Upstream has rejected this flag which would have let FEX close the gap
in functionality between binfmt_misc interpreters and PT_INTERP
interpreters for how `/proc/exe` is handled. Since we are unable to
change their opinions, just remove the code from FEX since it's never
going to happen.
Removes a little bit of confusing behaviour in execveat and
filemanagement handling. Leaving us with only the regular confusing
behaviour of trying to track accesses to `/proc/exe` instead.
Adds support for binfmt_misc through systemd configuration paths. Their
configuration files are basically the raw kernel interface description
in a .conf file, quite a bit more simple than the legacy debian path.
Default enable this path since systemd is the expected default
arrangement these days.
Fixes#2417
This app bypasses the glX functions exported by libGL and instead sends GLX
requests directly via xcb. FEX won't support forwarding this usage pattern in
the foreseeable future.
Fixes#3479
As of the Steam update on Feb 29 2024, this is no longer necessary and
actually causes steamwebhelper to abort.
Steam has started using SLR to launch steamwebhelper, which already
passes in --no-sandbox. Adding this argument twice seemingly breaks the
application since it starts complaining that it doesn't understand the
argument and closes with a SIGABRT.
With this removed Steam starts working again.
This was only required on x86 devices trying to escape the emulation.
Since x86 is now remove, this is entirely unnecessary.
When Steam launches applications with `/bin/sh`, this will remain under
the emulation and not escape these days.
This is a new procfs symlink path that changes behaviour of binfmt_misc
when exposed. We need to check both procfs/exe and procfs/interpreter
and see if they exist AND also differ.
Once/if they do then we can disable a bunch of checking of paths once
they do. The fallback when none of this is supported has the same
behaviour has previously where it still does all the regular checking.
During binfmt_misc install cmake will check the kernel version for the
raw binfmt_misc writing. Which will never pass until we have a real
kernel version that it is upstreamed in.
For update-binfmts we add a new optional argument where the tool will
drop the flag if the host kernel version isn't new enough to handle the
option.
I was hitting an issue where thunking in Wine+Vulkan applications was breaking
unless both OpenGL and Vulkan was enabled.
Turns out this was because Vulkan enabled only XCB, which didn't enable
X11. So when XCB is thunked but X11 isn't, this causes weird issues
where X11 calls in to XCB functions and gets in desync'ed state. Causing
hangs to appear in xcb_take_socket.
Now we can enabled just `Vulkan` as a thunk and it'll work fine.
```
(gdb) bt
from target:/usr/lib/fex-emu/HostThunks//libvulkan-host.so
```
Removes the @PREFIX_ARCH@ replacement string in the thunks path.
The library prefix paths now get generated upfront and everything gets
replaced to handle the differences between multiarch distros.
Fixes Thunks on Arch and Fedora.
This is known to cause issues in some cases. We hit the first game that
checks for this bit and early exits if it is found.
Lets the MMORPG Tibia run in non-VM situations.
Looks like they have more checks for VMs other than hypervisor bit, so
running under Parallels still won't work. Running on bare Linux is fine.
These require the previous commit's RIP block synchronization.
This is due to the fact that these rely on exceptions to occur on
try-catch blocks.
With us ensuring RIP synchronization on block entry, this solves the
problem of these crashing before doing anything.
Wine 6.x didn't require this, but 7.x does.
Fixes Proton Experimental hangs when it is installing the VC runtimes.
Since we have switched over to thunking the vulkan loader, behaviour has
changed here and we need to thunk this library.
While a bit unsafe to thunk arbitrary libraries, we know this one is
safe to thunk.
Fixes thunking Vulkan on steam games which have been broken since
switching over to vulkan loader thunking.
In the future this may become unnecessary but it is required for now.
Instead of duplicating prefixes in the ThunksDB json file even more,
just do a prefix replacement when the thunks database is being parsed.
Changes the JSON overlay arrays over to @PREFIX@ and reduce the
duplication.
Adds support for the pressure-vessel prefix `/usr/lib/pressure-vessel/overrides/lib`
This gets thunks ready for running under pressure-vessel, once vulkan
thunking switches from device libraries to the vulkan loader it should
just work.
Steam's webhelper has started enabling its sandbox which completely
breaks under FEX since we don't support seccomp.
Curiously the Chromium code is actually supposed to support a fallback
namespace only mode, which is used in glibc 2.34 environments.
The startup script for this will try to use this namespace only mode,
but Chromium developers never tested this in an environment that doesn't
support seccomp.
Due to an early check in their sandbox code, it checks for bpf support
before checking for which sandbox mode it is entering. This returns
early with a false statement which brings the entire browser instance
down with an assert.
Inject the --no-sandbox argument so we get around this and the sandbox
is disabled.
This lets us support the final two flags in binfmt_misc that we needed.
1) Support open_binary
2) Support preserve
1)
We already supported the credentials flag, which implied open_binary, but we weren't handling half of it.
With the open_binary flag, the Linux kernel passes us the executable in an FD instead of as a pathname.
This can be found inside of auxv on startup, inside of AT_EXECFD.
If AT_EXECFD is available then we prioritize using that instead of the pathname passed in.
This fixes a potential permissions issue where an executable is executed without read permissions.
2)
The preserve flag has the Linux kernel preserve the original argv[0] that was passed to the application.
Prior to supporting this flag, the kernel would provide us with a resolved program path.
This can happen in the instance where something like `blah` resolves to `/usr/loca/bin/blah` which
isn't what the user originally typed.
This works around this problem by handing the interpreter both the resolved path and the original typed path.
Alongside open_binary, we can just use the FD passed in instead of the resolved path, this means
we can just drop the argv[0] for the guest (which is the kernel resolved path) and pass through arguments
unmangled.
We do have to make a minor assumption here that if we are using EXECFD that we assume preserve.
It isn't until kernel v5.12 that we can actually check AT_FLAGS to see if that was true.
We had hardcoded paths in our binfmt_misc files. Change it to a generated
file instead.
Additionally for the binfmt_misc install targets, since we aren't installing to the
global binfmt_misc folder, we need to pass in the import directory
Fixes#1169
Tony Wasserka