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-rw-r--r--pkg/safecopy/BUILD2
-rw-r--r--pkg/safecopy/safecopy.go5
-rw-r--r--pkg/safecopy/safecopy_unsafe.go37
-rw-r--r--pkg/sentry/platform/kvm/BUILD2
-rw-r--r--pkg/sentry/platform/kvm/bluepill.go4
-rw-r--r--pkg/sentry/platform/kvm/machine.go4
-rw-r--r--pkg/sighandling/sighandling_unsafe.go34
7 files changed, 43 insertions, 45 deletions
diff --git a/pkg/safecopy/BUILD b/pkg/safecopy/BUILD
index 0a045fc8e..2a1602e2b 100644
--- a/pkg/safecopy/BUILD
+++ b/pkg/safecopy/BUILD
@@ -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",
],
)
diff --git a/pkg/safecopy/safecopy.go b/pkg/safecopy/safecopy.go
index a9711e63d..0dd0aea83 100644
--- a/pkg/safecopy/safecopy.go
+++ b/pkg/safecopy/safecopy.go
@@ -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) {
diff --git a/pkg/safecopy/safecopy_unsafe.go b/pkg/safecopy/safecopy_unsafe.go
index 2365b2c0d..15f84abea 100644
--- a/pkg/safecopy/safecopy_unsafe.go
+++ b/pkg/safecopy/safecopy_unsafe.go
@@ -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
-}
diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index a26f54269..834d72408 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -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",
],
diff --git a/pkg/sentry/platform/kvm/bluepill.go b/pkg/sentry/platform/kvm/bluepill.go
index 826997e77..5be2215ed 100644
--- a/pkg/sentry/platform/kvm/bluepill.go
+++ b/pkg/sentry/platform/kvm/bluepill.go
@@ -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))
}
diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go
index dcf34015d..f1f7e4ea4 100644
--- a/pkg/sentry/platform/kvm/machine.go
+++ b/pkg/sentry/platform/kvm/machine.go
@@ -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{}
diff --git a/pkg/sighandling/sighandling_unsafe.go b/pkg/sighandling/sighandling_unsafe.go
index 3fe5c6770..7deeda042 100644
--- a/pkg/sighandling/sighandling_unsafe.go
+++ b/pkg/sighandling/sighandling_unsafe.go
@@ -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
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 09:24:20 +0000