diff options
Diffstat (limited to 'pkg/abi/linux')
| -rw-r--r-- | pkg/abi/linux/BUILD | 3 | ||||
| -rw-r--r-- | pkg/abi/linux/netfilter.go | 146 | ||||
| -rw-r--r-- | pkg/abi/linux/socket.go | 8 |
3 files changed, 145 insertions, 12 deletions
diff --git a/pkg/abi/linux/BUILD b/pkg/abi/linux/BUILD index 2b789c4ec..a4bb62013 100644 --- a/pkg/abi/linux/BUILD +++ b/pkg/abi/linux/BUILD @@ -72,6 +72,9 @@ go_library( "//pkg/abi", "//pkg/binary", "//pkg/bits", + "//pkg/usermem", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", ], ) diff --git a/pkg/abi/linux/netfilter.go b/pkg/abi/linux/netfilter.go index 46d8b0b42..a91f9f018 100644 --- a/pkg/abi/linux/netfilter.go +++ b/pkg/abi/linux/netfilter.go @@ -14,6 +14,14 @@ package linux +import ( + "io" + + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" +) + // This file contains structures required to support netfilter, specifically // the iptables tool. @@ -76,6 +84,8 @@ const ( // IPTEntry is an iptable rule. It corresponds to struct ipt_entry in // include/uapi/linux/netfilter_ipv4/ip_tables.h. +// +// +marshal type IPTEntry struct { // IP is used to filter packets based on the IP header. IP IPTIP @@ -112,21 +122,41 @@ type IPTEntry struct { // SizeOfIPTEntry is the size of an IPTEntry. const SizeOfIPTEntry = 112 -// KernelIPTEntry is identical to IPTEntry, but includes the Elems field. This -// struct marshaled via the binary package to write an IPTEntry to userspace. +// KernelIPTEntry is identical to IPTEntry, but includes the Elems field. +// KernelIPTEntry itself is not Marshallable but it implements some methods of +// marshal.Marshallable that help in other implementations of Marshallable. type KernelIPTEntry struct { - IPTEntry + Entry IPTEntry // Elems holds the data for all this rule's matches followed by the // target. It is variable length -- users have to iterate over any // matches and use TargetOffset and NextOffset to make sense of the // data. - Elems []byte + Elems primitive.ByteSlice +} + +// SizeBytes implements marshal.Marshallable.SizeBytes. +func (ke *KernelIPTEntry) SizeBytes() int { + return ke.Entry.SizeBytes() + ke.Elems.SizeBytes() +} + +// MarshalBytes implements marshal.Marshallable.MarshalBytes. +func (ke *KernelIPTEntry) MarshalBytes(dst []byte) { + ke.Entry.MarshalBytes(dst) + ke.Elems.MarshalBytes(dst[ke.Entry.SizeBytes():]) +} + +// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes. +func (ke *KernelIPTEntry) UnmarshalBytes(src []byte) { + ke.Entry.UnmarshalBytes(src) + ke.Elems.UnmarshalBytes(src[ke.Entry.SizeBytes():]) } // IPTIP contains information for matching a packet's IP header. // It corresponds to struct ipt_ip in // include/uapi/linux/netfilter_ipv4/ip_tables.h. +// +// +marshal type IPTIP struct { // Src is the source IP address. Src InetAddr @@ -189,6 +219,8 @@ const SizeOfIPTIP = 84 // XTCounters holds packet and byte counts for a rule. It corresponds to struct // xt_counters in include/uapi/linux/netfilter/x_tables.h. +// +// +marshal type XTCounters struct { // Pcnt is the packet count. Pcnt uint64 @@ -321,6 +353,8 @@ const SizeOfXTRedirectTarget = 56 // IPTGetinfo is the argument for the IPT_SO_GET_INFO sockopt. It corresponds // to struct ipt_getinfo in include/uapi/linux/netfilter_ipv4/ip_tables.h. +// +// +marshal type IPTGetinfo struct { Name TableName ValidHooks uint32 @@ -336,6 +370,8 @@ const SizeOfIPTGetinfo = 84 // IPTGetEntries is the argument for the IPT_SO_GET_ENTRIES sockopt. It // corresponds to struct ipt_get_entries in // include/uapi/linux/netfilter_ipv4/ip_tables.h. +// +// +marshal type IPTGetEntries struct { Name TableName Size uint32 @@ -350,13 +386,103 @@ type IPTGetEntries struct { const SizeOfIPTGetEntries = 40 // KernelIPTGetEntries is identical to IPTGetEntries, but includes the -// Entrytable field. This struct marshaled via the binary package to write an -// KernelIPTGetEntries to userspace. +// Entrytable field. This has been manually made marshal.Marshallable since it +// is dynamically sized. type KernelIPTGetEntries struct { IPTGetEntries Entrytable []KernelIPTEntry } +// SizeBytes implements marshal.Marshallable.SizeBytes. +func (ke *KernelIPTGetEntries) SizeBytes() int { + res := ke.IPTGetEntries.SizeBytes() + for _, entry := range ke.Entrytable { + res += entry.SizeBytes() + } + return res +} + +// MarshalBytes implements marshal.Marshallable.MarshalBytes. +func (ke *KernelIPTGetEntries) MarshalBytes(dst []byte) { + ke.IPTGetEntries.MarshalBytes(dst) + marshalledUntil := ke.IPTGetEntries.SizeBytes() + for i := 0; i < len(ke.Entrytable); i++ { + ke.Entrytable[i].MarshalBytes(dst[marshalledUntil:]) + marshalledUntil += ke.Entrytable[i].SizeBytes() + } +} + +// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes. +func (ke *KernelIPTGetEntries) UnmarshalBytes(src []byte) { + ke.IPTGetEntries.UnmarshalBytes(src) + unmarshalledUntil := ke.IPTGetEntries.SizeBytes() + for i := 0; i < len(ke.Entrytable); i++ { + ke.Entrytable[i].UnmarshalBytes(src[unmarshalledUntil:]) + unmarshalledUntil += ke.Entrytable[i].SizeBytes() + } +} + +// Packed implements marshal.Marshallable.Packed. +func (ke *KernelIPTGetEntries) Packed() bool { + // KernelIPTGetEntries isn't packed because the ke.Entrytable contains an + // indirection to the actual data we want to marshal (the slice data + // pointer), and the memory for KernelIPTGetEntries contains the slice + // header which we don't want to marshal. + return false +} + +// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe. +func (ke *KernelIPTGetEntries) MarshalUnsafe(dst []byte) { + // Fall back to safe Marshal because the type in not packed. + ke.MarshalBytes(dst) +} + +// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe. +func (ke *KernelIPTGetEntries) UnmarshalUnsafe(src []byte) { + // Fall back to safe Unmarshal because the type in not packed. + ke.UnmarshalBytes(src) +} + +// CopyIn implements marshal.Marshallable.CopyIn. +func (ke *KernelIPTGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) { + buf := task.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay. + length, err := task.CopyInBytes(addr, buf) // escapes: okay. + // Unmarshal unconditionally. If we had a short copy-in, this results in a + // partially unmarshalled struct. + ke.UnmarshalBytes(buf) // escapes: fallback. + return length, err +} + +// CopyOut implements marshal.Marshallable.CopyOut. +func (ke *KernelIPTGetEntries) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) { + // Type KernelIPTGetEntries doesn't have a packed layout in memory, fall + // back to MarshalBytes. + return task.CopyOutBytes(addr, ke.marshalAll(task)) +} + +// CopyOutN implements marshal.Marshallable.CopyOutN. +func (ke *KernelIPTGetEntries) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) { + // Type KernelIPTGetEntries doesn't have a packed layout in memory, fall + // back to MarshalBytes. + return task.CopyOutBytes(addr, ke.marshalAll(task)[:limit]) +} + +func (ke *KernelIPTGetEntries) marshalAll(task marshal.Task) []byte { + buf := task.CopyScratchBuffer(ke.SizeBytes()) + ke.MarshalBytes(buf) + return buf +} + +// WriteTo implements io.WriterTo.WriteTo. +func (ke *KernelIPTGetEntries) WriteTo(w io.Writer) (int64, error) { + buf := make([]byte, ke.SizeBytes()) + ke.MarshalBytes(buf) + length, err := w.Write(buf) + return int64(length), err +} + +var _ marshal.Marshallable = (*KernelIPTGetEntries)(nil) + // IPTReplace is the argument for the IPT_SO_SET_REPLACE sockopt. It // corresponds to struct ipt_replace in // include/uapi/linux/netfilter_ipv4/ip_tables.h. @@ -374,12 +500,6 @@ type IPTReplace struct { // Entries [0]IPTEntry } -// KernelIPTReplace is identical to IPTReplace, but includes the Entries field. -type KernelIPTReplace struct { - IPTReplace - Entries [0]IPTEntry -} - // SizeOfIPTReplace is the size of an IPTReplace. const SizeOfIPTReplace = 96 @@ -392,6 +512,8 @@ func (en ExtensionName) String() string { } // TableName holds the name of a netfilter table. +// +// +marshal type TableName [XT_TABLE_MAXNAMELEN]byte // String implements fmt.Stringer. diff --git a/pkg/abi/linux/socket.go b/pkg/abi/linux/socket.go index 95337c168..c24a8216e 100644 --- a/pkg/abi/linux/socket.go +++ b/pkg/abi/linux/socket.go @@ -234,6 +234,8 @@ const ( const SockAddrMax = 128 // InetAddr is struct in_addr, from uapi/linux/in.h. +// +// +marshal type InetAddr [4]byte // SockAddrInet is struct sockaddr_in, from uapi/linux/in.h. @@ -303,6 +305,8 @@ func (s *SockAddrUnix) implementsSockAddr() {} func (s *SockAddrNetlink) implementsSockAddr() {} // Linger is struct linger, from include/linux/socket.h. +// +// +marshal type Linger struct { OnOff int32 Linger int32 @@ -317,6 +321,8 @@ const SizeOfLinger = 8 // the end of this struct or within existing unusued space, so its size grows // over time. The current iteration is based on linux v4.17. New versions are // always backwards compatible. +// +// +marshal type TCPInfo struct { State uint8 CaState uint8 @@ -414,6 +420,8 @@ var SizeOfControlMessageHeader = int(binary.Size(ControlMessageHeader{})) // A ControlMessageCredentials is an SCM_CREDENTIALS socket control message. // // ControlMessageCredentials represents struct ucred from linux/socket.h. +// +// +marshal type ControlMessageCredentials struct { PID int32 UID uint32 |