mirror of
https://github.com/golang/go
synced 2024-09-30 15:18:32 -06:00
675eb72c28
These signals are used by glibc to broadcast setuid/setgid to all threads and to send pthread cancellations. Unlike other signals, the Go runtime does not intercept these because they must invoke the libc handlers (see issues #3871 and #6997). However, because 1) these signals may be issued asynchronously by a thread running C code to another thread running Go code and 2) glibc does not set SA_ONSTACK for its handlers, glibc's signal handler may be run on a Go stack. Signal frames range from 1.5K on amd64 to many kilobytes on ppc64, so this may overflow the Go stack and corrupt heap (or other stack) data. Fix this by ensuring that these signal handlers have the SA_ONSTACK flag (but not otherwise taking over the handler). This has been a problem since Go 1.1, but it's likely that people haven't encountered it because it only affects setuid/setgid and pthread_cancel. Fixes #9600. Change-Id: I6cf5f5c2d3aa48998d632f61f1ddc2778dcfd300 Reviewed-on: https://go-review.googlesource.com/1887 Reviewed-by: Ian Lance Taylor <iant@golang.org>
59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// Test that SIGSETXID runs on signal stack, since it's likely to
|
|
// overflow if it runs on the Go stack.
|
|
|
|
package cgotest
|
|
|
|
/*
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
*/
|
|
import "C"
|
|
|
|
import (
|
|
"runtime"
|
|
"sync/atomic"
|
|
"testing"
|
|
|
|
"./issue9400"
|
|
)
|
|
|
|
func test9400(t *testing.T) {
|
|
// We synchronize through a shared variable, so we need two procs
|
|
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
|
|
|
|
// Start signaller
|
|
atomic.StoreInt32(&issue9400.Baton, 0)
|
|
go func() {
|
|
// Wait for RewindAndSetgid
|
|
for atomic.LoadInt32(&issue9400.Baton) == 0 {
|
|
runtime.Gosched()
|
|
}
|
|
// Broadcast SIGSETXID
|
|
runtime.LockOSThread()
|
|
C.setgid(0)
|
|
// Indicate that signalling is done
|
|
atomic.StoreInt32(&issue9400.Baton, 0)
|
|
}()
|
|
|
|
// Grow the stack and put down a test pattern
|
|
const pattern = 0x123456789abcdef
|
|
var big [1024]uint64 // len must match assmebly
|
|
for i := range big {
|
|
big[i] = pattern
|
|
}
|
|
|
|
// Temporarily rewind the stack and trigger SIGSETXID
|
|
issue9400.RewindAndSetgid()
|
|
|
|
// Check test pattern
|
|
for i := range big {
|
|
if big[i] != pattern {
|
|
t.Fatalf("entry %d of test pattern is wrong; %#x != %#x", i, big[i], pattern)
|
|
}
|
|
}
|
|
}
|