Commit Graph

2747 Commits

Author SHA1 Message Date
Mimi Zohar
76bda31c54 ima: relax requiring a file signature for new files with zero length
[ Upstream commit b7e27bc1d42e8e0cc58b602b529c25cd0071b336 ]

Custom policies can require file signatures based on LSM labels.  These
files are normally created and only afterwards labeled, requiring them
to be signed.

Instead of requiring file signatures based on LSM labels, entire
filesystems could require file signatures.  In this case, we need the
ability of writing new files without requiring file signatures.

The definition of a "new" file was originally defined as any file with
a length of zero.  Subsequent patches redefined a "new" file to be based
on the FILE_CREATE open flag.  By combining the open flag with a file
size of zero, this patch relaxes the file signature requirement.

Fixes: 1ac202e978e1 ima: accept previously set IMA_NEW_FILE
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-22 09:23:30 +01:00
John Johansen
5f540051a2 apparmor: Make path_max parameter readonly
[ Upstream commit 622f6e3265707ebf02ba776ac6e68003bcc31213 ]

The path_max parameter determines the max size of buffers allocated
but it should  not be setable at run time. If can be used to cause an
oops

root@ubuntu:~# echo 16777216 > /sys/module/apparmor/parameters/path_max
root@ubuntu:~# cat /sys/module/apparmor/parameters/path_max
Killed

[  122.141911] BUG: unable to handle kernel paging request at ffff880080945fff
[  122.143497] IP: [<ffffffff81228844>] d_absolute_path+0x44/0xa0
[  122.144742] PGD 220c067 PUD 0
[  122.145453] Oops: 0002 [#1] SMP
[  122.146204] Modules linked in: vmw_vsock_vmci_transport vsock ppdev vmw_balloon snd_ens1371 btusb snd_ac97_codec gameport snd_rawmidi btrtl snd_seq_device ac97_bus btbcm btintel snd_pcm input_leds bluetooth snd_timer snd joydev soundcore serio_raw coretemp shpchp nfit parport_pc i2c_piix4 8250_fintek vmw_vmci parport mac_hid ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic usbhid hid crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd vmwgfx psmouse mptspi ttm mptscsih drm_kms_helper mptbase syscopyarea scsi_transport_spi sysfillrect
[  122.163365]  ahci sysimgblt e1000 fb_sys_fops libahci drm pata_acpi fjes
[  122.164747] CPU: 3 PID: 1501 Comm: bash Not tainted 4.4.0-59-generic #80-Ubuntu
[  122.166250] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015
[  122.168611] task: ffff88003496aa00 ti: ffff880076474000 task.ti: ffff880076474000
[  122.170018] RIP: 0010:[<ffffffff81228844>]  [<ffffffff81228844>] d_absolute_path+0x44/0xa0
[  122.171525] RSP: 0018:ffff880076477b90  EFLAGS: 00010206
[  122.172462] RAX: ffff880080945fff RBX: 0000000000000000 RCX: 0000000001000000
[  122.173709] RDX: 0000000000ffffff RSI: ffff880080946000 RDI: ffff8800348a1010
[  122.174978] RBP: ffff880076477bb8 R08: ffff880076477c80 R09: 0000000000000000
[  122.176227] R10: 00007ffffffff000 R11: ffff88007f946000 R12: ffff88007f946000
[  122.177496] R13: ffff880076477c80 R14: ffff8800348a1010 R15: ffff8800348a2400
[  122.178745] FS:  00007fd459eb4700(0000) GS:ffff88007b6c0000(0000) knlGS:0000000000000000
[  122.180176] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  122.181186] CR2: ffff880080945fff CR3: 0000000073422000 CR4: 00000000001406e0
[  122.182469] Stack:
[  122.182843]  00ffffff00000001 ffff880080946000 0000000000000000 0000000000000000
[  122.184409]  00000000570f789c ffff880076477c30 ffffffff81385671 ffff88007a2e7a58
[  122.185810]  0000000000000000 ffff880076477c88 01000000008a1000 0000000000000000
[  122.187231] Call Trace:
[  122.187680]  [<ffffffff81385671>] aa_path_name+0x81/0x370
[  122.188637]  [<ffffffff813875dd>] profile_transition+0xbd/0xb80
[  122.190181]  [<ffffffff811af9bc>] ? zone_statistics+0x7c/0xa0
[  122.191674]  [<ffffffff81389b20>] apparmor_bprm_set_creds+0x9b0/0xac0
[  122.193288]  [<ffffffff812e1971>] ? ext4_xattr_get+0x81/0x220
[  122.194793]  [<ffffffff812e800c>] ? ext4_xattr_security_get+0x1c/0x30
[  122.196392]  [<ffffffff813449b9>] ? get_vfs_caps_from_disk+0x69/0x110
[  122.198004]  [<ffffffff81232d4f>] ? mnt_may_suid+0x3f/0x50
[  122.199737]  [<ffffffff81344b03>] ? cap_bprm_set_creds+0xa3/0x600
[  122.201377]  [<ffffffff81346e53>] security_bprm_set_creds+0x33/0x50
[  122.203024]  [<ffffffff81214ce5>] prepare_binprm+0x85/0x190
[  122.204515]  [<ffffffff81216545>] do_execveat_common.isra.33+0x485/0x710
[  122.206200]  [<ffffffff81216a6a>] SyS_execve+0x3a/0x50
[  122.207615]  [<ffffffff81838795>] stub_execve+0x5/0x5
[  122.208978]  [<ffffffff818384f2>] ? entry_SYSCALL_64_fastpath+0x16/0x71
[  122.210615] Code: f8 31 c0 48 63 c2 83 ea 01 48 c7 45 e8 00 00 00 00 48 01 c6 85 d2 48 c7 45 f0 00 00 00 00 48 89 75 e0 89 55 dc 78 0c 48 8d 46 ff <c6> 46 ff 00 48 89 45 e0 48 8d 55 e0 48 8d 4d dc 48 8d 75 e8 e8
[  122.217320] RIP  [<ffffffff81228844>] d_absolute_path+0x44/0xa0
[  122.218860]  RSP <ffff880076477b90>
[  122.219919] CR2: ffff880080945fff
[  122.220936] ---[ end trace 506cdbd85eb6c55e ]---

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-22 09:23:24 +01:00
Alexander Potapenko
89aadbc66e selinux: check for address length in selinux_socket_bind()
[ Upstream commit e2f586bd83177d22072b275edd4b8b872daba924 ]

KMSAN (KernelMemorySanitizer, a new error detection tool) reports use of
uninitialized memory in selinux_socket_bind():

==================================================================
BUG: KMSAN: use of unitialized memory
inter: 0
CPU: 3 PID: 1074 Comm: packet2 Tainted: G    B           4.8.0-rc6+ #1916
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 0000000000000000 ffff8800882ffb08 ffffffff825759c8 ffff8800882ffa48
 ffffffff818bf551 ffffffff85bab870 0000000000000092 ffffffff85bab550
 0000000000000000 0000000000000092 00000000bb0009bb 0000000000000002
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff825759c8>] dump_stack+0x238/0x290 lib/dump_stack.c:51
 [<ffffffff818bdee6>] kmsan_report+0x276/0x2e0 mm/kmsan/kmsan.c:1008
 [<ffffffff818bf0fb>] __msan_warning+0x5b/0xb0 mm/kmsan/kmsan_instr.c:424
 [<ffffffff822dae71>] selinux_socket_bind+0xf41/0x1080 security/selinux/hooks.c:4288
 [<ffffffff8229357c>] security_socket_bind+0x1ec/0x240 security/security.c:1240
 [<ffffffff84265d98>] SYSC_bind+0x358/0x5f0 net/socket.c:1366
 [<ffffffff84265a22>] SyS_bind+0x82/0xa0 net/socket.c:1356
 [<ffffffff81005678>] do_syscall_64+0x58/0x70 arch/x86/entry/common.c:292
 [<ffffffff8518217c>] entry_SYSCALL64_slow_path+0x25/0x25 arch/x86/entry/entry_64.o:?
chained origin: 00000000ba6009bb
 [<ffffffff810bb7a7>] save_stack_trace+0x27/0x50 arch/x86/kernel/stacktrace.c:67
 [<     inline     >] kmsan_save_stack_with_flags mm/kmsan/kmsan.c:322
 [<     inline     >] kmsan_save_stack mm/kmsan/kmsan.c:337
 [<ffffffff818bd2b8>] kmsan_internal_chain_origin+0x118/0x1e0 mm/kmsan/kmsan.c:530
 [<ffffffff818bf033>] __msan_set_alloca_origin4+0xc3/0x130 mm/kmsan/kmsan_instr.c:380
 [<ffffffff84265b69>] SYSC_bind+0x129/0x5f0 net/socket.c:1356
 [<ffffffff84265a22>] SyS_bind+0x82/0xa0 net/socket.c:1356
 [<ffffffff81005678>] do_syscall_64+0x58/0x70 arch/x86/entry/common.c:292
 [<ffffffff8518217c>] return_from_SYSCALL_64+0x0/0x6a arch/x86/entry/entry_64.o:?
origin description: ----address@SYSC_bind (origin=00000000b8c00900)
==================================================================

(the line numbers are relative to 4.8-rc6, but the bug persists upstream)

, when I run the following program as root:

=======================================================
  #include <string.h>
  #include <sys/socket.h>
  #include <netinet/in.h>

  int main(int argc, char *argv[]) {
    struct sockaddr addr;
    int size = 0;
    if (argc > 1) {
      size = atoi(argv[1]);
    }
    memset(&addr, 0, sizeof(addr));
    int fd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
    bind(fd, &addr, size);
    return 0;
  }
=======================================================

(for different values of |size| other error reports are printed).

This happens because bind() unconditionally copies |size| bytes of
|addr| to the kernel, leaving the rest uninitialized. Then
security_socket_bind() reads the IP address bytes, including the
uninitialized ones, to determine the port, or e.g. pass them further to
sel_netnode_find(), which uses them to calculate a hash.

Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
[PM: fixed some whitespace damage]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-22 09:23:20 +01:00
Paul Moore
002924ab7b selinux: skip bounded transition processing if the policy isn't loaded
commit 4b14752ec4e0d87126e636384cf37c8dd9df157c upstream.

We can't do anything reasonable in security_bounded_transition() if we
don't have a policy loaded, and in fact we could run into problems
with some of the code inside expecting a policy.  Fix these problems
like we do many others in security/selinux/ss/services.c by checking
to see if the policy is loaded (ss_initialized) and returning quickly
if it isn't.

Reported-by: syzbot <syzkaller-bugs@googlegroups.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-25 11:03:36 +01:00
Paul Moore
d6233121d5 selinux: ensure the context is NUL terminated in security_context_to_sid_core()
commit ef28df55ac27e1e5cd122e19fa311d886d47a756 upstream.

The syzbot/syzkaller automated tests found a problem in
security_context_to_sid_core() during early boot (before we load the
SELinux policy) where we could potentially feed context strings without
NUL terminators into the strcmp() function.

We already guard against this during normal operation (after the SELinux
policy has been loaded) by making a copy of the context strings and
explicitly adding a NUL terminator to the end.  The patch extends this
protection to the early boot case (no loaded policy) by moving the context
copy earlier in security_context_to_sid_core().

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reviewed-By: William Roberts <william.c.roberts@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-25 11:03:36 +01:00
Eric Biggers
33813d43dd KEYS: encrypted: fix buffer overread in valid_master_desc()
commit 794b4bc292f5d31739d89c0202c54e7dc9bc3add upstream.

With the 'encrypted' key type it was possible for userspace to provide a
data blob ending with a master key description shorter than expected,
e.g. 'keyctl add encrypted desc "new x" @s'.  When validating such a
master key description, validate_master_desc() could read beyond the end
of the buffer.  Fix this by using strncmp() instead of memcmp().  [Also
clean up the code to deduplicate some logic.]

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
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: Jin Qian <jinqian@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-16 20:09:38 +01:00
Mark Salyzyn
d489d1e03c selinux: general protection fault in sock_has_perm
In the absence of commit a4298e4522d6 ("net: add SOCK_RCU_FREE socket
flag") and all the associated infrastructure changes to take advantage
of a RCU grace period before freeing, there is a heightened
possibility that a security check is performed while an ill-timed
setsockopt call races in from user space.  It then is prudent to null
check sk_security, and if the case, reject the permissions.

Because of the nature of this problem, hard to duplicate, no clear
path, this patch is a simplified band-aid for stable trees lacking the
infrastructure for the series of commits leading up to providing a
suitable RCU grace period.  This adjustment is orthogonal to
infrastructure improvements that may nullify the needed check, but
could be added as good code hygiene in all trees.

general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 14233 Comm: syz-executor2 Not tainted 4.4.112-g5f6325b #28
task: ffff8801d1095f00 task.stack: ffff8800b5950000
RIP: 0010:[<ffffffff81b69b7e>]  [<ffffffff81b69b7e>] sock_has_perm+0x1fe/0x3e0 security/selinux/hooks.c:4069
RSP: 0018:ffff8800b5957ce0  EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 1ffff10016b2af9f RCX: ffffffff81b69b51
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000010
RBP: ffff8800b5957de0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff10016b2af68 R12: ffff8800b5957db8
R13: 0000000000000000 R14: ffff8800b7259f40 R15: 00000000000000d7
FS:  00007f72f5ae2700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000a2fa38 CR3: 00000001d7980000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81b69a1f ffff8800b5957d58 00008000b5957d30 0000000041b58ab3
 ffffffff83fc82f2 ffffffff81b69980 0000000000000246 ffff8801d1096770
 ffff8801d3165668 ffffffff8157844b ffff8801d1095f00
 ffff880000000001
Call Trace:
[<ffffffff81b6a19d>] selinux_socket_setsockopt+0x4d/0x80 security/selinux/hooks.c:4338
[<ffffffff81b4873d>] security_socket_setsockopt+0x7d/0xb0 security/security.c:1257
[<ffffffff82df1ac8>] SYSC_setsockopt net/socket.c:1757 [inline]
[<ffffffff82df1ac8>] SyS_setsockopt+0xe8/0x250 net/socket.c:1746
[<ffffffff83776499>] entry_SYSCALL_64_fastpath+0x16/0x92
Code: c2 42 9b b6 81 be 01 00 00 00 48 c7 c7 a0 cb 2b 84 e8
f7 2f 6d ff 49 8d 7d 10 48 b8 00 00 00 00 00 fc ff df 48 89
fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 83 01 00
00 41 8b 75 10 31
RIP  [<ffffffff81b69b7e>] sock_has_perm+0x1fe/0x3e0 security/selinux/hooks.c:4069
RSP <ffff8800b5957ce0>
---[ end trace 7b5aaf788fef6174 ]---

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: selinux@tycho.nsa.gov
Cc: linux-security-module@vger.kernel.org
Cc: Eric Paris <eparis@parisplace.org>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03 17:04:30 +01:00
Kees Cook
3e1457d6bf KPTI: Rename to PAGE_TABLE_ISOLATION
This renames CONFIG_KAISER to CONFIG_PAGE_TABLE_ISOLATION.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05 15:44:26 +01:00
Borislav Petkov
750fb627d7 x86/kaiser: Reenable PARAVIRT
Now that the required bits have been addressed, reenable
PARAVIRT.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05 15:44:26 +01:00
Hugh Dickins
b9d2ccc54e kaiser: delete KAISER_REAL_SWITCH option
We fail to see what CONFIG_KAISER_REAL_SWITCH is for: it seems to be
left over from early development, and now just obscures tricky parts
of the code.  Delete it before adding PCIDs, or nokaiser boot option.

(Or if there is some good reason to keep the option, then it needs
a help text - and a "depends on KAISER", so that all those without
KAISER are not asked the question.)

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05 15:44:24 +01:00
Hugh Dickins
d94df20135 kaiser: KAISER depends on SMP
It is absurd that KAISER should depend on SMP, but apparently nobody
has tried a UP build before: which breaks on implicit declaration of
function 'per_cpu_offset' in arch/x86/mm/kaiser.c.

Now, you would expect that to be trivially fixed up; but looking at
the System.map when that block is #ifdef'ed out of kaiser_init(),
I see that in a UP build __per_cpu_user_mapped_end is precisely at
__per_cpu_user_mapped_start, and the items carefully gathered into
that section for user-mapping on SMP, dispersed elsewhere on UP.

So, some other kind of section assignment will be needed on UP,
but implementing that is not a priority: just make KAISER depend
on SMP for now.

Also inserted a blank line before the option, tidied up the
brief Kconfig help message, and added an "If unsure, Y".

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05 15:44:23 +01:00
Dave Hansen
bed9bb7f3e kaiser: merged update
Merged fixes and cleanups, rebased to 4.4.89 tree (no 5-level paging).

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05 15:44:23 +01:00
Richard Fellner
8a43ddfb93 KAISER: Kernel Address Isolation
This patch introduces our implementation of KAISER (Kernel Address Isolation to
have Side-channels Efficiently Removed), a kernel isolation technique to close
hardware side channels on kernel address information.

More information about the patch can be found on:

        https://github.com/IAIK/KAISER

From: Richard Fellner <richard.fellner@student.tugraz.at>
From: Daniel Gruss <daniel.gruss@iaik.tugraz.at>
X-Subject: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode
Date: Thu, 4 May 2017 14:26:50 +0200
Link: http://marc.info/?l=linux-kernel&m=149390087310405&w=2
Kaiser-4.10-SHA1: c4b1831d44c6144d3762ccc72f0c4e71a0c713e5

To: <linux-kernel@vger.kernel.org>
To: <kernel-hardening@lists.openwall.com>
Cc: <clementine.maurice@iaik.tugraz.at>
Cc: <moritz.lipp@iaik.tugraz.at>
Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at>
Cc: Richard Fellner <richard.fellner@student.tugraz.at>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <kirill.shutemov@linux.intel.com>
Cc: <anders.fogh@gdata-adan.de>

After several recent works [1,2,3] KASLR on x86_64 was basically
considered dead by many researchers. We have been working on an
efficient but effective fix for this problem and found that not mapping
the kernel space when running in user mode is the solution to this
problem [4] (the corresponding paper [5] will be presented at ESSoS17).

With this RFC patch we allow anybody to configure their kernel with the
flag CONFIG_KAISER to add our defense mechanism.

If there are any questions we would love to answer them.
We also appreciate any comments!

Cheers,
Daniel (+ the KAISER team from Graz University of Technology)

[1] http://www.ieee-security.org/TC/SP2013/papers/4977a191.pdf
[2] https://www.blackhat.com/docs/us-16/materials/us-16-Fogh-Using-Undocumented-CPU-Behaviour-To-See-Into-Kernel-Mode-And-Break-KASLR-In-The-Process.pdf
[3] https://www.blackhat.com/docs/us-16/materials/us-16-Jang-Breaking-Kernel-Address-Space-Layout-Randomization-KASLR-With-Intel-TSX.pdf
[4] https://github.com/IAIK/KAISER
[5] https://gruss.cc/files/kaiser.pdf

[patch based also on
https://raw.githubusercontent.com/IAIK/KAISER/master/KAISER/0001-KAISER-Kernel-Address-Isolation.patch]

Signed-off-by: Richard Fellner <richard.fellner@student.tugraz.at>
Signed-off-by: Moritz Lipp <moritz.lipp@iaik.tugraz.at>
Signed-off-by: Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Signed-off-by: Michael Schwarz <michael.schwarz@iaik.tugraz.at>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05 15:44:23 +01:00
Eric Biggers
13e86efb2e KEYS: add missing permission check for request_key() destination
commit 4dca6ea1d9432052afb06baf2e3ae78188a4410b upstream.

When the request_key() syscall is not passed a destination keyring, it
links the requested key (if constructed) into the "default" request-key
keyring.  This should require Write permission to the keyring.  However,
there is actually no permission check.

This can be abused to add keys to any keyring to which only Search
permission is granted.  This is because Search permission allows joining
the keyring.  keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_SESSION_KEYRING)
then will set the default request-key keyring to the session keyring.
Then, request_key() can be used to add keys to the keyring.

Both negatively and positively instantiated keys can be added using this
method.  Adding negative keys is trivial.  Adding a positive key is a
bit trickier.  It requires that either /sbin/request-key positively
instantiates the key, or that another thread adds the key to the process
keyring at just the right time, such that request_key() misses it
initially but then finds it in construct_alloc_key().

Fix this bug by checking for Write permission to the keyring in
construct_get_dest_keyring() when the default keyring is being used.

We don't do the permission check for non-default keyrings because that
was already done by the earlier call to lookup_user_key().  Also,
request_key_and_link() is currently passed a 'struct key *' rather than
a key_ref_t, so the "possessed" bit is unavailable.

We also don't do the permission check for the "requestor keyring", to
continue to support the use case described by commit 8bbf4976b5
("KEYS: Alter use of key instantiation link-to-keyring argument") where
/sbin/request-key recursively calls request_key() to add keys to the
original requestor's destination keyring.  (I don't know of any users
who actually do that, though...)

Fixes: 3e30148c3d ("[PATCH] Keys: Make request-key create an authorisation key")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-20 10:04:52 +01:00
Boshi Wang
80f93e24ec ima: fix hash algorithm initialization
[ Upstream commit ebe7c0a7be92bbd34c6ff5b55810546a0ee05bee ]

The hash_setup function always sets the hash_setup_done flag, even
when the hash algorithm is invalid.  This prevents the default hash
algorithm defined as CONFIG_IMA_DEFAULT_HASH from being used.

This patch sets hash_setup_done flag only for valid hash algorithms.

Fixes: e7a2ad7eb6 "ima: enable support for larger default filedata hash algorithms"
Signed-off-by: Boshi Wang <wangboshi@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-09 18:42:38 +01:00
Roberto Sassu
a9100b6f1a ima: do not update security.ima if appraisal status is not INTEGRITY_PASS
commit 020aae3ee58c1af0e7ffc4e2cc9fe4dc630338cb upstream.

Commit b65a9cfc2c ("Untangling ima mess, part 2: deal with counters")
moved the call of ima_file_check() from may_open() to do_filp_open() at a
point where the file descriptor is already opened.

This breaks the assumption made by IMA that file descriptors being closed
belong to files whose access was granted by ima_file_check(). The
consequence is that security.ima and security.evm are updated with good
values, regardless of the current appraisal status.

For example, if a file does not have security.ima, IMA will create it after
opening the file for writing, even if access is denied. Access to the file
will be allowed afterwards.

Avoid this issue by checking the appraisal status before updating
security.ima.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-24 08:32:24 +01:00
Bilal Amarni
c8f13916c4 security/keys: add CONFIG_KEYS_COMPAT to Kconfig
commit 47b2c3fff4932e6fc17ce13d51a43c6969714e20 upstream.

CONFIG_KEYS_COMPAT is defined in arch-specific Kconfigs and is missing for
several 64-bit architectures : mips, parisc, tile.

At the moment and for those architectures, calling in 32-bit userspace the
keyctl syscall would return an ENOSYS error.

This patch moves the CONFIG_KEYS_COMPAT option to security/keys/Kconfig, to
make sure the compatibility wrapper is registered by default for any 64-bit
architecture as long as it is configured with CONFIG_COMPAT.

[DH: Modified to remove arm64 compat enablement also as requested by Eric
 Biggers]

Signed-off-by: Bilal Amarni <bilal.amarni@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
cc: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Cc: James Cowgill <james.cowgill@mips.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-18 11:11:07 +01:00
Eric Biggers
df5371592a KEYS: trusted: fix writing past end of buffer in trusted_read()
commit a3c812f7cfd80cf51e8f5b7034f7418f6beb56c1 upstream.

When calling keyctl_read() on a key of type "trusted", if the
user-supplied buffer was too small, the kernel ignored the buffer length
and just wrote past the end of the buffer, potentially corrupting
userspace memory.  Fix it by instead returning the size required, as per
the documentation for keyctl_read().

We also don't even fill the buffer at all in this case, as this is
slightly easier to implement than doing a short read, and either
behavior appears to be permitted.  It also makes it match the behavior
of the "encrypted" key type.

Fixes: d00a1c72f7 ("keys: add new trusted key-type")
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-15 17:13:11 +01:00
Eric Biggers
939cafad2f KEYS: trusted: sanitize all key material
commit ee618b4619b72527aaed765f0f0b74072b281159 upstream.

As the previous patch did for encrypted-keys, zero sensitive any
potentially sensitive data related to the "trusted" key type before it
is freed.  Notably, we were not zeroing the tpm_buf structures in which
the actual key is stored for TPM seal and unseal, nor were we zeroing
the trusted_key_payload in certain error paths.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Safford <safford@us.ibm.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-15 17:13:11 +01:00
Eric Biggers
97c5668c97 KEYS: return full count in keyring_read() if buffer is too small
commit 3239b6f29bdfb4b0a2ba59df995fc9e6f4df7f1f upstream.

Commit e645016abc80 ("KEYS: fix writing past end of user-supplied buffer
in keyring_read()") made keyring_read() stop corrupting userspace memory
when the user-supplied buffer is too small.  However it also made the
return value in that case be the short buffer size rather than the size
required, yet keyctl_read() is actually documented to return the size
required.  Therefore, switch it over to the documented behavior.

Note that for now we continue to have it fill the short buffer, since it
did that before (pre-v3.13) and dump_key_tree_aux() in keyutils arguably
relies on it.

Fixes: e645016abc80 ("KEYS: fix writing past end of user-supplied buffer in keyring_read()")
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-08 10:06:27 +01:00
David Howells
8a004caec1 KEYS: Fix race between updating and finding a negative key
commit 363b02dab09b3226f3bd1420dad9c72b79a42a76 upstream.

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: 146aa8b145 ("KEYS: Merge the type-specific data with the payload data")
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-27 10:23:18 +02:00
David Howells
33dea302f9 KEYS: don't let add_key() update an uninstantiated key
commit 60ff5b2f547af3828aebafd54daded44cfb0807a upstream.

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-g428490e38b2e #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

Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-27 10:23:17 +02:00
Eric Biggers
2b7e02267d KEYS: encrypted: fix dereference of NULL user_key_payload
commit 13923d0865ca96312197962522e88bc0aedccd74 upstream.

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: 7e70cb4978 ("keys: add new key-type encrypted")
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Safford <safford@us.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-27 10:23:17 +02:00
Casey Schaufler
dd1f96a0a7 lsm: fix smack_inode_removexattr and xattr_getsecurity memleak
commit 57e7ba04d422c3d41c8426380303ec9b7533ded9 upstream.

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: Casey Schaufler <casey@schaufler-ca.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-12 11:27:32 +02:00
Eric Biggers
638b385050 KEYS: prevent KEYCTL_READ on negative key
commit 37863c43b2c6464f252862bf2e9768264e961678 upstream.

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: 61ea0c0ba9 ("KEYS: Skip key state checks when checking for possession")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-05 09:41:45 +02:00