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apparmor: remove the "task" arg from may_change_ptraced_domain()

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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 <oleg@redhat.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
Oleg Nesterov 2013-10-08 05:46:03 -07:00 committed by John Johansen
parent 4a7fc3018f
commit 51775fe736
1 changed files with 6 additions and 8 deletions
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14
security/apparmor/domain.c
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@ -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;