netbird/gvisor
0
0
Fork 0
mirror of https://github.com/netbirdio/gvisor.git synced 2026-05-22 17:12:49 -07:00
Code Issues Packages Projects Releases Wiki Activity

Move safecopy.ReplaceSignalHandler into sighandling package.

Browse Source 
PiperOrigin-RevId: 399560357
This commit is contained in:
Etienne Perot
2021-09-28 16:56:39 -07:00
committed by gVisor bot
parent fa4c30c635
commit 65698b627e
7 changed files with 43 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/safecopy/BUILD
+1 -1
View File
@@ -18,9 +18,9 @@ go_library(
],
visibility = ["//:sandbox"],
deps = [
"//pkg/abi/linux",
"//pkg/errors",
"//pkg/errors/linuxerr",
"//pkg/sighandling",
"@org_golang_x_sys//unix:go_default_library",
],
)
pkg/safecopy/safecopy.go
+3 -2
View File
@@ -23,6 +23,7 @@ import (
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/errors"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sighandling"
)
// SegvError is returned when a safecopy function receives SIGSEGV.
@@ -132,10 +133,10 @@ func initializeAddresses() {
func init() {
initializeAddresses()
if err := ReplaceSignalHandler(unix.SIGSEGV, addrOfSignalHandler(), &savedSigSegVHandler); err != nil {
if err := sighandling.ReplaceSignalHandler(unix.SIGSEGV, addrOfSignalHandler(), &savedSigSegVHandler); err != nil {
panic(fmt.Sprintf("Unable to set handler for SIGSEGV: %v", err))
}
if err := ReplaceSignalHandler(unix.SIGBUS, addrOfSignalHandler(), &savedSigBusHandler); err != nil {
if err := sighandling.ReplaceSignalHandler(unix.SIGBUS, addrOfSignalHandler(), &savedSigBusHandler); err != nil {
panic(fmt.Sprintf("Unable to set handler for SIGBUS: %v", err))
}
linuxerr.AddErrorUnwrapper(func(e error) (*errors.Error, bool) {
pkg/safecopy/safecopy_unsafe.go
-37
View File
@@ -20,7 +20,6 @@ import (
"unsafe"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/abi/linux"
)
// maxRegisterSize is the maximum register size used in memcpy and memclr. It
@@ -332,39 +331,3 @@ func errorFromFaultSignal(addr uintptr, sig int32) error {
panic(fmt.Sprintf("safecopy got unexpected signal %d at address %#x", sig, addr))
}
}
// ReplaceSignalHandler replaces the existing signal handler for the provided
// signal with the one that handles faults in safecopy-protected functions.
//
// It stores the value of the previously set handler in previous.
//
// This function will be called on initialization in order to install safecopy
// handlers for appropriate signals. These handlers will call the previous
// handler however, and if this is function is being used externally then the
// same courtesy is expected.
func ReplaceSignalHandler(sig unix.Signal, handler uintptr, previous *uintptr) error {
var sa linux.SigAction
const maskLen = 8
// Get the existing signal handler information, and save the current
// handler. Once we replace it, we will use this pointer to fall back to
// it when we receive other signals.
if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 {
return e
}
// Fail if there isn't a previous handler.
if sa.Handler == 0 {
return fmt.Errorf("previous handler for signal %x isn't set", sig)
}
*previous = uintptr(sa.Handler)
// Install our own handler.
sa.Handler = uint64(handler)
if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 {
return e
}
return nil
}
pkg/sentry/platform/kvm/BUILD
+1 -1
View File
@@ -63,7 +63,6 @@ go_library(
"//pkg/procid",
"//pkg/ring0",
"//pkg/ring0/pagetables",
"//pkg/safecopy",
"//pkg/seccomp",
"//pkg/sentry/arch",
"//pkg/sentry/arch/fpu",
@@ -71,6 +70,7 @@ go_library(
"//pkg/sentry/platform",
"//pkg/sentry/platform/interrupt",
"//pkg/sentry/time",
"//pkg/sighandling",
"//pkg/sync",
"@org_golang_x_sys//unix:go_default_library",
],
pkg/sentry/platform/kvm/bluepill.go
+2 -2
View File
@@ -19,8 +19,8 @@ import (
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/ring0"
"gvisor.dev/gvisor/pkg/safecopy"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sighandling"
)
// bluepill enters guest mode.
@@ -97,7 +97,7 @@ func (c *vCPU) die(context *arch.SignalContext64, msg string) {
func init() {
// Install the handler.
if err := safecopy.ReplaceSignalHandler(bluepillSignal, addrOfSighandler(), &savedHandler); err != nil {
if err := sighandling.ReplaceSignalHandler(bluepillSignal, addrOfSighandler(), &savedHandler); err != nil {
panic(fmt.Sprintf("Unable to set handler for signal %d: %v", bluepillSignal, err))
}
pkg/sentry/platform/kvm/machine.go
+2 -2
View File
@@ -28,9 +28,9 @@ import (
"gvisor.dev/gvisor/pkg/procid"
"gvisor.dev/gvisor/pkg/ring0"
"gvisor.dev/gvisor/pkg/ring0/pagetables"
"gvisor.dev/gvisor/pkg/safecopy"
"gvisor.dev/gvisor/pkg/seccomp"
ktime "gvisor.dev/gvisor/pkg/sentry/time"
"gvisor.dev/gvisor/pkg/sighandling"
"gvisor.dev/gvisor/pkg/sync"
)
@@ -723,7 +723,7 @@ func addrOfSigsysHandler() uintptr
func seccompMmapRules(m *machine) {
seccompMmapRulesOnce.Do(func() {
// Install the handler.
if err := safecopy.ReplaceSignalHandler(unix.SIGSYS, addrOfSigsysHandler(), &savedSigsysHandler); err != nil {
if err := sighandling.ReplaceSignalHandler(unix.SIGSYS, addrOfSigsysHandler(), &savedSigsysHandler); err != nil {
panic(fmt.Sprintf("Unable to set handler for signal %d: %v", bluepillSignal, err))
}
rules := []seccomp.RuleSet{}
pkg/sighandling/sighandling_unsafe.go
+34
View File
@@ -15,6 +15,7 @@
package sighandling
import (
"fmt"
"unsafe"
"golang.org/x/sys/unix"
@@ -37,3 +38,36 @@ func IgnoreChildStop() error {
return nil
}
// ReplaceSignalHandler replaces the existing signal handler for the provided
// signal with the function pointer at `handler`. This bypasses the Go runtime
// signal handlers, and should only be used for low-level signal handlers where
// use of signal.Notify is not appropriate.
//
// It stores the value of the previously set handler in previous.
func ReplaceSignalHandler(sig unix.Signal, handler uintptr, previous *uintptr) error {
var sa linux.SigAction
const maskLen = 8
// Get the existing signal handler information, and save the current
// handler. Once we replace it, we will use this pointer to fall back to
// it when we receive other signals.
if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 {
return e
}
// Fail if there isn't a previous handler.
if sa.Handler == 0 {
return fmt.Errorf("previous handler for signal %x isn't set", sig)
}
*previous = uintptr(sa.Handler)
// Install our own handler.
sa.Handler = uint64(handler)
if _, _, e := unix.RawSyscall6(unix.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 {
return e
}
return nil
}