Unless task == current ptrace_parent(task) is not safe even under
rcu_read_lock() and most of the current users are not right.
So may_change_ptraced_domain(task) looks wrong as well. However it
is always called with task == current so the code is actually fine.
Remove this argument to make this fact clear.
Note: perhaps we should simply kill ptrace_parent(), it buys almost
nothing. And it is obviously racy, perhaps this should be fixed.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
security/apparmor/domain.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 26c607c..8423558 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -50,23 +50,21 @@ void aa_free_domain_entries(struct aa_domain *domain)
/**
* may_change_ptraced_domain - check if can change profile on ptraced task
- * @task: task we want to change profile of (NOT NULL)
* @to_profile: profile to change to (NOT NULL)
*
- * Check if the task is ptraced and if so if the tracing task is allowed
+ * Check if current is ptraced and if so if the tracing task is allowed
* to trace the new domain
*
* Returns: %0 or error if change not allowed
*/
-static int may_change_ptraced_domain(struct task_struct *task,
- struct aa_profile *to_profile)
+static int may_change_ptraced_domain(struct aa_profile *to_profile)
{
struct task_struct *tracer;
struct aa_profile *tracerp = NULL;
int error = 0;
rcu_read_lock();
- tracer = ptrace_parent(task);
+ tracer = ptrace_parent(current);
if (tracer)
/* released below */
tracerp = aa_get_task_profile(tracer);
@@ -477,7 +475,7 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
}
if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
- error = may_change_ptraced_domain(current, new_profile);
+ error = may_change_ptraced_domain(new_profile);
if (error) {
aa_put_profile(new_profile);
goto audit;
@@ -690,7 +688,7 @@ int aa_change_hat(const char *hats[], int count, u64 token,
bool permtest)
}
}
- error = may_change_ptraced_domain(current, hat);
+ error = may_change_ptraced_domain(hat);
if (error) {
info = "ptraced";
error = -EPERM;
@@ -829,7 +827,7 @@ int aa_change_profile(const char *ns_name, const char
*hname, bool onexec,
}
/* check if tracing task is allowed to trace target domain */
- error = may_change_ptraced_domain(current, target);
+ error = may_change_ptraced_domain(target);
if (error) {
info = "ptrace prevents transition";
goto audit;
--
1.5.5.1
--
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