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/windows/init.go | 26 +++----------------------- 1 file changed, 3 insertions(+), 23 deletions(-) (limited to 'sys/windows/init.go') diff --git a/sys/windows/init.go b/sys/windows/init.go index 8e3761024..7729f3260 100644 --- a/sys/windows/init.go +++ b/sys/windows/init.go @@ -15,19 +15,9 @@ func initTarget(target *prog.Target) { PAGE_EXECUTE_READWRITE: target.ConstMap["PAGE_EXECUTE_READWRITE"], } - target.PageSize = pageSize - target.DataOffset = dataOffset - target.MmapSyscall = arch.virtualAllocSyscall target.MakeMmap = arch.makeMmap - target.AnalyzeMmap = arch.analyzeMmap } -const ( - // TODO(dvyukov): what should we do about 4k vs 64k? - pageSize = 4 << 10 - dataOffset = 512 << 20 -) - type arch struct { virtualAllocSyscall *prog.Syscall @@ -36,26 +26,16 @@ type arch struct { PAGE_EXECUTE_READWRITE uint64 } -func (arch *arch) makeMmap(start, npages uint64) *prog.Call { +func (arch *arch) makeMmap(addr, size uint64) *prog.Call { meta := arch.virtualAllocSyscall 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), prog.MakeConstArg(meta.Args[2], arch.MEM_COMMIT|arch.MEM_RESERVE), prog.MakeConstArg(meta.Args[3], arch.PAGE_EXECUTE_READWRITE), }, Ret: prog.MakeReturnArg(meta.Ret), } } - -func (arch *arch) analyzeMmap(c *prog.Call) (start, npages uint64, mapped bool) { - switch c.Meta.Name { - case "VirtualAlloc": - npages = c.Args[1].(*prog.ConstArg).Val / pageSize - start = c.Args[0].(*prog.PointerArg).PageIndex - mapped = true - } - return -} -- cgit mrf-deployment