// Copyright 2019 The gVisor Authors. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package proc import ( "bytes" "fmt" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/sentry/context" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" ) // newSysDir returns the dentry corresponding to /proc/sys directory. func newSysDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry { return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "kernel": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "hostname": newDentry(root, inoGen.NextIno(), 0444, &hostnameData{}), "shmall": newDentry(root, inoGen.NextIno(), 0444, shmData(linux.SHMALL)), "shmmax": newDentry(root, inoGen.NextIno(), 0444, shmData(linux.SHMMAX)), "shmmni": newDentry(root, inoGen.NextIno(), 0444, shmData(linux.SHMMNI)), }), "vm": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "mmap_min_addr": newDentry(root, inoGen.NextIno(), 0444, &mmapMinAddrData{}), "overcommit_memory": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0\n")), }), "net": newSysNetDir(root, inoGen), }) } // newSysNetDir returns the dentry corresponding to /proc/sys/net directory. func newSysNetDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry { return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "net": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "ipv4": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ // Add tcp_sack. // TODO(gvisor.dev/issue/1195): tcp_sack allows write(2) // "tcp_sack": newTCPSackInode(ctx, msrc, s), // The following files are simple stubs until they are implemented in // netstack, most of these files are configuration related. We use the // value closest to the actual netstack behavior or any empty file, all // of these files will have mode 0444 (read-only for all users). "ip_local_port_range": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("16000 65535")), "ip_local_reserved_ports": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("")), "ipfrag_time": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("30")), "ip_nonlocal_bind": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "ip_no_pmtu_disc": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")), // tcp_allowed_congestion_control tell the user what they are able to // do as an unprivledged process so we leave it empty. "tcp_allowed_congestion_control": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("")), "tcp_available_congestion_control": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("reno")), "tcp_congestion_control": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("reno")), // Many of the following stub files are features netstack doesn't // support. The unsupported features return "0" to indicate they are // disabled. "tcp_base_mss": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1280")), "tcp_dsack": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_early_retrans": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_fack": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_fastopen": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_fastopen_key": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("")), "tcp_invalid_ratelimit": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_keepalive_intvl": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_keepalive_probes": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_keepalive_time": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("7200")), "tcp_mtu_probing": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_no_metrics_save": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")), "tcp_probe_interval": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_probe_threshold": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "tcp_retries1": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("3")), "tcp_retries2": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("15")), "tcp_rfc1337": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")), "tcp_slow_start_after_idle": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")), "tcp_synack_retries": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("5")), "tcp_syn_retries": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("3")), "tcp_timestamps": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")), }), "core": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "default_qdisc": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("pfifo_fast")), "message_burst": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("10")), "message_cost": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("5")), "optmem_max": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")), "rmem_default": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")), "rmem_max": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")), "somaxconn": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("128")), "wmem_default": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")), "wmem_max": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")), }), }), }) } // mmapMinAddrData implements vfs.DynamicBytesSource for // /proc/sys/vm/mmap_min_addr. // // +stateify savable type mmapMinAddrData struct { kernfs.DynamicBytesFile k *kernel.Kernel } var _ dynamicInode = (*mmapMinAddrData)(nil) // Generate implements vfs.DynamicBytesSource.Generate. func (d *mmapMinAddrData) Generate(ctx context.Context, buf *bytes.Buffer) error { fmt.Fprintf(buf, "%d\n", d.k.Platform.MinUserAddress()) return nil } // hostnameData implements vfs.DynamicBytesSource for /proc/sys/kernel/hostname. // // +stateify savable type hostnameData struct { kernfs.DynamicBytesFile } var _ dynamicInode = (*hostnameData)(nil) // Generate implements vfs.DynamicBytesSource.Generate. func (*hostnameData) Generate(ctx context.Context, buf *bytes.Buffer) error { utsns := kernel.UTSNamespaceFromContext(ctx) buf.WriteString(utsns.HostName()) buf.WriteString("\n") return nil }