From 07a1e55270bd34ee526ad328d597fa01a8e17619 Mon Sep 17 00:00:00 2001
From: Jordan Whited <jordan@tailscale.com>
Date: Tue, 14 Mar 2023 20:28:07 -0700
Subject: [PATCH] conn: fix getSrcFromControl() iteration
We only expect a single control message in the normal case, but this
would loop infinitely if there were more.
Reviewed-by: Adrian Dewhurst <adrian@tailscale.com>
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
conn/sticky_linux.go | 2 +-
conn/sticky_linux_test.go | 28 ++++++++++++++++++++++++++++
2 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/conn/sticky_linux.go b/conn/sticky_linux.go
index 342e739..278eb19 100644
--- a/conn/sticky_linux.go
+++ b/conn/sticky_linux.go
@@ -25,7 +25,7 @@ func getSrcFromControl(control []byte, ep *StdNetEndpoint) {
)
for len(rem) > unix.SizeofCmsghdr {
- hdr, data, rem, err = unix.ParseOneSocketControlMessage(control)
+ hdr, data, rem, err = unix.ParseOneSocketControlMessage(rem)
if err != nil {
return
}
diff --git a/conn/sticky_linux_test.go b/conn/sticky_linux_test.go
index 672b67e..503c342 100644
--- a/conn/sticky_linux_test.go
+++ b/conn/sticky_linux_test.go
@@ -150,6 +150,34 @@ func Test_getSrcFromControl(t *testing.T) {
t.Errorf("unexpected ifindex: %d", ep.src.ifidx)
}
})
+ t.Run("Multiple", func(t *testing.T) {
+ zeroControl := make([]byte, unix.CmsgSpace(0))
+ zeroHdr := (*unix.Cmsghdr)(unsafe.Pointer(&zeroControl[0]))
+ zeroHdr.SetLen(unix.CmsgLen(0))
+
+ control := make([]byte, srcControlSize)
+ hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+ hdr.Level = unix.IPPROTO_IP
+ hdr.Type = unix.IP_PKTINFO
+ hdr.SetLen(unix.CmsgLen(int(unsafe.Sizeof(unix.Inet4Pktinfo{}))))
+ info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&control[unix.CmsgLen(0)]))
+ info.Spec_dst = [4]byte{127, 0, 0, 1}
+ info.Ifindex = 5
+
+ combined := make([]byte, 0)
+ combined = append(combined, zeroControl...)
+ combined = append(combined, control...)
+
+ ep := &StdNetEndpoint{}
+ getSrcFromControl(combined, ep)
+
+ if ep.src.Addr != netip.MustParseAddr("127.0.0.1") {
+ t.Errorf("unexpected address: %v", ep.src.Addr)
+ }
+ if ep.src.ifidx != 5 {
+ t.Errorf("unexpected ifindex: %d", ep.src.ifidx)
+ }
+ })
}
func Test_listenConfig(t *testing.T) {