linux-stable.git/security, branch v3.2.72

fs: create and use seq_show_option for escaping

2015-10-13T02:46:08+00:00

commit a068acf2ee77693e0bf39d6e07139ba704f461c3 upstream.

Many file systems that implement the show_options hook fail to correctly
escape their output which could lead to unescaped characters (e.g.  new
lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files.  This
could lead to confusion, spoofed entries (resulting in things like
systemd issuing false d-bus "mount" notifications), and who knows what
else.  This looks like it would only be the root user stepping on
themselves, but it's possible weird things could happen in containers or
in other situations with delegated mount privileges.

Here's an example using overlay with setuid fusermount trusting the
contents of /proc/mounts (via the /etc/mtab symlink).  Imagine the use
of "sudo" is something more sneaky:

  $ BASE="ovl"
  $ MNT="$BASE/mnt"
  $ LOW="$BASE/lower"
  $ UP="$BASE/upper"
  $ WORK="$BASE/work/ 0 0
  none /proc fuse.pwn user_id=1000"
  $ mkdir -p "$LOW" "$UP" "$WORK"
  $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt
  $ cat /proc/mounts
  none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0
  none /proc fuse.pwn user_id=1000 0 0
  $ fusermount -u /proc
  $ cat /proc/mounts
  cat: /proc/mounts: No such file or directory

This fixes the problem by adding new seq_show_option and
seq_show_option_n helpers, and updating the vulnerable show_option
handlers to use them as needed.  Some, like SELinux, need to be open
coded due to unusual existing escape mechanisms.

[akpm@linux-foundation.org: add lost chunk, per Kees]
[keescook@chromium.org: seq_show_option should be using const parameters]
Signed-off-by: Kees Cook 
Acked-by: Serge Hallyn 
Acked-by: Jan Kara 
Acked-by: Paul Moore 
Cc: J. R. Okajima 
Signed-off-by: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2:
 - Drop changes to overlayfs, reiserfs
 - Drop vers option from cifs
 - ceph changes are all in one file
 - Adjust context]
Signed-off-by: Ben Hutchings

selinux/nlmsg: add XFRM_MSG_MAPPING

2015-08-06T23:32:04+00:00

commit bd2cba07381a6dba60bc1c87ed8b37931d244da1 upstream.

This command is missing.

Fixes: 3a2dfbe8acb1 ("xfrm: Notify changes in UDP encapsulation via netlink")
CC: Martin Willi 
Reported-by: Stephen Smalley 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

selinux/nlmsg: add XFRM_MSG_MIGRATE

2015-08-06T23:32:04+00:00

commit 8d465bb777179c4bea731b828ec484088cc9fbc1 upstream.

This command is missing.

Fixes: 5c79de6e79cd ("[XFRM]: User interface for handling XFRM_MSG_MIGRATE")
Reported-by: Stephen Smalley 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

selinux/nlmsg: add XFRM_MSG_REPORT

2015-08-06T23:32:04+00:00

commit b0b59b0056acd6f157a04cc895f7e24692fb08aa upstream.

This command is missing.

Fixes: 97a64b4577ae ("[XFRM]: Introduce XFRM_MSG_REPORT.")
Reported-by: Stephen Smalley 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

selinux/nlmsg: add XFRM_MSG_[NEW|GET]SADINFO

2015-08-06T23:32:03+00:00

commit 5b5800fad072133e4a9c2efbf735baaac83dec86 upstream.

These commands are missing.

Fixes: 28d8909bc790 ("[XFRM]: Export SAD info.")
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

selinux/nlmsg: add XFRM_MSG_GETSPDINFO

2015-08-06T23:32:03+00:00

commit 5e6deebafb45fb271ae6939d48832e920b8fb74e upstream.

This command is missing.

Fixes: ecfd6b183780 ("[XFRM]: Export SPD info")
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

selinux: fix sel_write_enforce broken return value

2015-05-09T22:16:32+00:00

commit 6436a123a147db51a0b06024a8350f4c230e73ff upstream.

Return a negative error value like the rest of the entries in this function.

Signed-off-by: Joe Perches 
Acked-by:  Stephen Smalley 
[PM: tweaked subject line]
Signed-off-by: Paul Moore 
Signed-off-by: Ben Hutchings

smack: fix possible use after frees in task_security() callers

2015-05-09T22:16:13+00:00

commit 6d1cff2a885850b78b40c34777b46cf5da5d1050 upstream.

We hit use after free on dereferncing pointer to task_smack struct in
smk_of_task() called from smack_task_to_inode().

task_security() macro uses task_cred_xxx() to get pointer to the task_smack.
task_cred_xxx() could be used only for non-pointer members of task's
credentials. It cannot be used for pointer members since what they point
to may disapper after dropping RCU read lock.

Mainly task_security() used this way:
	smk_of_task(task_security(p))

Intead of this introduce function smk_of_task_struct() which
takes task_struct as argument and returns pointer to smk_known struct
and do this under RCU read lock.
Bogus task_security() macro is not used anymore, so remove it.

KASan's report for this:

	AddressSanitizer: use after free in smack_task_to_inode+0x50/0x70 at addr c4635600
	=============================================================================
	BUG kmalloc-64 (Tainted: PO): kasan error
	-----------------------------------------------------------------------------

	Disabling lock debugging due to kernel taint
	INFO: Allocated in new_task_smack+0x44/0xd8 age=39 cpu=0 pid=1866
		kmem_cache_alloc_trace+0x88/0x1bc
		new_task_smack+0x44/0xd8
		smack_cred_prepare+0x48/0x21c
		security_prepare_creds+0x44/0x4c
		prepare_creds+0xdc/0x110
		smack_setprocattr+0x104/0x150
		security_setprocattr+0x4c/0x54
		proc_pid_attr_write+0x12c/0x194
		vfs_write+0x1b0/0x370
		SyS_write+0x5c/0x94
		ret_fast_syscall+0x0/0x48
	INFO: Freed in smack_cred_free+0xc4/0xd0 age=27 cpu=0 pid=1564
		kfree+0x270/0x290
		smack_cred_free+0xc4/0xd0
		security_cred_free+0x34/0x3c
		put_cred_rcu+0x58/0xcc
		rcu_process_callbacks+0x738/0x998
		__do_softirq+0x264/0x4cc
		do_softirq+0x94/0xf4
		irq_exit+0xbc/0x120
		handle_IRQ+0x104/0x134
		gic_handle_irq+0x70/0xac
		__irq_svc+0x44/0x78
		_raw_spin_unlock+0x18/0x48
		sync_inodes_sb+0x17c/0x1d8
		sync_filesystem+0xac/0xfc
		vdfs_file_fsync+0x90/0xc0
		vfs_fsync_range+0x74/0x7c
	INFO: Slab 0xd3b23f50 objects=32 used=31 fp=0xc4635600 flags=0x4080
	INFO: Object 0xc4635600 @offset=5632 fp=0x  (null)

	Bytes b4 c46355f0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  ZZZZZZZZZZZZZZZZ
	Object c4635600: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
	Object c4635610: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
	Object c4635620: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
	Object c4635630: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5  kkkkkkkkkkkkkkk.
	Redzone c4635640: bb bb bb bb                                      ....
	Padding c46356e8: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  ZZZZZZZZZZZZZZZZ
	Padding c46356f8: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
	CPU: 5 PID: 834 Comm: launchpad_prelo Tainted: PBO 3.10.30 #1
	Backtrace:
	[] (dump_backtrace+0x0/0x158) from [] (show_stack+0x20/0x24)
	 r7:c4634010 r6:d3b23f50 r5:c4635600 r4:d1002140
	[] (show_stack+0x0/0x24) from [] (dump_stack+0x20/0x28)
	[] (dump_stack+0x0/0x28) from [] (print_trailer+0x124/0x144)
	[] (print_trailer+0x0/0x144) from [] (object_err+0x3c/0x44)
	 r7:c4635600 r6:d1002140 r5:d3b23f50 r4:c4635600
	[] (object_err+0x0/0x44) from [] (kasan_report_error+0x2b8/0x538)
	 r6:d1002140 r5:d3b23f50 r4:c6429cf8 r3:c09e1aa7
	[] (kasan_report_error+0x0/0x538) from [] (__asan_load4+0xd4/0xf8)
	[] (__asan_load4+0x0/0xf8) from [] (smack_task_to_inode+0x50/0x70)
	 r5:c4635600 r4:ca9da000
	[] (smack_task_to_inode+0x0/0x70) from [] (security_task_to_inode+0x3c/0x44)
	 r5:cca25e80 r4:c0ba9780
	[] (security_task_to_inode+0x0/0x44) from [] (pid_revalidate+0x124/0x178)
	 r6:00000000 r5:cca25e80 r4:cbabe3c0 r3:00008124
	[] (pid_revalidate+0x0/0x178) from [] (lookup_fast+0x35c/0x43y4)
	 r9:c6429efc r8:00000101 r7:c079d940 r6:c6429e90 r5:c6429ed8 r4:c83c4148
	[] (lookup_fast+0x0/0x434) from [] (do_last.isra.24+0x1c0/0x1108)
	[] (do_last.isra.24+0x0/0x1108) from [] (path_openat.isra.25+0xf4/0x648)
	[] (path_openat.isra.25+0x0/0x648) from [] (do_filp_open+0x3c/0x88)
	[] (do_filp_open+0x0/0x88) from [] (do_sys_open+0xf0/0x198)
	 r7:00000001 r6:c0ea2180 r5:0000000b r4:00000000
	[] (do_sys_open+0x0/0x198) from [] (SyS_open+0x30/0x34)
	[] (SyS_open+0x0/0x34) from [] (ret_fast_syscall+0x0/0x48)
	Read of size 4 by thread T834:
	Memory state around the buggy address:
	 c4635380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	 c4635400: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
	 c4635480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	 c4635500: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
	 c4635580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	>c4635600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
	           ^
	 c4635680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
	 c4635700: 00 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc
	 c4635780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	 c4635800: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc
	 c4635880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	==================================================================

Signed-off-by: Andrey Ryabinin 
[bwh: Backported to 3.2:
 - smk_of_task() and similar functions return char * not struct smack_known *
 - The callers of task_security() are quite different, but most can be changed
   to use smk_of_task_struct() just as in the upstream version
 - Use open-coded RCU locking in the one place using smk_of_forked() instead
   of smk_of_task()]
Signed-off-by: Ben Hutchings

KEYS: close race between key lookup and freeing

2015-02-20T00:49:41+00:00

commit a3a8784454692dd72e5d5d34dcdab17b4420e74c upstream.

When a key is being garbage collected, it's key->user would get put before
the ->destroy() callback is called, where the key is removed from it's
respective tracking structures.

This leaves a key hanging in a semi-invalid state which leaves a window open
for a different task to try an access key->user. An example is
find_keyring_by_name() which would dereference key->user for a key that is
in the process of being garbage collected (where key->user was freed but
->destroy() wasn't called yet - so it's still present in the linked list).

This would cause either a panic, or corrupt memory.

Fixes CVE-2014-9529.

Signed-off-by: Sasha Levin 
Signed-off-by: David Howells 
[bwh: Backported to 3.2: adjust indentation]
Signed-off-by: Ben Hutchings

KEYS: Fix stale key registration at error path

2015-02-20T00:49:29+00:00

commit b26bdde5bb27f3f900e25a95e33a0c476c8c2c48 upstream.

When loading encrypted-keys module, if the last check of
aes_get_sizes() in init_encrypted() fails, the driver just returns an
error without unregistering its key type.  This results in the stale
entry in the list.  In addition to memory leaks, this leads to a kernel
crash when registering a new key type later.

This patch fixes the problem by swapping the calls of aes_get_sizes()
and register_key_type(), and releasing resources properly at the error
paths.

Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=908163
Signed-off-by: Takashi Iwai 
Signed-off-by: Mimi Zohar 
Signed-off-by: Ben Hutchings