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| author | Oleg Nesterov <oleg@redhat.com> | 2013-12-23 17:45:01 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-01-09 12:24:20 -0800 |
| commit | 2b25925431bfedfbd1b234afcadbcdf4f09901f8 (patch) | |
| tree | 9c923c41a91e3a0be26ec58eb0dff090c5aa067d /security | |
| parent | faecbbe4213acc9da2aa44d0577cad1a9f419946 (diff) | |
| download | lwn-2b25925431bfedfbd1b234afcadbcdf4f09901f8.tar.gz lwn-2b25925431bfedfbd1b234afcadbcdf4f09901f8.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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security')
| -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 57a7b362c86d..87c8e20c468a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5454,11 +5454,11 @@ 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, |