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From: Paul Moore <paul@paul-moore.com>
To: Casey Schaufler <casey@schaufler-ca.com>,
	John Johansen <john.johansen@canonical.com>
Cc: selinux@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-audit@redhat.com
Subject: [RFC PATCH 4/4] apparmor: differentiate between subjective and objective task credentials
Date: Fri, 19 Feb 2021 18:29:23 -0500
Message-ID: <161377736385.87807.7033400948278183233.stgit@sifl> (raw)
In-Reply-To: <161377712068.87807.12246856567527156637.stgit@sifl>

With the split of the security_task_getsecid() into subjective and
objective variants it's time to update AppArmor to ensure it is
using the correct task creds.

Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 security/apparmor/domain.c       |    2 +-
 security/apparmor/include/cred.h |   19 ++++++++++++++++---
 security/apparmor/include/task.h |    3 ++-
 security/apparmor/lsm.c          |   23 +++++++++++++++--------
 security/apparmor/task.c         |   23 ++++++++++++++++++++---
 5 files changed, 54 insertions(+), 16 deletions(-)

diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index f919ebd042fd2..9ed00b8dcdf0c 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -67,7 +67,7 @@ static int may_change_ptraced_domain(struct aa_label *to_label,
 	tracer = ptrace_parent(current);
 	if (tracer)
 		/* released below */
-		tracerl = aa_get_task_label(tracer);
+		tracerl = aa_get_task_label_subj(tracer);
 
 	/* not ptraced */
 	if (!tracer || unconfined(tracerl))
diff --git a/security/apparmor/include/cred.h b/security/apparmor/include/cred.h
index 0b9ae4804ef73..43c21ef5568ab 100644
--- a/security/apparmor/include/cred.h
+++ b/security/apparmor/include/cred.h
@@ -64,14 +64,27 @@ static inline struct aa_label *aa_get_newest_cred_label(const struct cred *cred)
 }
 
 /**
- * __aa_task_raw_label - retrieve another task's label
+ * __aa_task_raw_label_subj - retrieve another task's subjective label
  * @task: task to query  (NOT NULL)
  *
- * Returns: @task's label without incrementing its ref count
+ * Returns: @task's subjective label without incrementing its ref count
  *
  * If @task != current needs to be called in RCU safe critical section
  */
-static inline struct aa_label *__aa_task_raw_label(struct task_struct *task)
+static inline struct aa_label *__aa_task_raw_label_subj(struct task_struct *task)
+{
+	return aa_cred_raw_label(rcu_dereference(task->cred));
+}
+
+/**
+ * __aa_task_raw_label_obj - retrieve another task's objective label
+ * @task: task to query  (NOT NULL)
+ *
+ * Returns: @task's objective label without incrementing its ref count
+ *
+ * If @task != current needs to be called in RCU safe critical section
+ */
+static inline struct aa_label *__aa_task_raw_label_obj(struct task_struct *task)
 {
 	return aa_cred_raw_label(__task_cred(task));
 }
diff --git a/security/apparmor/include/task.h b/security/apparmor/include/task.h
index f13d12373b25e..27a2961558555 100644
--- a/security/apparmor/include/task.h
+++ b/security/apparmor/include/task.h
@@ -33,7 +33,8 @@ int aa_replace_current_label(struct aa_label *label);
 int aa_set_current_onexec(struct aa_label *label, bool stack);
 int aa_set_current_hat(struct aa_label *label, u64 token);
 int aa_restore_previous_label(u64 cookie);
-struct aa_label *aa_get_task_label(struct task_struct *task);
+struct aa_label *aa_get_task_label_subj(struct task_struct *task);
+struct aa_label *aa_get_task_label_obj(struct task_struct *task);
 
 /**
  * aa_free_task_ctx - free a task_ctx
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 15e37b9132679..38430851675b9 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -119,7 +119,7 @@ static int apparmor_ptrace_access_check(struct task_struct *child,
 	int error;
 
 	tracer = __begin_current_label_crit_section();
-	tracee = aa_get_task_label(child);
+	tracee = aa_get_task_label_obj(child);
 	error = aa_may_ptrace(tracer, tracee,
 			(mode & PTRACE_MODE_READ) ? AA_PTRACE_READ
 						  : AA_PTRACE_TRACE);
@@ -135,7 +135,7 @@ static int apparmor_ptrace_traceme(struct task_struct *parent)
 	int error;
 
 	tracee = __begin_current_label_crit_section();
-	tracer = aa_get_task_label(parent);
+	tracer = aa_get_task_label_subj(parent);
 	error = aa_may_ptrace(tracer, tracee, AA_PTRACE_TRACE);
 	aa_put_label(tracer);
 	__end_current_label_crit_section(tracee);
@@ -719,9 +719,16 @@ static void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
 	return;
 }
 
-static void apparmor_task_getsecid(struct task_struct *p, u32 *secid)
+static void apparmor_task_getsecid_subj(struct task_struct *p, u32 *secid)
 {
-	struct aa_label *label = aa_get_task_label(p);
+	struct aa_label *label = aa_get_task_label_subj(p);
+	*secid = label->secid;
+	aa_put_label(label);
+}
+
+static void apparmor_task_getsecid_obj(struct task_struct *p, u32 *secid)
+{
+	struct aa_label *label = aa_get_task_label_obj(p);
 	*secid = label->secid;
 	aa_put_label(label);
 }
@@ -750,7 +757,7 @@ static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo
 		 * Dealing with USB IO specific behavior
 		 */
 		cl = aa_get_newest_cred_label(cred);
-		tl = aa_get_task_label(target);
+		tl = aa_get_task_label_obj(target);
 		error = aa_may_signal(cl, tl, sig);
 		aa_put_label(cl);
 		aa_put_label(tl);
@@ -758,7 +765,7 @@ static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo
 	}
 
 	cl = __begin_current_label_crit_section();
-	tl = aa_get_task_label(target);
+	tl = aa_get_task_label_obj(target);
 	error = aa_may_signal(cl, tl, sig);
 	aa_put_label(tl);
 	__end_current_label_crit_section(cl);
@@ -1243,8 +1250,8 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 
 	LSM_HOOK_INIT(task_free, apparmor_task_free),
 	LSM_HOOK_INIT(task_alloc, apparmor_task_alloc),
-	LSM_HOOK_INIT(task_getsecid_subj, apparmor_task_getsecid),
-	LSM_HOOK_INIT(task_getsecid_obj, apparmor_task_getsecid),
+	LSM_HOOK_INIT(task_getsecid_subj, apparmor_task_getsecid_subj),
+	LSM_HOOK_INIT(task_getsecid_obj, apparmor_task_getsecid_obj),
 	LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
 	LSM_HOOK_INIT(task_kill, apparmor_task_kill),
 
diff --git a/security/apparmor/task.c b/security/apparmor/task.c
index d17130ee6795d..c03c8e3928055 100644
--- a/security/apparmor/task.c
+++ b/security/apparmor/task.c
@@ -16,17 +16,34 @@
 #include "include/task.h"
 
 /**
- * aa_get_task_label - Get another task's label
+ * aa_get_task_label_subj - Get another task's subjective label
  * @task: task to query  (NOT NULL)
  *
  * Returns: counted reference to @task's label
  */
-struct aa_label *aa_get_task_label(struct task_struct *task)
+struct aa_label *aa_get_task_label_subj(struct task_struct *task)
 {
 	struct aa_label *p;
 
 	rcu_read_lock();
-	p = aa_get_newest_label(__aa_task_raw_label(task));
+	p = aa_get_newest_label(__aa_task_raw_label_subj(task));
+	rcu_read_unlock();
+
+	return p;
+}
+
+/**
+ * aa_get_task_label_obj - Get another task's objective label
+ * @task: task to query  (NOT NULL)
+ *
+ * Returns: counted reference to @task's label
+ */
+struct aa_label *aa_get_task_label_obj(struct task_struct *task)
+{
+	struct aa_label *p;
+
+	rcu_read_lock();
+	p = aa_get_newest_label(__aa_task_raw_label_obj(task));
 	rcu_read_unlock();
 
 	return p;

--
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  parent reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19 23:28 [RFC PATCH 0/4] Split security_task_getsecid() into subj and obj variants Paul Moore
2021-02-19 23:29 ` [RFC PATCH 1/4] lsm: separate security_task_getsecid() into subjective and objective variants Paul Moore
2021-02-20  2:55   ` James Morris
2021-02-20 14:44     ` Paul Moore
2021-03-04 10:04       ` Jeffrey Vander Stoep
2021-03-04 23:43         ` Paul Moore
2021-03-10  8:21           ` Jeffrey Vander Stoep
2021-03-11  1:56             ` Paul Moore
2021-02-21 12:51   ` John Johansen
2021-02-21 22:09     ` Paul Moore
2021-03-04  0:44     ` Paul Moore
2021-03-10  0:28       ` Paul Moore
2021-03-10  3:09         ` John Johansen
2021-02-24 16:49   ` Mimi Zohar
2021-03-08 19:25   ` Richard Guy Briggs
2021-03-10  0:23     ` Paul Moore
2021-03-10  1:03   ` John Johansen
2021-03-11  1:55     ` Paul Moore
2021-02-19 23:29 ` [RFC PATCH 2/4] selinux: clarify task subjective and objective credentials Paul Moore
2021-02-21 12:55   ` John Johansen
2021-03-08 19:26   ` Richard Guy Briggs
2021-03-10  3:05   ` John Johansen
2021-03-11  4:32     ` Paul Moore
2021-03-17 22:56       ` Paul Moore
2021-02-19 23:29 ` [RFC PATCH 3/4] smack: differentiate between subjective and objective task credentials Paul Moore
2021-02-21 12:56   ` John Johansen
2021-03-08 19:26   ` Richard Guy Briggs
2021-03-10  1:04   ` John Johansen
2021-02-19 23:29 ` Paul Moore [this message]
2021-02-21 12:57   ` [RFC PATCH 4/4] apparmor: " John Johansen
2021-02-21 22:12     ` Paul Moore
2021-02-20  1:49 ` [RFC PATCH 0/4] Split security_task_getsecid() into subj and obj variants Casey Schaufler
2021-02-20 14:41   ` Paul Moore
2021-02-22 23:58     ` Casey Schaufler
2021-02-23 14:14       ` Mimi Zohar
2021-02-24  0:03         ` Paul Moore
2021-03-04  0:46       ` Paul Moore
2021-03-04  2:21         ` Casey Schaufler
2021-03-04 23:41           ` Paul Moore

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