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authorSerge E. Hallyn <serge@hallyn.com>2011-03-23 16:43:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-23 19:47:02 -0700
commit3486740a4f32a6a466f5ac931654d154790ba648 (patch)
treeac5d968a66057fa84933b8f89fd3e916270dffed /include/linux/security.h
parent59607db367c57f515183cb203642291bb14d9c40 (diff)
downloadlinux-3486740a4f32a6a466f5ac931654d154790ba648.tar.gz
userns: security: make capabilities relative to the user namespace
- Introduce ns_capable to test for a capability in a non-default user namespace. - Teach cap_capable to handle capabilities in a non-default user namespace. The motivation is to get to the unprivileged creation of new namespaces. It looks like this gets us 90% of the way there, with only potential uid confusion issues left. I still need to handle getting all caps after creation but otherwise I think I have a good starter patch that achieves all of your goals. Changelog: 11/05/2010: [serge] add apparmor 12/14/2010: [serge] fix capabilities to created user namespaces Without this, if user serge creates a user_ns, he won't have capabilities to the user_ns he created. THis is because we were first checking whether his effective caps had the caps he needed and returning -EPERM if not, and THEN checking whether he was the creator. Reverse those checks. 12/16/2010: [serge] security_real_capable needs ns argument in !security case 01/11/2011: [serge] add task_ns_capable helper 01/11/2011: [serge] add nsown_capable() helper per Bastian Blank suggestion 02/16/2011: [serge] fix a logic bug: the root user is always creator of init_user_ns, but should not always have capabilities to it! Fix the check in cap_capable(). 02/21/2011: Add the required user_ns parameter to security_capable, fixing a compile failure. 02/23/2011: Convert some macros to functions as per akpm comments. Some couldn't be converted because we can't easily forward-declare them (they are inline if !SECURITY, extern if SECURITY). Add a current_user_ns function so we can use it in capability.h without #including cred.h. Move all forward declarations together to the top of the #ifdef __KERNEL__ section, and use kernel-doc format. 02/23/2011: Per dhowells, clean up comment in cap_capable(). 02/23/2011: Per akpm, remove unreachable 'return -EPERM' in cap_capable. (Original written and signed off by Eric; latest, modified version acked by him) [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: export current_user_ns() for ecryptfs] [serge.hallyn@canonical.com: remove unneeded extra argument in selinux's task_has_capability] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Acked-by: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/security.h')
-rw-r--r--include/linux/security.h28
1 files changed, 17 insertions, 11 deletions
diff --git a/include/linux/security.h b/include/linux/security.h
index 56cac520d01..ca02f171673 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -47,13 +47,14 @@
struct ctl_table;
struct audit_krule;
+struct user_namespace;
/*
* These functions are in security/capability.c and are used
* as the default capabilities functions
*/
extern int cap_capable(struct task_struct *tsk, const struct cred *cred,
- int cap, int audit);
+ struct user_namespace *ns, int cap, int audit);
extern int cap_settime(const struct timespec *ts, const struct timezone *tz);
extern int cap_ptrace_access_check(struct task_struct *child, unsigned int mode);
extern int cap_ptrace_traceme(struct task_struct *parent);
@@ -1262,6 +1263,7 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* credentials.
* @tsk contains the task_struct for the process.
* @cred contains the credentials to use.
+ * @ns contains the user namespace we want the capability in
* @cap contains the capability <include/linux/capability.h>.
* @audit: Whether to write an audit message or not
* Return 0 if the capability is granted for @tsk.
@@ -1384,7 +1386,7 @@ struct security_operations {
const kernel_cap_t *inheritable,
const kernel_cap_t *permitted);
int (*capable) (struct task_struct *tsk, const struct cred *cred,
- int cap, int audit);
+ struct user_namespace *ns, int cap, int audit);
int (*quotactl) (int cmds, int type, int id, struct super_block *sb);
int (*quota_on) (struct dentry *dentry);
int (*syslog) (int type);
@@ -1665,9 +1667,12 @@ int security_capset(struct cred *new, const struct cred *old,
const kernel_cap_t *effective,
const kernel_cap_t *inheritable,
const kernel_cap_t *permitted);
-int security_capable(const struct cred *cred, int cap);
-int security_real_capable(struct task_struct *tsk, int cap);
-int security_real_capable_noaudit(struct task_struct *tsk, int cap);
+int security_capable(struct user_namespace *ns, const struct cred *cred,
+ int cap);
+int security_real_capable(struct task_struct *tsk, struct user_namespace *ns,
+ int cap);
+int security_real_capable_noaudit(struct task_struct *tsk,
+ struct user_namespace *ns, int cap);
int security_quotactl(int cmds, int type, int id, struct super_block *sb);
int security_quota_on(struct dentry *dentry);
int security_syslog(int type);
@@ -1860,28 +1865,29 @@ static inline int security_capset(struct cred *new,
return cap_capset(new, old, effective, inheritable, permitted);
}
-static inline int security_capable(const struct cred *cred, int cap)
+static inline int security_capable(struct user_namespace *ns,
+ const struct cred *cred, int cap)
{
- return cap_capable(current, cred, cap, SECURITY_CAP_AUDIT);
+ return cap_capable(current, cred, ns, cap, SECURITY_CAP_AUDIT);
}
-static inline int security_real_capable(struct task_struct *tsk, int cap)
+static inline int security_real_capable(struct task_struct *tsk, struct user_namespace *ns, int cap)
{
int ret;
rcu_read_lock();
- ret = cap_capable(tsk, __task_cred(tsk), cap, SECURITY_CAP_AUDIT);
+ ret = cap_capable(tsk, __task_cred(tsk), ns, cap, SECURITY_CAP_AUDIT);
rcu_read_unlock();
return ret;
}
static inline
-int security_real_capable_noaudit(struct task_struct *tsk, int cap)
+int security_real_capable_noaudit(struct task_struct *tsk, struct user_namespace *ns, int cap)
{
int ret;
rcu_read_lock();
- ret = cap_capable(tsk, __task_cred(tsk), cap,
+ ret = cap_capable(tsk, __task_cred(tsk), ns, cap,
SECURITY_CAP_NOAUDIT);
rcu_read_unlock();
return ret;