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authorXiyu Yang <xiyuyang19@fudan.edu.cn>2020-04-20 13:35:28 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-05-27 17:37:37 +0200
commitc7018495028f9cc5585b204e49e540ba8930e211 (patch)
treeceb8f118cd982083f1a229358a6f9f108dbb8fec /security
parentdd73adb161fec02d9303ce98e0e5bf844c5d791e (diff)
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apparmor: Fix aa_label refcnt leak in policy_update
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 <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security')
-rw-r--r--security/apparmor/apparmorfs.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index 0a57d105cc5b..1ec1e928cc09 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -424,7 +424,7 @@ static ssize_t policy_update(u32 mask, const char __user *buf, size_t size,
*/
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, const char __user *buf, size_t size,
error = aa_replace_profiles(ns, label, mask, data);
aa_put_loaddata(data);
}
+end_section:
end_current_label_crit_section(label);
return error;