diff options
| author | Michael Pratt <mpratt@google.com> | 2019-06-05 13:59:01 -0700 |
|---|---|---|
| committer | Shentubot <shentubot@google.com> | 2019-06-05 14:00:13 -0700 |
| commit | d3ed9baac0dc967eaf6d3e3f986cafe60604121a (patch) | |
| tree | 47121539775297207ba205b60b136c9093d5d393 /pkg/sentry/syscalls/linux/sys_prctl.go | |
| parent | cecb71dc37a77d8e4e88cdfada92a37a72c67602 (diff) | |
Implement dumpability tracking and checks
We don't actually support core dumps, but some applications want to
get/set dumpability, which still has an effect in procfs.
Lack of support for set-uid binaries or fs creds simplifies things a
bit.
As-is, processes started via CreateProcess (i.e., init and sentryctl
exec) have normal dumpability. I'm a bit torn on whether sentryctl exec
tasks should be dumpable, but at least since they have no parent normal
UID/GID checks should protect them.
PiperOrigin-RevId: 251712714
Diffstat (limited to 'pkg/sentry/syscalls/linux/sys_prctl.go')
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_prctl.go | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_prctl.go b/pkg/sentry/syscalls/linux/sys_prctl.go index 117ae1a0e..1b7e5616b 100644 --- a/pkg/sentry/syscalls/linux/sys_prctl.go +++ b/pkg/sentry/syscalls/linux/sys_prctl.go @@ -15,6 +15,7 @@ package linux import ( + "fmt" "syscall" "gvisor.googlesource.com/gvisor/pkg/abi/linux" @@ -23,6 +24,7 @@ import ( "gvisor.googlesource.com/gvisor/pkg/sentry/kernel" "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/auth" "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/kdefs" + "gvisor.googlesource.com/gvisor/pkg/sentry/mm" ) // Prctl implements linux syscall prctl(2). @@ -44,6 +46,33 @@ func Prctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall _, err := t.CopyOut(args[1].Pointer(), int32(t.ParentDeathSignal())) return 0, nil, err + case linux.PR_GET_DUMPABLE: + d := t.MemoryManager().Dumpability() + switch d { + case mm.NotDumpable: + return linux.SUID_DUMP_DISABLE, nil, nil + case mm.UserDumpable: + return linux.SUID_DUMP_USER, nil, nil + case mm.RootDumpable: + return linux.SUID_DUMP_ROOT, nil, nil + default: + panic(fmt.Sprintf("Unknown dumpability %v", d)) + } + + case linux.PR_SET_DUMPABLE: + var d mm.Dumpability + switch args[1].Int() { + case linux.SUID_DUMP_DISABLE: + d = mm.NotDumpable + case linux.SUID_DUMP_USER: + d = mm.UserDumpable + default: + // N.B. Userspace may not pass SUID_DUMP_ROOT. + return 0, nil, syscall.EINVAL + } + t.MemoryManager().SetDumpability(d) + return 0, nil, nil + case linux.PR_GET_KEEPCAPS: if t.Credentials().KeepCaps { return 1, nil, nil @@ -171,9 +200,7 @@ func Prctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } return 0, nil, t.DropBoundingCapability(cp) - case linux.PR_GET_DUMPABLE, - linux.PR_SET_DUMPABLE, - linux.PR_GET_TIMING, + case linux.PR_GET_TIMING, linux.PR_SET_TIMING, linux.PR_GET_TSC, linux.PR_SET_TSC, |