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EtiennePerotEtiennePerot
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Implement personality(2) for no-op personality bits.
Fixes #10756
1 parent 979bbf2 commit 91d3665

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12 files changed

+255
-2
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12 files changed

+255
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‎pkg/abi/linux/BUILD

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@@ -58,6 +58,7 @@ go_library(
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"netlink.go",
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"netlink_route.go",
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"nf_tables.go",
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"personality.go",
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"poll.go",
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"prctl.go",
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"ptrace.go",

‎pkg/abi/linux/personality.go

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@@ -0,0 +1,29 @@
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// Copyright 2024 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package linux
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// Personality flags, used by personality(2),
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// from include/uapi/linux/personality.h.
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const (
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SHORT_INODE = 0x1000000
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WHOLE_SECONDS = 0x2000000
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PER_LINUX = 0x0000
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PER_BSD = 0x0006
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)
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// NOTE: All of the above flags are non-security-sensitive and may be copied
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// from parent task to child task. However, this is not the case for all
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// personality bits. If adding more, check PER_CLEAR_ON_SETID and ensure that
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// these are cleared on suid/sgid execs.

‎pkg/sentry/kernel/kernel.go

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@@ -1157,6 +1157,7 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID,
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InitialCgroups: args.InitialCgroups,
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UserCounters: k.GetUserCounters(args.Credentials.RealKUID),
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Origin: args.Origin,
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Personality: linux.PER_LINUX,
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// A task with no parent starts out with no session keyring.
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SessionKeyring: nil,
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}

‎pkg/sentry/kernel/task.go

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@@ -608,6 +608,9 @@ type Task struct {
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// +checklocks:mu
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sessionKeyring *auth.Key
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// personality is the task's personality(2) bits.
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personality atomicbitops.Uint32
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// Origin is the origin of the task.
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Origin TaskOrigin
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}
@@ -869,3 +872,14 @@ func (t *Task) ResetKcov() {
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t.kcov = nil
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}
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}
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// Personality returns the task's personality.
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func (t *Task) Personality() uint32 {
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return t.personality.Load()
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}
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// SetPersonality sets the task's personality.
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// It returns the task's former personality.
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func (t *Task) SetPersonality(personality uint32) uint32 {
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return t.personality.Swap(personality)
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}

‎pkg/sentry/kernel/task_clone.go

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@@ -265,6 +265,7 @@ func (t *Task) Clone(args *linux.CloneArgs) (ThreadID, *SyscallControl, error) {
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ContainerID: t.ContainerID(),
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UserCounters: uc,
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SessionKeyring: sessionKeyring,
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Personality: t.personality.Load(),
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Origin: t.Origin,
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}
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if args.Flags&linux.CLONE_THREAD == 0 {

‎pkg/sentry/kernel/task_start.go

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@@ -104,6 +104,9 @@ type TaskConfig struct {
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// It may be nil.
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SessionKeyring *auth.Key
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// Personality is the personality of the parent task.
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Personality uint32
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Origin TaskOrigin
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}
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@@ -174,6 +177,7 @@ func (ts *TaskSet) newTask(ctx context.Context, cfg *TaskConfig) (*Task, error)
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cgroups: make(map[Cgroup]struct{}),
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userCounters: cfg.UserCounters,
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sessionKeyring: cfg.SessionKeyring,
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personality: atomicbitops.FromUint32(cfg.Personality),
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Origin: cfg.Origin,
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}
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t.netns = cfg.NetworkNamespace

‎pkg/sentry/syscalls/linux/BUILD

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@@ -33,6 +33,7 @@ go_library(
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"sys_mount.go",
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"sys_mq.go",
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"sys_msgqueue.go",
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"sys_personality.go",
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"sys_pipe.go",
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"sys_poll.go",
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"sys_prctl.go",

‎pkg/sentry/syscalls/linux/linux64.go

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@@ -187,7 +187,7 @@ var AMD64 = &kernel.SyscallTable{
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132: syscalls.Supported("utime", Utime),
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133: syscalls.Supported("mknod", Mknod),
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134: syscalls.Error("uselib", linuxerr.ENOSYS, "Obsolete", nil),
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135: syscalls.ErrorWithEvent("personality", linuxerr.EINVAL, "Unable to change personality.", nil),
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135: syscalls.PartiallySupported("personality", Personality, "Only setting no-op personality bits and retrieving them are supported.", nil),
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136: syscalls.ErrorWithEvent("ustat", linuxerr.ENOSYS, "Needs filesystem support.", nil),
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137: syscalls.Supported("statfs", Statfs),
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138: syscalls.Supported("fstatfs", Fstatfs),
@@ -523,7 +523,7 @@ var ARM64 = &kernel.SyscallTable{
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89: syscalls.CapError("acct", linux.CAP_SYS_PACCT, "", nil),
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90: syscalls.Supported("capget", Capget),
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91: syscalls.Supported("capset", Capset),
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92: syscalls.ErrorWithEvent("personality", linuxerr.EINVAL, "Unable to change personality.", nil),
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92: syscalls.PartiallySupported("personality", Personality, "Only setting no-op personality bits and retrieving them are supported.", nil),
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93: syscalls.Supported("exit", Exit),
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94: syscalls.Supported("exit_group", ExitGroup),
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95: syscalls.Supported("waitid", Waitid),

‎pkg/sentry/syscalls/linux/sys_personality.go

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@@ -0,0 +1,43 @@
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// Copyright 2024 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
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package linux
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/errors/linuxerr"
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"gvisor.dev/gvisor/pkg/sentry/arch"
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"gvisor.dev/gvisor/pkg/sentry/kernel"
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)
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const (
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// getPersonality may be passed to `personality(2)` to get the current
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// personality bits without modifying them.
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getPersonality = 0xffffffff
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)
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// Personality implements Linux syscall personality(2).
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func Personality(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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// allowedPersonalityBits are the personality bits that are allowed to be set.
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const allowedPersonalityBits = linux.PER_LINUX | linux.PER_BSD | linux.SHORT_INODE | linux.WHOLE_SECONDS
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personality := args[0].Uint()
36+
if personality == getPersonality {
37+
return uintptr(t.Personality()), nil, nil
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}
39+
if personality&allowedPersonalityBits != personality {
40+
return 0, nil, linuxerr.EINVAL
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}
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return uintptr(t.SetPersonality(personality)), nil, nil
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}

‎test/syscalls/BUILD

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@@ -479,6 +479,10 @@ syscall_test(
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test = "//test/syscalls/linux:pause_test",
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)
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syscall_test(
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test = "//test/syscalls/linux:personality_test",
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)
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syscall_test(
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size = "medium",
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add_hostinet = True,

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