mirror of
https://github.com/gravitational/teleport.git
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Edoardo Spadolini
3da0f44c80
* Clean up unneeded forwarder for reexec.IsReexec * Disallow reexec through common.Run * Remove the checkhomedir SSH subsystem * Add true reexec subcommand * Assume /proc/self/exe is always usable * Add sessionhelper embed logic
88 lines
2.7 KiB
Go
88 lines
2.7 KiB
Go
/*
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* Teleport
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* Copyright (C) 2023 Gravitational, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package reexec
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import (
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"os"
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"os/exec"
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"syscall"
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"github.com/gravitational/trace"
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)
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func CommandOSTweaks(cmd *exec.Cmd) {
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setLinuxReexecPath(cmd)
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if cmd.SysProcAttr == nil {
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cmd.SysProcAttr = new(syscall.SysProcAttr)
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}
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// Linux only: when parent process (node) dies unexpectedly without
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// cleaning up child processes, send a signal for graceful shutdown
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// to children.
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cmd.SysProcAttr.Pdeathsig = syscall.SIGQUIT
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}
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// if we ever need to run parkers on macOS or other platforms with no PDEATHSIG
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// we should rework the parker to block on a pipe so it can exit when its parent
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// is terminated
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func parkerCommandOSTweaks(cmd *exec.Cmd) {
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setLinuxReexecPath(cmd)
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if cmd.SysProcAttr == nil {
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cmd.SysProcAttr = new(syscall.SysProcAttr)
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}
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// parker processes can leak if their PDEATHSIG is SIGQUIT, otherwise we
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// could just use [commandOSTweaks]
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cmd.SysProcAttr.Pdeathsig = syscall.SIGKILL
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}
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func userCommandOSTweaks(cmd *exec.Cmd) {
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if cmd.SysProcAttr == nil {
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cmd.SysProcAttr = new(syscall.SysProcAttr)
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}
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// Linux only: when parent process (this process) dies unexpectedly, kill
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// the child process instead of orphaning it.
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// SIGKILL because we don't control the child process, and it could choose
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// to ignore other signals.
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cmd.SysProcAttr.Pdeathsig = syscall.SIGKILL
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}
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// setNeutralOOMScore sets the OOM score for the current process to 0 (the
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// middle between -1000 and 1000). This value is inherited by all child processes.
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func setNeutralOOMScore() error {
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// Use os.OpenFile() instead of os.WriteFile() to avoid creating the file
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// if for some extremely weird reason doesn't exist. Permission in this case
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// won't be used as os.O_WRONLY won't create the file.
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f, err := os.OpenFile("/proc/self/oom_score_adj", os.O_WRONLY, 0)
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if err != nil {
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return trace.ConvertSystemError(err)
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}
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if _, err := f.WriteString("0"); err != nil {
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return trace.NewAggregate(err, f.Close())
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}
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// Make sure to return errors from Close(),
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// as sync error may be returned here.
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return trace.Wrap(f.Close())
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}
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