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authorgVisor bot <gvisor-bot@google.com>2020-11-14 01:16:29 +0000
committergVisor bot <gvisor-bot@google.com>2020-11-14 01:16:29 +0000
commitd993a110370df43fb21ec6a5dfebcbc63f4d819b (patch)
tree2285118c1975a18cdde76e53580a15036f7cac67 /pkg
parentc94b57b6922c66fdd30e558ba1ad732a0bdad43c (diff)
parent0fee59c8c84bff0185e681b4550ba077a65739f2 (diff)
Merge release-20201030.0-95-g0fee59c8c (automated)
Diffstat (limited to 'pkg')
-rw-r--r--pkg/tcpip/header/ipv4.go19
-rw-r--r--pkg/tcpip/network/ipv4/icmp.go4
-rw-r--r--pkg/tcpip/network/ipv4/ipv4.go4
3 files changed, 17 insertions, 10 deletions
diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go
index 713d476d6..91fe7b6a5 100644
--- a/pkg/tcpip/header/ipv4.go
+++ b/pkg/tcpip/header/ipv4.go
@@ -89,7 +89,17 @@ type IPv4Fields struct {
// DstAddr is the "destination ip address" of an IPv4 packet.
DstAddr tcpip.Address
- // Options is between 0 and 40 bytes or nil if empty.
+ // Options must be 40 bytes or less as they must fit along with the
+ // rest of the IPv4 header into the maximum size describable in the
+ // IHL field. RFC 791 section 3.1 says:
+ // IHL: 4 bits
+ //
+ // Internet Header Length is the length of the internet header in 32
+ // bit words, and thus points to the beginning of the data. Note that
+ // the minimum value for a correct header is 5.
+ //
+ // That leaves ten 32 bit (4 byte) fields for options. An attempt to encode
+ // more will fail.
Options IPv4Options
}
@@ -284,13 +294,10 @@ func (o IPv4Options) SizeWithPadding() int {
return (len(o) + IPv4IHLStride - 1) & ^(IPv4IHLStride - 1)
}
-// Options returns a buffer holding the options or nil.
+// Options returns a buffer holding the options.
func (b IPv4) Options() IPv4Options {
hdrLen := b.HeaderLength()
- if hdrLen > IPv4MinimumSize {
- return IPv4Options(b[options:hdrLen:hdrLen])
- }
- return nil
+ return IPv4Options(b[options:hdrLen:hdrLen])
}
// TransportProtocol implements Network.TransportProtocol.
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index 58a19e74a..204b182e6 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -90,7 +90,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
iph := header.IPv4(pkt.NetworkHeader().View())
var newOptions header.IPv4Options
- if len(iph) > header.IPv4MinimumSize {
+ if opts := iph.Options(); len(opts) != 0 {
// RFC 1122 section 3.2.2.6 (page 43) (and similar for other round trip
// type ICMP packets):
// If a Record Route and/or Time Stamp option is received in an
@@ -106,7 +106,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
} else {
op = &optionUsageReceive{}
}
- aux, tmp, err := e.processIPOptions(pkt, iph.Options(), op)
+ aux, tmp, err := e.processIPOptions(pkt, opts, op)
if err != nil {
switch {
case
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index b4f21d61e..a9a38b851 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -713,11 +713,11 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) {
e.handleICMP(pkt)
return
}
- if len(h.Options()) != 0 {
+ if opts := h.Options(); len(opts) != 0 {
// TODO(gvisor.dev/issue/4586):
// When we add forwarding support we should use the verified options
// rather than just throwing them away.
- aux, _, err := e.processIPOptions(pkt, h.Options(), &optionUsageReceive{})
+ aux, _, err := e.processIPOptions(pkt, opts, &optionUsageReceive{})
if err != nil {
switch {
case