linux-toradex.git/security/integrity/evm, branch v3.2.73

evm: check xattr value length and type in evm_inode_setxattr()

2014-12-14T16:23:52+00:00

commit 3b1deef6b1289a99505858a3b212c5b50adf0c2f upstream.

evm_inode_setxattr() can be called with no value. The function does not
check the length so that following command can be used to produce the
kernel oops: setfattr -n security.evm FOO. This patch fixes it.

Changes in v3:
* there is no reason to return different error codes for EVM_XATTR_HMAC
  and non EVM_XATTR_HMAC. Remove unnecessary test then.

Changes in v2:
* testing for validity of xattr type

[ 1106.396921] BUG: unable to handle kernel NULL pointer dereference at           (null)
[ 1106.398192] IP: [] evm_inode_setxattr+0x2a/0x48
[ 1106.399244] PGD 29048067 PUD 290d7067 PMD 0
[ 1106.399953] Oops: 0000 [#1] SMP
[ 1106.400020] Modules linked in: bridge stp llc evdev serio_raw i2c_piix4 button fuse
[ 1106.400020] CPU: 0 PID: 3635 Comm: setxattr Not tainted 3.16.0-kds+ #2936
[ 1106.400020] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1106.400020] task: ffff8800291a0000 ti: ffff88002917c000 task.ti: ffff88002917c000
[ 1106.400020] RIP: 0010:[]  [] evm_inode_setxattr+0x2a/0x48
[ 1106.400020] RSP: 0018:ffff88002917fd50  EFLAGS: 00010246
[ 1106.400020] RAX: 0000000000000000 RBX: ffff88002917fdf8 RCX: 0000000000000000
[ 1106.400020] RDX: 0000000000000000 RSI: ffffffff818136d3 RDI: ffff88002917fdf8
[ 1106.400020] RBP: ffff88002917fd68 R08: 0000000000000000 R09: 00000000003ec1df
[ 1106.400020] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800438a0a00
[ 1106.400020] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 1106.400020] FS:  00007f7dfa7d7740(0000) GS:ffff88005da00000(0000) knlGS:0000000000000000
[ 1106.400020] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1106.400020] CR2: 0000000000000000 CR3: 000000003763e000 CR4: 00000000000006f0
[ 1106.400020] Stack:
[ 1106.400020]  ffff8800438a0a00 ffff88002917fdf8 0000000000000000 ffff88002917fd98
[ 1106.400020]  ffffffff812a1030 ffff8800438a0a00 ffff88002917fdf8 0000000000000000
[ 1106.400020]  0000000000000000 ffff88002917fde0 ffffffff8116d08a ffff88002917fdc8
[ 1106.400020] Call Trace:
[ 1106.400020]  [] security_inode_setxattr+0x5d/0x6a
[ 1106.400020]  [] vfs_setxattr+0x6b/0x9f
[ 1106.400020]  [] setxattr+0x122/0x16c
[ 1106.400020]  [] ? mnt_want_write+0x21/0x45
[ 1106.400020]  [] ? __sb_start_write+0x10f/0x143
[ 1106.400020]  [] ? mnt_want_write+0x21/0x45
[ 1106.400020]  [] ? __mnt_want_write+0x48/0x4f
[ 1106.400020]  [] SyS_setxattr+0x6e/0xb0
[ 1106.400020]  [] system_call_fastpath+0x16/0x1b
[ 1106.400020] Code: c3 0f 1f 44 00 00 55 48 89 e5 41 55 49 89 d5 41 54 49 89 fc 53 48 89 f3 48 c7 c6 d3 36 81 81 48 89 df e8 18 22 04 00 85 c0 75 07 <41> 80 7d 00 02 74 0d 48 89 de 4c 89 e7 e8 5a fe ff ff eb 03 83
[ 1106.400020] RIP  [] evm_inode_setxattr+0x2a/0x48
[ 1106.400020]  RSP 
[ 1106.400020] CR2: 0000000000000000
[ 1106.428061] ---[ end trace ae08331628ba3050 ]---

Reported-by: Jan Kara 
Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar 
Signed-off-by: Ben Hutchings

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

2014-07-11T12:33:50+00:00

commit 2fb1c9a4f2dbc2f0bd2431c7fa64d0b5483864e4 upstream.

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 
Signed-off-by: Ben Hutchings

evm: checking if removexattr is not a NULL

2013-02-06T04:33:40+00:00

commit a67adb997419fb53540d4a4f79c6471c60bc69b6 upstream.

The following lines of code produce a kernel oops.

fd = socket(PF_FILE, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
fchmod(fd, 0666);

[  139.922364] BUG: unable to handle kernel NULL pointer dereference at   (null)
[  139.924982] IP: [<  (null)>]   (null)
[  139.924982] *pde = 00000000
[  139.924982] Oops: 0000 [#5] SMP
[  139.924982] Modules linked in: fuse dm_crypt dm_mod i2c_piix4 serio_raw evdev binfmt_misc button
[  139.924982] Pid: 3070, comm: acpid Tainted: G      D      3.8.0-rc2-kds+ #465 Bochs Bochs
[  139.924982] EIP: 0060:[<00000000>] EFLAGS: 00010246 CPU: 0
[  139.924982] EIP is at 0x0
[  139.924982] EAX: cf5ef000 EBX: cf5ef000 ECX: c143d600 EDX: c15225f2
[  139.924982] ESI: cf4d2a1c EDI: cf4d2a1c EBP: cc02df10 ESP: cc02dee4
[  139.924982]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[  139.924982] CR0: 80050033 CR2: 00000000 CR3: 0c059000 CR4: 000006d0
[  139.924982] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  139.924982] DR6: ffff0ff0 DR7: 00000400
[  139.924982] Process acpid (pid: 3070, ti=cc02c000 task=d7705340 task.ti=cc02c000)
[  139.924982] Stack:
[  139.924982]  c1203c88 00000000 cc02def4 cf4d2a1c ae21eefa 471b60d5 1083c1ba c26a5940
[  139.924982]  e891fb5e 00000041 00000004 cc02df1c c1203964 00000000 cc02df4c c10e20c3
[  139.924982]  00000002 00000000 00000000 22222222 c1ff2222 cf5ef000 00000000 d76efb08
[  139.924982] Call Trace:
[  139.924982]  [] ? evm_update_evmxattr+0x5b/0x62
[  139.924982]  [] evm_inode_post_setattr+0x22/0x26
[  139.924982]  [] notify_change+0x25f/0x281
[  139.924982]  [] chmod_common+0x59/0x76
[  139.924982]  [] ? put_unused_fd+0x33/0x33
[  139.924982]  [] sys_fchmod+0x39/0x5c
[  139.924982]  [] syscall_call+0x7/0xb
[  139.924982] Code:  Bad EIP value.

This happens because sockets do not define the removexattr operation.
Before removing the xattr, verify the removexattr function pointer is
not NULL.

Signed-off-by: Dmitry Kasatkin 
Signed-off-by: Mimi Zohar 
Signed-off-by: James Morris 
Signed-off-by: Ben Hutchings

evm: prevent racing during tfm allocation

2011-12-20T15:50:08+00:00

There is a small chance of racing during tfm allocation.
This patch fixes it.

Signed-off-by: Dmitry Kasatkin 
Acked-by: Mimi Zohar 
Signed-off-by: James Morris

evm: key must be set once during initialization

2011-12-20T15:45:45+00:00

On multi-core systems, setting of the key before every caclculation,
causes invalid HMAC calculation for other tfm users, because internal
state (ipad, opad) can be invalid before set key call returns.
It needs to be set only once during initialization.

Signed-off-by: Dmitry Kasatkin 
Acked-by: Mimi Zohar 
Signed-off-by: James Morris

evm: permit mode bits to be updated

2011-09-14T19:24:52+00:00

Before permitting 'security.evm' to be updated, 'security.evm' must
exist and be valid.  In the case that there are no existing EVM protected
xattrs, it is safe for posix acls to update the mode bits.

To differentiate between no 'security.evm' xattr and no xattrs used to
calculate 'security.evm', this patch defines INTEGRITY_NOXATTR.

Signed-off-by: Mimi Zohar

evm: posix acls modify i_mode

2011-09-14T19:24:51+00:00

The posix xattr acls are 'system' prefixed, which normally would not
affect security.evm.  An interesting side affect of writing posix xattr
acls is their modifying of the i_mode, which is included in security.evm.

This patch updates security.evm when posix xattr acls are written.

Signed-off-by: Mimi Zohar

evm: limit verifying current security.evm integrity

2011-09-14T19:24:51+00:00

evm_protect_xattr unnecessarily validates the current security.evm
integrity, before updating non-evm protected extended attributes
and other file metadata. This patch limits validating the current
security.evm integrity to evm protected metadata.

Signed-off-by: Mimi Zohar

evm: remove TCG_TPM dependency

2011-09-14T19:24:49+00:00

All tristates selected by EVM(boolean) are forced to be builtin, except
in the TCG_TPM(tristate) dependency case. Arnaud Lacombe summarizes the
Kconfig bug as, "So it would seem direct dependency state influence the
state of reverse dependencies.."  For a detailed explanation, refer to
Arnaud Lacombe's posting http://lkml.org/lkml/2011/8/23/498.

With the "encrypted-keys: remove trusted-keys dependency" patch, EVM
can now be built without a dependency on TCG_TPM.  The trusted-keys
dependency requires trusted-keys to either be builtin or not selected.
This dependency will prevent the boolean/tristate mismatch from
occuring.

Reported-by: Stephen Rothwell ,
             Randy Dunlap 
Signed-off-by: Mimi Zohar

evm: add Kconfig TCG_TPM dependency

2011-08-18T02:58:12+00:00

Although the EVM encrypted-key should be encrypted/decrypted using a
trusted-key, a user-defined key could be used instead. When using a user-
defined key, a TCG_TPM dependency should not be required.  Unfortunately,
the encrypted-key code needs to be refactored a bit in order to remove
this dependency.

This patch adds the TCG_TPM dependency.

Reported-by: Stephen Rothwell ,
	     Randy Dunlap 
Signed-off-by: Mimi Zohar 
Signed-off-by: James Morris