From fd6845ddda3f80cdd24a8f94c42acce6bff0c41f Mon Sep 17 00:00:00 2001 From: Thomas Parrott Date: Fri, 29 Apr 2022 11:12:48 +0100 Subject: [PATCH] lxd/secommp: Fix sysinfo syscall interception on 32 bit platforms Fixes #10347 Backport: Signed-off-by: Thomas Parrott --- lxd/seccomp/seccomp.go | 22 ++++++++++++++-------- lxd/seccomp/sysinfo.go | 13 +++++++++++++ lxd/seccomp/sysinfo_32.go | 19 +++++++++++++++++++ lxd/seccomp/sysinfo_64.go | 19 +++++++++++++++++++ 4 files changed, 65 insertions(+), 8 deletions(-) create mode 100644 lxd/seccomp/sysinfo.go create mode 100644 lxd/seccomp/sysinfo_32.go create mode 100644 lxd/seccomp/sysinfo_64.go diff --git a/lxd/seccomp/seccomp.go b/lxd/seccomp/seccomp.go index 03fee3c71a09..203d408a8286 100644 --- a/lxd/seccomp/seccomp.go +++ b/lxd/seccomp/seccomp.go @@ -1709,6 +1709,7 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { defer l.Debug("Handling sysinfo syscall") + // Pre-fill sysinfo struct with metrics from host system. info := unix.Sysinfo_t{} err := unix.Sysinfo(&info) if err != nil { @@ -1718,6 +1719,8 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { return 0 } + instMetrics := Sysinfo{} // Architecture independent place to hold instance metrics. + cg, err := cgroup.NewFileReadWriter(int(siov.msg.init_pid), liblxc.HasApiExtension("cgroup2")) if err != nil { l.Warn("Failed loading cgroup", logger.Ctx{"err": err, "pid": siov.msg.init_pid}) @@ -1735,7 +1738,7 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { return 0 } - info.Uptime = int64(time.Now().Sub(f.ModTime()).Seconds()) + instMetrics.Uptime = int64(time.Now().Sub(f.ModTime()).Seconds()) // Get instance process count. pids, err := cg.GetTotalProcesses() @@ -1746,7 +1749,7 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { return 0 } - info.Procs = uint16(pids) + instMetrics.Procs = uint16(pids) // Get instance memory stats. memStats, err := cg.GetMemoryStats() @@ -1760,9 +1763,9 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { for k, v := range memStats { switch k { case "shmem": - info.Sharedram = v + instMetrics.Sharedram = v case "cache": - info.Bufferram = v + instMetrics.Bufferram = v } } @@ -1784,8 +1787,8 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { return 0 } - info.Totalram = uint64(memoryLimit) - info.Freeram = info.Totalram - uint64(memoryUsage) - info.Bufferram + instMetrics.Totalram = uint64(memoryLimit) + instMetrics.Freeram = instMetrics.Totalram - uint64(memoryUsage) - instMetrics.Bufferram // Get instance swap info. if s.s.OS.CGInfo.Supports(cgroup.MemorySwapUsage, cg) { @@ -1805,14 +1808,17 @@ func (s *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int { return 0 } - info.Totalswap = uint64(swapLimit) - info.Freeswap = info.Totalswap - uint64(swapUsage) + instMetrics.Totalswap = uint64(swapLimit) + instMetrics.Freeswap = instMetrics.Totalswap - uint64(swapUsage) } // Get writable pointer to buffer of sysinfo syscall result. const sz = int(unsafe.Sizeof(info)) var b []byte = (*(*[sz]byte)(unsafe.Pointer(&info)))[:] + // Write instance metrics to native sysinfo struct. + instMetrics.ToNative(&info) + // Write sysinfo response into buffer. _, err = unix.Pwrite(siov.memFd, b, int64(siov.req.data.args[0])) if err != nil { diff --git a/lxd/seccomp/sysinfo.go b/lxd/seccomp/sysinfo.go new file mode 100644 index 000000000000..b255894af26e --- /dev/null +++ b/lxd/seccomp/sysinfo.go @@ -0,0 +1,13 @@ +package seccomp + +// Sysinfo architecture independent sysinfo struct. +type Sysinfo struct { + Uptime int64 + Totalram uint64 + Freeram uint64 + Sharedram uint64 + Bufferram uint64 + Totalswap uint64 + Freeswap uint64 + Procs uint16 +} diff --git a/lxd/seccomp/sysinfo_32.go b/lxd/seccomp/sysinfo_32.go new file mode 100644 index 000000000000..e52808300dd0 --- /dev/null +++ b/lxd/seccomp/sysinfo_32.go @@ -0,0 +1,19 @@ +//go:build 386 || arm || ppc || s390 || mips || mipsle + +package seccomp + +import ( + "golang.org/x/sys/unix" +) + +// ToNative fills fields from s into native fields. +func (s *Sysinfo) ToNative(n *unix.Sysinfo_t) { + n.Bufferram = uint32(s.Bufferram) + n.Freeram = uint32(s.Freeram) + n.Freeswap = uint32(s.Freeswap) + n.Procs = s.Procs + n.Sharedram = uint32(s.Sharedram) + n.Totalram = uint32(s.Totalram) + n.Totalswap = uint32(s.Totalswap) + n.Uptime = int32(s.Uptime) +} diff --git a/lxd/seccomp/sysinfo_64.go b/lxd/seccomp/sysinfo_64.go new file mode 100644 index 000000000000..84383b1c5a86 --- /dev/null +++ b/lxd/seccomp/sysinfo_64.go @@ -0,0 +1,19 @@ +//go:build amd64 || ppc64 || ppc64le || arm64 || s390x || mips64 || mips64le || riscv64 + +package seccomp + +import ( + "golang.org/x/sys/unix" +) + +// ToNative fills fields from s into native fields. +func (s *Sysinfo) ToNative(n *unix.Sysinfo_t) { + n.Bufferram = s.Bufferram + n.Freeram = s.Freeram + n.Freeswap = s.Freeswap + n.Procs = s.Procs + n.Sharedram = s.Sharedram + n.Totalram = s.Totalram + n.Totalswap = s.Totalswap + n.Uptime = s.Uptime +} -- 2.35.1