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.
The pledge.com command now supports the new [WIP] unveil() support. For
example, to strongly sandbox our command for listing directories.
o//tool/build/assimilate.com o//examples/ls.com
pledge.com -v /etc -p 'stdio rpath' o//examples/ls.com /etc
This file system sandboxing is going to be perfect for us, because APE
binaries are self-contained static executables that really don't use the
filesystem that much. On the other hand, with non-static executables,
sandboxing is going to be more difficult. For example, here's how to
sandbox the `ls` command on the latest Alpine:
pledge.com -v rx:/lib -v /usr/lib -v /etc -p 'stdio rpath exec' ls /etc
This change fixes the `execpromises` API with pledge().
This change also adds unix.unveil() to redbean.
Fixes#494
- Wrap clock_getres()
- Wrap sched_setscheduler()
- Make sleep() api conformant
- Polyfill sleep() using select()
- Improve clock_gettime() polyfill
- Make nanosleep() POSIX conformant
- Slightly improve some DNS functions
- Further strengthen pledge() sandboxing
- Improve rounding of timeval / timespec
- Allow layering of pledge() calls on Linux
- Polyfill sched_yield() using select() on XNU
- Delete more system constants we probably don't need
- Add rusage to redbean Lua API
- Add more redbean documentation
- Add pledge() to redbean Lua API
- Polyfill OpenBSD pledge() for Linux
- Increase PATH_MAX limit to 1024 characters
- Untrack sibling processes after fork() on Windows
