dotcloud/docker

package oci // import "github.com/docker/docker/oci"

import (
    "fmt"
    "regexp"
    "strconv"

    specs "github.com/opencontainers/runtime-spec/specs-go"
)

// TODO verify if this regex is correct for "a" (all);
//
// The docs (https://github.com/torvalds/linux/blob/v5.10/Documentation/admin-guide/cgroup-v1/devices.rst) describe:
// "'all' means it applies to all types and all major and minor numbers", and shows an example
// that *only* passes `a` as value: `echo a > /sys/fs/cgroup/1/devices.allow, which would be
// the "implicit" equivalent of "a *:* rwm". Source-code also looks to confirm this, and returns
// early for "a" (all); https://github.com/torvalds/linux/blob/v5.10/security/device_cgroup.c#L614-L642
var deviceCgroupRuleRegex = regexp.MustCompile("^([acb]) ([0-9]+|\\*):([0-9]+|\\*) ([rwm]{1,3})$") //nolint: gosimple

// SetCapabilities sets the provided capabilities on the spec
// All capabilities are added if privileged is true.
func SetCapabilities(s *specs.Spec, caplist []string) error {
    if s.Process == nil {
        s.Process = &specs.Process{}
    }
    s.Process.Capabilities = &specs.LinuxCapabilities{
        Effective: caplist,
        Bounding:  caplist,
        Permitted: caplist,
    }
    return nil
}

// AppendDevicePermissionsFromCgroupRules takes rules for the devices cgroup to append to the default set
func AppendDevicePermissionsFromCgroupRules(devPermissions []specs.LinuxDeviceCgroup, rules []string) ([]specs.LinuxDeviceCgroup, error) {
    for _, deviceCgroupRule := range rules {
        ss := deviceCgroupRuleRegex.FindAllStringSubmatch(deviceCgroupRule, -1)
        if len(ss) == 0 || len(ss[0]) != 5 {
            return nil, fmt.Errorf("invalid device cgroup rule format: '%s'", deviceCgroupRule)
        }
        matches := ss[0]

        dPermissions := specs.LinuxDeviceCgroup{
            Allow:  true,
            Type:   matches[1],
            Access: matches[4],
        }
        if matches[2] == "*" {
            major := int64(-1)
            dPermissions.Major = &major
        } else {
            major, err := strconv.ParseInt(matches[2], 10, 64)
            if err != nil {
                return nil, fmt.Errorf("invalid major value in device cgroup rule format: '%s'", deviceCgroupRule)
            }
            dPermissions.Major = &major
        }
        if matches[3] == "*" {
            minor := int64(-1)
            dPermissions.Minor = &minor
        } else {
            minor, err := strconv.ParseInt(matches[3], 10, 64)
            if err != nil {
                return nil, fmt.Errorf("invalid minor value in device cgroup rule format: '%s'", deviceCgroupRule)
            }
            dPermissions.Minor = &minor
        }
        devPermissions = append(devPermissions, dPermissions)
    }
    return devPermissions, nil
}