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authorMicah Morton <mortonm@chromium.org>2019-01-07 16:10:53 -0800
committerJames Morris <james.morris@microsoft.com>2019-01-10 14:16:06 -0800
commitc1a85a00ea66cb6f0bd0f14e47c28c2b0999799f (patch)
tree310c082e0b41d2d3ff8b619553ed5e45ad244862 /kernel/capability.c
parent2233975cd7927672525361c4c6eebc0b8d018a74 (diff)
downloadlinux-c1a85a00ea66cb6f0bd0f14e47c28c2b0999799f.tar.bz2
LSM: generalize flag passing to security_capable
This patch provides a general mechanism for passing flags to the security_capable LSM hook. It replaces the specific 'audit' flag that is used to tell security_capable whether it should log an audit message for the given capability check. The reason for generalizing this flag passing is so we can add an additional flag that signifies whether security_capable is being called by a setid syscall (which is needed by the proposed SafeSetID LSM). Signed-off-by: Micah Morton <mortonm@chromium.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com>
Diffstat (limited to 'kernel/capability.c')
-rw-r--r--kernel/capability.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/kernel/capability.c b/kernel/capability.c
index 1e1c0236f55b..7718d7dcadc7 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -299,7 +299,7 @@ bool has_ns_capability(struct task_struct *t,
int ret;
rcu_read_lock();
- ret = security_capable(__task_cred(t), ns, cap);
+ ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NONE);
rcu_read_unlock();
return (ret == 0);
@@ -340,7 +340,7 @@ bool has_ns_capability_noaudit(struct task_struct *t,
int ret;
rcu_read_lock();
- ret = security_capable_noaudit(__task_cred(t), ns, cap);
+ ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NOAUDIT);
rcu_read_unlock();
return (ret == 0);
@@ -363,7 +363,9 @@ 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)
+static bool ns_capable_common(struct user_namespace *ns,
+ int cap,
+ unsigned int opts)
{
int capable;
@@ -372,8 +374,7 @@ static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
BUG();
}
- capable = audit ? security_capable(current_cred(), ns, cap) :
- security_capable_noaudit(current_cred(), ns, cap);
+ capable = security_capable(current_cred(), ns, cap, opts);
if (capable == 0) {
current->flags |= PF_SUPERPRIV;
return true;
@@ -394,7 +395,7 @@ static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
*/
bool ns_capable(struct user_namespace *ns, int cap)
{
- return ns_capable_common(ns, cap, true);
+ return ns_capable_common(ns, cap, CAP_OPT_NONE);
}
EXPORT_SYMBOL(ns_capable);
@@ -412,7 +413,7 @@ EXPORT_SYMBOL(ns_capable);
*/
bool ns_capable_noaudit(struct user_namespace *ns, int cap)
{
- return ns_capable_common(ns, cap, false);
+ return ns_capable_common(ns, cap, CAP_OPT_NOAUDIT);
}
EXPORT_SYMBOL(ns_capable_noaudit);
@@ -448,10 +449,11 @@ EXPORT_SYMBOL(capable);
bool file_ns_capable(const struct file *file, struct user_namespace *ns,
int cap)
{
+
if (WARN_ON_ONCE(!cap_valid(cap)))
return false;
- if (security_capable(file->f_cred, ns, cap) == 0)
+ if (security_capable(file->f_cred, ns, cap, CAP_OPT_NONE) == 0)
return true;
return false;
@@ -500,10 +502,12 @@ bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns)
{
int ret = 0; /* An absent tracer adds no restrictions */
const struct cred *cred;
+
rcu_read_lock();
cred = rcu_dereference(tsk->ptracer_cred);
if (cred)
- ret = security_capable_noaudit(cred, ns, CAP_SYS_PTRACE);
+ ret = security_capable(cred, ns, CAP_SYS_PTRACE,
+ CAP_OPT_NOAUDIT);
rcu_read_unlock();
return (ret == 0);
}