIBC_STR_PATH_H_
#define _kPathAbs 1
#define _kPathDev 2
#define _kPathRoot 4
#define _kPathDos 8
#define _kPathWin 16
#define _kPathNt 32
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
int _classifypath(const char *) libcesque nosideeffect;
bool _isabspath(const char *) libcesque strlenesque;
bool _isdirsep(int) libcesque pureconst;
char *_joinpaths(char *, size_t, const char *, const char *);
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_STR_PATH_H_ */