unix, plan9: avoid writing to p when Pipe(p) fails
Generally speaking Go functions make no guarantees
about what has happened to result parameters on error,
and Pipe is no exception: callers should avoid looking at
p if Pipe returns an error.
However, we had a bug in which ForkExec was using the
content of p after a failed Pipe, and others may too.
As a robustness fix, make Pipe avoid writing to p on failure.
windows.Pipe already avoided writing to p on failure.
For golang/go#50057.
Change-Id: I93ed06b06a9981793c119c1d7df689fbe79b4116
Reviewed-on: https://go-review.googlesource.com/c/sys/+/370614
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/plan9/syscall_plan9.go b/plan9/syscall_plan9.go
index 84e1471..723b1f4 100644
--- a/plan9/syscall_plan9.go
+++ b/plan9/syscall_plan9.go
@@ -132,8 +132,10 @@
}
var pp [2]int32
err = pipe(&pp)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return
}
diff --git a/unix/syscall_aix.go b/unix/syscall_aix.go
index 6192750..4f55c8d 100644
--- a/unix/syscall_aix.go
+++ b/unix/syscall_aix.go
@@ -519,8 +519,10 @@
}
var pp [2]_C_int
err = pipe(&pp)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return
}
diff --git a/unix/syscall_darwin.go b/unix/syscall_darwin.go
index 8826f41..0eaab91 100644
--- a/unix/syscall_darwin.go
+++ b/unix/syscall_darwin.go
@@ -159,8 +159,10 @@
}
var x [2]int32
err = pipe(&x)
- p[0] = int(x[0])
- p[1] = int(x[1])
+ if err == nil {
+ p[0] = int(x[0])
+ p[1] = int(x[1])
+ }
return
}
diff --git a/unix/syscall_dragonfly.go b/unix/syscall_dragonfly.go
index 5af108a..2e37c31 100644
--- a/unix/syscall_dragonfly.go
+++ b/unix/syscall_dragonfly.go
@@ -101,7 +101,10 @@
if len(p) != 2 {
return EINVAL
}
- p[0], p[1], err = pipe()
+ r, w, err := pipe()
+ if err == nil {
+ p[0], p[1] = r, w
+ }
return
}
@@ -114,7 +117,10 @@
var pp [2]_C_int
// pipe2 on dragonfly takes an fds array as an argument, but still
// returns the file descriptors.
- p[0], p[1], err = pipe2(&pp, flags)
+ r, w, err := pipe2(&pp, flags)
+ if err == nil {
+ p[0], p[1] = r, w
+ }
return err
}
diff --git a/unix/syscall_freebsd.go b/unix/syscall_freebsd.go
index 18c392c..2f650ae 100644
--- a/unix/syscall_freebsd.go
+++ b/unix/syscall_freebsd.go
@@ -110,8 +110,10 @@
}
var pp [2]_C_int
err := pipe2(&pp, flags)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return err
}
diff --git a/unix/syscall_linux.go b/unix/syscall_linux.go
index 4bc5baf..f432b06 100644
--- a/unix/syscall_linux.go
+++ b/unix/syscall_linux.go
@@ -131,8 +131,10 @@
}
var pp [2]_C_int
err := pipe2(&pp, flags)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return err
}
diff --git a/unix/syscall_netbsd.go b/unix/syscall_netbsd.go
index 853d5f0..4e06c0b 100644
--- a/unix/syscall_netbsd.go
+++ b/unix/syscall_netbsd.go
@@ -128,8 +128,10 @@
}
var pp [2]_C_int
err := pipe2(&pp, flags)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return err
}
diff --git a/unix/syscall_openbsd.go b/unix/syscall_openbsd.go
index 22b5503..11b1d41 100644
--- a/unix/syscall_openbsd.go
+++ b/unix/syscall_openbsd.go
@@ -87,8 +87,10 @@
}
var pp [2]_C_int
err := pipe2(&pp, flags)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return err
}
diff --git a/unix/syscall_solaris.go b/unix/syscall_solaris.go
index 8b88ac2..5c81392 100644
--- a/unix/syscall_solaris.go
+++ b/unix/syscall_solaris.go
@@ -66,8 +66,10 @@
if n != 0 {
return err
}
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return nil
}
@@ -79,8 +81,10 @@
}
var pp [2]_C_int
err := pipe2(&pp, flags)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return err
}
diff --git a/unix/syscall_zos_s390x.go b/unix/syscall_zos_s390x.go
index 5fb76a1..f8616f4 100644
--- a/unix/syscall_zos_s390x.go
+++ b/unix/syscall_zos_s390x.go
@@ -579,8 +579,10 @@
}
var pp [2]_C_int
err = pipe(&pp)
- p[0] = int(pp[0])
- p[1] = int(pp[1])
+ if err == nil {
+ p[0] = int(pp[0])
+ p[1] = int(pp[1])
+ }
return
}
