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Subject[PATCH 4.19 45/81] apparmor: Fix aa_label refcnt leak in policy_update
From: Xiyu Yang <>

commit c6b39f070722ea9963ffe756bfe94e89218c5e63 upstream.

policy_update() invokes begin_current_label_crit_section(), which
returns a reference of the updated aa_label object to "label" with
increased refcount.

When policy_update() returns, "label" becomes invalid, so the refcount
should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
policy_update(). When aa_may_manage_policy() returns not NULL, the
refcnt increased by begin_current_label_crit_section() is not decreased,
causing a refcnt leak.

Fix this issue by jumping to "end_section" label when
aa_may_manage_policy() returns not NULL.

Fixes: 5ac8c355ae00 ("apparmor: allow introspecting the loaded policy pre internal transform")
Signed-off-by: Xiyu Yang <>
Signed-off-by: Xin Tan <>
Signed-off-by: John Johansen <>
Signed-off-by: Greg Kroah-Hartman <>

security/apparmor/apparmorfs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -424,7 +424,7 @@ static ssize_t policy_update(u32 mask, c
error = aa_may_manage_policy(label, ns, mask);
if (error)
- return error;
+ goto end_section;

data = aa_simple_write_to_buffer(buf, size, size, pos);
error = PTR_ERR(data);
@@ -432,6 +432,7 @@ static ssize_t policy_update(u32 mask, c
error = aa_replace_profiles(ns, label, mask, data);

return error;

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