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Create utility for integer-based proc files. #10415

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merged 1 commit into from
May 21, 2024
Merged

Create utility for integer-based proc files. #10415

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97 changes: 35 additions & 62 deletions pkg/sentry/fsimpl/proc/tasks_sys.go
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Original file line number Diff line number Diff line change
Expand Up @@ -227,22 +227,15 @@ func (d *tcpSackData) Write(ctx context.Context, _ *vfs.FileDescription, src use
// No need to handle partial writes thus far.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}

// Limit the amount of memory allocated.
src = src.TakeFirst(hostarch.PageSize - 1)

var v int32
n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
if err != nil {
buf := make([]int32, 1)
n, err := ParseInt32Vec(ctx, src, buf)
if err != nil || n == 0 {
return 0, err
}
if d.enabled == nil {
d.enabled = new(bool)
}
*d.enabled = v != 0
*d.enabled = buf[0] != 0
return n, d.stack.SetTCPSACKEnabled(*d.enabled)
}

Expand Down Expand Up @@ -275,19 +268,12 @@ func (d *tcpRecoveryData) Write(ctx context.Context, _ *vfs.FileDescription, src
// No need to handle partial writes thus far.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}

// Limit the amount of memory allocated.
src = src.TakeFirst(hostarch.PageSize - 1)

var v int32
n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
if err != nil {
buf := make([]int32, 1)
n, err := ParseInt32Vec(ctx, src, buf)
if err != nil || n == 0 {
return 0, err
}
if err := d.stack.SetTCPRecovery(inet.TCPLossRecovery(v)); err != nil {
if err := d.stack.SetTCPRecovery(inet.TCPLossRecovery(buf[0])); err != nil {
return 0, err
}
return n, nil
Expand Down Expand Up @@ -329,21 +315,15 @@ func (d *tcpMemData) Write(ctx context.Context, _ *vfs.FileDescription, src user
// No need to handle partial writes thus far.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}
d.mu.Lock()
defer d.mu.Unlock()

// Limit the amount of memory allocated.
src = src.TakeFirst(hostarch.PageSize - 1)
size, err := d.readSizeLocked()
if err != nil {
return 0, err
}
buf := []int32{int32(size.Min), int32(size.Default), int32(size.Max)}
n, err := usermem.CopyInt32StringsInVec(ctx, src.IO, src.Addrs, buf, src.Opts)
if err != nil {
n, err := ParseInt32Vec(ctx, src, buf)
if err != nil || n == 0 {
return 0, err
}
newSize := inet.TCPBufferSize{
Expand Down Expand Up @@ -414,19 +394,12 @@ func (ipf *ipForwarding) Write(ctx context.Context, _ *vfs.FileDescription, src
// No need to handle partial writes thus far.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}

// Limit input size so as not to impact performance if input size is large.
src = src.TakeFirst(hostarch.PageSize - 1)

var v int32
n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
if err != nil {
buf := make([]int32, 1)
n, err := ParseInt32Vec(ctx, src, buf)
if err != nil || n == 0 {
return 0, err
}
ipf.enabled = v != 0
ipf.enabled = buf[0] != 0
if err := ipf.stack.SetForwarding(ipv4.ProtocolNumber, ipf.enabled); err != nil {
return 0, err
}
Expand Down Expand Up @@ -467,17 +440,10 @@ func (pr *portRange) Write(ctx context.Context, _ *vfs.FileDescription, src user
// No need to handle partial writes thus far.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}

// Limit input size so as not to impact performance if input size is
// large.
src = src.TakeFirst(hostarch.PageSize - 1)

ports := make([]int32, 2)
n, err := usermem.CopyInt32StringsInVec(ctx, src.IO, src.Addrs, ports, src.Opts)
if err != nil {
n, err := ParseInt32Vec(ctx, src, ports)
if err != nil || n == 0 {
return 0, err
}

Expand Down Expand Up @@ -523,24 +489,17 @@ func (f *atomicInt32File) Write(ctx context.Context, _ *vfs.FileDescription, src
// Ignore partial writes.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}

// Limit the amount of memory allocated.
src = src.TakeFirst(hostarch.PageSize - 1)

var v int32
n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
if err != nil {
buf := make([]int32, 1)
n, err := ParseInt32Vec(ctx, src, buf)
if err != nil || n == 0 {
return 0, err
}

if v < f.min || v > f.max {
if buf[0] < f.min || buf[0] > f.max {
return 0, linuxerr.EINVAL
}

f.val.Store(v)
f.val.Store(buf[0])
return n, nil
}

Expand All @@ -555,3 +514,17 @@ func randUUID() string {
uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4 (random)
return fmt.Sprintf("%x-%x-%x-%x-%x\n", uuid[:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:])
}

// ParseInt32Vec interprets src as string encoding slice of int32, and
// returns the parsed value and the number of bytes read.
//
// The numbers of int32 will be populated even if an error is returned eventually.
func ParseInt32Vec(ctx context.Context, src usermem.IOSequence, buf []int32) (int64, error) {
if src.NumBytes() == 0 {
return 0, nil
}
// Limit input size so as not to impact performance if input size is large.
src = src.TakeFirst(hostarch.PageSize - 1)

return usermem.CopyInt32StringsInVec(ctx, src.IO, src.Addrs, buf, src.Opts)
}
57 changes: 57 additions & 0 deletions pkg/sentry/fsimpl/proc/tasks_sys_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@ package proc
import (
"bytes"
"reflect"
"slices"
"testing"

"gvisor.dev/gvisor/pkg/abi/linux"
Expand Down Expand Up @@ -147,3 +148,59 @@ func TestConfigureIPForwarding(t *testing.T) {
})
}
}

func TestParseInt32Vec(t *testing.T) {
ctx := context.Background()
tests := []struct {
name string
src []byte
buf []int32
expectedBuf []int32
expectedBytes int64
}{
{
name: "EmptyInput",
src: []byte(""),
buf: []int32{},
expectedBuf: []int32{},
expectedBytes: 0,
},
{
name: "SingleNum",
src: []byte("123"),
buf: []int32{0},
expectedBuf: []int32{123},
expectedBytes: 3,
},
{
name: "MultipleNum",
src: []byte("123 456"),
buf: []int32{0, 0},
expectedBuf: []int32{123, 456},
expectedBytes: 7,
},
{
name: "FirstNNum",
src: []byte("123 456"),
buf: []int32{0, 0, 789},
expectedBuf: []int32{123, 456, 789},
expectedBytes: 7,
},
{
name: "ParsePartially",
src: []byte("123 a"),
buf: []int32{0},
expectedBuf: []int32{123},
expectedBytes: 4,
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
originalBuf := append([]int32(nil), test.buf...)
n, err := ParseInt32Vec(ctx, usermem.BytesIOSequence(test.src), test.buf)
if !slices.Equal(test.buf, test.expectedBuf) || n != test.expectedBytes {
t.Errorf("ParseInt32Vec(ctx, %v, %v) returns %v, %v, result buffer is %v; expected: %v, %v", test.src, originalBuf, n, err, test.buf, test.expectedBuf, test.expectedBytes)
}
})
}
}
18 changes: 5 additions & 13 deletions pkg/sentry/fsimpl/proc/yama.go
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@ import (
"gvisor.dev/gvisor/pkg/atomicbitops"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
Expand Down Expand Up @@ -61,24 +60,17 @@ func (s *yamaPtraceScope) Write(ctx context.Context, _ *vfs.FileDescription, src
// Ignore partial writes.
return 0, linuxerr.EINVAL
}
if src.NumBytes() == 0 {
return 0, nil
}

// Limit the amount of memory allocated.
src = src.TakeFirst(hostarch.PageSize - 1)

var v int32
n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
if err != nil {
buf := make([]int32, 1)
n, err := ParseInt32Vec(ctx, src, buf)
if err != nil || n == 0 {
return 0, err
}

// We do not support YAMA levels > YAMA_SCOPE_RELATIONAL.
if v < linux.YAMA_SCOPE_DISABLED || v > linux.YAMA_SCOPE_RELATIONAL {
if buf[0] < linux.YAMA_SCOPE_DISABLED || buf[0] > linux.YAMA_SCOPE_RELATIONAL {
return 0, linuxerr.EINVAL
}

s.level.Store(v)
s.level.Store(buf[0])
return n, nil
}
2 changes: 0 additions & 2 deletions pkg/sentry/vfs/file_description_impl_util.go
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Original file line number Diff line number Diff line change
Expand Up @@ -256,8 +256,6 @@ func (s *StaticData) Generate(ctx context.Context, buf *bytes.Buffer) error {

// WritableDynamicBytesSource extends DynamicBytesSource to allow writes to the
// underlying source.
//
// TODO(b/179825241): Make utility for integer-based writable files.
type WritableDynamicBytesSource interface {
DynamicBytesSource

Expand Down