From 700132347e0702a3e5f100fba2752993b8de9600 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Fri, 2 Apr 2021 11:45:21 -0600 Subject: [PATCH] windows: allocate SECURITY_DESCRIPTOR with uintptr alignment This struct has pointers in it, which means checkptr expects for it to be aligned properly. When we're copying a Windows-allocated struct to a Go-allocated one, make sure that the Go allocation is aligned to the pointer size. This fixes the following checkptr splat: goroutine 29 [running]: runtime.throw(0x4f8dd9, 0x3a) C:/hostedtoolcache/windows/go/1.16.2/x64/src/runtime/panic.go:1117 +0x79 fp=0xc000041c50 sp=0xc000041c20 pc=0x2f9879 runtime.checkptrAlignment(0xc00009c180, 0x4d8a00, 0x1) C:/hostedtoolcache/windows/go/1.16.2/x64/src/runtime/checkptr.go:20 +0xc9 fp=0xc000041c80 sp=0xc000041c50 pc=0x2c4d09 golang.org/x/sys/windows.(*SECURITY_DESCRIPTOR).copySelfRelativeSecurityDescriptor(0x227284caa00, 0x2) C:/Users/runneradmin/go/pkg/mod/golang.org/x/sys@v0.0.0-20210309040221-94ec62e08169/windows/security_windows.go:1347 +0x11f fp=0xc000041ce8 sp=0xc000041c80 pc=0x467f9f golang.org/x/sys/windows.SecurityDescriptorFromString(0x4ebfb0, 0x2, 0x0, 0x0, 0x0) Change-Id: I7eb9c07e7afb7f139473b660f82a23541663ec50 Reviewed-on: https://go-review.googlesource.com/c/sys/+/306889 Trust: Jason A. Donenfeld Trust: Josh Bleecher Snyder Run-TryBot: Jason A. Donenfeld TryBot-Result: Go Bot Reviewed-by: Josh Bleecher Snyder --- windows/security_windows.go | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/windows/security_windows.go b/windows/security_windows.go index 0e428ecb..dd683724 100644 --- a/windows/security_windows.go +++ b/windows/security_windows.go @@ -1342,7 +1342,15 @@ func (selfRelativeSD *SECURITY_DESCRIPTOR) copySelfRelativeSecurityDescriptor() h.Len = sdLen h.Cap = sdLen - dst := make([]byte, sdLen) + const psize = int(unsafe.Sizeof(uintptr(0))) + + var dst []byte + h = (*unsafeheader.Slice)(unsafe.Pointer(&dst)) + alloc := make([]uintptr, (sdLen+psize-1)/psize) + h.Data = (*unsafeheader.Slice)(unsafe.Pointer(&alloc)).Data + h.Len = sdLen + h.Cap = sdLen + copy(dst, src) return (*SECURITY_DESCRIPTOR)(unsafe.Pointer(&dst[0])) }