ipv4: work around FreeBSD 11.3 or 12 kernel running COMPAT_FREEBSD32
On FreeBSD 11.3 or 12 kernel running COMPAT_FREEBSD32, it looks like the
system call recvmsg always returns an incorrect length for the
out-of-band data. This change adjusts the length when it looks incorrect
and the running kernel is FreeBSD 11.3 or above.
Fixes golang/go#30899.
Change-Id: Ia58d8b4bd4caf3783d2e38161ee4afd1a64ca522
Reviewed-on: https://go-review.googlesource.com/c/net/+/168297
Run-TryBot: Mikio Hara <mikioh.public.networking@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/ipv4/batch.go b/ipv4/batch.go
index fbe0cfd..1a3a4fc 100644
--- a/ipv4/batch.go
+++ b/ipv4/batch.go
@@ -89,6 +89,9 @@
n = 0
err = &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
}
+ if compatFreeBSD32 && ms[0].NN > 0 {
+ adjustFreeBSD32(&ms[0])
+ }
return n, err
}
}
@@ -152,6 +155,9 @@
n = 0
err = &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
}
+ if compatFreeBSD32 && ms[0].NN > 0 {
+ adjustFreeBSD32(&ms[0])
+ }
return n, err
}
}
diff --git a/ipv4/helper.go b/ipv4/helper.go
index d054952..a4457d6 100644
--- a/ipv4/helper.go
+++ b/ipv4/helper.go
@@ -8,6 +8,8 @@
"errors"
"net"
"runtime"
+
+ "golang.org/x/net/internal/socket"
)
var (
@@ -23,9 +25,20 @@
errNotImplemented = errors.New("not implemented on " + runtime.GOOS + "/" + runtime.GOARCH)
// See http://www.freebsd.org/doc/en/books/porters-handbook/freebsd-versions.html.
- freebsdVersion uint32
+ freebsdVersion uint32
+ compatFreeBSD32 bool // 386 emulation on amd64
)
+// See golang.org/issue/30899.
+func adjustFreeBSD32(m *socket.Message) {
+ if freebsdVersion >= 1103000 {
+ l := (m.NN + 4 - 1) &^ (4 - 1)
+ if m.NN < l && l <= len(m.OOB) {
+ m.NN = l
+ }
+ }
+}
+
func boolint(b bool) int {
if b {
return 1
diff --git a/ipv4/packet.go b/ipv4/packet.go
index 30e0951..7d784e0 100644
--- a/ipv4/packet.go
+++ b/ipv4/packet.go
@@ -46,6 +46,9 @@
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
}
if m.NN > 0 {
+ if compatFreeBSD32 {
+ adjustFreeBSD32(&m)
+ }
cm = new(ControlMessage)
if err := cm.Parse(m.OOB[:m.NN]); err != nil {
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
diff --git a/ipv4/payload_cmsg.go b/ipv4/payload_cmsg.go
index e8b21c5..0693067 100644
--- a/ipv4/payload_cmsg.go
+++ b/ipv4/payload_cmsg.go
@@ -49,6 +49,9 @@
return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: errInvalidConnType}
}
if m.NN > 0 {
+ if compatFreeBSD32 {
+ adjustFreeBSD32(&m)
+ }
cm = new(ControlMessage)
if err := cm.Parse(m.OOB[:m.NN]); err != nil {
return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
diff --git a/ipv4/sys_ssmreq.go b/ipv4/sys_ssmreq.go
index 95eea2b..eeced7f 100644
--- a/ipv4/sys_ssmreq.go
+++ b/ipv4/sys_ssmreq.go
@@ -13,8 +13,6 @@
"golang.org/x/net/internal/socket"
)
-var compatFreeBSD32 bool // 386 emulation on amd64
-
func (so *sockOpt) setGroupReq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
var gr groupReq
if ifi != nil {
