Break the per cpu buffer atomic section when creating a new null
complain profile. In learning mode this won't matter and we can
safely re-aquire the buffer.

This fixes the following lockdep BUG trace
   nov. 14 14:09:09 cyclope audit[7152]: AVC apparmor="ALLOWED" operation="exec" profile="/usr/sbin/sssd" name="/usr/sbin/adcli" pid=7152 comm="sssd_be" requested_mask="x" denied_mask="x" fsuid=0 ouid=0 target="/usr/sbin/sssd//null-/usr/sbin/adcli"
    nov. 14 14:09:09 cyclope kernel: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747
    nov. 14 14:09:09 cyclope kernel: in_atomic(): 1, irqs_disabled(): 0, pid: 7152, name: sssd_be
    nov. 14 14:09:09 cyclope kernel: 1 lock held by sssd_be/7152:
    nov. 14 14:09:09 cyclope kernel:  #0:  (&sig->cred_guard_mutex){....}, at: [<ffffffff8182d53e>] prepare_bprm_creds+0x4e/0x100
    nov. 14 14:09:09 cyclope kernel: CPU: 3 PID: 7152 Comm: sssd_be Not tainted 4.14.0prahal+intel #150
    nov. 14 14:09:09 cyclope kernel: Hardware name: LENOVO 20CDCTO1WW/20CDCTO1WW, BIOS GQET53WW (1.33 ) 09/15/2017
    nov. 14 14:09:09 cyclope kernel: Call Trace:
    nov. 14 14:09:09 cyclope kernel:  dump_stack+0xb0/0x135
    nov. 14 14:09:09 cyclope kernel:  ? _atomic_dec_and_lock+0x15b/0x15b
    nov. 14 14:09:09 cyclope kernel:  ? lockdep_print_held_locks+0xc4/0x130
    nov. 14 14:09:09 cyclope kernel:  ___might_sleep+0x29c/0x320
    nov. 14 14:09:09 cyclope kernel:  ? rq_clock+0xf0/0xf0
    nov. 14 14:09:09 cyclope kernel:  ? __kernel_text_address+0xd/0x40
    nov. 14 14:09:09 cyclope kernel:  __might_sleep+0x95/0x190
    nov. 14 14:09:09 cyclope kernel:  ? aa_new_null_profile+0x50a/0x960
    nov. 14 14:09:09 cyclope kernel:  __mutex_lock+0x13e/0x1a20
    nov. 14 14:09:09 cyclope kernel:  ? aa_new_null_profile+0x50a/0x960
    nov. 14 14:09:09 cyclope kernel:  ? save_stack+0x43/0xd0
    nov. 14 14:09:09 cyclope kernel:  ? kmem_cache_alloc_trace+0x13f/0x290
    nov. 14 14:09:09 cyclope kernel:  ? mutex_lock_io_nested+0x1880/0x1880
    nov. 14 14:09:09 cyclope kernel:  ? profile_transition+0x932/0x2d40
    nov. 14 14:09:09 cyclope kernel:  ? apparmor_bprm_set_creds+0x1479/0x1f70
    nov. 14 14:09:09 cyclope kernel:  ? security_bprm_set_creds+0x5a/0x80
    nov. 14 14:09:09 cyclope kernel:  ? prepare_binprm+0x366/0x980
    nov. 14 14:09:09 cyclope kernel:  ? do_execveat_common.isra.30+0x12a9/0x2350
    nov. 14 14:09:09 cyclope kernel:  ? SyS_execve+0x2c/0x40
    nov. 14 14:09:09 cyclope kernel:  ? do_syscall_64+0x228/0x650
    nov. 14 14:09:09 cyclope kernel:  ? entry_SYSCALL64_slow_path+0x25/0x25
    nov. 14 14:09:09 cyclope kernel:  ? deactivate_slab.isra.62+0x49d/0x5e0
    nov. 14 14:09:09 cyclope kernel:  ? save_stack_trace+0x16/0x20
    nov. 14 14:09:09 cyclope kernel:  ? init_object+0x88/0x90
    nov. 14 14:09:09 cyclope kernel:  ? ___slab_alloc+0x520/0x590
    nov. 14 14:09:09 cyclope kernel:  ? ___slab_alloc+0x520/0x590
    nov. 14 14:09:09 cyclope kernel:  ? aa_alloc_proxy+0xab/0x200
    nov. 14 14:09:09 cyclope kernel:  ? lock_downgrade+0x7e0/0x7e0
    nov. 14 14:09:09 cyclope kernel:  ? memcg_kmem_get_cache+0x970/0x970
    nov. 14 14:09:09 cyclope kernel:  ? kasan_unpoison_shadow+0x35/0x50
    nov. 14 14:09:09 cyclope kernel:  ? kasan_unpoison_shadow+0x35/0x50
    nov. 14 14:09:09 cyclope kernel:  ? kasan_kmalloc+0xad/0xe0
    nov. 14 14:09:09 cyclope kernel:  ? aa_alloc_proxy+0xab/0x200
    nov. 14 14:09:09 cyclope kernel:  ? kmem_cache_alloc_trace+0x13f/0x290
    nov. 14 14:09:09 cyclope kernel:  ? aa_alloc_proxy+0xab/0x200
    nov. 14 14:09:09 cyclope kernel:  ? aa_alloc_proxy+0xab/0x200
    nov. 14 14:09:09 cyclope kernel:  ? _raw_spin_unlock+0x22/0x30
    nov. 14 14:09:09 cyclope kernel:  ? vec_find+0xa0/0xa0
    nov. 14 14:09:09 cyclope kernel:  ? aa_label_init+0x6f/0x230
    nov. 14 14:09:09 cyclope kernel:  ? __label_insert+0x3e0/0x3e0
    nov. 14 14:09:09 cyclope kernel:  ? kmem_cache_alloc_trace+0x13f/0x290
    nov. 14 14:09:09 cyclope kernel:  ? aa_alloc_profile+0x58/0x200
    nov. 14 14:09:09 cyclope kernel:  mutex_lock_nested+0x16/0x20
    nov. 14 14:09:09 cyclope kernel:  ? mutex_lock_nested+0x16/0x20
    nov. 14 14:09:09 cyclope kernel:  aa_new_null_profile+0x50a/0x960
    nov. 14 14:09:09 cyclope kernel:  ? aa_fqlookupn_profile+0xdc0/0xdc0
    nov. 14 14:09:09 cyclope kernel:  ? aa_compute_fperms+0x4b5/0x640
    nov. 14 14:09:09 cyclope kernel:  ? disconnect.isra.2+0x1b0/0x1b0
    nov. 14 14:09:09 cyclope kernel:  ? aa_str_perms+0x8d/0xe0
    nov. 14 14:09:09 cyclope kernel:  profile_transition+0x932/0x2d40
    nov. 14 14:09:09 cyclope kernel:  ? up_read+0x1a/0x40
    nov. 14 14:09:09 cyclope kernel:  ? ext4_xattr_get+0x15c/0xaf0 [ext4]
    nov. 14 14:09:09 cyclope kernel:  ? x_table_lookup+0x190/0x190
    nov. 14 14:09:09 cyclope kernel:  ? ext4_xattr_ibody_get+0x590/0x590 [ext4]
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? ext4_xattr_security_get+0x1a/0x20 [ext4]
    nov. 14 14:09:09 cyclope kernel:  ? __vfs_getxattr+0x6d/0xa0
    nov. 14 14:09:09 cyclope kernel:  ? get_vfs_caps_from_disk+0x114/0x720
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? tsc_resume+0x10/0x10
    nov. 14 14:09:09 cyclope kernel:  ? get_vfs_caps_from_disk+0x720/0x720
    nov. 14 14:09:09 cyclope kernel:  ? native_sched_clock_from_tsc+0x201/0x2b0
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock_cpu+0x1b/0x170
    nov. 14 14:09:09 cyclope kernel:  ? find_held_lock+0x3c/0x1e0
    nov. 14 14:09:09 cyclope kernel:  ? rb_insert_color_cached+0x1660/0x1660
    nov. 14 14:09:09 cyclope kernel:  apparmor_bprm_set_creds+0x1479/0x1f70
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? handle_onexec+0x31d0/0x31d0
    nov. 14 14:09:09 cyclope kernel:  ? tsc_resume+0x10/0x10
    nov. 14 14:09:09 cyclope kernel:  ? graph_lock+0xd0/0xd0
    nov. 14 14:09:09 cyclope kernel:  ? tsc_resume+0x10/0x10
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock_cpu+0x1b/0x170
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock+0x9/0x10
    nov. 14 14:09:09 cyclope kernel:  ? sched_clock_cpu+0x1b/0x170
    nov. 14 14:09:09 cyclope kernel:  ? find_held_lock+0x3c/0x1e0
    nov. 14 14:09:09 cyclope kernel:  security_bprm_set_creds+0x5a/0x80
    nov. 14 14:09:09 cyclope kernel:  prepare_binprm+0x366/0x980
    nov. 14 14:09:09 cyclope kernel:  ? install_exec_creds+0x150/0x150
    nov. 14 14:09:09 cyclope kernel:  ? __might_fault+0x89/0xb0
    nov. 14 14:09:09 cyclope kernel:  ? up_read+0x40/0x40
    nov. 14 14:09:09 cyclope kernel:  ? get_user_arg_ptr.isra.18+0x2c/0x70
    nov. 14 14:09:09 cyclope kernel:  ? count.isra.20.constprop.32+0x7c/0xf0
    nov. 14 14:09:09 cyclope kernel:  do_execveat_common.isra.30+0x12a9/0x2350
    nov. 14 14:09:09 cyclope kernel:  ? prepare_bprm_creds+0x100/0x100
    nov. 14 14:09:09 cyclope kernel:  ? _raw_spin_unlock+0x22/0x30
    nov. 14 14:09:09 cyclope kernel:  ? deactivate_slab.isra.62+0x49d/0x5e0
    nov. 14 14:09:09 cyclope kernel:  ? save_stack_trace+0x16/0x20
    nov. 14 14:09:09 cyclope kernel:  ? init_object+0x88/0x90
    nov. 14 14:09:09 cyclope kernel:  ? ___slab_alloc+0x520/0x590
    nov. 14 14:09:09 cyclope kernel:  ? ___slab_alloc+0x520/0x590
    nov. 14 14:09:09 cyclope kernel:  ? kasan_check_write+0x14/0x20
    nov. 14 14:09:09 cyclope kernel:  ? memcg_kmem_get_cache+0x970/0x970
    nov. 14 14:09:09 cyclope kernel:  ? kasan_unpoison_shadow+0x35/0x50
    nov. 14 14:09:09 cyclope kernel:  ? glob_match+0x730/0x730
    nov. 14 14:09:09 cyclope kernel:  ? kmem_cache_alloc+0x225/0x280
    nov. 14 14:09:09 cyclope kernel:  ? getname_flags+0xb8/0x510
    nov. 14 14:09:09 cyclope kernel:  ? mm_fault_error+0x2e0/0x2e0
    nov. 14 14:09:09 cyclope kernel:  ? getname_flags+0xf6/0x510
    nov. 14 14:09:09 cyclope kernel:  ? ptregs_sys_vfork+0x10/0x10
    nov. 14 14:09:09 cyclope kernel:  SyS_execve+0x2c/0x40
    nov. 14 14:09:09 cyclope kernel:  do_syscall_64+0x228/0x650
    nov. 14 14:09:09 cyclope kernel:  ? syscall_return_slowpath+0x2f0/0x2f0
    nov. 14 14:09:09 cyclope kernel:  ? syscall_return_slowpath+0x167/0x2f0
    nov. 14 14:09:09 cyclope kernel:  ? prepare_exit_to_usermode+0x220/0x220
    nov. 14 14:09:09 cyclope kernel:  ? prepare_exit_to_usermode+0xda/0x220
    nov. 14 14:09:09 cyclope kernel:  ? perf_trace_sys_enter+0x1060/0x1060
    nov. 14 14:09:09 cyclope kernel:  ? __put_user_4+0x1c/0x30
    nov. 14 14:09:09 cyclope kernel:  entry_SYSCALL64_slow_path+0x25/0x25
    nov. 14 14:09:09 cyclope kernel: RIP: 0033:0x7f9320f23637
    nov. 14 14:09:09 cyclope kernel: RSP: 002b:00007fff783be338 EFLAGS: 00000202 ORIG_RAX: 000000000000003b
    nov. 14 14:09:09 cyclope kernel: RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9320f23637
    nov. 14 14:09:09 cyclope kernel: RDX: 0000558c35002a70 RSI: 0000558c3505bd10 RDI: 0000558c35018b90
    nov. 14 14:09:09 cyclope kernel: RBP: 0000558c34b63ae8 R08: 0000558c3505bd10 R09: 0000000000000080
    nov. 14 14:09:09 cyclope kernel: R10: 0000000000000095 R11: 0000000000000202 R12: 0000000000000001
    nov. 14 14:09:09 cyclope kernel: R13: 0000558c35018b90 R14: 0000558c3505bd18 R15: 0000558c3505bd10

Fixes: 4227c333 ("apparmor: Move path lookup to using preallocated buffers")
BugLink: http://bugs.launchpad.net/bugs/173228Reported-by: NAlban Browaeys <prahal@yahoo.com>
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

It used to be that unconfined would never attach. However that is not
the case anymore as some special profiles can be marked as unconfined,
that are not the namespaces unconfined profile, and may have an
attachment.

Fixes: f1bd9041 ("apparmor: add the base fns() for domain labels")
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Profiles that have an undecidable overlap in their attachments are
being incorrectly handled. Instead of failing to attach the first one
encountered is being used.

eg.
  profile A /** { .. }
  profile B /*foo { .. }

have an unresolvable longest left attachment, they both have an exact
match on / and then have an overlapping expression that has no clear
winner.

Currently the winner will be the profile that is loaded first which
can result in non-deterministic behavior. Instead in this situation
the exec should fail.

Fixes: 898127c3 ("AppArmor: functions for domain transitions")
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Fixes: d07881d2 ("apparmor: move new_null_profile to after profile lookup fns()")
Reported-by: NSeth Arnold <seth.arnold@canonical.com>
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

The boolean variable 'stop' is being set but never read. This
is a redundant variable and can be removed.

Cleans up clang warning: Value stored to 'stop' is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Bool initializations should use true and false. Bool tests don't need
comparisons.
Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

gcc-4.4 points out suspicious code in compute_mnt_perms, where
the aa_perms structure is only partially initialized before getting
returned:

security/apparmor/mount.c: In function 'compute_mnt_perms':
security/apparmor/mount.c:227: error: 'perms.prompt' is used uninitialized in this function
security/apparmor/mount.c:227: error: 'perms.hide' is used uninitialized in this function
security/apparmor/mount.c:227: error: 'perms.cond' is used uninitialized in this function
security/apparmor/mount.c:227: error: 'perms.complain' is used uninitialized in this function
security/apparmor/mount.c:227: error: 'perms.stop' is used uninitialized in this function
security/apparmor/mount.c:227: error: 'perms.deny' is used uninitialized in this function

Returning or assigning partially initialized structures is a bit tricky,
in particular it is explicitly allowed in c99 to assign a partially
initialized structure to another, as long as only members are read that
have been initialized earlier. Looking at what various compilers do here,
the version that produced the warning copied uninitialized stack data,
while newer versions (and also clang) either set the other members to
zero or don't update the parts of the return buffer that are not modified
in the temporary structure, but they never warn about this.

In case of apparmor, it seems better to be a little safer and always
initialize the aa_perms structure. Most users already do that, this
changes the remaining ones, including the one instance that I got the
warning for.

Fixes: fa488437d0f9 ("apparmor: add mount mediation")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NSeth Arnold <seth.arnold@canonical.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Trivial fix to spelling mistake in comment and also with text in
audit_resource call.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

This reverts commit 651e28c5.

This caused a regression:
 "The specific problem is that dnsmasq refuses to start on openSUSE Leap
  42.2.  The specific cause is that and attempt to open a PF_LOCAL socket
  gets EACCES.  This means that networking doesn't function on a system
  with a 4.14-rc2 system."

Sadly, the developers involved seemed to be in denial for several weeks
about this, delaying the revert.  This has not been a good release for
the security subsystem, and this area needs to change development
practices.
Reported-and-bisected-by: NJames Bottomley <James.Bottomley@hansenpartnership.com>
Tracked-by: NThorsten Leemhuis <regressions@leemhuis.info>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Seth Arnold <seth.arnold@canonical.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The pointer fs_ns is assigned from inode->i_ib->s_user_ns before
a null pointer check on inode, hence if inode is actually null we
will get a null pointer dereference on this assignment. Fix this
by only dereferencing inode after the null pointer check on
inode.

Detected by CoverityScan CID#1455328 ("Dereference before null check")

Fixes: 8db6c34f ("Introduce v3 namespaced file capabilities")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Cc: stable@vger.kernel.org
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

In proc_keys_show(), the key semaphore is not held, so the key ->flags
and ->expiry can be changed concurrently.  We therefore should read them
atomically just once.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Similar to the case for key_validate(), we should load the key ->expiry
once atomically in keyring_search_iterator(), since it can be changed
concurrently with the flags whenever the key semaphore isn't held.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In key_validate(), load the flags and expiry time once atomically, since
these can change concurrently if key_validate() is called without the
key semaphore held.  And we don't want to get inconsistent results if a
variable is referenced multiple times.  For example, key->expiry was
referenced in both 'if (key->expiry)' and in 'if (now.tv_sec >=
key->expiry)', making it theoretically possible to see a spurious
EKEYEXPIRED while the expiration time was being removed, i.e. set to 0.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Currently, when passed a key that already exists, add_key() will call the
key's ->update() method if such exists.  But this is heavily broken in the
case where the key is uninstantiated because it doesn't call
__key_instantiate_and_link().  Consequently, it doesn't do most of the
things that are supposed to happen when the key is instantiated, such as
setting the instantiation state, clearing KEY_FLAG_USER_CONSTRUCT and
awakening tasks waiting on it, and incrementing key->user->nikeys.

It also never takes key_construction_mutex, which means that
->instantiate() can run concurrently with ->update() on the same key.  In
the case of the "user" and "logon" key types this causes a memory leak, at
best.  Maybe even worse, the ->update() methods of the "encrypted" and
"trusted" key types actually just dereference a NULL pointer when passed an
uninstantiated key.

Change key_create_or_update() to wait interruptibly for the key to finish
construction before continuing.

This patch only affects *uninstantiated* keys.  For now we still allow a
negatively instantiated key to be updated (thereby positively
instantiating it), although that's broken too (the next patch fixes it)
and I'm not sure that anyone actually uses that functionality either.

Here is a simple reproducer for the bug using the "encrypted" key type
(requires CONFIG_ENCRYPTED_KEYS=y), though as noted above the bug
pertained to more than just the "encrypted" key type:

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

    int main(void)
    {
        int ringid = keyctl_join_session_keyring(NULL);

        if (fork()) {
            for (;;) {
                const char payload[] = "update user:foo 32";

                usleep(rand() % 10000);
                add_key("encrypted", "desc", payload, sizeof(payload), ringid);
                keyctl_clear(ringid);
            }
        } else {
            for (;;)
                request_key("encrypted", "desc", "callout_info", ringid);
        }
    }

It causes:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
    IP: encrypted_update+0xb0/0x170
    PGD 7a178067 P4D 7a178067 PUD 77269067 PMD 0
    PREEMPT SMP
    CPU: 0 PID: 340 Comm: reproduce Tainted: G      D         4.14.0-rc1-00025-g428490e3 #796
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    task: ffff8a467a39a340 task.stack: ffffb15c40770000
    RIP: 0010:encrypted_update+0xb0/0x170
    RSP: 0018:ffffb15c40773de8 EFLAGS: 00010246
    RAX: 0000000000000000 RBX: ffff8a467a275b00 RCX: 0000000000000000
    RDX: 0000000000000005 RSI: ffff8a467a275b14 RDI: ffffffffb742f303
    RBP: ffffb15c40773e20 R08: 0000000000000000 R09: ffff8a467a275b17
    R10: 0000000000000020 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000000 R14: ffff8a4677057180 R15: ffff8a467a275b0f
    FS:  00007f5d7fb08700(0000) GS:ffff8a467f200000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000018 CR3: 0000000077262005 CR4: 00000000001606f0
    Call Trace:
     key_create_or_update+0x2bc/0x460
     SyS_add_key+0x10c/0x1d0
     entry_SYSCALL_64_fastpath+0x1f/0xbe
    RIP: 0033:0x7f5d7f211259
    RSP: 002b:00007ffed03904c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8
    RAX: ffffffffffffffda RBX: 000000003b2a7955 RCX: 00007f5d7f211259
    RDX: 00000000004009e4 RSI: 00000000004009ff RDI: 0000000000400a04
    RBP: 0000000068db8bad R08: 000000003b2a7955 R09: 0000000000000004
    R10: 000000000000001a R11: 0000000000000246 R12: 0000000000400868
    R13: 00007ffed03905d0 R14: 0000000000000000 R15: 0000000000000000
    Code: 77 28 e8 64 34 1f 00 45 31 c0 31 c9 48 8d 55 c8 48 89 df 48 8d 75 d0 e8 ff f9 ff ff 85 c0 41 89 c4 0f 88 84 00 00 00 4c 8b 7d c8 <49> 8b 75 18 4c 89 ff e8 24 f8 ff ff 85 c0 41 89 c4 78 6d 49 8b
    RIP: encrypted_update+0xb0/0x170 RSP: ffffb15c40773de8
    CR2: 0000000000000018

Cc: <stable@vger.kernel.org> # v2.6.12+
Reported-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Eric Biggers <ebiggers@google.com>

Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection
error into one field such that:

 (1) The instantiation state can be modified/read atomically.

 (2) The error can be accessed atomically with the state.

 (3) The error isn't stored unioned with the payload pointers.

This deals with the problem that the state is spread over three different
objects (two bits and a separate variable) and reading or updating them
atomically isn't practical, given that not only can uninstantiated keys
change into instantiated or rejected keys, but rejected keys can also turn
into instantiated keys - and someone accessing the key might not be using
any locking.

The main side effect of this problem is that what was held in the payload
may change, depending on the state.  For instance, you might observe the
key to be in the rejected state.  You then read the cached error, but if
the key semaphore wasn't locked, the key might've become instantiated
between the two reads - and you might now have something in hand that isn't
actually an error code.

The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error
code if the key is negatively instantiated.  The key_is_instantiated()
function is replaced with key_is_positive() to avoid confusion as negative
keys are also 'instantiated'.

Additionally, barriering is included:

 (1) Order payload-set before state-set during instantiation.

 (2) Order state-read before payload-read when using the key.

Further separate barriering is necessary if RCU is being used to access the
payload content after reading the payload pointers.

Fixes: 146aa8b1 ("KEYS: Merge the type-specific data with the payload data")
Cc: stable@vger.kernel.org # v4.4+
Reported-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NEric Biggers <ebiggers@google.com>

The recent rework introduced a possible randconfig build failure
when CONFIG_CRYPTO configured to only allow modules:

security/keys/big_key.o: In function `big_key_crypt':
big_key.c:(.text+0x29f): undefined reference to `crypto_aead_setkey'
security/keys/big_key.o: In function `big_key_init':
big_key.c:(.init.text+0x1a): undefined reference to `crypto_alloc_aead'
big_key.c:(.init.text+0x45): undefined reference to `crypto_aead_setauthsize'
big_key.c:(.init.text+0x77): undefined reference to `crypto_destroy_tfm'
crypto/gcm.o: In function `gcm_hash_crypt_remain_continue':
gcm.c:(.text+0x167): undefined reference to `crypto_ahash_finup'
crypto/gcm.o: In function `crypto_gcm_exit_tfm':
gcm.c:(.text+0x847): undefined reference to `crypto_destroy_tfm'

When we 'select CRYPTO' like the other users, we always get a
configuration that builds.

Fixes: 428490e3 ("security/keys: rewrite all of big_key crypto")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

A key of type "encrypted" references a "master key" which is used to
encrypt and decrypt the encrypted key's payload.  However, when we
accessed the master key's payload, we failed to handle the case where
the master key has been revoked, which sets the payload pointer to NULL.
Note that request_key() *does* skip revoked keys, but there is still a
window where the key can be revoked before we acquire its semaphore.

Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.

This was an issue for master keys of type "user" only.  Master keys can
also be of type "trusted", but those cannot be revoked.

Fixes: 7e70cb49 ("keys: add new key-type encrypted")
Reviewed-by: NJames Morris <james.l.morris@oracle.com>
Cc: <stable@vger.kernel.org>    [v2.6.38+]
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Safford <safford@us.ibm.com>
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

security_inode_getsecurity() provides the text string value
of a security attribute. It does not provide a "secctx".
The code in xattr_getsecurity() that calls security_inode_getsecurity()
and then calls security_release_secctx() happened to work because
SElinux and Smack treat the attribute and the secctx the same way.
It fails for cap_inode_getsecurity(), because that module has no
secctx that ever needs releasing. It turns out that Smack is the
one that's doing things wrong by not allocating memory when instructed
to do so by the "alloc" parameter.

The fix is simple enough. Change the security_release_secctx() to
kfree() because it isn't a secctx being returned by
security_inode_getsecurity(). Change Smack to allocate the string when
told to do so.

Note: this also fixes memory leaks for LSMs which implement
inode_getsecurity but not release_secctx, such as capabilities.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Reported-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

This started out as just replacing the use of crypto/rng with
get_random_bytes_wait, so that we wouldn't use bad randomness at boot
time. But, upon looking further, it appears that there were even deeper
underlying cryptographic problems, and that this seems to have been
committed with very little crypto review. So, I rewrote the whole thing,
trying to keep to the conventions introduced by the previous author, to
fix these cryptographic flaws.

It makes no sense to seed crypto/rng at boot time and then keep
using it like this, when in fact there's already get_random_bytes_wait,
which can ensure there's enough entropy and be a much more standard way
of generating keys. Since this sensitive material is being stored
untrusted, using ECB and no authentication is simply not okay at all. I
find it surprising and a bit horrifying that this code even made it past
basic crypto review, which perhaps points to some larger issues. This
patch moves from using AES-ECB to using AES-GCM. Since keys are uniquely
generated each time, we can set the nonce to zero. There was also a race
condition in which the same key would be reused at the same time in
different threads. A mutex fixes this issue now.

So, to summarize, this commit fixes the following vulnerabilities:

  * Low entropy key generation, allowing an attacker to potentially
    guess or predict keys.
  * Unauthenticated encryption, allowing an attacker to modify the
    cipher text in particular ways in order to manipulate the plaintext,
    which is is even more frightening considering the next point.
  * Use of ECB mode, allowing an attacker to trivially swap blocks or
    compare identical plaintext blocks.
  * Key re-use.
  * Faulty memory zeroing.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: NEric Biggers <ebiggers3@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: security@kernel.org
Cc: stable@vger.kernel.org

Error paths forgot to zero out sensitive material, so this patch changes
some kfrees into a kzfrees.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NEric Biggers <ebiggers3@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: security@kernel.org
Cc: stable@vger.kernel.org

kmemdup() is preferred to kmalloc() followed by memcpy().
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

When checking for permission to view keys whilst reading from
/proc/keys, we should use the credentials with which the /proc/keys file
was opened.  This is because, in a classic type of exploit, it can be
possible to bypass checks for the *current* credentials by passing the
file descriptor to a suid program.

Following commit 34dbbcdb ("Make file credentials available to the
seqfile interfaces") we can finally fix it.  So let's do it.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In key_user_lookup(), if there is no key_user for the given uid, we drop
key_user_lock, allocate a new key_user, and search the tree again.  But
we failed to set 'parent' to NULL at the beginning of the second search.
If the tree were to be empty for the second search, the insertion would
be done with an invalid 'parent', scribbling over freed memory.

Fortunately this can't actually happen currently because the tree always
contains at least the root_key_user.  But it still should be fixed to
make the code more robust.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Because keyctl_read_key() looks up the key with no permissions
requested, it may find a negatively instantiated key.  If the key is
also possessed, we went ahead and called ->read() on the key.  But the
key payload will actually contain the ->reject_error rather than the
normal payload.  Thus, the kernel oopses trying to read the
user_key_payload from memory address (int)-ENOKEY = 0x00000000ffffff82.

Fortunately the payload data is stored inline, so it shouldn't be
possible to abuse this as an arbitrary memory read primitive...

Reproducer:
    keyctl new_session
    keyctl request2 user desc '' @s
    keyctl read $(keyctl show | awk '/user: desc/ {print $1}')

It causes a crash like the following:
     BUG: unable to handle kernel paging request at 00000000ffffff92
     IP: user_read+0x33/0xa0
     PGD 36a54067 P4D 36a54067 PUD 0
     Oops: 0000 [#1] SMP
     CPU: 0 PID: 211 Comm: keyctl Not tainted 4.14.0-rc1 #337
     Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
     task: ffff90aa3b74c3c0 task.stack: ffff9878c0478000
     RIP: 0010:user_read+0x33/0xa0
     RSP: 0018:ffff9878c047bee8 EFLAGS: 00010246
     RAX: 0000000000000001 RBX: ffff90aa3d7da340 RCX: 0000000000000017
     RDX: 0000000000000000 RSI: 00000000ffffff82 RDI: ffff90aa3d7da340
     RBP: ffff9878c047bf00 R08: 00000024f95da94f R09: 0000000000000000
     R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
     R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
     FS:  00007f58ece69740(0000) GS:ffff90aa3e200000(0000) knlGS:0000000000000000
     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
     CR2: 00000000ffffff92 CR3: 0000000036adc001 CR4: 00000000003606f0
     Call Trace:
      keyctl_read_key+0xac/0xe0
      SyS_keyctl+0x99/0x120
      entry_SYSCALL_64_fastpath+0x1f/0xbe
     RIP: 0033:0x7f58ec787bb9
     RSP: 002b:00007ffc8d401678 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa
     RAX: ffffffffffffffda RBX: 00007ffc8d402800 RCX: 00007f58ec787bb9
     RDX: 0000000000000000 RSI: 00000000174a63ac RDI: 000000000000000b
     RBP: 0000000000000004 R08: 00007ffc8d402809 R09: 0000000000000020
     R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffc8d402800
     R13: 00007ffc8d4016e0 R14: 0000000000000000 R15: 0000000000000000
     Code: e5 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb e8 a4 b4 ad ff 85 c0 74 09 80 3d b9 4c 96 00 00 74 43 48 8b b3 20 01 00 00 4d 85 ed <0f> b7 5e 10 74 29 4d 85 e4 74 24 4c 39 e3 4c 89 e2 4c 89 ef 48
     RIP: user_read+0x33/0xa0 RSP: ffff9878c047bee8
     CR2: 00000000ffffff92

Fixes: 61ea0c0b ("KEYS: Skip key state checks when checking for possession")
Cc: <stable@vger.kernel.org>	[v3.13+]
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

It was possible for an unprivileged user to create the user and user
session keyrings for another user.  For example:

    sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u
                           keyctl add keyring _uid_ses.4000 "" @u
                           sleep 15' &
    sleep 1
    sudo -u '#4000' keyctl describe @u
    sudo -u '#4000' keyctl describe @us

This is problematic because these "fake" keyrings won't have the right
permissions.  In particular, the user who created them first will own
them and will have full access to them via the possessor permissions,
which can be used to compromise the security of a user's keys:

    -4: alswrv-----v------------  3000     0 keyring: _uid.4000
    -5: alswrv-----v------------  3000     0 keyring: _uid_ses.4000

Fix it by marking user and user session keyrings with a flag
KEY_FLAG_UID_KEYRING.  Then, when searching for a user or user session
keyring by name, skip all keyrings that don't have the flag set.

Fixes: 69664cf1 ("keys: don't generate user and user session keyrings unless they're accessed")
Cc: <stable@vger.kernel.org>	[v2.6.26+]
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Userspace can call keyctl_read() on a keyring to get the list of IDs of
keys in the keyring.  But if the user-supplied buffer is too small, the
kernel would write the full list anyway --- which will corrupt whatever
userspace memory happened to be past the end of the buffer.  Fix it by
only filling the space that is available.

Fixes: b2a4df20 ("KEYS: Expand the capacity of a keyring")
Cc: <stable@vger.kernel.org>	[v3.13+]
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In keyctl_read_key(), if key_permission() were to return an error code
other than EACCES, we would leak a the reference to the key.  This can't
actually happen currently because key_permission() can only return an
error code other than EACCES if security_key_permission() does, only
SELinux and Smack implement that hook, and neither can return an error
code other than EACCES.  But it should still be fixed, as it is a bug
waiting to happen.

Fixes: 29db9190 ("[PATCH] Keys: Add LSM hooks for key management [try #3]")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In keyctl_assume_authority(), if keyctl_change_reqkey_auth() were to
fail, we would leak the reference to the 'authkey'.  Currently this can
only happen if prepare_creds() fails to allocate memory.  But it still
should be fixed, as it is a more severe bug waiting to happen.

This patch also moves the read of 'authkey->serial' to before the
reference to the authkey is dropped.  Doing the read after dropping the
reference is very fragile because it assumes we still hold another
reference to the key.  (Which we do, in current->cred->request_key_auth,
but there's no reason not to write it in the "obviously correct" way.)

Fixes: d84f4f99 ("CRED: Inaugurate COW credentials")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

If key_instantiate_and_link() were to fail (which fortunately isn't
possible currently), the call to key_revoke(authkey) would crash with a
NULL pointer dereference in request_key_auth_revoke() because the key
has not yet been instantiated.

Fix this by removing the call to key_revoke().  key_put() is sufficient,
as it's not possible for an uninstantiated authkey to have been used for
anything yet.

Fixes: b5f545c8 ("[PATCH] keys: Permit running process to instantiate keys")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In request_key_auth_new(), if key_alloc() or key_instantiate_and_link()
were to fail, we would leak a reference to the 'struct cred'.  Currently
this can only happen if key_alloc() fails to allocate memory.  But it
still should be fixed, as it is a more severe bug waiting to happen.

Fix it by cleaning things up to use a helper function which frees a
'struct request_key_auth' correctly.

Fixes: d84f4f99 ("CRED: Inaugurate COW credentials")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

cap_inode_need_killpriv returns 1 if security.capability exists and
has a value and inode_killpriv() is required, 0 otherwise. Fix the
description of the return value to reflect this.
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

The DAC access permissions for several apparmorfs files are wrong.

.access - needs to be writable by all tasks to perform queries
the others in the set only provide a read fn so should be read only.

With policy namespace virtualization all apparmor needs to control
the permission and visibility checks directly which means DAC
access has to be allowed for all user, group, and other.

BugLink: http://bugs.launchpad.net/bugs/1713103
Fixes: c97204ba ("apparmor: rename apparmor file fns and data to indicate use")
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

  In file included from security/apparmor/ipc.c:23:0:
  security/apparmor/include/sig_names.h:26:3: error: 'SIGSTKFLT' undeclared here (not in a function)
    [SIGSTKFLT] = 16, /* -, 16, - */
     ^
  security/apparmor/include/sig_names.h:26:3: error: array index in initializer not of integer type
  security/apparmor/include/sig_names.h:26:3: note: (near initialization for 'sig_map')
  security/apparmor/include/sig_names.h:51:3: error: 'SIGUNUSED' undeclared here (not in a function)
    [SIGUNUSED] = 34, /* -, 31, - */
     ^
  security/apparmor/include/sig_names.h:51:3: error: array index in initializer not of integer type
  security/apparmor/include/sig_names.h:51:3: note: (near initialization for 'sig_map')
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Fixes: c6bf1adaecaa ("apparmor: add the ability to mediate signals")
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

sparse reports

poisoning the proxy->label before freeing the struct is resulting in
a sparse build warning.
../security/apparmor/label.c:52:30: warning: incorrect type in assignment (different address spaces)
../security/apparmor/label.c:52:30:    expected struct aa_label [noderef] <asn:4>*label
../security/apparmor/label.c:52:30:    got struct aa_label *<noident>

fix with RCU_INIT_POINTER as this is one of those cases where
rcu_assign_pointer() is not needed.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Generally unconfined has early bailout tests and does not need the
dfas initialized, however if an early bailout test is ever missed
it will result in an oops.

Be defensive and initialize the unconfined profile to have null dfas
(no permission) so if an early bailout test is missed we fail
closed (no perms granted) instead of oopsing.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

There is a race when null- profile is being created between the
initial lookup/creation of the profile and lock/addition of the
profile. This could result in multiple version of a profile being
added to the list which need to be removed/replaced.

Since these are learning profile their is no affect on mediation.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

new_null_profile will need to use some of the profile lookup fns()
so move instead of doing forward fn declarations.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Provide a basic mediation of sockets. This is not a full net mediation
but just whether a spcific family of socket can be used by an
application, along with setting up some basic infrastructure for
network mediation to follow.

the user space rule hav the basic form of
  NETWORK RULE = [ QUALIFIERS ] 'network' [ DOMAIN ]
                 [ TYPE | PROTOCOL ]

  DOMAIN = ( 'inet' | 'ax25' | 'ipx' | 'appletalk' | 'netrom' |
             'bridge' | 'atmpvc' | 'x25' | 'inet6' | 'rose' |
	     'netbeui' | 'security' | 'key' | 'packet' | 'ash' |
	     'econet' | 'atmsvc' | 'sna' | 'irda' | 'pppox' |
	     'wanpipe' | 'bluetooth' | 'netlink' | 'unix' | 'rds' |
	     'llc' | 'can' | 'tipc' | 'iucv' | 'rxrpc' | 'isdn' |
	     'phonet' | 'ieee802154' | 'caif' | 'alg' | 'nfc' |
	     'vsock' | 'mpls' | 'ib' | 'kcm' ) ','

  TYPE = ( 'stream' | 'dgram' | 'seqpacket' |  'rdm' | 'raw' |
           'packet' )

  PROTOCOL = ( 'tcp' | 'udp' | 'icmp' )

eg.
  network,
  network inet,
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NSeth Arnold <seth.arnold@canonical.com>

Signed-off-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NSeth Arnold <seth.arnold@canonical.com>

Switch unpack auditing to using the generic name field in the audit
struct and make it so we can start adding new info messages about
why an unpack failed.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NSeth Arnold <seth.arnold@canonical.com>