unix: add ptracePtr that accepts pointer arg as unsafe.Pointer

The existing ptrace wrapper accepts pointer argument as an uintptr which
often points to the memory allocated in Go. This violates unsafe.Pointer safety
rules.

For golang/go#58387

Change-Id: Ib3b4c50368725191f0862c6c7c6d46b0568523c7
Reviewed-on: https://go-review.googlesource.com/c/sys/+/469835
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>

Author: dmgk

unix/linux/mkall.go

@@ -790,13 +790,13 @@ func generatePtraceRegSet(arch string) error {
 	fmt.Fprintf(buf, "// PtraceGetRegSet%s fetches the registers used by %s binaries.\n", uarch, arch)
 	fmt.Fprintf(buf, "func PtraceGetRegSet%s(pid, addr int, regsout *PtraceRegs%s) error {\n", uarch, uarch)
 	fmt.Fprintf(buf, "\tiovec := Iovec{(*byte)(unsafe.Pointer(regsout)), uint64(unsafe.Sizeof(*regsout))}\n")
-	fmt.Fprintf(buf, "\treturn ptrace(PTRACE_GETREGSET, pid, uintptr(addr), uintptr(unsafe.Pointer(&iovec)))\n")
+	fmt.Fprintf(buf, "\treturn ptracePtr(PTRACE_GETREGSET, pid, uintptr(addr), unsafe.Pointer(&iovec))\n")
 	fmt.Fprintf(buf, "}\n")
 	fmt.Fprintf(buf, "\n")
 	fmt.Fprintf(buf, "// PtraceSetRegSet%s sets the registers used by %s binaries.\n", uarch, arch)
 	fmt.Fprintf(buf, "func PtraceSetRegSet%s(pid, addr int, regs *PtraceRegs%s) error {\n", uarch, uarch)
 	fmt.Fprintf(buf, "\tiovec := Iovec{(*byte)(unsafe.Pointer(regs)), uint64(unsafe.Sizeof(*regs))}\n")
-	fmt.Fprintf(buf, "\treturn ptrace(PTRACE_SETREGSET, pid, uintptr(addr), uintptr(unsafe.Pointer(&iovec)))\n")
+	fmt.Fprintf(buf, "\treturn ptracePtr(PTRACE_SETREGSET, pid, uintptr(addr), unsafe.Pointer(&iovec))\n")
 	fmt.Fprintf(buf, "}\n")
 	if err := buf.Flush(); err != nil {
 		return err
@@ -834,12 +834,12 @@ func writeOnePtrace(w io.Writer, arch, def string) {
 	fmt.Fprintf(w, "\n")
 	fmt.Fprintf(w, "// PtraceGetRegs%s fetches the registers used by %s binaries.\n", uarch, arch)
 	fmt.Fprintf(w, "func PtraceGetRegs%s(pid int, regsout *PtraceRegs%s) error {\n", uarch, uarch)
-	fmt.Fprintf(w, "\treturn ptrace(PTRACE_GETREGS, pid, 0, uintptr(unsafe.Pointer(regsout)))\n")
+	fmt.Fprintf(w, "\treturn ptracePtr(PTRACE_GETREGS, pid, 0, unsafe.Pointer(regsout))\n")
 	fmt.Fprintf(w, "}\n")
 	fmt.Fprintf(w, "\n")
 	fmt.Fprintf(w, "// PtraceSetRegs%s sets the registers used by %s binaries.\n", uarch, arch)
 	fmt.Fprintf(w, "func PtraceSetRegs%s(pid int, regs *PtraceRegs%s) error {\n", uarch, uarch)
-	fmt.Fprintf(w, "\treturn ptrace(PTRACE_SETREGS, pid, 0, uintptr(unsafe.Pointer(regs)))\n")
+	fmt.Fprintf(w, "\treturn ptracePtr(PTRACE_SETREGS, pid, 0, unsafe.Pointer(regs))\n")
 	fmt.Fprintf(w, "}\n")
 }
 

unix/ptrace_darwin.go

@@ -7,6 +7,12 @@
 
 package unix
 
+import "unsafe"
+
 func ptrace(request int, pid int, addr uintptr, data uintptr) error {
 	return ptrace1(request, pid, addr, data)
 }
+
+func ptracePtr(request int, pid int, addr uintptr, data unsafe.Pointer) error {
+	return ptrace1Ptr(request, pid, addr, data)
+}

unix/ptrace_ios.go

@@ -7,6 +7,12 @@
 
 package unix
 
+import "unsafe"
+
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	return ENOTSUP
 }
+
+func ptracePtr(request int, pid int, addr uintptr, data unsafe.Pointer) (err error) {
+	return ENOTSUP
+}

unix/syscall_darwin_amd64.go

@@ -47,5 +47,6 @@ func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr,
 //sys	getfsstat(buf unsafe.Pointer, size uintptr, flags int) (n int, err error) = SYS_GETFSSTAT64
 //sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
 //sys	ptrace1(request int, pid int, addr uintptr, data uintptr) (err error) = SYS_ptrace
+//sys	ptrace1Ptr(request int, pid int, addr unsafe.Pointer, data uintptr) (err error) = SYS_ptrace
 //sys	Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
 //sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_STATFS64

unix/syscall_darwin_arm64.go

@@ -47,5 +47,6 @@ func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr,
 //sys	getfsstat(buf unsafe.Pointer, size uintptr, flags int) (n int, err error) = SYS_GETFSSTAT
 //sys	Lstat(path string, stat *Stat_t) (err error)
 //sys	ptrace1(request int, pid int, addr uintptr, data uintptr) (err error) = SYS_ptrace
+//sys	ptrace1Ptr(request int, pid int, addr unsafe.Pointer, data uintptr) (err error) = SYS_ptrace
 //sys	Stat(path string, stat *Stat_t) (err error)
 //sys	Statfs(path string, stat *Statfs_t) (err error)

unix/syscall_freebsd.go

@@ -254,6 +254,7 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 }
 
 //sys	ptrace(request int, pid int, addr uintptr, data int) (err error)
+//sys	ptracePtr(request int, pid int, addr unsafe.Pointer, data int) (err error)
 
 func PtraceAttach(pid int) (err error) {
 	return ptrace(PT_ATTACH, pid, 0, 0)
@@ -268,11 +269,11 @@ func PtraceDetach(pid int) (err error) {
 }
 
 func PtraceGetFpRegs(pid int, fpregsout *FpReg) (err error) {
-	return ptrace(PT_GETFPREGS, pid, uintptr(unsafe.Pointer(fpregsout)), 0)
+	return ptracePtr(PT_GETFPREGS, pid, unsafe.Pointer(fpregsout), 0)
 }
 
 func PtraceGetRegs(pid int, regsout *Reg) (err error) {
-	return ptrace(PT_GETREGS, pid, uintptr(unsafe.Pointer(regsout)), 0)
+	return ptracePtr(PT_GETREGS, pid, unsafe.Pointer(regsout), 0)
 }
 
 func PtraceIO(req int, pid int, offs uintptr, out []byte, countin int) (count int, err error) {
@@ -288,18 +289,16 @@ func PtraceIO(req int, pid int, offs uintptr, out []byte, countin int) (count in
 	}
 	ioDesc.SetLen(countin)
 
-	// TODO(#58387): It's not actually safe to pass &ioDesc as a uintptr here.
-	// Pass it as an unsafe.Pointer instead.
-	err = ptrace(PT_IO, pid, uintptr(unsafe.Pointer(&ioDesc)), 0)
+	err = ptracePtr(PT_IO, pid, unsafe.Pointer(&ioDesc), 0)
 	return int(ioDesc.Len), err
 }
 
 func PtraceLwpEvents(pid int, enable int) (err error) {
 	return ptrace(PT_LWP_EVENTS, pid, 0, enable)
 }
 
-func PtraceLwpInfo(pid int, info uintptr) (err error) {
-	return ptrace(PT_LWPINFO, pid, info, int(unsafe.Sizeof(PtraceLwpInfoStruct{})))
+func PtraceLwpInfo(pid int, info *PtraceLwpInfoStruct) (err error) {
+	return ptracePtr(PT_LWPINFO, pid, unsafe.Pointer(info), int(unsafe.Sizeof(*info)))
 }
 
 func PtracePeekData(pid int, addr uintptr, out []byte) (count int, err error) {
@@ -319,7 +318,7 @@ func PtracePokeText(pid int, addr uintptr, data []byte) (count int, err error) {
 }
 
 func PtraceSetRegs(pid int, regs *Reg) (err error) {
-	return ptrace(PT_SETREGS, pid, uintptr(unsafe.Pointer(regs)), 0)
+	return ptracePtr(PT_SETREGS, pid, unsafe.Pointer(regs), 0)
 }
 
 func PtraceSingleStep(pid int) (err error) {

unix/syscall_freebsd_386.go

@@ -61,5 +61,5 @@ func sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno)
 
 func PtraceGetFsBase(pid int, fsbase *int64) (err error) {
-	return ptrace(PT_GETFSBASE, pid, uintptr(unsafe.Pointer(fsbase)), 0)
+	return ptracePtr(PT_GETFSBASE, pid, unsafe.Pointer(fsbase), 0)
 }

unix/syscall_freebsd_amd64.go

@@ -61,5 +61,5 @@ func sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno)
 
 func PtraceGetFsBase(pid int, fsbase *int64) (err error) {
-	return ptrace(PT_GETFSBASE, pid, uintptr(unsafe.Pointer(fsbase)), 0)
+	return ptracePtr(PT_GETFSBASE, pid, unsafe.Pointer(fsbase), 0)
 }

unix/syscall_linux.go

@@ -1579,6 +1579,7 @@ func BindToDevice(fd int, device string) (err error) {
 }
 
 //sys	ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
+//sys	ptracePtr(request int, pid int, addr uintptr, data unsafe.Pointer) (err error)
 
 func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err error) {
 	// The peek requests are machine-size oriented, so we wrap it
@@ -1596,7 +1597,7 @@ func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err erro
 	// boundary.
 	n := 0
 	if addr%SizeofPtr != 0 {
-		err = ptrace(req, pid, addr-addr%SizeofPtr, uintptr(unsafe.Pointer(&buf[0])))
+		err = ptracePtr(req, pid, addr-addr%SizeofPtr, unsafe.Pointer(&buf[0]))
 		if err != nil {
 			return 0, err
 		}
@@ -1608,7 +1609,7 @@ func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err erro
 	for len(out) > 0 {
 		// We use an internal buffer to guarantee alignment.
 		// It's not documented if this is necessary, but we're paranoid.
-		err = ptrace(req, pid, addr+uintptr(n), uintptr(unsafe.Pointer(&buf[0])))
+		err = ptracePtr(req, pid, addr+uintptr(n), unsafe.Pointer(&buf[0]))
 		if err != nil {
 			return n, err
 		}
@@ -1640,7 +1641,7 @@ func ptracePoke(pokeReq int, peekReq int, pid int, addr uintptr, data []byte) (c
 	n := 0
 	if addr%SizeofPtr != 0 {
 		var buf [SizeofPtr]byte
-		err = ptrace(peekReq, pid, addr-addr%SizeofPtr, uintptr(unsafe.Pointer(&buf[0])))
+		err = ptracePtr(peekReq, pid, addr-addr%SizeofPtr, unsafe.Pointer(&buf[0]))
 		if err != nil {
 			return 0, err
 		}
@@ -1667,7 +1668,7 @@ func ptracePoke(pokeReq int, peekReq int, pid int, addr uintptr, data []byte) (c
 	// Trailing edge.
 	if len(data) > 0 {
 		var buf [SizeofPtr]byte
-		err = ptrace(peekReq, pid, addr+uintptr(n), uintptr(unsafe.Pointer(&buf[0])))
+		err = ptracePtr(peekReq, pid, addr+uintptr(n), unsafe.Pointer(&buf[0]))
 		if err != nil {
 			return n, err
 		}
@@ -1696,11 +1697,11 @@ func PtracePokeUser(pid int, addr uintptr, data []byte) (count int, err error) {
 }
 
 func PtraceGetRegs(pid int, regsout *PtraceRegs) (err error) {
-	return ptrace(PTRACE_GETREGS, pid, 0, uintptr(unsafe.Pointer(regsout)))
+	return ptracePtr(PTRACE_GETREGS, pid, 0, unsafe.Pointer(regsout))
 }
 
 func PtraceSetRegs(pid int, regs *PtraceRegs) (err error) {
-	return ptrace(PTRACE_SETREGS, pid, 0, uintptr(unsafe.Pointer(regs)))
+	return ptracePtr(PTRACE_SETREGS, pid, 0, unsafe.Pointer(regs))
 }
 
 func PtraceSetOptions(pid int, options int) (err error) {
@@ -1709,7 +1710,7 @@ func PtraceSetOptions(pid int, options int) (err error) {
 
 func PtraceGetEventMsg(pid int) (msg uint, err error) {
 	var data _C_long
-	err = ptrace(PTRACE_GETEVENTMSG, pid, 0, uintptr(unsafe.Pointer(&data)))
+	err = ptracePtr(PTRACE_GETEVENTMSG, pid, 0, unsafe.Pointer(&data))
 	msg = uint(data)
 	return
 }