linux-stable.git/security/apparmor, branch v4.19.129

apparmor: Fix aa_label refcnt leak in policy_update

2020-05-27T15:37:37+00:00

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

apparmor: fix potential label refcnt leak in aa_change_profile

2020-05-27T15:37:37+00:00

commit a0b845ffa0d91855532b50fc040aeb2d8338dca4 upstream.

aa_change_profile() invokes aa_get_current_label(), which returns
a reference of the current task's label.

According to the comment of aa_get_current_label(), the returned
reference must be put with aa_put_label().
However, when the original object pointed by "label" becomes
unreachable because aa_change_profile() returns or a new object
is assigned to "label", reference count increased by
aa_get_current_label() is not decreased, causing a refcnt leak.

Fix this by calling aa_put_label() before aa_change_profile() return
and dropping unnecessary aa_get_current_label().

Fixes: 9fcf78cca198 ("apparmor: update domain transitions that are subsets of confinement at nnp")
Signed-off-by: Xiyu Yang 
Signed-off-by: Xin Tan 
Signed-off-by: John Johansen 
Signed-off-by: Greg Kroah-Hartman

apparmor: Fix use-after-free in aa_audit_rule_init

2020-05-27T15:37:37+00:00

commit c54d481d71c6849e044690d3960aaebc730224cc upstream.

In the implementation of aa_audit_rule_init(), when aa_label_parse()
fails the allocated memory for rule is released using
aa_audit_rule_free(). But after this release, the return statement
tries to access the label field of the rule which results in
use-after-free. Before releasing the rule, copy errNo and return it
after release.

Fixes: 52e8c38001d8 ("apparmor: Fix memory leak of rule on error exit path")
Signed-off-by: Navid Emamdoost 
Signed-off-by: John Johansen 
Signed-off-by: Greg Kroah-Hartman

apparmor: don't try to replace stale label in ptrace access check

2020-01-27T13:49:55+00:00

[ Upstream commit 1f8266ff58840d698a1e96d2274189de1bdf7969 ]

As a comment above begin_current_label_crit_section() explains,
begin_current_label_crit_section() must run in sleepable context because
when label_is_stale() is true, aa_replace_current_label() runs, which uses
prepare_creds(), which can sleep.
Until now, the ptrace access check (which runs with a task lock held)
violated this rule.

Also add a might_sleep() assertion to begin_current_label_crit_section(),
because asserts are less likely to be ignored than comments.

Fixes: b2d09ae449ced ("apparmor: move ptrace checks to using labels")
Signed-off-by: Jann Horn 
Signed-off-by: John Johansen 
Signed-off-by: Sasha Levin

apparmor: Fix network performance issue in aa_label_sk_perm

2020-01-27T13:49:54+00:00

[ Upstream commit 5f997580e8b12b9f585e34cc16304925d26ce49e ]

The netperf benchmark shows a 5.73% reduction in throughput for
small (64 byte) transfers by unconfined tasks.

DEFINE_AUDIT_SK() in aa_label_sk_perm() should not be performed
unconditionally, rather only when the label is confined.

netperf-tcp
                            56974a6fc^              56974a6fc
Min       64         563.48 (   0.00%)      531.17 (  -5.73%)
Min       128       1056.92 (   0.00%)      999.44 (  -5.44%)
Min       256       1945.95 (   0.00%)     1867.97 (  -4.01%)
Min       1024      6761.40 (   0.00%)     6364.23 (  -5.87%)
Min       2048     11110.53 (   0.00%)    10606.20 (  -4.54%)
Min       3312     13692.67 (   0.00%)    13158.41 (  -3.90%)
Min       4096     14926.29 (   0.00%)    14457.46 (  -3.14%)
Min       8192     18399.34 (   0.00%)    18091.65 (  -1.67%)
Min       16384    21384.13 (   0.00%)    21158.05 (  -1.06%)
Hmean     64         564.96 (   0.00%)      534.38 (  -5.41%)
Hmean     128       1064.42 (   0.00%)     1010.12 (  -5.10%)
Hmean     256       1965.85 (   0.00%)     1879.16 (  -4.41%)
Hmean     1024      6839.77 (   0.00%)     6478.70 (  -5.28%)
Hmean     2048     11154.80 (   0.00%)    10671.13 (  -4.34%)
Hmean     3312     13838.12 (   0.00%)    13249.01 (  -4.26%)
Hmean     4096     15009.99 (   0.00%)    14561.36 (  -2.99%)
Hmean     8192     18975.57 (   0.00%)    18326.54 (  -3.42%)
Hmean     16384    21440.44 (   0.00%)    21324.59 (  -0.54%)
Stddev    64           1.24 (   0.00%)        2.85 (-130.64%)
Stddev    128          4.51 (   0.00%)        6.53 ( -44.84%)
Stddev    256         11.67 (   0.00%)        8.50 (  27.16%)
Stddev    1024        48.33 (   0.00%)       75.07 ( -55.34%)
Stddev    2048        54.82 (   0.00%)       65.16 ( -18.86%)
Stddev    3312       153.57 (   0.00%)       56.29 (  63.35%)
Stddev    4096       100.25 (   0.00%)       88.50 (  11.72%)
Stddev    8192       358.13 (   0.00%)      169.99 (  52.54%)
Stddev    16384       43.99 (   0.00%)      141.82 (-222.39%)

Signed-off-by: Tony Jones 
Fixes: 56974a6fcfef ("apparmor: add base infastructure for socket
mediation")
Signed-off-by: John Johansen 
Signed-off-by: Sasha Levin

LSM: generalize flag passing to security_capable

2020-01-23T07:21:29+00:00

[ Upstream commit c1a85a00ea66cb6f0bd0f14e47c28c2b0999799f ]

This patch provides a general mechanism for passing flags to the
security_capable LSM hook. It replaces the specific 'audit' flag that is
used to tell security_capable whether it should log an audit message for
the given capability check. The reason for generalizing this flag
passing is so we can add an additional flag that signifies whether
security_capable is being called by a setid syscall (which is needed by
the proposed SafeSetID LSM).

Signed-off-by: Micah Morton 
Reviewed-by: Kees Cook 
Signed-off-by: James Morris 
Signed-off-by: Sasha Levin

apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock

2020-01-09T09:19:02+00:00

commit 8c62ed27a12c00e3db1c9f04bc0f272bdbb06734 upstream.

aa_xattrs_match() is unfortunately calling vfs_getxattr_alloc() from a
context protected by an rcu_read_lock. This can not be done as
vfs_getxattr_alloc() may sleep regardles of the gfp_t value being
passed to it.

Fix this by breaking the rcu_read_lock on the policy search when the
xattr match feature is requested and restarting the search if a policy
changes occur.

Fixes: 8e51f9087f40 ("apparmor: Add support for attaching profiles via xattr, presence and value")
Reported-by: Jia-Ju Bai 
Reported-by: Al Viro 
Signed-off-by: John Johansen 
Signed-off-by: Greg Kroah-Hartman

apparmor: fix unsigned len comparison with less than zero

2020-01-04T18:13:08+00:00

[ Upstream commit 00e0590dbaec6f1bcaa36a85467d7e3497ced522 ]

The sanity check in macro update_for_len checks to see if len
is less than zero, however, len is a size_t so it can never be
less than zero, so this sanity check is a no-op.  Fix this by
making len a ssize_t so the comparison will work and add ulen
that is a size_t copy of len so that the min() macro won't
throw warnings about comparing different types.

Addresses-Coverity: ("Macro compares unsigned to 0")
Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels")
Signed-off-by: Colin Ian King 
Signed-off-by: John Johansen 
Signed-off-by: Sasha Levin

apparmor: delete the dentry in aafs_remove() to avoid a leak

2019-12-05T08:21:19+00:00

[ Upstream commit 201218e4d3dfa1346e30997f48725acce3f26d01 ]

Although the apparmorfs dentries are always dropped from the dentry cache
when the usage count drops to zero, there is no guarantee that this will
happen in aafs_remove(), as another thread might still be using it. In
this scenario, this means that the dentry will temporarily continue to
appear in the results of lookups, even after the call to aafs_remove().

In the case of removal of a profile - it also causes simple_rmdir()
on the profile directory to fail, as the directory won't be empty until
the usage counts of all child dentries have decreased to zero. This
results in the dentry for the profile directory leaking and appearing
empty in the file system tree forever.

Signed-off-by: Chris Coulson 
Signed-off-by: John Johansen 
Signed-off-by: Sasha Levin

apparmor: reset pos on failure to unpack for various functions

2019-09-16T06:22:16+00:00

[ Upstream commit 156e42996bd84eccb6acf319f19ce0cb140d00e3 ]

Each function that manipulates the aa_ext struct should reset it's "pos"
member on failure. This ensures that, on failure, no changes are made to
the state of the aa_ext struct.

There are paths were elements are optional and the error path is
used to indicate the optional element is not present. This means
instead of just aborting on error the unpack stream can become
unsynchronized on optional elements, if using one of the affected
functions.

Cc: stable@vger.kernel.org
Fixes: 736ec752d95e ("AppArmor: policy routines for loading and unpacking policy")
Signed-off-by: Mike Salvatore 
Signed-off-by: John Johansen 
Signed-off-by: Sasha Levin