From 75a7c5e2d1f09a4a58e7e1f1f4ef0b0f55a33413 Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Mon, 19 Feb 2018 19:35:04 +0100 Subject: prog: rework address allocation 1. mmap all memory always, without explicit mmap calls in the program. This makes lots of things much easier and removes lots of code. Makes mmap not a special syscall and allows to fuzz without mmap enabled. 2. Change address assignment algorithm. Current algorithm allocates unmapped addresses too frequently and allows collisions between arguments of a single syscall. The new algorithm analyzes actual allocations in the program and places new arguments at unused locations. --- sys/fuchsia/init.go | 25 +++---------------------- 1 file changed, 3 insertions(+), 22 deletions(-) (limited to 'sys/fuchsia/init.go') diff --git a/sys/fuchsia/init.go b/sys/fuchsia/init.go index 12ee37daf..f3299e178 100644 --- a/sys/fuchsia/init.go +++ b/sys/fuchsia/init.go @@ -12,40 +12,21 @@ func initTarget(target *prog.Target) { mmapSyscall: target.SyscallMap["syz_mmap"], } - target.PageSize = pageSize - target.DataOffset = dataOffset - target.MmapSyscall = arch.mmapSyscall target.MakeMmap = arch.makeMmap - target.AnalyzeMmap = arch.analyzeMmap } -const ( - pageSize = 4 << 10 - dataOffset = 512 << 20 -) - type arch struct { mmapSyscall *prog.Syscall } -func (arch *arch) makeMmap(start, npages uint64) *prog.Call { +func (arch *arch) makeMmap(addr, size uint64) *prog.Call { meta := arch.mmapSyscall return &prog.Call{ Meta: meta, Args: []prog.Arg{ - prog.MakePointerArg(meta.Args[0], start, 0, npages, nil), - prog.MakeConstArg(meta.Args[1], npages*pageSize), + prog.MakeVmaPointerArg(meta.Args[0], addr, size), + prog.MakeConstArg(meta.Args[1], size), }, Ret: prog.MakeReturnArg(meta.Ret), } } - -func (arch *arch) analyzeMmap(c *prog.Call) (start, npages uint64, mapped bool) { - switch c.Meta.Name { - case "syz_mmap": - npages = c.Args[1].(*prog.ConstArg).Val / pageSize - start = c.Args[0].(*prog.PointerArg).PageIndex - mapped = true - } - return -} -- cgit mrf-deployment