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authorJohn Johansen <john.johansen@canonical.com>2015-12-17 05:09:10 +0300
committerJohn Johansen <john.johansen@canonical.com>2016-07-12 18:43:10 +0300
commitde7c4cc947f9f56f61520ee7edaf380434a98c8d (patch)
tree8da638b921498bba5fca1fc2b4192166f45700ef /security
parent0b938a2e2cf0b0a2c8bac9769111545aff0fee97 (diff)
downloadlinux-de7c4cc947f9f56f61520ee7edaf380434a98c8d.tar.xz
apparmor: fix refcount race when finding a child profile
When finding a child profile via an rcu critical section, the profile may be put and scheduled for deletion after the child is found but before its refcount is incremented. Protect against this by repeating the lookup if the profiles refcount is 0 and is one its way to deletion. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
Diffstat (limited to 'security')
-rw-r--r--security/apparmor/policy.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index ca402d028db8..780712553651 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -766,7 +766,9 @@ struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
struct aa_profile *profile;
rcu_read_lock();
- profile = aa_get_profile(__find_child(&parent->base.profiles, name));
+ do {
+ profile = __find_child(&parent->base.profiles, name);
+ } while (profile && !aa_get_profile_not0(profile));
rcu_read_unlock();
/* refcount released by caller */