linux-stable.git/security, branch v5.5.4

selinux: fall back to ref-walk if audit is required

2020-02-14T21:53:07+00:00

commit 0188d5c025ca8fe756ba3193bd7d150139af5a88 upstream.

commit bda0be7ad994 ("security: make inode_follow_link RCU-walk aware")
passed down the rcu flag to the SELinux AVC, but failed to adjust the
test in slow_avc_audit() to also return -ECHILD on LSM_AUDIT_DATA_DENTRY.
Previously, we only returned -ECHILD if generating an audit record with
LSM_AUDIT_DATA_INODE since this was only relevant from inode_permission.
Move the handling of MAY_NOT_BLOCK to avc_audit() and its inlined
equivalent in selinux_inode_permission() immediately after we determine
that audit is required, and always fall back to ref-walk in this case.

Fixes: bda0be7ad994 ("security: make inode_follow_link RCU-walk aware")
Reported-by: Will Deacon 
Suggested-by: Al Viro 
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: fix regression introduced by move_mount(2) syscall

2020-02-14T21:53:06+00:00

commit 98aa00345de54b8340dc2ddcd87f446d33387b5e upstream.

commit 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around")
introduced a new move_mount(2) system call and a corresponding new LSM
security_move_mount hook but did not implement this hook for any existing
LSM.  This creates a regression for SELinux with respect to consistent
checking of mounts; the existing selinux_mount hook checks mounton
permission to the mount point path.  Provide a SELinux hook
implementation for move_mount that applies this same check for
consistency.  In the future we may wish to add a new move_mount
filesystem permission and check as well, but this addresses
the immediate regression.

Fixes: 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around")
Signed-off-by: Stephen Smalley 
Reviewed-by: Ondrej Mosnacek 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: revert "stop passing MAY_NOT_BLOCK to the AVC upon follow_link"

2020-02-14T21:53:06+00:00

commit 1a37079c236d55fb31ebbf4b59945dab8ec8764c upstream.

This reverts commit e46e01eebbbc ("selinux: stop passing MAY_NOT_BLOCK
to the AVC upon follow_link"). The correct fix is to instead fall
back to ref-walk if audit is required irrespective of the specific
audit data type.  This is done in the next commit.

Fixes: e46e01eebbbc ("selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link")
Reported-by: Will Deacon 
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

broken ping to ipv6 linklocal addresses on debian buster

2020-02-11T12:37:16+00:00

commit 87fbfffcc89b92a4281b0aa53bd06af714087889 upstream.

I am seeing ping failures to IPv6 linklocal addresses with Debian
buster. Easiest example to reproduce is:

$ ping -c1 -w1 ff02::1%eth1
connect: Invalid argument

$ ping -c1 -w1 ff02::1%eth1
PING ff02::01%eth1(ff02::1%eth1) 56 data bytes
64 bytes from fe80::e0:f9ff:fe0c:37%eth1: icmp_seq=1 ttl=64 time=0.059 ms

git bisect traced the failure to
commit b9ef5513c99b ("smack: Check address length before reading address family")

Arguably ping is being stupid since the buster version is not setting
the address family properly (ping on stretch for example does):

$ strace -e connect ping6 -c1 -w1 ff02::1%eth1
connect(5, {sa_family=AF_UNSPEC,
sa_data="\4\1\0\0\0\0\377\2\0\0\0\0\0\0\0\0\0\0\0\0\0\1\3\0\0\0"}, 28)
= -1 EINVAL (Invalid argument)

but the command works fine on kernels prior to this commit, so this is
breakage which goes against the Linux paradigm of "don't break userspace"

Cc: stable@vger.kernel.org
Reported-by: David Ahern 
Suggested-by: Tetsuo Handa 
Signed-off-by: Casey Schaufler 
Signed-off-by: Greg Kroah-Hartman 

 security/smack/smack_lsm.c | 41 +++++++++++++++++++----------------------
 security/smack/smack_lsm.c |   41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

tomoyo: Use atomic_t for statistics counter

2020-02-04T18:18:02+00:00

commit a8772fad0172aeae339144598b809fd8d4823331 upstream.

syzbot is reporting that there is a race at tomoyo_stat_update() [1].
Although it is acceptable to fail to track exact number of times policy
was updated, convert to atomic_t because this is not a hot path.

[1] https://syzkaller.appspot.com/bug?id=a4d7b973972eeed410596e6604580e0133b0fc04

Reported-by: syzbot 
Signed-off-by: Tetsuo Handa 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'apparmor-pr-2020-01-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

2020-01-05T03:28:30+00:00

Pull apparmor fixes from John Johansen:

 - performance regression: only get a label reference if the fast path
   check fails

 - fix aa_xattrs_match() may sleep while holding a RCU lock

 - fix bind mounts aborting with -ENOMEM

* tag 'apparmor-pr-2020-01-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
  apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock
  apparmor: only get a label reference if the fast path check fails
  apparmor: fix bind mounts aborting with -ENOMEM

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

2020-01-04T23:56:44+00:00

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

apparmor: only get a label reference if the fast path check fails

2020-01-02T13:31:40+00:00

The common fast path check can be done under rcu_read_lock() and
doesn't need a reference count on the label. Only take a reference
count if entering the slow path.

Fixes reported hackbench regression
  - sha1 79e178a57dae ("Merge tag 'apparmor-pr-2019-12-03' of
    git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor")

  hackbench -l (256000/#grp) -g #grp
   128 groups     19.679 ±0.90%

  - previous sha1 01d1dff64662 ("Merge tag 's390-5.5-2' of
    git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux")

  hackbench -l (256000/#grp) -g #grp
   128 groups     3.1689 ±3.04%

Reported-by: Vincent Guittot 
Tested-by: Vincent Guittot 
Tested-by: Sebastian Andrzej Siewior 
Fixes: bce4e7e9c45e ("apparmor: reduce rcu_read_lock scope for aa_file_perm mediation")
Signed-off-by: John Johansen

apparmor: fix bind mounts aborting with -ENOMEM

2020-01-02T13:31:40+00:00

With commit df323337e507 ("apparmor: Use a memory pool instead per-CPU
caches, 2019-05-03"), AppArmor code was converted to use memory pools. In
that conversion, a bug snuck into the code that polices bind mounts that
causes all bind mounts to fail with -ENOMEM, as we erroneously error out
if `aa_get_buffer` returns a pointer instead of erroring out when it
does _not_ return a valid pointer.

Fix the issue by correctly checking for valid pointers returned by
`aa_get_buffer` to fix bind mounts with AppArmor.

Fixes: df323337e507 ("apparmor: Use a memory pool instead per-CPU caches")
Signed-off-by: Patrick Steinhardt 
Signed-off-by: John Johansen

Merge tag 'tomoyo-fixes-for-5.5' of git://git.osdn.net/gitroot/tomoyo/tomoyo-test1

2019-12-31T18:51:27+00:00

Pull tomoyo fixes from Tetsuo Handa:
 "Two bug fixes:

   - Suppress RCU warning at list_for_each_entry_rcu()

   - Don't use fancy names on sockets"

* tag 'tomoyo-fixes-for-5.5' of git://git.osdn.net/gitroot/tomoyo/tomoyo-test1:
  tomoyo: Suppress RCU warning at list_for_each_entry_rcu().
  tomoyo: Don't use nifty names on sockets.