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| author | Xiyu Yang <xiyuyang19@fudan.edu.cn> | 2020-04-20 07:35:28 +0200 |
|---|---|---|
| committer | John Johansen <john.johansen@canonical.com> | 2020-05-22 00:25:51 +0200 |
| commit | c6b39f070722ea9963ffe756bfe94e89218c5e63 (patch) | |
| tree | 5c8de2d138cd172138ab19c204884366960a6f55 /security/apparmor | |
| parent | apparmor: fix potential label refcnt leak in aa_change_profile (diff) | |
| download | linux-c6b39f070722ea9963ffe756bfe94e89218c5e63.tar.xz linux-c6b39f070722ea9963ffe756bfe94e89218c5e63.zip | |
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 <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Diffstat (limited to 'security/apparmor')
| -rw-r--r-- | security/apparmor/apparmorfs.c | 3 |
1 files changed, 2 insertions, 1 deletions
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; |