linux-stable.git/security, branch linux-3.18.y Linux kernel stable tree device_cgroup: fix RCU imbalance in error case 2019-04-27T07:30:31+00:00 Jann Horn jannh@google.com 2019-03-19T01:36:59+00:00 73d117dcbb1d7d128f2389b2649698c7424e1e78 commit 0fcc4c8c044e117ac126ab6df4138ea9a67fa2a9 upstream. When dev_exception_add() returns an error (due to a failed memory allocation), make sure that we move the RCU preemption count back to where it was before we were called. We dropped the RCU read lock inside the loop body, so we can't just "break". sparse complains about this, too: $ make -s C=2 security/device_cgroup.o ./include/linux/rcupdate.h:647:9: warning: context imbalance in 'propagate_exception' - unexpected unlock Fixes: d591fb56618f ("device_cgroup: simplify cgroup tree walk in propagate_exception()") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0fcc4c8c044e117ac126ab6df4138ea9a67fa2a9 upstream.

When dev_exception_add() returns an error (due to a failed memory
allocation), make sure that we move the RCU preemption count back to where
it was before we were called. We dropped the RCU read lock inside the loop
body, so we can't just "break".

sparse complains about this, too:

$ make -s C=2 security/device_cgroup.o
./include/linux/rcupdate.h:647:9: warning: context imbalance in
'propagate_exception' - unexpected unlock

Fixes: d591fb56618f ("device_cgroup: simplify cgroup tree walk in propagate_exception()")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
missing barriers in some of unix_sock ->addr and ->path accesses 2019-03-23T07:18:58+00:00 Al Viro viro@zeniv.linux.org.uk 2019-02-15T20:09:35+00:00 10a16ff0ef80eaa7842ccdd4b5a83ec92f804e25 [ Upstream commit ae3b564179bfd06f32d051b9e5d72ce4b2a07c37 ] Several u->addr and u->path users are not holding any locks in common with unix_bind(). unix_state_lock() is useless for those purposes. u->addr is assign-once and *(u->addr) is fully set up by the time we set u->addr (all under unix_table_lock). u->path is also set in the same critical area, also before setting u->addr, and any unix_sock with ->path filled will have non-NULL ->addr. So setting ->addr with smp_store_release() is all we need for those "lockless" users - just have them fetch ->addr with smp_load_acquire() and don't even bother looking at ->path if they see NULL ->addr. Users of ->addr and ->path fall into several classes now: 1) ones that do smp_load_acquire(u->addr) and access *(u->addr) and u->path only if smp_load_acquire() has returned non-NULL. 2) places holding unix_table_lock. These are guaranteed that *(u->addr) is seen fully initialized. If unix_sock is in one of the "bound" chains, so's ->path. 3) unix_sock_destructor() using ->addr is safe. All places that set u->addr are guaranteed to have seen all stores *(u->addr) while holding a reference to u and unix_sock_destructor() is called when (atomic) refcount hits zero. 4) unix_release_sock() using ->path is safe. unix_bind() is serialized wrt unix_release() (normally - by struct file refcount), and for the instances that had ->path set by unix_bind() unix_release_sock() comes from unix_release(), so they are fine. Instances that had it set in unix_stream_connect() either end up attached to a socket (in unix_accept()), in which case the call chain to unix_release_sock() and serialization are the same as in the previous case, or they never get accept'ed and unix_release_sock() is called when the listener is shut down and its queue gets purged. In that case the listener's queue lock provides the barriers needed - unix_stream_connect() shoves our unix_sock into listener's queue under that lock right after having set ->path and eventual unix_release_sock() caller picks them from that queue under the same lock right before calling unix_release_sock(). 5) unix_find_other() use of ->path is pointless, but safe - it happens with successful lookup by (abstract) name, so ->path.dentry is guaranteed to be NULL there. earlier-variant-reviewed-by: "Paul E. McKenney" <paulmck@linux.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit ae3b564179bfd06f32d051b9e5d72ce4b2a07c37 ]

Several u->addr and u->path users are not holding any locks in
common with unix_bind().  unix_state_lock() is useless for those
purposes.

u->addr is assign-once and *(u->addr) is fully set up by the time
we set u->addr (all under unix_table_lock).  u->path is also
set in the same critical area, also before setting u->addr, and
any unix_sock with ->path filled will have non-NULL ->addr.

So setting ->addr with smp_store_release() is all we need for those
"lockless" users - just have them fetch ->addr with smp_load_acquire()
and don't even bother looking at ->path if they see NULL ->addr.

Users of ->addr and ->path fall into several classes now:
    1) ones that do smp_load_acquire(u->addr) and access *(u->addr)
and u->path only if smp_load_acquire() has returned non-NULL.
    2) places holding unix_table_lock.  These are guaranteed that
*(u->addr) is seen fully initialized.  If unix_sock is in one of the
"bound" chains, so's ->path.
    3) unix_sock_destructor() using ->addr is safe.  All places
that set u->addr are guaranteed to have seen all stores *(u->addr)
while holding a reference to u and unix_sock_destructor() is called
when (atomic) refcount hits zero.
    4) unix_release_sock() using ->path is safe.  unix_bind()
is serialized wrt unix_release() (normally - by struct file
refcount), and for the instances that had ->path set by unix_bind()
unix_release_sock() comes from unix_release(), so they are fine.
Instances that had it set in unix_stream_connect() either end up
attached to a socket (in unix_accept()), in which case the call
chain to unix_release_sock() and serialization are the same as in
the previous case, or they never get accept'ed and unix_release_sock()
is called when the listener is shut down and its queue gets purged.
In that case the listener's queue lock provides the barriers needed -
unix_stream_connect() shoves our unix_sock into listener's queue
under that lock right after having set ->path and eventual
unix_release_sock() caller picks them from that queue under the
same lock right before calling unix_release_sock().
    5) unix_find_other() use of ->path is pointless, but safe -
it happens with successful lookup by (abstract) name, so ->path.dentry
is guaranteed to be NULL there.

earlier-variant-reviewed-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
KEYS: always initialize keyring_index_key::desc_len 2019-03-23T07:18:52+00:00 Eric Biggers ebiggers@google.com 2019-02-22T15:36:18+00:00 15ef496907f658c46b747e222c064077950e3cf2 commit ede0fa98a900e657d1fcd80b50920efc896c1a4c upstream. syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() called from construct_alloc_key() during sys_request_key(), because the length of the key description was never calculated. The problem is that we rely on ->desc_len being initialized by search_process_keyrings(), specifically by search_nested_keyrings(). But, if the process isn't subscribed to any keyrings that never happens. Fix it by always initializing keyring_index_key::desc_len as soon as the description is set, like we already do in some places. The following program reproduces the BUG_ON() when it's run as root and no session keyring has been installed. If it doesn't work, try removing pam_keyinit.so from /etc/pam.d/login and rebooting. #include <stdlib.h> #include <unistd.h> #include <keyutils.h> int main(void) { int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); keyctl_setperm(id, KEY_OTH_WRITE); setreuid(5000, 5000); request_key("user", "desc", "", id); } Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: James Morris <james.morris@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ede0fa98a900e657d1fcd80b50920efc896c1a4c upstream.

syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin()
called from construct_alloc_key() during sys_request_key(), because the
length of the key description was never calculated.

The problem is that we rely on ->desc_len being initialized by
search_process_keyrings(), specifically by search_nested_keyrings().
But, if the process isn't subscribed to any keyrings that never happens.

Fix it by always initializing keyring_index_key::desc_len as soon as the
description is set, like we already do in some places.

The following program reproduces the BUG_ON() when it's run as root and
no session keyring has been installed.  If it doesn't work, try removing
pam_keyinit.so from /etc/pam.d/login and rebooting.

    #include <stdlib.h>
    #include <unistd.h>
    #include <keyutils.h>

    int main(void)
    {
            int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING);

            keyctl_setperm(id, KEY_OTH_WRITE);
            setreuid(5000, 5000);
            request_key("user", "desc", "", id);
    }

Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com
Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
KEYS: allow reaching the keys quotas exactly 2019-03-23T07:18:50+00:00 Eric Biggers ebiggers@google.com 2019-02-14T16:20:01+00:00 b4043fbb9960bbf6f565b8fd8bf3564ea9c6dafe commit a08bf91ce28ed3ae7b6fef35d843fef8dc8c2cd9 upstream. If the sysctl 'kernel.keys.maxkeys' is set to some number n, then actually users can only add up to 'n - 1' keys. Likewise for 'kernel.keys.maxbytes' and the root_* versions of these sysctls. But these sysctls are apparently supposed to be *maximums*, as per their names and all documentation I could find -- the keyrings(7) man page, Documentation/security/keys/core.rst, and all the mentions of EDQUOT meaning that the key quota was *exceeded* (as opposed to reached). Thus, fix the code to allow reaching the quotas exactly. Fixes: 0b77f5bfb45c ("keys: make the keyring quotas controllable through /proc/sys") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.morris@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a08bf91ce28ed3ae7b6fef35d843fef8dc8c2cd9 upstream.

If the sysctl 'kernel.keys.maxkeys' is set to some number n, then
actually users can only add up to 'n - 1' keys.  Likewise for
'kernel.keys.maxbytes' and the root_* versions of these sysctls.  But
these sysctls are apparently supposed to be *maximums*, as per their
names and all documentation I could find -- the keyrings(7) man page,
Documentation/security/keys/core.rst, and all the mentions of EDQUOT
meaning that the key quota was *exceeded* (as opposed to reached).

Thus, fix the code to allow reaching the quotas exactly.

Fixes: 0b77f5bfb45c ("keys: make the keyring quotas controllable through /proc/sys")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
smack: fix access permissions for keyring 2019-02-20T09:08:58+00:00 Zoran Markovic zmarkovic@sierrawireless.com 2018-10-17T23:25:44+00:00 e51ff4fd1f0c0c6b91758eb8f01bfa9a610ccd7d [ Upstream commit 5b841bfab695e3b8ae793172a9ff7990f99cc3e2 ] Function smack_key_permission() only issues smack requests for the following operations: - KEY_NEED_READ (issues MAY_READ) - KEY_NEED_WRITE (issues MAY_WRITE) - KEY_NEED_LINK (issues MAY_WRITE) - KEY_NEED_SETATTR (issues MAY_WRITE) A blank smack request is issued in all other cases, resulting in smack access being granted if there is any rule defined between subject and object, or denied with -EACCES otherwise. Request MAY_READ access for KEY_NEED_SEARCH and KEY_NEED_VIEW. Fix the logic in the unlikely case when both MAY_READ and MAY_WRITE are needed. Validate access permission field for valid contents. Signed-off-by: Zoran Markovic <zmarkovic@sierrawireless.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 5b841bfab695e3b8ae793172a9ff7990f99cc3e2 ]

Function smack_key_permission() only issues smack requests for the
following operations:
 - KEY_NEED_READ (issues MAY_READ)
 - KEY_NEED_WRITE (issues MAY_WRITE)
 - KEY_NEED_LINK (issues MAY_WRITE)
 - KEY_NEED_SETATTR (issues MAY_WRITE)
A blank smack request is issued in all other cases, resulting in
smack access being granted if there is any rule defined between
subject and object, or denied with -EACCES otherwise.

Request MAY_READ access for KEY_NEED_SEARCH and KEY_NEED_VIEW.
Fix the logic in the unlikely case when both MAY_READ and
MAY_WRITE are needed. Validate access permission field for valid
contents.

Signed-off-by: Zoran Markovic <zmarkovic@sierrawireless.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
selinux: fix GPF on invalid policy 2019-01-26T08:44:26+00:00 Stephen Smalley sds@tycho.nsa.gov 2019-01-09T15:55:10+00:00 f643372c915bbb9d11787b785890642fce3c1ab2 commit 5b0e7310a2a33c06edc7eb81ffc521af9b2c5610 upstream. levdatum->level can be NULL if we encounter an error while loading the policy during sens_read prior to initializing it. Make sure sens_destroy handles that case correctly. Reported-by: syzbot+6664500f0f18f07a5c0e@syzkaller.appspotmail.com Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5b0e7310a2a33c06edc7eb81ffc521af9b2c5610 upstream.

levdatum->level can be NULL if we encounter an error while loading
the policy during sens_read prior to initializing it.  Make sure
sens_destroy handles that case correctly.

Reported-by: syzbot+6664500f0f18f07a5c0e@syzkaller.appspotmail.com
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Yama: Check for pid death before checking ancestry 2019-01-26T08:44:25+00:00 Kees Cook keescook@chromium.org 2019-01-16T18:31:09+00:00 d90b262c51ce9baa7ec0086a2cc252062a96d606 commit 9474f4e7cd71a633fa1ef93b7daefd44bbdfd482 upstream. It's possible that a pid has died before we take the rcu lock, in which case we can't walk the ancestry list as it may be detached. Instead, check for death first before doing the walk. Reported-by: syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com Fixes: 2d514487faf1 ("security: Yama LSM") Cc: stable@vger.kernel.org Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9474f4e7cd71a633fa1ef93b7daefd44bbdfd482 upstream.

It's possible that a pid has died before we take the rcu lock, in which
case we can't walk the ancestry list as it may be detached. Instead, check
for death first before doing the walk.

Reported-by: syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com
Fixes: 2d514487faf1 ("security: Yama LSM")
Cc: stable@vger.kernel.org
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ima: fix showing large 'violations' or 'runtime_measurements_count' 2018-11-22T06:32:43+00:00 Eric Biggers ebiggers@google.com 2018-09-07T21:33:24+00:00 2d5aa48311da92befed1d23f8290d74e9b6c3672 commit 1e4c8dafbb6bf72fb5eca035b861e39c5896c2b7 upstream. The 12 character temporary buffer is not necessarily long enough to hold a 'long' value. Increase it. Signed-off-by: Eric Biggers <ebiggers@google.com> Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1e4c8dafbb6bf72fb5eca035b861e39c5896c2b7 upstream.

The 12 character temporary buffer is not necessarily long enough to hold
a 'long' value.  Increase it.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
KEYS: put keyring if install_session_keyring_to_cred() fails 2018-11-10T15:39:21+00:00 Eric Biggers ebiggers@google.com 2017-06-08T13:48:03+00:00 7938ba3f9260bfc992762733f37153d6412e3300 [ Upstream commit d636bd9f12a66ea3775c9fabbf3f8e118253467a ] In join_session_keyring(), if install_session_keyring_to_cred() were to fail, we would leak the keyring reference, just like in the bug fixed by commit 23567fd052a9 ("KEYS: Fix keyring ref leak in join_session_keyring()"). Fortunately this cannot happen currently, but we really should be more careful. Do this by adding and using a new error label at which the keyring reference is dropped. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d636bd9f12a66ea3775c9fabbf3f8e118253467a ]

In join_session_keyring(), if install_session_keyring_to_cred() were to
fail, we would leak the keyring reference, just like in the bug fixed by
commit 23567fd052a9 ("KEYS: Fix keyring ref leak in
join_session_keyring()").  Fortunately this cannot happen currently, but
we really should be more careful.  Do this by adding and using a new
error label at which the keyring reference is dropped.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Smack: Mark inode instant in smack_task_to_inode 2018-08-28T05:21:34+00:00 Casey Schaufler casey@schaufler-ca.com 2018-06-22T17:54:45+00:00 f1630f80adfc82cddb9d1a0ba984b619ff38f0ec [ Upstream commit 7b4e88434c4e7982fb053c49657e1c8bbb8692d9 ] Smack: Mark inode instant in smack_task_to_inode /proc clean-up in commit 1bbc55131e59bd099fdc568d3aa0b42634dbd188 resulted in smack_task_to_inode() being called before smack_d_instantiate. This resulted in the smk_inode value being ignored, even while present for files in /proc/self. Marking the inode as instant here fixes that. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <james.morris@microsoft.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 7b4e88434c4e7982fb053c49657e1c8bbb8692d9 ]

Smack: Mark inode instant in smack_task_to_inode

/proc clean-up in commit 1bbc55131e59bd099fdc568d3aa0b42634dbd188
resulted in smack_task_to_inode() being called before smack_d_instantiate.
This resulted in the smk_inode value being ignored, even while present
for files in /proc/self. Marking the inode as instant here fixes that.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>