Add support for FreeBSD

[pythononedog]

I found image_ Build without freebsd.why does s2e not support freebsd?What do I need to do if I want it to support freebsd?

[pythononedog]

I want to use s2e to analyze freebsd.

[vitalych]

The S2E engine shouldn't have any issues running FreeBSD or any other x86 OS. However, all the tooling around S2E only supports Linux and Windows. Here's what you could do to get started:

• Build a VM image with BSD using vanilla QEMU, e.g., image.raw (it is important to have a raw image, not vmdk or something else).
• Rename image.raw to image.raw.s2e. The s2e suffix will tell S2E that this should be handled with S2E image handler.
• Boot the image in S2E mode using libs2e.so, save a "ready" snapshot (savevm ready command in QEMU console).
• Resume the image.

s2e image_build builds Linux and Windows images in such a way that when they are resumed by launch-s2e.sh, they fetch a bootstrap script from the host. See [1] for details. Note that fetching files from the host requires the s2ecmd binary to be built for FreeBSD. Please check the guest/ folder, you may need to cross-compile it.

[1] https://s2e.systems/docs/ImageInstallation.html

Once you have guest tools built, you can technically start symbolic execution. Use that tool to create symbolic files in a ramdisk.

You may want to study the Linux tooling and tweak that for FreeBSD (e.g., s2e image_build, s2e new_project, etc).

To have full plugin support, you will need to create a FreeBSDMonitor plugin, similar to LinuxMonitor and WindowsMonitor. This may require instrumenting the kernel in order to provide the monitor all the required information to implement the OSMonitor interface.

[pythononedog]

thanks,i'll give it a try.

[pythononedog]

When I customize the freebsd VM image,I am unable to save the snapshot.

[vitaly-cyberhaven]

That's because qemu thinks it's a raw image. Those don't support snapshots.
You need to use something like this: -drive if=ide,index=0,file=image.raw.s2e,format=s2e,cache=writeback