From 1e1921e2acdb7357972257219fdffb9edf17bf55 Mon Sep 17 00:00:00 2001
From: Kevin Krakauer <krakauer@google.com>
Date: Wed, 8 Jan 2020 11:15:46 -0800
Subject: Minor fixes to comments and logging

---
 pkg/sentry/socket/netfilter/netfilter.go | 10 +++++++---
 pkg/sentry/socket/netstack/netstack.go   |  8 +++++---
 pkg/sentry/syscalls/linux/sys_socket.go  |  2 +-
 3 files changed, 13 insertions(+), 7 deletions(-)

(limited to 'pkg/sentry')

diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
index 8c7f3c7fc..b7867a576 100644
--- a/pkg/sentry/socket/netfilter/netfilter.go
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -157,9 +157,7 @@ func convertNetstackToBinary(name string, table iptables.Table) (linux.KernelIPT
 				meta.HookEntry[hook] = entries.Size
 			}
 		}
-		// Is this a chain underflow point? The underflow rule is the last rule
-		// in the chain, and is an unconditional rule (i.e. it matches any
-		// packet). This is enforced when saving iptables.
+		// Is this a chain underflow point?
 		for underflow, underflowRuleIdx := range table.Underflows {
 			if underflowRuleIdx == ruleIdx {
 				meta.Underflow[underflow] = entries.Size
@@ -290,6 +288,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
 
 	// Get the basic rules data (struct ipt_replace).
 	if len(optVal) < linux.SizeOfIPTReplace {
+		log.Infof("netfilter.SetEntries: optVal has insufficient size for replace %d", len(optVal))
 		return syserr.ErrInvalidArgument
 	}
 	var replace linux.IPTReplace
@@ -313,6 +312,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
 	for entryIdx := uint32(0); entryIdx < replace.NumEntries; entryIdx++ {
 		// Get the struct ipt_entry.
 		if len(optVal) < linux.SizeOfIPTEntry {
+			log.Infof("netfilter: optVal has insufficient size for entry %d", len(optVal))
 			return syserr.ErrInvalidArgument
 		}
 		var entry linux.IPTEntry
@@ -328,6 +328,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
 		// filtering. We reject any nonzero IPTIP values for now.
 		emptyIPTIP := linux.IPTIP{}
 		if entry.IP != emptyIPTIP {
+			log.Infof("netfilter: non-empty struct iptip found")
 			return syserr.ErrInvalidArgument
 		}
 
@@ -386,6 +387,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
 // along with the number of bytes it occupies in optVal.
 func parseTarget(optVal []byte) (iptables.Target, uint32, *syserr.Error) {
 	if len(optVal) < linux.SizeOfXTEntryTarget {
+		log.Infof("netfilter: optVal has insufficient size for entry target %d", len(optVal))
 		return nil, 0, syserr.ErrInvalidArgument
 	}
 	var target linux.XTEntryTarget
@@ -395,6 +397,7 @@ func parseTarget(optVal []byte) (iptables.Target, uint32, *syserr.Error) {
 	case "":
 		// Standard target.
 		if len(optVal) < linux.SizeOfXTStandardTarget {
+			log.Infof("netfilter.SetEntries: optVal has insufficient size for standard target %d", len(optVal))
 			return nil, 0, syserr.ErrInvalidArgument
 		}
 		var target linux.XTStandardTarget
@@ -420,6 +423,7 @@ func parseTarget(optVal []byte) (iptables.Target, uint32, *syserr.Error) {
 	case errorTargetName:
 		// Error target.
 		if len(optVal) < linux.SizeOfXTErrorTarget {
+			log.Infof("netfilter.SetEntries: optVal has insufficient size for error target %d", len(optVal))
 			return nil, 0, syserr.ErrInvalidArgument
 		}
 		var target linux.XTErrorTarget
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index f7caa45b4..8c07eef4b 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -326,7 +326,7 @@ func AddressAndFamily(sfamily int, addr []byte, strict bool) (tcpip.FullAddress,
 	}
 
 	family := usermem.ByteOrder.Uint16(addr)
-	if family != uint16(sfamily) && (!strict && family != linux.AF_UNSPEC) {
+	if family != uint16(sfamily) && (strict || family != linux.AF_UNSPEC) {
 		return tcpip.FullAddress{}, family, syserr.ErrAddressFamilyNotSupported
 	}
 
@@ -1357,7 +1357,8 @@ func (s *SocketOperations) SetSockOpt(t *kernel.Task, level int, name int, optVa
 	}
 
 	if s.skType == linux.SOCK_RAW && level == linux.IPPROTO_IP {
-		if name == linux.IPT_SO_SET_REPLACE {
+		switch name {
+		case linux.IPT_SO_SET_REPLACE:
 			if len(optVal) < linux.SizeOfIPTReplace {
 				return syserr.ErrInvalidArgument
 			}
@@ -1371,7 +1372,8 @@ func (s *SocketOperations) SetSockOpt(t *kernel.Task, level int, name int, optVa
 				return err
 			}
 			return nil
-		} else if name == linux.IPT_SO_SET_ADD_COUNTERS {
+
+		case linux.IPT_SO_SET_ADD_COUNTERS:
 			// TODO(gvisor.dev/issue/170): Counter support.
 			return nil
 		}
diff --git a/pkg/sentry/syscalls/linux/sys_socket.go b/pkg/sentry/syscalls/linux/sys_socket.go
index 4b5aafcc0..cda517a81 100644
--- a/pkg/sentry/syscalls/linux/sys_socket.go
+++ b/pkg/sentry/syscalls/linux/sys_socket.go
@@ -41,7 +41,7 @@ const maxListenBacklog = 1024
 const maxAddrLen = 200
 
 // maxOptLen is the maximum sockopt parameter length we're willing to accept.
-const maxOptLen = 1024
+const maxOptLen = 1024 * 8
 
 // maxControlLen is the maximum length of the msghdr.msg_control buffer we're
 // willing to accept. Note that this limit is smaller than Linux, which allows
-- 
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