diff options
Diffstat (limited to 'pkg/sentry')
| -rw-r--r-- | pkg/sentry/socket/netfilter/netfilter.go | 103 | ||||
| -rw-r--r-- | pkg/sentry/socket/netstack/stack.go | 6 |
2 files changed, 20 insertions, 89 deletions
diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go index 66015e2bc..f7abe77d3 100644 --- a/pkg/sentry/socket/netfilter/netfilter.go +++ b/pkg/sentry/socket/netfilter/netfilter.go @@ -41,19 +41,6 @@ const errorTargetName = "ERROR" // change the destination port/destination IP for packets. const redirectTargetName = "REDIRECT" -// Metadata is used to verify that we are correctly serializing and -// deserializing iptables into structs consumable by the iptables tool. We save -// a metadata struct when the tables are written, and when they are read out we -// verify that certain fields are the same. -// -// metadata is used by this serialization/deserializing code, not netstack. -type metadata struct { - HookEntry [linux.NF_INET_NUMHOOKS]uint32 - Underflow [linux.NF_INET_NUMHOOKS]uint32 - NumEntries uint32 - Size uint32 -} - // enableLogging controls whether to log the (de)serialization of netfilter // structs between userspace and netstack. These logs are useful when // developing iptables, but can pollute sentry logs otherwise. @@ -83,29 +70,13 @@ func GetInfo(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr) (linux.IPT return linux.IPTGetinfo{}, syserr.FromError(err) } - // Find the appropriate table. - table, err := findTable(stack, info.Name) + _, info, err := convertNetstackToBinary(stack, info.Name) if err != nil { - nflog("%v", err) + nflog("couldn't convert iptables: %v", err) return linux.IPTGetinfo{}, syserr.ErrInvalidArgument } - // Get the hooks that apply to this table. - info.ValidHooks = table.ValidHooks() - - // Grab the metadata struct, which is used to store information (e.g. - // the number of entries) that applies to the user's encoding of - // iptables, but not netstack's. - metadata := table.Metadata().(metadata) - - // Set values from metadata. - info.HookEntry = metadata.HookEntry - info.Underflow = metadata.Underflow - info.NumEntries = metadata.NumEntries - info.Size = metadata.Size - nflog("returning info: %+v", info) - return info, nil } @@ -118,23 +89,13 @@ func GetEntries(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr, outLen return linux.KernelIPTGetEntries{}, syserr.FromError(err) } - // Find the appropriate table. - table, err := findTable(stack, userEntries.Name) - if err != nil { - nflog("%v", err) - return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument - } - // Convert netstack's iptables rules to something that the iptables // tool can understand. - entries, meta, err := convertNetstackToBinary(userEntries.Name.String(), table) + entries, _, err := convertNetstackToBinary(stack, userEntries.Name) if err != nil { nflog("couldn't read entries: %v", err) return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument } - if meta != table.Metadata().(metadata) { - panic(fmt.Sprintf("Table %q metadata changed between writing and reading. Was saved as %+v, but is now %+v", userEntries.Name.String(), table.Metadata().(metadata), meta)) - } if binary.Size(entries) > uintptr(outLen) { nflog("insufficient GetEntries output size: %d", uintptr(outLen)) return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument @@ -143,44 +104,26 @@ func GetEntries(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr, outLen return entries, nil } -func findTable(stk *stack.Stack, tablename linux.TableName) (stack.Table, error) { - table, ok := stk.IPTables().GetTable(tablename.String()) - if !ok { - return stack.Table{}, fmt.Errorf("couldn't find table %q", tablename) - } - return table, nil -} - -// FillIPTablesMetadata populates stack's IPTables with metadata. -func FillIPTablesMetadata(stk *stack.Stack) { - stk.IPTables().ModifyTables(func(tables map[string]stack.Table) { - // In order to fill in the metadata, we have to translate ipt from its - // netstack format to Linux's giant-binary-blob format. - for name, table := range tables { - _, metadata, err := convertNetstackToBinary(name, table) - if err != nil { - panic(fmt.Errorf("Unable to set default IP tables: %v", err)) - } - table.SetMetadata(metadata) - tables[name] = table - } - }) -} - // convertNetstackToBinary converts the iptables as stored in netstack to the // format expected by the iptables tool. Linux stores each table as a binary // blob that can only be traversed by parsing a bit, reading some offsets, // jumping to those offsets, parsing again, etc. -func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelIPTGetEntries, metadata, error) { - // Return values. +func convertNetstackToBinary(stack *stack.Stack, tablename linux.TableName) (linux.KernelIPTGetEntries, linux.IPTGetinfo, error) { + table, ok := stack.IPTables().GetTable(tablename.String()) + if !ok { + return linux.KernelIPTGetEntries{}, linux.IPTGetinfo{}, fmt.Errorf("couldn't find table %q", tablename) + } + var entries linux.KernelIPTGetEntries - var meta metadata + var info linux.IPTGetinfo + info.ValidHooks = table.ValidHooks() // The table name has to fit in the struct. if linux.XT_TABLE_MAXNAMELEN < len(tablename) { - return linux.KernelIPTGetEntries{}, metadata{}, fmt.Errorf("table name %q too long.", tablename) + return linux.KernelIPTGetEntries{}, linux.IPTGetinfo{}, fmt.Errorf("table name %q too long", tablename) } - copy(entries.Name[:], tablename) + copy(info.Name[:], tablename[:]) + copy(entries.Name[:], tablename[:]) for ruleIdx, rule := range table.Rules { nflog("convert to binary: current offset: %d", entries.Size) @@ -189,14 +132,14 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI for hook, hookRuleIdx := range table.BuiltinChains { if hookRuleIdx == ruleIdx { nflog("convert to binary: found hook %d at offset %d", hook, entries.Size) - meta.HookEntry[hook] = entries.Size + info.HookEntry[hook] = entries.Size } } // Is this a chain underflow point? for underflow, underflowRuleIdx := range table.Underflows { if underflowRuleIdx == ruleIdx { nflog("convert to binary: found underflow %d at offset %d", underflow, entries.Size) - meta.Underflow[underflow] = entries.Size + info.Underflow[underflow] = entries.Size } } @@ -251,12 +194,12 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI entries.Size += uint32(entry.NextOffset) entries.Entrytable = append(entries.Entrytable, entry) - meta.NumEntries++ + info.NumEntries++ } - nflog("convert to binary: finished with an marshalled size of %d", meta.Size) - meta.Size = entries.Size - return entries, meta, nil + nflog("convert to binary: finished with an marshalled size of %d", info.Size) + info.Size = entries.Size + return entries, info, nil } func marshalTarget(target stack.Target) []byte { @@ -569,12 +512,6 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { // - There are no chains without an unconditional final rule. // - There are no chains without an unconditional underflow rule. - table.SetMetadata(metadata{ - HookEntry: replace.HookEntry, - Underflow: replace.Underflow, - NumEntries: replace.NumEntries, - Size: replace.Size, - }) stk.IPTables().ReplaceTable(replace.Name.String(), table) return nil diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go index f97f9b6f3..ee11742a6 100644 --- a/pkg/sentry/socket/netstack/stack.go +++ b/pkg/sentry/socket/netstack/stack.go @@ -18,7 +18,6 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/inet" - "gvisor.dev/gvisor/pkg/sentry/socket/netfilter" "gvisor.dev/gvisor/pkg/syserr" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/tcpip" @@ -366,11 +365,6 @@ func (s *Stack) IPTables() (*stack.IPTables, error) { return s.Stack.IPTables(), nil } -// FillIPTablesMetadata populates stack's IPTables with metadata. -func (s *Stack) FillIPTablesMetadata() { - netfilter.FillIPTablesMetadata(s.Stack) -} - // Resume implements inet.Stack.Resume. func (s *Stack) Resume() { s.Stack.Resume() |