From fd6845ddda3f80cdd24a8f94c42acce6bff0c41f Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott@canonical.com>
Date: Fri, 29 Apr 2022 11:12:48 +0100
Subject: [PATCH] lxd/secommp: Fix sysinfo syscall interception on 32 bit
platforms
Fixes #10347
Backport: <https://github.com/lxc/lxd/pull/10348>
Signed-off-by: Thomas Parrott <thomas.parrott@canonical.com>
---
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