LibAFL-qemu-bridge stop linking with latest rust nightly

[vringar]

Tested on cf01d04

Describe the bug

LibAFL/fuzzers/qemu_systemmode/target/classic/release/qemu_systemmode: error while loading shared libraries: libz.so.1: cannot open shared object file: No such file or directory

When running ldd LibAFL/fuzzers/qemu_systemmode/target/classic/release I get the following output:

ldd qemu_systemmode
	linux-vdso.so.1 (0x00007ffff7fc6000)
	libz.so.1 => not found
	libpixman-1.so.0 => not found
	libgmp.so.10 => not found
	libglib-2.0.so.0 => not found
	libgmodule-2.0.so.0 => not found
	libm.so.6 => /nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib/libm.so.6 (0x00007ffff7edb000)
	libnettle.so.8 => not found
	libhogweed.so.6 => not found
	libgcc_s.so.1 => /nix/store/nrwkk6ak3rgkrxbqhsscb01jpzmslf2r-xgcc-13.2.0-libgcc/lib/libgcc_s.so.1 (0x00007ffff7eb6000)
	libc.so.6 => /nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib/libc.so.6 (0x00007ffff5c13000)
	/nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib/ld-linux-x86-64.so.2 => /nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib64/ld-linux-x86-64.so.2 (0x00007ffff7fc8000)

To Reproduce
Steps to reproduce the behavior:

1. In fuzzers/qemu_systemmode run cargo make build and cargo make run
2. Observe the error message from the bug description

Expected behavior

The normal fuzzer output

Additional context

I can verify that everything still works on cargo 1.80.0-nightly (0ca60e940 2024-05-08) but doesn't on cargo 1.80.0-nightly (0de7f2ec6 2024-05-17).
I've seen that you have started cancelling qemu builds in CI, so I'm assuming you are aware of the issue. I just wanted to know if this is a bug in qemu_systemmode_build or if you have already filed an upstream bug?

[vringar]

Please lmk, if I can help with any part of this investigation.

[rmalmain]

I just tried to reproduce your issue. It seems to run as expected on my side.
Your output of ldd suggests some shared libraries cannot be found on your system.
I don't know how they are handled in nix, so I don't think I can be of much help if it is indeed nix-related.
Can you confirm the missing shared libraries from the ldd output are installed on your side?

[vringar]

The shared libraries are installed as shown by the fact that ldd returns the following for cargo 1.80.0-nightly (0ca60e940 2024-05-08)

linux-vdso.so.1 (0x00007ffe4c9fb000)
	libz.so.1 => /nix/store/nw1bnjadmzk9hnd4nbvxmqlh074vr16j-zlib-1.3.1/lib/libz.so.1 (0x00007fa7fe5b5000)
	libpixman-1.so.0 => /nix/store/wp39qd0w5z36qras2rm9dbxb4dh6z4bn-pixman-0.43.4/lib/libpixman-1.so.0 (0x00007fa7fe506000)
	libgmp.so.10 => /nix/store/rkj3k7pflfvjf7shraqvb1qd9s2dz1zs-gmp-with-cxx-6.3.0/lib/libgmp.so.10 (0x00007fa7fe463000)
	libglib-2.0.so.0 => /nix/store/bcms6vbac6jyffwyj8y630brpy1il4ks-glib-2.80.0/lib/libglib-2.0.so.0 (0x00007fa7fc0b5000)
	libgmodule-2.0.so.0 => /nix/store/bcms6vbac6jyffwyj8y630brpy1il4ks-glib-2.80.0/lib/libgmodule-2.0.so.0 (0x00007fa7fe45a000)
	libm.so.6 => /nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib/libm.so.6 (0x00007fa7fbfd2000)
	libnettle.so.8 => /nix/store/adalw59bvrk2fg2fl662xnc4y2bqn438-nettle-3.9.1/lib/libnettle.so.8 (0x00007fa7fbf7e000)
	libhogweed.so.6 => /nix/store/adalw59bvrk2fg2fl662xnc4y2bqn438-nettle-3.9.1/lib/libhogweed.so.6 (0x00007fa7fbf33000)
	libgcc_s.so.1 => /nix/store/p3ffjixpnfgkqh20nsrc13vrj3yfi0nj-gcc-13.2.0-lib/lib/libgcc_s.so.1 (0x00007fa7fbf0e000)
	libc.so.6 => /nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib/libc.so.6 (0x00007fa7fbd21000)
	/nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib/ld-linux-x86-64.so.2 => /nix/store/apab5i73dqa09wx0q27b6fbhd1r18ihl-glibc-2.39-31/lib64/ld-linux-x86-64.so.2 (0x00007fa7fe5d5000)
	libpcre2-8.so.0 => /nix/store/sik7a8dic5lxhm4cp9npibk97x9jcxwf-pcre2-10.43/lib/libpcre2-8.so.0 (0x00007fa7fbc81000)

(and I also explicitly declare most of them here.)

[vringar]

pkg-config --libs zlib also returns -L/nix/store/nw1bnjadmzk9hnd4nbvxmqlh074vr16j-zlib-1.3.1/lib -lz, so it is findable.

[vringar]

cat linkinfo.json| jq .libs returns

[
  "z",
  "pixman-1",
  "gmp",
  "glib-2.0",
  "gmodule-2.0",
  "m",
  "nettle",
  "hogweed",
  "util"
]

so this code should set everything correctly:

LibAFL/libafl_qemu/libafl_qemu_build/src/build.rs

Lines 616 to 620 in cf01d04

	for arg in linkinfo["libs"].members() {
	let val = arg
	.as_str()
	.expect("linkinfo.json `libs` values must be strings");
	println!("cargo:rustc-link-lib={val}");

[vringar]

This is because of the switch to an internal lld that is not patched to work with Nix. rust-lang/rust#125321