apparmor: Fix aa_label refcnt leak in policy_update
commit5.4-rM2-2.2.x-imx-squashedc6b39f0707
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:5ac8c355ae
("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>
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054934aa9f
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870a45e0b5
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@ -424,7 +424,7 @@ static ssize_t policy_update(u32 mask, const char __user *buf, size_t size,
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*/
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error = aa_may_manage_policy(label, ns, mask);
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if (error)
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return error;
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goto end_section;
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data = aa_simple_write_to_buffer(buf, size, size, pos);
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error = PTR_ERR(data);
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@ -432,6 +432,7 @@ static ssize_t policy_update(u32 mask, const char __user *buf, size_t size,
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error = aa_replace_profiles(ns, label, mask, data);
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aa_put_loaddata(data);
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}
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end_section:
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end_current_label_crit_section(label);
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return error;
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