From: Xiyu Yang Date: Mon, 20 Apr 2020 05:35:28 +0000 (+0800) Subject: apparmor: Fix aa_label refcnt leak in policy_update X-Git-Tag: Ubuntu-5.10.0-12.13~2858^2~1 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=c6b39f070722ea9963ffe756bfe94e89218c5e63;p=mirror_ubuntu-hirsute-kernel.git apparmor: Fix aa_label refcnt leak in policy_update 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 --- diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c index 280741fc0f5f..f6a3ecfadf80 100644 --- a/security/apparmor/apparmorfs.c +++ b/security/apparmor/apparmorfs.c @@ -454,7 +454,7 @@ 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); @@ -462,6 +462,7 @@ 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;