Commit dcb569cf authored by Casey Schaufler's avatar Casey Schaufler
Browse files

Smack: ptrace capability use fixes 



This fixes a pair of problems in the Smack ptrace checks
related to checking capabilities. In both cases, as reported
by Lukasz Pawelczyk, the raw capability calls are used rather
than the Smack wrapper that check addition restrictions.
In one case, as reported by Jann Horn, the wrong task is being
checked for capabilities.

Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
parent 76c9805b

security/smack/smack_lsm.c

+10 −3
Original line number Diff line number Diff line
@@ -421,6 +421,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer, 
	struct smk_audit_info ad, *saip = NULL;

	struct task_smack *tsp;

	struct smack_known *tracer_known;

	const struct cred *tracercred;



	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {

		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
@@ -429,7 +430,8 @@ static int smk_ptrace_rule_check(struct task_struct *tracer, 
	}



	rcu_read_lock();

	tsp = __task_cred(tracer)->security;

	tracercred = __task_cred(tracer);

	tsp = tracercred->security;

	tracer_known = smk_of_task(tsp);



	if ((mode & PTRACE_MODE_ATTACH) &&
@@ -439,7 +441,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer, 
			rc = 0;

		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)

			rc = -EACCES;

		else if (capable(CAP_SYS_PTRACE))

		else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))

			rc = 0;

		else

			rc = -EACCES;
@@ -1841,6 +1843,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk, 
{

	struct smack_known *skp;

	struct smack_known *tkp = smk_of_task(tsk->cred->security);

	const struct cred *tcred;

	struct file *file;

	int rc;

	struct smk_audit_info ad;
@@ -1854,8 +1857,12 @@ static int smack_file_send_sigiotask(struct task_struct *tsk, 
	skp = file->f_security;

	rc = smk_access(skp, tkp, MAY_DELIVER, NULL);

	rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);

	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))



	rcu_read_lock();

	tcred = __task_cred(tsk);

	if (rc != 0 && smack_privileged_cred(CAP_MAC_OVERRIDE, tcred))

		rc = 0;

	rcu_read_unlock();



	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);

	smk_ad_setfield_u_tsk(&ad, tsk);

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