go/src/runtime/os3_solaris.go
Austin Clements 675eb72c28 runtime: run libc SIGSETXID and SIGCANCEL handlers on signal stack
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>
2014-12-23 01:33:36 +00:00

492 lines
14 KiB
Go

// Copyright 2011 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.
package runtime
import "unsafe"
//go:cgo_export_dynamic runtime.end _end
//go:cgo_export_dynamic runtime.etext _etext
//go:cgo_export_dynamic runtime.edata _edata
//go:cgo_import_dynamic libc____errno ___errno "libc.so"
//go:cgo_import_dynamic libc_clock_gettime clock_gettime "libc.so"
//go:cgo_import_dynamic libc_close close "libc.so"
//go:cgo_import_dynamic libc_exit exit "libc.so"
//go:cgo_import_dynamic libc_fstat fstat "libc.so"
//go:cgo_import_dynamic libc_getcontext getcontext "libc.so"
//go:cgo_import_dynamic libc_getrlimit getrlimit "libc.so"
//go:cgo_import_dynamic libc_madvise madvise "libc.so"
//go:cgo_import_dynamic libc_malloc malloc "libc.so"
//go:cgo_import_dynamic libc_mmap mmap "libc.so"
//go:cgo_import_dynamic libc_munmap munmap "libc.so"
//go:cgo_import_dynamic libc_open open "libc.so"
//go:cgo_import_dynamic libc_pthread_attr_destroy pthread_attr_destroy "libc.so"
//go:cgo_import_dynamic libc_pthread_attr_getstack pthread_attr_getstack "libc.so"
//go:cgo_import_dynamic libc_pthread_attr_init pthread_attr_init "libc.so"
//go:cgo_import_dynamic libc_pthread_attr_setdetachstate pthread_attr_setdetachstate "libc.so"
//go:cgo_import_dynamic libc_pthread_attr_setstack pthread_attr_setstack "libc.so"
//go:cgo_import_dynamic libc_pthread_create pthread_create "libc.so"
//go:cgo_import_dynamic libc_raise raise "libc.so"
//go:cgo_import_dynamic libc_read read "libc.so"
//go:cgo_import_dynamic libc_select select "libc.so"
//go:cgo_import_dynamic libc_sched_yield sched_yield "libc.so"
//go:cgo_import_dynamic libc_sem_init sem_init "libc.so"
//go:cgo_import_dynamic libc_sem_post sem_post "libc.so"
//go:cgo_import_dynamic libc_sem_reltimedwait_np sem_reltimedwait_np "libc.so"
//go:cgo_import_dynamic libc_sem_wait sem_wait "libc.so"
//go:cgo_import_dynamic libc_setitimer setitimer "libc.so"
//go:cgo_import_dynamic libc_sigaction sigaction "libc.so"
//go:cgo_import_dynamic libc_sigaltstack sigaltstack "libc.so"
//go:cgo_import_dynamic libc_sigprocmask sigprocmask "libc.so"
//go:cgo_import_dynamic libc_sysconf sysconf "libc.so"
//go:cgo_import_dynamic libc_usleep usleep "libc.so"
//go:cgo_import_dynamic libc_write write "libc.so"
//go:linkname libc____errno libc____errno
//go:linkname libc_clock_gettime libc_clock_gettime
//go:linkname libc_close libc_close
//go:linkname libc_exit libc_exit
//go:linkname libc_fstat libc_fstat
//go:linkname libc_getcontext libc_getcontext
//go:linkname libc_getrlimit libc_getrlimit
//go:linkname libc_madvise libc_madvise
//go:linkname libc_malloc libc_malloc
//go:linkname libc_mmap libc_mmap
//go:linkname libc_munmap libc_munmap
//go:linkname libc_open libc_open
//go:linkname libc_pthread_attr_destroy libc_pthread_attr_destroy
//go:linkname libc_pthread_attr_getstack libc_pthread_attr_getstack
//go:linkname libc_pthread_attr_init libc_pthread_attr_init
//go:linkname libc_pthread_attr_setdetachstate libc_pthread_attr_setdetachstate
//go:linkname libc_pthread_attr_setstack libc_pthread_attr_setstack
//go:linkname libc_pthread_create libc_pthread_create
//go:linkname libc_raise libc_raise
//go:linkname libc_read libc_read
//go:linkname libc_select libc_select
//go:linkname libc_sched_yield libc_sched_yield
//go:linkname libc_sem_init libc_sem_init
//go:linkname libc_sem_post libc_sem_post
//go:linkname libc_sem_reltimedwait_np libc_sem_reltimedwait_np
//go:linkname libc_sem_wait libc_sem_wait
//go:linkname libc_setitimer libc_setitimer
//go:linkname libc_sigaction libc_sigaction
//go:linkname libc_sigaltstack libc_sigaltstack
//go:linkname libc_sigprocmask libc_sigprocmask
//go:linkname libc_sysconf libc_sysconf
//go:linkname libc_usleep libc_usleep
//go:linkname libc_write libc_write
var (
libc____errno,
libc_clock_gettime,
libc_close,
libc_exit,
libc_fstat,
libc_getcontext,
libc_getrlimit,
libc_madvise,
libc_malloc,
libc_mmap,
libc_munmap,
libc_open,
libc_pthread_attr_destroy,
libc_pthread_attr_getstack,
libc_pthread_attr_init,
libc_pthread_attr_setdetachstate,
libc_pthread_attr_setstack,
libc_pthread_create,
libc_raise,
libc_read,
libc_sched_yield,
libc_select,
libc_sem_init,
libc_sem_post,
libc_sem_reltimedwait_np,
libc_sem_wait,
libc_setitimer,
libc_sigaction,
libc_sigaltstack,
libc_sigprocmask,
libc_sysconf,
libc_usleep,
libc_write libcFunc
)
var sigset_none = sigset{}
var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
func getncpu() int32 {
n := int32(sysconf(__SC_NPROCESSORS_ONLN))
if n < 1 {
return 1
}
return n
}
func osinit() {
ncpu = getncpu()
}
func tstart_sysvicall()
func newosproc(mp *m, _ unsafe.Pointer) {
var (
attr pthreadattr
oset sigset
tid pthread
ret int32
size uint64
)
if pthread_attr_init(&attr) != 0 {
gothrow("pthread_attr_init")
}
if pthread_attr_setstack(&attr, 0, 0x200000) != 0 {
gothrow("pthread_attr_setstack")
}
if pthread_attr_getstack(&attr, unsafe.Pointer(&mp.g0.stack.hi), &size) != 0 {
gothrow("pthread_attr_getstack")
}
mp.g0.stack.lo = mp.g0.stack.hi - uintptr(size)
if pthread_attr_setdetachstate(&attr, _PTHREAD_CREATE_DETACHED) != 0 {
gothrow("pthread_attr_setdetachstate")
}
// Disable signals during create, so that the new thread starts
// with signals disabled. It will enable them in minit.
sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
ret = pthread_create(&tid, &attr, funcPC(tstart_sysvicall), unsafe.Pointer(mp))
sigprocmask(_SIG_SETMASK, &oset, nil)
if ret != 0 {
print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", ret, ")\n")
gothrow("newosproc")
}
}
var urandom_dev = []byte("/dev/random\x00")
//go:nosplit
func getRandomData(r []byte) {
fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
close(fd)
extendRandom(r, int(n))
}
func goenvs() {
goenvs_unix()
}
// Called to initialize a new m (including the bootstrap m).
// Called on the parent thread (main thread in case of bootstrap), can allocate memory.
func mpreinit(mp *m) {
mp.gsignal = malg(32 * 1024)
mp.gsignal.m = mp
}
func miniterrno()
// Called to initialize a new m (including the bootstrap m).
// Called on the new thread, can not allocate memory.
func minit() {
_g_ := getg()
asmcgocall(unsafe.Pointer(funcPC(miniterrno)), unsafe.Pointer(libc____errno))
// Initialize signal handling
signalstack((*byte)(unsafe.Pointer(_g_.m.gsignal.stack.lo)), 32*1024)
sigprocmask(_SIG_SETMASK, &sigset_none, nil)
}
// Called from dropm to undo the effect of an minit.
func unminit() {
signalstack(nil, 0)
}
func memlimit() uintptr {
/*
TODO: Convert to Go when something actually uses the result.
Rlimit rl;
extern byte runtime·text[], runtime·end[];
uintptr used;
if(runtime·getrlimit(RLIMIT_AS, &rl) != 0)
return 0;
if(rl.rlim_cur >= 0x7fffffff)
return 0;
// Estimate our VM footprint excluding the heap.
// Not an exact science: use size of binary plus
// some room for thread stacks.
used = runtime·end - runtime·text + (64<<20);
if(used >= rl.rlim_cur)
return 0;
// If there's not at least 16 MB left, we're probably
// not going to be able to do much. Treat as no limit.
rl.rlim_cur -= used;
if(rl.rlim_cur < (16<<20))
return 0;
return rl.rlim_cur - used;
*/
return 0
}
func sigtramp()
func setsig(i int32, fn uintptr, restart bool) {
var sa sigactiont
sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK
sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK
if restart {
sa.sa_flags |= _SA_RESTART
}
sa.sa_mask = sigset_all
if fn == funcPC(sighandler) {
fn = funcPC(sigtramp)
}
*((*uintptr)(unsafe.Pointer(&sa._funcptr))) = fn
sigaction(i, &sa, nil)
}
func setsigstack(i int32) {
gothrow("setsigstack")
}
func getsig(i int32) uintptr {
var sa sigactiont
sigaction(i, nil, &sa)
if *((*uintptr)(unsafe.Pointer(&sa._funcptr))) == funcPC(sigtramp) {
return funcPC(sighandler)
}
return *((*uintptr)(unsafe.Pointer(&sa._funcptr)))
}
func signalstack(p *byte, n int32) {
var st sigaltstackt
st.ss_sp = (*byte)(unsafe.Pointer(p))
st.ss_size = uint64(n)
st.ss_flags = 0
if p == nil {
st.ss_flags = _SS_DISABLE
}
sigaltstack(&st, nil)
}
func unblocksignals() {
sigprocmask(_SIG_SETMASK, &sigset_none, nil)
}
//go:nosplit
func semacreate() uintptr {
var sem *semt
_g_ := getg()
// Call libc's malloc rather than malloc. This will
// allocate space on the C heap. We can't call malloc
// here because it could cause a deadlock.
_g_.m.libcall.fn = uintptr(libc_malloc)
_g_.m.libcall.n = 1
memclr(unsafe.Pointer(&_g_.m.scratch), uintptr(len(_g_.m.scratch.v)))
_g_.m.scratch.v[0] = unsafe.Sizeof(*sem)
_g_.m.libcall.args = uintptr(unsafe.Pointer(&_g_.m.scratch))
asmcgocall(unsafe.Pointer(&asmsysvicall6), unsafe.Pointer(&_g_.m.libcall))
sem = (*semt)(unsafe.Pointer(_g_.m.libcall.r1))
if sem_init(sem, 0, 0) != 0 {
gothrow("sem_init")
}
return uintptr(unsafe.Pointer(sem))
}
//go:nosplit
func semasleep(ns int64) int32 {
_m_ := getg().m
if ns >= 0 {
_m_.ts.tv_sec = ns / 1000000000
_m_.ts.tv_nsec = ns % 1000000000
_m_.libcall.fn = uintptr(unsafe.Pointer(libc_sem_reltimedwait_np))
_m_.libcall.n = 2
memclr(unsafe.Pointer(&_m_.scratch), uintptr(len(_m_.scratch.v)))
_m_.scratch.v[0] = _m_.waitsema
_m_.scratch.v[1] = uintptr(unsafe.Pointer(&_m_.ts))
_m_.libcall.args = uintptr(unsafe.Pointer(&_m_.scratch))
asmcgocall(unsafe.Pointer(&asmsysvicall6), unsafe.Pointer(&_m_.libcall))
if *_m_.perrno != 0 {
if *_m_.perrno == _ETIMEDOUT || *_m_.perrno == _EAGAIN || *_m_.perrno == _EINTR {
return -1
}
gothrow("sem_reltimedwait_np")
}
return 0
}
for {
_m_.libcall.fn = uintptr(unsafe.Pointer(libc_sem_wait))
_m_.libcall.n = 1
memclr(unsafe.Pointer(&_m_.scratch), uintptr(len(_m_.scratch.v)))
_m_.scratch.v[0] = _m_.waitsema
_m_.libcall.args = uintptr(unsafe.Pointer(&_m_.scratch))
asmcgocall(unsafe.Pointer(&asmsysvicall6), unsafe.Pointer(&_m_.libcall))
if _m_.libcall.r1 == 0 {
break
}
if *_m_.perrno == _EINTR {
continue
}
gothrow("sem_wait")
}
return 0
}
//go:nosplit
func semawakeup(mp *m) {
if sem_post((*semt)(unsafe.Pointer(mp.waitsema))) != 0 {
gothrow("sem_post")
}
}
//go:nosplit
func close(fd int32) int32 {
return int32(sysvicall1(libc_close, uintptr(fd)))
}
//go:nosplit
func exit(r int32) {
sysvicall1(libc_exit, uintptr(r))
}
//go:nosplit
func getcontext(context *ucontext) /* int32 */ {
sysvicall1(libc_getcontext, uintptr(unsafe.Pointer(context)))
}
//go:nosplit
func madvise(addr unsafe.Pointer, n uintptr, flags int32) {
sysvicall3(libc_madvise, uintptr(addr), uintptr(n), uintptr(flags))
}
//go:nosplit
func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) unsafe.Pointer {
return unsafe.Pointer(sysvicall6(libc_mmap, uintptr(addr), uintptr(n), uintptr(prot), uintptr(flags), uintptr(fd), uintptr(off)))
}
//go:nosplit
func munmap(addr unsafe.Pointer, n uintptr) {
sysvicall2(libc_munmap, uintptr(addr), uintptr(n))
}
func nanotime1()
//go:nosplit
func nanotime() int64 {
return int64(sysvicall0(libcFunc(funcPC(nanotime1))))
}
//go:nosplit
func open(path *byte, mode, perm int32) int32 {
return int32(sysvicall3(libc_open, uintptr(unsafe.Pointer(path)), uintptr(mode), uintptr(perm)))
}
func pthread_attr_destroy(attr *pthreadattr) int32 {
return int32(sysvicall1(libc_pthread_attr_destroy, uintptr(unsafe.Pointer(attr))))
}
func pthread_attr_getstack(attr *pthreadattr, addr unsafe.Pointer, size *uint64) int32 {
return int32(sysvicall3(libc_pthread_attr_getstack, uintptr(unsafe.Pointer(attr)), uintptr(addr), uintptr(unsafe.Pointer(size))))
}
func pthread_attr_init(attr *pthreadattr) int32 {
return int32(sysvicall1(libc_pthread_attr_init, uintptr(unsafe.Pointer(attr))))
}
func pthread_attr_setdetachstate(attr *pthreadattr, state int32) int32 {
return int32(sysvicall2(libc_pthread_attr_setdetachstate, uintptr(unsafe.Pointer(attr)), uintptr(state)))
}
func pthread_attr_setstack(attr *pthreadattr, addr uintptr, size uint64) int32 {
return int32(sysvicall3(libc_pthread_attr_setstack, uintptr(unsafe.Pointer(attr)), uintptr(addr), uintptr(size)))
}
func pthread_create(thread *pthread, attr *pthreadattr, fn uintptr, arg unsafe.Pointer) int32 {
return int32(sysvicall4(libc_pthread_create, uintptr(unsafe.Pointer(thread)), uintptr(unsafe.Pointer(attr)), uintptr(fn), uintptr(arg)))
}
func raise(sig int32) /* int32 */ {
sysvicall1(libc_raise, uintptr(sig))
}
//go:nosplit
func read(fd int32, buf unsafe.Pointer, nbyte int32) int32 {
return int32(sysvicall3(libc_read, uintptr(fd), uintptr(buf), uintptr(nbyte)))
}
//go:nosplit
func sem_init(sem *semt, pshared int32, value uint32) int32 {
return int32(sysvicall3(libc_sem_init, uintptr(unsafe.Pointer(sem)), uintptr(pshared), uintptr(value)))
}
//go:nosplit
func sem_post(sem *semt) int32 {
return int32(sysvicall1(libc_sem_post, uintptr(unsafe.Pointer(sem))))
}
//go:nosplit
func sem_reltimedwait_np(sem *semt, timeout *timespec) int32 {
return int32(sysvicall2(libc_sem_reltimedwait_np, uintptr(unsafe.Pointer(sem)), uintptr(unsafe.Pointer(timeout))))
}
//go:nosplit
func sem_wait(sem *semt) int32 {
return int32(sysvicall1(libc_sem_wait, uintptr(unsafe.Pointer(sem))))
}
func setitimer(which int32, value *itimerval, ovalue *itimerval) /* int32 */ {
sysvicall3(libc_setitimer, uintptr(which), uintptr(unsafe.Pointer(value)), uintptr(unsafe.Pointer(ovalue)))
}
func sigaction(sig int32, act *sigactiont, oact *sigactiont) /* int32 */ {
sysvicall3(libc_sigaction, uintptr(sig), uintptr(unsafe.Pointer(act)), uintptr(unsafe.Pointer(oact)))
}
func sigaltstack(ss *sigaltstackt, oss *sigaltstackt) /* int32 */ {
sysvicall2(libc_sigaltstack, uintptr(unsafe.Pointer(ss)), uintptr(unsafe.Pointer(oss)))
}
func sigprocmask(how int32, set *sigset, oset *sigset) /* int32 */ {
sysvicall3(libc_sigprocmask, uintptr(how), uintptr(unsafe.Pointer(set)), uintptr(unsafe.Pointer(oset)))
}
func sysconf(name int32) int64 {
return int64(sysvicall1(libc_sysconf, uintptr(name)))
}
func usleep1(uint32)
//go:nosplit
func usleep(µs uint32) {
usleep1(µs)
}
//go:nosplit
func write(fd uintptr, buf unsafe.Pointer, nbyte int32) int32 {
return int32(sysvicall3(libc_write, uintptr(fd), uintptr(buf), uintptr(nbyte)))
}
func osyield1()
//go:nosplit
func osyield() {
_g_ := getg()
// Check the validity of m because we might be called in cgo callback
// path early enough where there isn't a m available yet.
if _g_ != nil && _g_.m != nil {
sysvicall0(libc_sched_yield)
return
}
osyield1()
}