Merge pull request #880 from dqminh/wking-linux-only-capabilities-again

rebase: config: Make capabilities, noNewPrivileges, and rlimits Linux-only (again)

config.md

@@ -156,33 +156,48 @@ For POSIX platforms the `mounts` structure has the following fields:
 * **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2008's `environ`][ieee-1003.1-2008-xbd-c8.1].
 * **`args`** (array of strings, REQUIRED) with similar semantics to [IEEE Std 1003.1-2008 `execvp`'s *argv*][ieee-1003.1-2008-xsh-exec].
  This specification extends the IEEE standard in that at least one entry is REQUIRED, and that entry is used with the same semantics as `execvp`'s *file*.
-* **`capabilities`** (object, OPTIONAL) is an object containing arrays that specifies the sets of capabilities for the process.
- Valid values are platform-specific.
- For example, valid values for Linux are defined in the [capabilities(7)][capabilities.7] man page, such as `CAP_CHOWN`.
- Any value which cannot be mapped to a relevant kernel interface MUST cause an error.
- `capabilities` contains the following properties:
- * **`effective`** (array of strings, OPTIONAL) - the `effective` field is an array of effective capabilities that are kept for the process.
- * **`bounding`** (array of strings, OPTIONAL) - the `bounding` field is an array of bounding capabilities that are kept for the process.
- * **`inheritable`** (array of strings, OPTIONAL) - the `inheritable` field is an array of inheritable capabilities that are kept for the process.
- * **`permitted`** (array of strings, OPTIONAL) - the `permitted` field is an array of permitted capabilities that are kept for the process.
- * **`ambient`** (array of strings, OPTIONAL) - the `ambient` field is an array of ambient capabilities that are kept for the process.
+
+### <a name="configPOSIXProcess" />POSIX process
+
+For systems that support POSIX rlimits (for example Linux and Solaris), the `process` object supports the following process-specific properties:
+
 * **`rlimits`** (array of objects, OPTIONAL) allows setting resource limits for the process.
  Each entry has the following structure:
 
- * **`type`** (string, REQUIRED) - the platform resource being limited, for example on Linux as defined in the [setrlimit(2)][setrlimit.2] man page.
- * **`soft`** (uint64, REQUIRED) - the value of the limit enforced for the corresponding resource.
- * **`hard`** (uint64, REQUIRED) - the ceiling for the soft limit that could be set by an unprivileged process.
- Only a privileged process (e.g. under Linux: one with the CAP_SYS_RESOURCE capability) can raise a hard limit.
+ * **`type`** (string, REQUIRED) the platform resource being limited.
+ * Linux: valid values are defined in the [`getrlimit(2)`][getrlimit.2] man page, such as `RLIMIT_MSGQUEUE`.
+ * Solaris: valid values are defined in the [`getrlimit(3)`][getrlimit.3] man page, such as `RLIMIT_CORE`.
 
- If `rlimits` contains duplicated entries with same `type`, the runtime MUST error out.
+ The runtime MUST [generate an error](runtime.md#errors) for any values which cannot be mapped to a relevant kernel interface
+ For each entry in `rlimits`, a [`getrlimit(3)`][getrlimit.3] on `type` MUST succeed.
+ For the following properties, `rlim` refers to the status returned by the `getrlimit(3)` call.
 
-* **`noNewPrivileges`** (bool, OPTIONAL) setting `noNewPrivileges` to true prevents the process from gaining additional privileges.
- As an example, the ['no_new_privs'][no-new-privs] article in the kernel documentation has information on how this is achieved using a prctl system call on Linux.
+ * **`soft`** (uint64, REQUIRED) the value of the limit enforced for the corresponding resource.
+ `rlim.rlim_cur` MUST match the configured value.
+ * **`hard`** (uint64, REQUIRED) the ceiling for the soft limit that could be set by an unprivileged process.
+ `rlim.rlim_max` MUST match the configured value.
+ Only a privileged process (e.g. one with the `CAP_SYS_RESOURCE` capability) can raise a hard limit.
 
-For Linux-based systems the process structure supports the following process-specific fields.
+ If `rlimits` contains duplicated entries with same `type`, the runtime MUST [generate an error](runtime.md#errors).
+
+### <a name="configLinuxProcess" />Linux Process
+
+For Linux-based systems, the `process` object supports the following process-specific properties.
 
 * **`apparmorProfile`** (string, OPTIONAL) specifies the name of the AppArmor profile for the process.
  For more information about AppArmor, see [AppArmor documentation][apparmor].
+* **`capabilities`** (object, OPTIONAL) is an object containing arrays that specifies the sets of capabilities for the process.
+ Valid values are defined in the [capabilities(7)][capabilities.7] man page, such as `CAP_CHOWN`.
+ Any value which cannot be mapped to a relevant kernel interface MUST cause an error.
+ `capabilities` contains the following properties:
+
+ * **`effective`** (array of strings, OPTIONAL) the `effective` field is an array of effective capabilities that are kept for the process.
+ * **`bounding`** (array of strings, OPTIONAL) the `bounding` field is an array of bounding capabilities that are kept for the process.
+ * **`inheritable`** (array of strings, OPTIONAL) the `inheritable` field is an array of inheritable capabilities that are kept for the process.
+ * **`permitted`** (array of strings, OPTIONAL) the `permitted` field is an array of permitted capabilities that are kept for the process.
+ * **`ambient`** (array of strings, OPTIONAL) the `ambient` field is an array of ambient capabilities that are kept for the process.
+* **`noNewPrivileges`** (bool, OPTIONAL) setting `noNewPrivileges` to true prevents the process from gaining additional privileges.
+ As an example, the [`no_new_privs`][no-new-privs] article in the kernel documentation has information on how this is achieved using a `prctl` system call on Linux.
 * **`oomScoreAdj`** *(int, OPTIONAL)* adjusts the oom-killer score in `[pid]/oom_score_adj` for the process's `[pid]` in a [proc pseudo-filesystem][procfs].
  If `oomScoreAdj` is set, the runtime MUST set `oom_score_adj` to the given value.
  If `oomScoreAdj` is not set, the runtime MUST NOT change the value of `oom_score_adj`.
@@ -838,7 +853,8 @@ Here is a full example `config.json` for reference.
 [mount.8]: http://man7.org/linux/man-pages/man8/mount.8.html
 [mount.8-filesystem-independent]: http://man7.org/linux/man-pages/man8/mount.8.html#FILESYSTEM-INDEPENDENT_MOUNT%20OPTIONS
 [mount.8-filesystem-specific]: http://man7.org/linux/man-pages/man8/mount.8.html#FILESYSTEM-SPECIFIC_MOUNT%20OPTIONS
-[setrlimit.2]: http://man7.org/linux/man-pages/man2/setrlimit.2.html
+[getrlimit.2]: http://man7.org/linux/man-pages/man2/getrlimit.2.html
+[getrlimit.3]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/getrlimit.html
 [stdin.3]: http://man7.org/linux/man-pages/man3/stdin.3.html
 [uts-namespace.7]: http://man7.org/linux/man-pages/man7/namespaces.7.html
 [zonecfg.1m]: http://docs.oracle.com/cd/E86824_01/html/E54764/zonecfg-1m.html

specs-go/config.go

@@ -45,7 +45,7 @@ type Process struct {
  // Capabilities are Linux capabilities that are kept for the process.
  Capabilities *LinuxCapabilities `json:"capabilities,omitempty" platform:"linux"`
  // Rlimits specifies rlimit options to apply to the process.
- Rlimits []LinuxRlimit `json:"rlimits,omitempty" platform:"linux"`
+ Rlimits []POSIXRlimit `json:"rlimits,omitempty" platform:"linux,solaris"`
  // NoNewPrivileges controls whether additional privileges could be gained by processes in the container.
  NoNewPrivileges bool `json:"noNewPrivileges,omitempty" platform:"linux"`
  // ApparmorProfile specifies the apparmor profile for the container.
@@ -202,8 +202,8 @@ type LinuxIDMapping struct {
  Size uint32 `json:"size"`
 }
 
-// LinuxRlimit type and restrictions
-type LinuxRlimit struct {
+// POSIXRlimit type and restrictions
+type POSIXRlimit struct {
  // Type of the rlimit to set
  Type string `json:"type"`
  // Hard is the hard limit for the specified type