From dcb569cf6ac99ca899b8109c128b6ae52477a015 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Tue, 18 Sep 2018 16:09:16 -0700 Subject: 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: Casey Schaufler --- security/smack/smack_lsm.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'security') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 340fc30ad85d..70d3066e69fe 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -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); -- cgit v1.2.1