When manager is stopped there are sometimes runaway qemu
processes still running. Set PDEATHSIG for all subprocesses.
We never need child processes outliving parents.
For some racy bugs syzkaller can generate a C reproducer with tun
enabled, when it's not actuallly required to trigger the bug.
Some kernel developers (that don't have CONFIG_TUN=y on their setups)
complain about such C repros.
When tun is not available, instead of exiting, print a message that tun
initialization failed and proceed.
There is no need to specify '-' as the filename for sed(1):
- The default behavior is to read stdin
- It was not done in all places
- It breaks on NetBSD sed(1) (although I am tempted to fix it now :-)
and it does not work
We currently use more complex and functional protocol on linux,
and a simple ad-hoc protocol on other OSes.
This leads to code duplication in both ipc and executor.
Linux supports coverage, shared memory communication and fork server,
which would also be useful for most other OSes.
Unify communication protocol and parametrize it by
(1) use of shmem or only pipes, (2) use of fork server.
This reduces duplication in ipc and executor and will
allow to support the useful features for other OSes easily.
Finally, this fixes akaros support as it currently uses
syz-stress running on host (linux) and executor running on akaros.
We print all other output to stderr, write debug output to stderr as well.
This does not matter for the main use case of running syz-execprog -debug,
but can is helpful if we want to communicate with syz-executor via stdin/stdout.
Currently we always send 2MB of data to executor in ipc_simple.go.
Send only what's consumed by the program, and don't send the trailing zeros.
Serialized programs usually take only few KBs.
A recent linux commit "tun: enable napi_gro_frags() for TUN/TAP driver"
added support for fragmentation when emitting packets via tun.
Support this feature in syz_emit_ethernet.
This breaks circular dependency between:
sysgen -> sys/linux -> sys -> sysgen
With this circular dependency it is very difficult to
update format of generated descriptions because sysgen does not build.
Now each prog function accepts the desired target explicitly.
No global, implicit state involved.
This is much cleaner and allows cross-OS/arch testing, etc.
Large overhaul moves syscalls and arg types from sys to prog.
Sys package now depends on prog and contains only generated
descriptions of syscalls.
Introduce prog.Target type that encapsulates all targer properties,
like syscall list, ptr/page size, etc. Also moves OS-dependent pieces
like mmap call generation from prog to sys.
Update #191
We currently use uintptr for all values.
This won't work for 32-bit archs.
Moreover in some cases we use uintptr but assume
that it is always 64-bits (e.g. in encodingexec).
Switch everything to uint64.
Update #324
Repro can generate Sandbox="namespace"/UseTmpDir=false.
This combination is broken for two reasons:
- on second and subsequent executions of the program,
it fails to create syz-tmp dir
- with Procs>1, it fails right away, because all procs
try to create syz-tmp dir
Don't generate such combination.
We currently have 2 invalid options combinations:
- collide without threads
- procs>1 without repeat
They are invalid in the sense that result of csource.Write
is the same for them. Filter out these combinations.
This cuts csource testing time in half and reduces repro minimization time.
Locking memory is a reasonably legitimate local DoS vector.
E.g. bpf maps allow allocation of large chunks of kernel memory
without RLIMIT_MEMLOCK, which leads to hangups.
Set RLIMIT_MEMLOCK=8MB in executor.
We can't know the exact values of those sleeps in advance, they can be
different for different bugs. Making them random increases the chance that
the C repro executes with the right timings at some point.
Currently we have unix permissions for new files/dirs
hardcoded throughout the code base. Some places use 0644,
some - 0640, some - 0600 and a variety of other constants.
Introduce osutil.MkdirAll/WriteFile that use the default
permissions and use them throughout the code base.
This makes permissions consistent and also allows to easily
change the permissions later if we change our minds.
Also merge pkg/fileutil into pkg/osutil as they become
dependent on each other. The line between them was poorly
defined anyway as both operate on files.
