linux-stable.git/security/integrity, branch v3.16.7

ima: provide flag to identify new empty files

2014-10-30T16:40:16+00:00

commit b151d6b00bbb798c58f2f21305e7d43fa763f34f upstream.

On ima_file_free(), newly created empty files are not labeled with
an initial security.ima value, because the iversion did not change.
Commit dff6efc "fs: fix iversion handling" introduced a change in
iversion behavior.  To verify this change use the shell command:

  $ (exec >foo)
  $ getfattr -h -e hex -d -m security foo

This patch defines the IMA_NEW_FILE flag.  The flag is initially
set, when IMA detects that a new file is created, and subsequently
checked on the ima_file_free() hook to set the initial security.ima
value.

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

ima: fix fallback to use new_sync_read()

2014-10-30T16:40:16+00:00

commit 27cd1fc3ae5374a4a86662c67033f15ef27b2461 upstream.

3.16 commit aad4f8bb42af06371aa0e85bf0cd9d52c0494985
'switch simple generic_file_aio_read() users to ->read_iter()'
replaced ->aio_read with ->read_iter in most of the file systems
and introduced new_sync_read() as a replacement for do_sync_read().

Most of file systems set '->read' and ima_kernel_read is not affected.
When ->read is not set, this patch adopts fallback call changes from the
vfs_read.

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

ima: introduce ima_kernel_read()

2014-06-12T21:58:08+00:00

Commit 8aac62706 "move exit_task_namespaces() outside of exit_notify"
introduced the kernel opps since the kernel v3.10, which happens when
Apparmor and IMA-appraisal are enabled at the same time.

----------------------------------------------------------------------
[  106.750167] BUG: unable to handle kernel NULL pointer dereference at
0000000000000018
[  106.750221] IP: [] our_mnt+0x1a/0x30
[  106.750241] PGD 0
[  106.750254] Oops: 0000 [#1] SMP
[  106.750272] Modules linked in: cuse parport_pc ppdev bnep rfcomm
bluetooth rpcsec_gss_krb5 nfsd auth_rpcgss nfs_acl nfs lockd sunrpc
fscache dm_crypt intel_rapl x86_pkg_temp_thermal intel_powerclamp
kvm_intel snd_hda_codec_hdmi kvm crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul
ablk_helper cryptd snd_hda_codec_realtek dcdbas snd_hda_intel
snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi
snd_seq_midi_event snd_rawmidi psmouse snd_seq microcode serio_raw
snd_timer snd_seq_device snd soundcore video lpc_ich coretemp mac_hid lp
parport mei_me mei nbd hid_generic e1000e usbhid ahci ptp hid libahci
pps_core
[  106.750658] CPU: 6 PID: 1394 Comm: mysqld Not tainted 3.13.0-rc7-kds+ #15
[  106.750673] Hardware name: Dell Inc. OptiPlex 9010/0M9KCM, BIOS A08
09/19/2012
[  106.750689] task: ffff8800de804920 ti: ffff880400fca000 task.ti:
ffff880400fca000
[  106.750704] RIP: 0010:[]  []
our_mnt+0x1a/0x30
[  106.750725] RSP: 0018:ffff880400fcba60  EFLAGS: 00010286
[  106.750738] RAX: 0000000000000000 RBX: 0000000000000100 RCX:
ffff8800d51523e7
[  106.750764] RDX: ffffffffffffffea RSI: ffff880400fcba34 RDI:
ffff880402d20020
[  106.750791] RBP: ffff880400fcbae0 R08: 0000000000000000 R09:
0000000000000001
[  106.750817] R10: 0000000000000000 R11: 0000000000000001 R12:
ffff8800d5152300
[  106.750844] R13: ffff8803eb8df510 R14: ffff880400fcbb28 R15:
ffff8800d51523e7
[  106.750871] FS:  0000000000000000(0000) GS:ffff88040d200000(0000)
knlGS:0000000000000000
[  106.750910] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  106.750935] CR2: 0000000000000018 CR3: 0000000001c0e000 CR4:
00000000001407e0
[  106.750962] Stack:
[  106.750981]  ffffffff813434eb ffff880400fcbb20 ffff880400fcbb18
0000000000000000
[  106.751037]  ffff8800de804920 ffffffff8101b9b9 0001800000000000
0000000000000100
[  106.751093]  0000010000000000 0000000000000002 000000000000000e
ffff8803eb8df500
[  106.751149] Call Trace:
[  106.751172]  [] ? aa_path_name+0x2ab/0x430
[  106.751199]  [] ? sched_clock+0x9/0x10
[  106.751225]  [] aa_path_perm+0x7d/0x170
[  106.751250]  [] ? native_sched_clock+0x15/0x80
[  106.751276]  [] aa_file_perm+0x33/0x40
[  106.751301]  [] common_file_perm+0x8e/0xb0
[  106.751327]  [] apparmor_file_permission+0x18/0x20
[  106.751355]  [] security_file_permission+0x23/0xa0
[  106.751382]  [] rw_verify_area+0x52/0xe0
[  106.751407]  [] vfs_read+0x6d/0x170
[  106.751432]  [] kernel_read+0x41/0x60
[  106.751457]  [] ima_calc_file_hash+0x225/0x280
[  106.751483]  [] ? ima_calc_file_hash+0x32/0x280
[  106.751509]  [] ima_collect_measurement+0x9d/0x160
[  106.751536]  [] ? trace_hardirqs_on+0xd/0x10
[  106.751562]  [] ? ima_file_free+0x6c/0xd0
[  106.751587]  [] ima_update_xattr+0x34/0x60
[  106.751612]  [] ima_file_free+0xc0/0xd0
[  106.751637]  [] __fput+0xd5/0x300
[  106.751662]  [] ____fput+0xe/0x10
[  106.751687]  [] task_work_run+0xc4/0xe0
[  106.751712]  [] do_exit+0x2bd/0xa90
[  106.751738]  [] ? retint_swapgs+0x13/0x1b
[  106.751763]  [] do_group_exit+0x4c/0xc0
[  106.751788]  [] SyS_exit_group+0x14/0x20
[  106.751814]  [] system_call_fastpath+0x1a/0x1f
[  106.751839] Code: c3 0f 1f 44 00 00 55 48 89 e5 e8 22 fe ff ff 5d c3
0f 1f 44 00 00 55 65 48 8b 04 25 c0 c9 00 00 48 8b 80 28 06 00 00 48 89
e5 5d <48> 8b 40 18 48 39 87 c0 00 00 00 0f 94 c0 c3 0f 1f 80 00 00 00
[  106.752185] RIP  [] our_mnt+0x1a/0x30
[  106.752214]  RSP 
[  106.752236] CR2: 0000000000000018
[  106.752258] ---[ end trace 3c520748b4732721 ]---
----------------------------------------------------------------------

The reason for the oops is that IMA-appraisal uses "kernel_read()" when
file is closed. kernel_read() honors LSM security hook which calls
Apparmor handler, which uses current->nsproxy->mnt_ns. The 'guilty'
commit changed the order of cleanup code so that nsproxy->mnt_ns was
not already available for Apparmor.

Discussion about the issue with Al Viro and Eric W. Biederman suggested
that kernel_read() is too high-level for IMA. Another issue, except
security checking, that was identified is mandatory locking. kernel_read
honors it as well and it might prevent IMA from calculating necessary hash.
It was suggested to use simplified version of the function without security
and locking checks.

This patch introduces special version ima_kernel_read(), which skips security
and mandatory locking checking. It prevents the kernel oops to happen.

Signed-off-by: Dmitry Kasatkin 
Suggested-by: Eric W. Biederman 
Signed-off-by: Mimi Zohar 
Cc:

evm: prohibit userspace writing 'security.evm' HMAC value

2014-06-12T21:58:07+00:00

Calculating the 'security.evm' HMAC value requires access to the
EVM encrypted key.  Only the kernel should have access to it.  This
patch prevents userspace tools(eg. setfattr, cp --preserve=xattr)
from setting/modifying the 'security.evm' HMAC value directly.

Signed-off-by: Mimi Zohar 
Cc:

ima: check inode integrity cache in violation check

2014-06-12T21:58:07+00:00

When IMA did not support ima-appraisal, existance of the S_IMA flag
clearly indicated that the file was measured. With IMA appraisal S_IMA
flag indicates that file was measured and/or appraised. Because of
this, when measurement is not enabled by the policy, violations are
still reported.

To differentiate between measurement and appraisal policies this
patch checks the inode integrity cache flags.  The IMA_MEASURED
flag indicates whether the file was actually measured, while the
IMA_MEASURE flag indicates whether the file should be measured.
Unfortunately, the IMA_MEASURED flag is reset to indicate the file
needs to be re-measured.  Thus, this patch checks the IMA_MEASURE
flag.

This patch limits the false positive violation reports, but does
not fix it entirely.  The IMA_MEASURE/IMA_MEASURED flags are
indications that, at some point in time, the file opened for read
was in policy, but might not be in policy now (eg. different uid).
Other changes would be needed to further limit false positive
violation reports.

Changelog:
- expanded patch description based on conversation with Roberto (Mimi)

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar

ima: prevent unnecessary policy checking

2014-06-12T21:58:06+00:00

ima_rdwr_violation_check is called for every file openning.
The function checks the policy even when violation condition
is not met. It causes unnecessary policy checking.

This patch does policy checking only if violation condition is met.

Changelog:
- check writecount is greater than zero (Mimi)

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar

evm: provide option to protect additional SMACK xattrs

2014-06-12T21:58:06+00:00

Newer versions of SMACK introduced following security xattrs:
SMACK64EXEC, SMACK64TRANSMUTE and SMACK64MMAP.

To protect these xattrs, this patch includes them in the HMAC
calculation.  However, for backwards compatibility with existing
labeled filesystems, including these xattrs needs to be
configurable.

Changelog:
- Add SMACK dependency on new option (Mimi)

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar

evm: replace HMAC version with attribute mask

2014-06-12T21:58:06+00:00

Using HMAC version limits the posibility to arbitrarily add new
attributes such as SMACK64EXEC to the hmac calculation.

This patch replaces hmac version with attribute mask.
Desired attributes can be enabled with configuration parameter.
It allows to build kernels which works with previously labeled
filesystems.

Currently supported attribute is 'fsuuid' which is equivalent of
the former version 2.

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar

ima: prevent new digsig xattr from being replaced

2014-06-12T21:58:05+00:00

Even though a new xattr will only be appraised on the next access,
set the DIGSIG flag to prevent a signature from being replaced with
a hash on file close.

Signed-off-by: Mimi Zohar

Merge branch 'serge-next-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux-security

2014-06-10T17:05:36+00:00

Pull security layer updates from Serge Hallyn:
 "This is a merge of James Morris' security-next tree from 3.14 to
  yesterday's master, plus four patches from Paul Moore which are in
  linux-next, plus one patch from Mimi"

* 'serge-next-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux-security:
  ima: audit log files opened with O_DIRECT flag
  selinux: conditionally reschedule in hashtab_insert while loading selinux policy
  selinux: conditionally reschedule in mls_convert_context while loading selinux policy
  selinux: reject setexeccon() on MNT_NOSUID applications with -EACCES
  selinux:  Report permissive mode in avc: denied messages.
  Warning in scanf string typing
  Smack: Label cgroup files for systemd
  Smack: Verify read access on file open - v3
  security: Convert use of typedef ctl_table to struct ctl_table
  Smack: bidirectional UDS connect check
  Smack: Correctly remove SMACK64TRANSMUTE attribute
  SMACK: Fix handling value==NULL in post setxattr
  bugfix patch for SMACK
  Smack: adds smackfs/ptrace interface
  Smack: unify all ptrace accesses in the smack
  Smack: fix the subject/object order in smack_ptrace_traceme()
  Minor improvement of 'smack_sb_kern_mount'
  smack: fix key permission verification
  KEYS: Move the flags representing required permission to linux/key.h