We now have a bunch of targets compiled into each binary.
All targets are initialized eagerly on startup time.
As the result a do nothing binary starts for ~0.58s and
consumes ~21MB.
Initialize targets lazily. Usually only 1 target is used.
This reduces startup time to ~0.00s and memory consumption
to ~5.4MB.
Clone program only once.
Preallocate slices in clone.
Remove the clone full mode.
Always mutate args in place.
Allocate replacers map lazily.
Don't allocate res map at all (calculate valus on the go).
Remove sliceToUint64, pad.
benchmark old ns/op new ns/op delta
BenchmarkHints 122100048 7466013 -93.89%
The race initially showed up on the new benchmark (see race report below).
The race indicated a wrong call passed to replaceArg,
as the result we sanitized the wrong call and left the new call un-sanitized.
Fix this.
Add test that exposes this.
Run benchmarks in race mode during presubmit
(benchmarks have higher chances of uncovering races than tests).
WARNING: DATA RACE
Write at 0x00c42000d3f0 by goroutine 18:
github.com/google/syzkaller/sys/linux.(*arch).sanitizeCall()
sys/linux/init.go:155 +0x256
github.com/google/syzkaller/sys/linux.(*arch).(github.com/google/syzkaller/sys/linux.sanitizeCall)-fm()
sys/linux/init.go:42 +0x4b
github.com/google/syzkaller/prog.(*Prog).replaceArg()
prog/prog.go:357 +0x239
github.com/google/syzkaller/prog.generateHints.func2()
prog/hints.go:105 +0x124
github.com/google/syzkaller/prog.checkConstArg()
prog/hints.go:128 +0xf3
github.com/google/syzkaller/prog.generateHints()
prog/hints.go:120 +0x495
github.com/google/syzkaller/prog.(*Prog).MutateWithHints.func1()
prog/hints.go:72 +0x67
github.com/google/syzkaller/prog.foreachSubargImpl.func1()
prog/analysis.go:86 +0x9f
github.com/google/syzkaller/prog.foreachSubargImpl()
prog/analysis.go:104 +0xc8
github.com/google/syzkaller/prog.foreachArgArray()
prog/analysis.go:113 +0x89
github.com/google/syzkaller/prog.foreachArg()
prog/analysis.go:121 +0x50
github.com/google/syzkaller/prog.(*Prog).MutateWithHints()
prog/hints.go:71 +0x18e
github.com/google/syzkaller/prog.BenchmarkHints.func1()
prog/hints_test.go:477 +0x77
testing.(*B).RunParallel.func1()
testing/benchmark.go:626 +0x156
Previous read at 0x00c42000d3f0 by goroutine 17:
github.com/google/syzkaller/prog.clone()
prog/clone.go:38 +0xbaa
github.com/google/syzkaller/prog.(*Prog).cloneImpl()
prog/clone.go:21 +0x17f
github.com/google/syzkaller/prog.generateHints()
prog/hints.go:95 +0xd0
github.com/google/syzkaller/prog.(*Prog).MutateWithHints.func1()
prog/hints.go:72 +0x67
github.com/google/syzkaller/prog.foreachSubargImpl.func1()
prog/analysis.go:86 +0x9f
github.com/google/syzkaller/prog.foreachSubargImpl()
prog/analysis.go:104 +0xc8
github.com/google/syzkaller/prog.foreachArgArray()
prog/analysis.go:113 +0x89
github.com/google/syzkaller/prog.foreachArg()
prog/analysis.go:121 +0x50
github.com/google/syzkaller/prog.(*Prog).MutateWithHints()
prog/hints.go:71 +0x18e
github.com/google/syzkaller/prog.BenchmarkHints.func1()
prog/hints_test.go:477 +0x77
testing.(*B).RunParallel.func1()
testing/benchmark.go:626 +0x156
Hints for data args don't work.
We do all the work, but at the final stage we patch
arg in the _old_ program, not in the _new_ one.
So programs passed to the callback are all the same
and don't contain any mutations.
Tests did not catch this because they work right before that point
(don't test the actual interface function MutateWithHints).
Fix that and add a test that catches this.
In some cases we need to extend a buffer by a large
margin to pass the next if in kernel (a size check).
Currently we only append a single byte, so we can
never pass the if incrementally (size is always
smaller than threshold, so 1-byte larger inputs
are not added to corpus).
Boot and minimally test images before declaring them as good
and switching to using them.
If image build/boot/test fails, upload report about this to dashboard.
For string[N] we successfully deserialize a string of any length.
Similarly for a fixed-size array[T, N] we successfully deserialize
an array of any size.
Such programs later crash in foreachSubargOffset because static size
Type.Size() does not match what we've calculated iterating over fields.
The crash happens only in SerializeForExec in syz-fuzzer,
which is especially bad.
Fix this from both sides:
1. Validate sizes of arrays/buffers in Validate.
2. Repair incorrect sizes in Deserialize.
There is effectively infinite number of possible crypto
algorithm names due to templates. Plus there is tricky
relation between algorithms and algorithm type names.
This change adds custom mutator for sockaddr_alg struct
to improve variance in generated algorithms.
During smashing we know what call gave new coverage,
so we can concentrate just on it.
This helps to reduce amount of hints generated (we have too many of them).
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.
The call index check episodically fails:
2017/10/02 22:07:32 bad call index 1, calls 1, program:
under unknown circumstances. I've looked at the code again
and don't see where/how we can mess CallIndex.
Added a new test for minimization that especially checks resulting
CallIndex.
It would be good to understand what happens, but we don't have
any reproducers. CallIndex is actually unused at this point.
Manager only needs call name. So remove CallIndex entirely.
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
A hint is basically a tuple consisting of a pointer to an argument
in one of the syscalls of a program and a value, which should be
assigned to that argument.
A simplified version of hints workflow looks like this:
1. Fuzzer launches a program and collects all the comparisons' data
for every syscall in the program.
2. Next it tries to match the obtained comparison operands' values
vs. the input arguments' values.
3. For every such match the fuzzer mutates the program by
replacing the pointed argument with the saved value.
4. If a valid program is obtained, then fuzzer launches it and
checks if new coverage is obtained.
This commit includes:
1. All the code related to hints generation, parsing and mutations.
2. Fuzzer functions to launch the process.
3. Some new stats gathered by fuzzer and manager, related to hints.
4. An updated version of execprog to test the hints process.
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
During minimization we create a single memory mapping that contains all
the smaller mmap() ranges, so that other mmap() calls can be dropped.
This "uber-mmap" used to start at 0x7f0000000000 regardless of where the
smaller mappings were located. Change its starting address to the
beginning of the first small mmap() range.
Due to https://github.com/google/syzkaller/issues/316 there're too many
mmap() calls in the programs, and syzkaller is spending quite a bit of
time mutating them. Most of the time changing mmap() calls won't give
us new coverage, so let's not do it too often.
