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oci/deviceFromPath(): correctly check device types

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This ports the changes of 95a59bf206
to this repository.

From that PR:

    (mode&S_IFCHR == S_IFCHR) is the wrong way of checking the type of an
    inode because the S_IF* bits are actually not a bitmask and instead must
    be checked using S_IF*. This bug was neatly hidden behind a (major == 0)
    sanity-check but that was removed by [1].

    In addition, add a test that makes sure that HostDevices() doesn't give
    rubbish results -- because we broke this and fixed this before[2].

    [1]: 24388be71e ("configs: use different types for .Devices and .Resources.Devices")
    [2]: 3ed492ad33 ("Handle non-devices correctly in DeviceFromPath")

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This commit is contained in:
Sebastiaan van Stijn
2021-12-01 11:51:17 +01:00
parent 591d7097e7
commit 94462d8f5d
2 changed files with 65 additions and 8 deletions
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29
oci/utils_unix.go
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@@ -91,6 +91,9 @@ func getDevices(path, containerPath string) ([]specs.LinuxDevice, error) {
}
return nil, err
}
if device.Type == fifoDevice {
continue
}
if containerPath != "" {
device.Path = filepath.Join(containerPath, filepath.Base(f.Name()))
}
@@ -99,6 +102,14 @@ func getDevices(path, containerPath string) ([]specs.LinuxDevice, error) {
return out, nil
}
// TODO consider adding these consts to the OCI runtime-spec.
const (
wildcardDevice = "a" //nolint // currently unused, but should be included when upstreaming to OCI runtime-spec.
blockDevice = "b"
charDevice = "c" // or "u"
fifoDevice = "p"
)
func deviceFromPath(path string) (*specs.LinuxDevice, error) {
var stat unix.Stat_t
if err := unix.Lstat(path, &stat); err != nil {
@@ -110,19 +121,21 @@ func deviceFromPath(path string) (*specs.LinuxDevice, error) {
major = unix.Major(devNumber)
minor = unix.Minor(devNumber)
)
if major == 0 {
return nil, errNotADevice
}
var (
devType string
mode = stat.Mode
)
switch {
case mode&unix.S_IFBLK == unix.S_IFBLK:
devType = "b"
case mode&unix.S_IFCHR == unix.S_IFCHR:
devType = "c"
switch mode & unix.S_IFMT {
case unix.S_IFBLK:
devType = blockDevice
case unix.S_IFCHR:
devType = charDevice
case unix.S_IFIFO:
devType = fifoDevice
default:
return nil, errNotADevice
}
fm := os.FileMode(mode &^ unix.S_IFMT)
return &specs.LinuxDevice{