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//go:build linux | ||
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/* | ||
Copyright The containerd Authors. | ||
Licensed under the Apache License, Version 2.0 (the "License"); | ||
you may not use this file except in compliance with the License. | ||
You may obtain a copy of the License at | ||
http://www.apache.org/licenses/LICENSE-2.0 | ||
Unless required by applicable law or agreed to in writing, software | ||
distributed under the License is distributed on an "AS IS" BASIS, | ||
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
See the License for the specific language governing permissions and | ||
limitations under the License. | ||
*/ | ||
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package fsverity | ||
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import ( | ||
"bufio" | ||
"encoding/binary" | ||
"fmt" | ||
"os" | ||
"path/filepath" | ||
"strings" | ||
"syscall" | ||
"testing" | ||
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"github.com/containerd/containerd/v2/pkg/testutil" | ||
) | ||
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type superblockROFeatures struct { | ||
_ [100]byte | ||
Features uint32 | ||
} | ||
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func TestEnable(t *testing.T) { | ||
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testutil.RequiresRoot(t) | ||
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rootDir := filepath.Join(t.TempDir(), "content") | ||
err := os.Mkdir(rootDir, 0755) | ||
if err != nil { | ||
t.Errorf("could not create temporary directory: %s", err.Error()) | ||
} | ||
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device, err := resolveDevicePath(rootDir) | ||
if err != nil { | ||
t.Skipf("invalid device: %s", err.Error()) | ||
} | ||
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var expected bool | ||
enabled, err := ext4IsVerity(device) | ||
if !enabled || err != nil { | ||
t.Logf("fsverity not enabled on ext4 file system: %s", err.Error()) | ||
expected = false | ||
} else { | ||
t.Logf("fsverity enabled on ext4 file system") | ||
expected = true | ||
} | ||
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verityFile := filepath.Join(rootDir, "fsverityFile") | ||
f, err := os.Create(verityFile) | ||
if err != nil { | ||
t.Errorf("could not create fsverity test file: %s", err.Error()) | ||
} | ||
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err = f.Close() | ||
if err != nil { | ||
t.Errorf("error closing fsverity test file: %s", err.Error()) | ||
} | ||
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defer func() { | ||
err := os.Remove(verityFile) | ||
if err != nil { | ||
t.Logf("error removing fsverity test file: %s", err.Error()) | ||
} | ||
}() | ||
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err = Enable(verityFile) | ||
if err != nil && expected { | ||
t.Errorf("fsverity Enable failed: %s", err.Error()) | ||
} | ||
if err == nil && !expected { | ||
t.Errorf("fsverity Enable succeeded, expected Enable to fail") | ||
} | ||
} | ||
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func TestIsEnabled(t *testing.T) { | ||
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testDir := filepath.Join(t.TempDir(), "content") | ||
err := os.Mkdir(testDir, 0755) | ||
if err != nil { | ||
t.Errorf("could not create temporary directory: %s", err.Error()) | ||
} | ||
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if supported, err := IsSupported(testDir); !supported || err != nil { | ||
t.Skipf("fsverity is not supported") | ||
} | ||
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verityFile := filepath.Join(testDir, "fsverityFile") | ||
f, err := os.Create(verityFile) | ||
if err != nil { | ||
t.Errorf("could not create fsverity test file: %s", err.Error()) | ||
} | ||
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err = f.Close() | ||
if err != nil { | ||
t.Errorf("error closing fsverity test file: %s", err.Error()) | ||
} | ||
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defer func() { | ||
err := os.Remove(verityFile) | ||
if err != nil { | ||
t.Logf("error removing fsverity test file: %s", err.Error()) | ||
} | ||
}() | ||
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err = Enable(verityFile) | ||
if err != nil { | ||
t.Errorf("fsverity Enable failed: %s", err.Error()) | ||
} | ||
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if enabled, err := IsEnabled(verityFile); !enabled || err != nil { | ||
t.Errorf("expected fsverity to be enabled on file, received enabled: %t; error: %s", enabled, err.Error()) | ||
} | ||
} | ||
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func resolveDevicePath(path string) (_ string, e error) { | ||
var devicePath string | ||
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s, err := os.Stat(path) | ||
if err != nil { | ||
return devicePath, err | ||
} | ||
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sys := s.Sys() | ||
stat, ok := sys.(*syscall.Stat_t) | ||
if !ok { | ||
return devicePath, fmt.Errorf("type assert to syscall.Stat_t failed") | ||
} | ||
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// resolve to device path | ||
maj := (stat.Dev >> 8) & 0xff | ||
min := stat.Dev & 0xff | ||
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m, err := os.Open("/proc/self/mountinfo") | ||
if err != nil { | ||
return devicePath, err | ||
} | ||
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defer func() { | ||
err := m.Close() | ||
if err != nil { | ||
e = fmt.Errorf("could not close mountinfo: %v", err) | ||
} | ||
}() | ||
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// scan for major:minor id and get the device path | ||
scanner := bufio.NewScanner(m) | ||
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var entry string | ||
sub := fmt.Sprintf("%d:%d", maj, min) | ||
for scanner.Scan() { | ||
if strings.Contains(scanner.Text(), sub) { | ||
entry = scanner.Text() | ||
break | ||
} | ||
} | ||
if entry == "" { | ||
return devicePath, fmt.Errorf("device mount not found for device id %s", sub) | ||
} | ||
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entryReader := strings.NewReader(entry) | ||
extScan := bufio.NewScanner(entryReader) | ||
extScan.Split(bufio.ScanWords) | ||
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var word string | ||
for (word != "-") && extScan.Scan() { | ||
word = extScan.Text() | ||
} | ||
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if !extScan.Scan() { | ||
return devicePath, fmt.Errorf("scanning mounts failed: %w", extScan.Err()) | ||
} | ||
fs := extScan.Text() | ||
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if fs != "ext4" { | ||
return devicePath, fmt.Errorf("not an ext4 file system, skipping device") | ||
} | ||
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if !extScan.Scan() { | ||
return devicePath, fmt.Errorf("scanning mounts failed: %w", extScan.Err()) | ||
} | ||
devicePath = extScan.Text() | ||
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return devicePath, nil | ||
} | ||
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func ext4IsVerity(fpath string) (bool, error) { | ||
b := superblockROFeatures{} | ||
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r, err := os.Open(fpath) | ||
if err != nil { | ||
return false, err | ||
} | ||
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defer func() { | ||
err := r.Close() | ||
if err != nil { | ||
fmt.Printf("failed to close %s: %s\n", fpath, err.Error()) | ||
} | ||
}() | ||
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// seek to superblock | ||
_, err = r.Seek(1024, 0) | ||
if err != nil { | ||
return false, err | ||
} | ||
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err = binary.Read(r, binary.LittleEndian, &b) | ||
if err != nil { | ||
return false, err | ||
} | ||
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// extract fsverity flag | ||
var verityMask uint32 = 0x8000 | ||
res := verityMask & b.Features | ||
if res > 0 { | ||
return true, nil | ||
} | ||
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return false, fmt.Errorf("fsverity not enabled on ext4 file system %s", fpath) | ||
} |
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