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| author | Oleg Nesterov <oleg@redhat.com> | 2013-12-23 17:45:01 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-02-15 19:20:15 +0000 |
| commit | 5826e620694c056e27dae2f1e1e31005c93ab7e0 (patch) | |
| tree | 732dc4456289f783edc49d4c7bd2ea33bc991fe9 | |
| parent | 3831c7b4d90558d946d67c83cc04c6eca2a9ef99 (diff) | |
| download | lwn-5826e620694c056e27dae2f1e1e31005c93ab7e0.tar.gz lwn-5826e620694c056e27dae2f1e1e31005c93ab7e0.zip | |
selinux: selinux_setprocattr()->ptrace_parent() needs rcu_read_lock()
commit c0c1439541f5305b57a83d599af32b74182933fe upstream.
selinux_setprocattr() does ptrace_parent(p) under task_lock(p),
but task_struct->alloc_lock doesn't pin ->parent or ->ptrace,
this looks confusing and triggers the "suspicious RCU usage"
warning because ptrace_parent() does rcu_dereference_check().
And in theory this is wrong, spin_lock()->preempt_disable()
doesn't necessarily imply rcu_read_lock() we need to access
the ->parent.
Reported-by: Evan McNabb <emcnabb@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | security/selinux/hooks.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index b910072eaaad..1ae374b2d126 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5374,11 +5374,11 @@ static int selinux_setprocattr(struct task_struct *p, /* Check for ptracing, and update the task SID if ok. Otherwise, leave SID unchanged and fail. */ ptsid = 0; - task_lock(p); + rcu_read_lock(); tracer = ptrace_parent(p); if (tracer) ptsid = task_sid(tracer); - task_unlock(p); + rcu_read_unlock(); if (tracer) { error = avc_has_perm(ptsid, sid, SECCLASS_PROCESS, |