[RFC PATCH 4/4] apparmor: differentiate between subjective and objective task credentials

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(a)paul-moore.com&gt; --- 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;