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authorOleg Nesterov <oleg@redhat.com>2013-12-23 17:45:01 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-08 09:42:10 -0800
commit58c2314ac41e8f24a2a594bd866915e38de9648e (patch)
tree25b4928360576d7d6501a1e0d01fcab7e6003226
parent351381d8cea3036cfe021eb29994584d0e5c0e73 (diff)
downloadlinux-linaro-stable-58c2314ac41e8f24a2a594bd866915e38de9648e.tar.gz
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--security/selinux/hooks.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 714eb58b4c1c..43e64768db2c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5445,11 +5445,11 @@ 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,