File Fix-ptsname-for-big-endian-architectures-again.patch of Package runc.21021
From a2612510eb095c6db04e056a0fc6f892a35f518a Mon Sep 17 00:00:00 2001
From: Kir Kolyshkin <kolyshkin@gmail.com>
Date: Tue, 6 Apr 2021 10:45:51 -0700
Subject: [PATCH 1/2] Fix ptsname() for big-endian architectures (again)
This reverts commit f1b333f2c5050f (Use Ioctl{SetPointerInt,GetInt} from
golang.org/x/sys/unix on linux), changing the code to what it was after
commit dbd69c59b81. This fixes a blocker bug on s390.
The original description from commit dbd69c59b81 follows:
On big-endian architectures unix.IoctlGetInt() leads to a wrong result
because a 32 bit value is stored into a 64 bit buffer. When dereferencing
the result is left shifted by 32. Without this patch ptsname() returns
a wrong path from the second pty onwards.
To protect syscalls against re-arranging by the GC the conversion from
unsafe.Pointer to uintptr must occur in the Syscall expression itself.
See the documentation of the unsafe package for details.
Cc: Peter Morjan <peter.morjan@de.ibm.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
---
tc_linux.go | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/tc_linux.go b/tc_linux.go
index 75f8694..1bdd68e 100644
--- a/vendor/github.com/containerd/console/tc_linux.go
+++ b/vendor/github.com/containerd/console/tc_linux.go
@@ -19,6 +19,7 @@ package console
import (
"fmt"
"os"
+ "unsafe"
"golang.org/x/sys/unix"
)
@@ -31,13 +32,17 @@ const (
// unlockpt unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by f.
// unlockpt should be called before opening the slave side of a pty.
func unlockpt(f *os.File) error {
- return unix.IoctlSetPointerInt(int(f.Fd()), unix.TIOCSPTLCK, 0)
+ var u int32
+ if _, _, err := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.TIOCSPTLCK, uintptr(unsafe.Pointer(&u))); err != 0 {
+ return err
+ }
+ return nil
}
// ptsname retrieves the name of the first available pts for the given master.
func ptsname(f *os.File) (string, error) {
- u, err := unix.IoctlGetInt(int(f.Fd()), unix.TIOCGPTN)
- if err != nil {
+ var u uint32
+ if _, _, err := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.TIOCGPTN, uintptr(unsafe.Pointer(&u))); err != 0 {
return "", err
}
return fmt.Sprintf("/dev/pts/%d", u), nil
From 073d1657b8570d499c8cb0a31742209ae93cf7f0 Mon Sep 17 00:00:00 2001
From: Kir Kolyshkin <kolyshkin@gmail.com>
Date: Wed, 7 Apr 2021 11:38:55 -0700
Subject: [PATCH 2/2] tc_linux.go: add a warning to not change the code
... with a pointer to a detailed explanation.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
---
tc_linux.go | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tc_linux.go b/tc_linux.go
index 1bdd68e..7d552ea 100644
--- a/vendor/github.com/containerd/console/tc_linux.go
+++ b/vendor/github.com/containerd/console/tc_linux.go
@@ -33,6 +33,7 @@ const (
// unlockpt should be called before opening the slave side of a pty.
func unlockpt(f *os.File) error {
var u int32
+ // XXX do not use unix.IoctlSetPointerInt here, see commit dbd69c59b81.
if _, _, err := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.TIOCSPTLCK, uintptr(unsafe.Pointer(&u))); err != 0 {
return err
}
@@ -42,6 +43,7 @@ func unlockpt(f *os.File) error {
// ptsname retrieves the name of the first available pts for the given master.
func ptsname(f *os.File) (string, error) {
var u uint32
+ // XXX do not use unix.IoctlGetInt here, see commit dbd69c59b81.
if _, _, err := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.TIOCGPTN, uintptr(unsafe.Pointer(&u))); err != 0 {
return "", err
}
