2011-03-03 02:56:13

by Serge Hallyn

[permalink] [raw]
Subject: [PATCH mmotm 1/3] userns: remove unneeded extra argument in selinux's task_has_capability

The user_namespace argument is not used by task_has_capability, so get
rid of it. Note that it was spuriously added by the user namespace
patchset, so we're just cleaning up our own mess.

Signed-off-by: Serge E. Hallyn <[email protected]>
---
security/selinux/hooks.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

Index: linux-2.6/security/selinux/hooks.c
===================================================================
--- linux-2.6.orig/security/selinux/hooks.c 2011-03-03 01:47:01.113745084 +0000
+++ linux-2.6/security/selinux/hooks.c 2011-03-03 01:47:48.017090039 +0000
@@ -1419,7 +1419,6 @@
/* Check whether a task is allowed to use a capability. */
static int task_has_capability(struct task_struct *tsk,
const struct cred *cred,
- struct user_namespace *ns,
int cap, int audit)
{
struct common_audit_data ad;
@@ -1856,7 +1855,7 @@
if (rc)
return rc;

- return task_has_capability(tsk, cred, ns, cap, audit);
+ return task_has_capability(tsk, cred, cap, audit);
}

static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
@@ -2886,8 +2885,8 @@

case KDSKBENT:
case KDSKBSENT:
- error = task_has_capability(current, cred, &init_user_ns,
- CAP_SYS_TTY_CONFIG, SECURITY_CAP_AUDIT);
+ error = task_has_capability(current, cred, CAP_SYS_TTY_CONFIG,
+ SECURITY_CAP_AUDIT);
break;

/* default case assumes that the command will go


2011-03-03 02:57:20

by Serge Hallyn

[permalink] [raw]
Subject: [PATCH mmotm 2/3] userns: don't define init_user_ns in ipc_namespace.h

It shouldn't be needed since ipc/msgutil.c includes security.h
which includes fs.h, which forward declares it.

---
include/linux/ipc_namespace.h | 1 -
1 file changed, 1 deletion(-)

Index: linux-2.6/include/linux/ipc_namespace.h
===================================================================
--- linux-2.6.orig/include/linux/ipc_namespace.h 2011-03-03 01:55:46.191177396 +0000
+++ linux-2.6/include/linux/ipc_namespace.h 2011-03-03 01:58:51.964414007 +0000
@@ -17,7 +17,6 @@
#define IPCNS_CALLBACK_PRI 0

struct user_namespace;
-extern struct user_namespace init_user_ns;

struct ipc_ids {
int in_use;

2011-03-03 02:58:08

by Serge Hallyn

[permalink] [raw]
Subject: [PATCH mmotm 3/3] userns: make has_capability* into real functions

so we can let type safety keep things sane, and as a bonus we can
remove the declaration of init_user_ns in capability.h.

---
include/linux/capability.h | 34 +++-----------------------
kernel/capability.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 61 insertions(+), 30 deletions(-)

Index: linux-2.6/include/linux/capability.h
===================================================================
--- linux-2.6.orig/include/linux/capability.h 2011-03-03 02:17:17.533467959 +0000
+++ linux-2.6/include/linux/capability.h 2011-03-03 02:26:56.524786760 +0000
@@ -371,8 +371,6 @@
struct dentry;
struct user_namespace;

-extern struct user_namespace init_user_ns;
-
struct user_namespace *current_user_ns(void);

extern const kernel_cap_t __cap_empty_set;
@@ -541,34 +539,10 @@
cap_intersect(permitted, __cap_nfsd_set));
}

-/**
- * has_capability - Determine if a task has a superior capability available
- * @t: The task in question
- * @cap: The capability to be tested for
- *
- * Return true if the specified task has the given superior capability
- * currently in effect, false if not.
- *
- * Note that this does not set PF_SUPERPRIV on the task.
- */
-#define has_capability(t, cap) (security_real_capable((t), &init_user_ns, (cap)) == 0)
-
-#define has_ns_capability(t, ns, cap) (security_real_capable((t), (ns), (cap)) == 0)
-
-/**
- * has_capability_noaudit - Determine if a task has a superior capability available (unaudited)
- * @t: The task in question
- * @cap: The capability to be tested for
- *
- * Return true if the specified task has the given superior capability
- * currently in effect, false if not, but don't write an audit message for the
- * check.
- *
- * Note that this does not set PF_SUPERPRIV on the task.
- */
-#define has_capability_noaudit(t, cap) \
- (security_real_capable_noaudit((t), &init_user_ns, (cap)) == 0)
-
+extern bool has_capability(struct task_struct *t, int cap);
+extern bool has_ns_capability(struct task_struct *t,
+ struct user_namespace *ns, int cap);
+extern bool has_capability_noaudit(struct task_struct *t, int cap);
extern bool capable(int cap);
extern bool ns_capable(struct user_namespace *ns, int cap);
extern bool task_ns_capable(struct task_struct *t, int cap);
Index: linux-2.6/kernel/capability.c
===================================================================
--- linux-2.6.orig/kernel/capability.c 2011-03-03 02:17:17.523467247 +0000
+++ linux-2.6/kernel/capability.c 2011-03-03 02:52:11.652778780 +0000
@@ -291,6 +291,60 @@
}

/**
+ * has_capability - Does a task have a capability in init_user_ns
+ * @t: The task in question
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the initial user namespace, false if not.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_capability(struct task_struct *t, int cap)
+{
+ int ret = security_real_capable(t, &init_user_ns, cap);
+
+ return (ret == 0);
+}
+
+/**
+ * has_capability - Does a task have a capability in a specific user ns
+ * @t: The task in question
+ * @ns: target user namespace
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the specified user namespace, false if not.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_ns_capability(struct task_struct *t,
+ struct user_namespace *ns, int cap)
+{
+ int ret = security_real_capable(t, ns, cap);
+
+ return (ret == 0);
+}
+
+/**
+ * has_capability_noaudit - Does a task have a capability (unaudited)
+ * @t: The task in question
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to init_user_ns, false if not. Don't write an
+ * audit message for the check.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_capability_noaudit(struct task_struct *t, int cap)
+{
+ int ret = security_real_capable_noaudit(t, &init_user_ns, cap);
+
+ return (ret == 0);
+}
+
+/**
* capable - Determine if the current task has a superior capability in effect
* @cap: The capability to be tested for
*