Commit 98f368e9 authored by Tyler Hicks's avatar Tyler Hicks Committed by James Morris
Browse files

kernel: Add noaudit variant of ns_capable()



When checking the current cred for a capability in a specific user
namespace, it isn't always desirable to have the LSMs audit the check.
This patch adds a noaudit variant of ns_capable() for when those
situations arise.

The common logic between ns_capable() and the new ns_capable_noaudit()
is moved into a single, shared function to keep duplicated code to a
minimum and ease maintainability.
Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
Acked-by: default avatarSerge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent 2885c1e3
......@@ -206,6 +206,7 @@ extern bool has_ns_capability_noaudit(struct task_struct *t,
struct user_namespace *ns, int cap);
extern bool capable(int cap);
extern bool ns_capable(struct user_namespace *ns, int cap);
extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
#else
static inline bool has_capability(struct task_struct *t, int cap)
{
......@@ -233,6 +234,10 @@ static inline bool ns_capable(struct user_namespace *ns, int cap)
{
return true;
}
static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
{
return true;
}
#endif /* CONFIG_MULTIUSER */
extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
......
......@@ -361,6 +361,24 @@ bool has_capability_noaudit(struct task_struct *t, int cap)
return has_ns_capability_noaudit(t, &init_user_ns, cap);
}
static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
{
int capable;
if (unlikely(!cap_valid(cap))) {
pr_crit("capable() called with invalid cap=%u\n", cap);
BUG();
}
capable = audit ? security_capable(current_cred(), ns, cap) :
security_capable_noaudit(current_cred(), ns, cap);
if (capable == 0) {
current->flags |= PF_SUPERPRIV;
return true;
}
return false;
}
/**
* ns_capable - Determine if the current task has a superior capability in effect
* @ns: The usernamespace we want the capability in
......@@ -374,19 +392,27 @@ bool has_capability_noaudit(struct task_struct *t, int cap)
*/
bool ns_capable(struct user_namespace *ns, int cap)
{
if (unlikely(!cap_valid(cap))) {
pr_crit("capable() called with invalid cap=%u\n", cap);
BUG();
}
if (security_capable(current_cred(), ns, cap) == 0) {
current->flags |= PF_SUPERPRIV;
return true;
}
return false;
return ns_capable_common(ns, cap, true);
}
EXPORT_SYMBOL(ns_capable);
/**
* ns_capable_noaudit - Determine if the current task has a superior capability
* (unaudited) in effect
* @ns: The usernamespace we want the capability in
* @cap: The capability to be tested for
*
* Return true if the current task has the given superior capability currently
* available for use, false if not.
*
* This sets PF_SUPERPRIV on the task if the capability is available on the
* assumption that it's about to be used.
*/
bool ns_capable_noaudit(struct user_namespace *ns, int cap)
{
return ns_capable_common(ns, cap, false);
}
EXPORT_SYMBOL(ns_capable_noaudit);
/**
* capable - Determine if the current task has a superior capability in effect
......
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