Commit Graph

597 Commits

Author SHA1 Message Date
Arnd Bergmann
dd979d7a08 apparmor: use get_unaligned() only for multi-byte words
Using get_unaligned() on a u8 pointer is pointless, and will
result in a compiler warning after a planned cleanup:

In file included from arch/x86/include/generated/asm/unaligned.h:1,
                 from security/apparmor/policy_unpack.c:16:
security/apparmor/policy_unpack.c: In function 'unpack_u8':
include/asm-generic/unaligned.h:13:15: error: 'packed' attribute ignored for field of type 'u8' {aka 'unsigned char'} [-Werror=attributes]
   13 |  const struct { type x __packed; } *__pptr = (typeof(__pptr))(ptr); \
      |               ^

Simply dereference this pointer directly.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: John Johansen <john.johansen@canonical.com>
2021-05-17 13:30:29 +02:00
Linus Torvalds
27787ba3fa Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Assorted stuff all over the place"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  useful constants: struct qstr for ".."
  hostfs_open(): don't open-code file_dentry()
  whack-a-mole: kill strlen_user() (again)
  autofs: should_expire() argument is guaranteed to be positive
  apparmor:match_mn() - constify devpath argument
  buffer: a small optimization in grow_buffers
  get rid of autofs_getpath()
  constify dentry argument of dentry_path()/dentry_path_raw()
2021-05-02 09:14:01 -07:00
Al Viro
64b2f34f38 apparmor:match_mn() - constify devpath argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-03-24 14:11:29 -04:00
Paul Moore
4ebd7651bf lsm: separate security_task_getsecid() into subjective and objective variants
Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials.  This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.

This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.

  void security_task_getsecid_subj(struct task_struct *p,
				   u32 *secid);
  void security_task_getsecid_obj(struct task_struct *p,
				  u32 *secid);

While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks.  The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.

Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-03-22 15:23:32 -04:00
Christian Brauner
3cee6079f6
apparmor: handle idmapped mounts
The i_uid and i_gid are mostly used when logging for AppArmor. This is
broken in a bunch of places where the global root id is reported instead
of the i_uid or i_gid of the file. Nonetheless, be kind and log the
mapped inode if we're coming from an idmapped mount. If the initial user
namespace is passed nothing changes so non-idmapped mounts will see
identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-26-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00
Christian Brauner
549c729771
fs: make helpers idmap mount aware
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00
Tycho Andersen
c7c7a1a18a
xattr: handle idmapped mounts
When interacting with extended attributes the vfs verifies that the
caller is privileged over the inode with which the extended attribute is
associated. For posix access and posix default extended attributes a uid
or gid can be stored on-disk. Let the functions handle posix extended
attributes on idmapped mounts. If the inode is accessed through an
idmapped mount we need to map it according to the mount's user
namespace. Afterwards the checks are identical to non-idmapped mounts.
This has no effect for e.g. security xattrs since they don't store uids
or gids and don't perform permission checks on them like posix acls do.

Link: https://lore.kernel.org/r/20210121131959.646623-10-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Tycho Andersen <tycho@tycho.pizza>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:17 +01:00
Andy Shevchenko
9801ca279a apparmor: remove duplicate macro list_entry_is_head()
Strangely I hadn't had noticed the existence of the list_entry_is_head()
in apparmor code when added the same one in the list.h.  Luckily it's
fully identical and didn't break builds.  In any case we don't need a
duplicate anymore, thus remove it from apparmor code.

Link: https://lkml.kernel.org/r/20201208100639.88182-1-andriy.shevchenko@linux.intel.com
Fixes: e130816164 ("include/linux/list.h: add a macro to test if entry is pointing to the head")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E . Hallyn " <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 22:46:19 -08:00
Florian Westphal
41dd9596d6 security: add const qualifier to struct sock in various places
A followup change to tcp_request_sock_op would have to drop the 'const'
qualifier from the 'route_req' function as the
'security_inet_conn_request' call is moved there - and that function
expects a 'struct sock *'.

However, it turns out its also possible to add a const qualifier to
security_inet_conn_request instead.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-12-03 12:56:03 -08:00
Gustavo A. R. Silva
df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Linus Torvalds
ce13266d97 Minor fixes for v5.9.
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEgycj0O+d1G2aycA8rZhLv9lQBTwFAl8xl0QACgkQrZhLv9lQ
 BTzEUA/+Muf7gha2mtxGJ49ZX/AsUOi/feHFDjt+NEA6lQTIaaqU5LxXNdtARu/5
 j+RlJkrw8+3QGJ4h544HIJodbLZHghWpp15AxBAy+1BaeAoswEnrW2/6mD1iUBEH
 pFI0P2OjnVYxEPJGubLhp4qQ0lnqVKwzciNbBDLMydr6SerwoPDz9h0h5SMDoOxF
 m4f1/dsoXrpyp86GSvHDVa9NRs/GMKz/qIeC6DXuMRoqGX15EZVV1iABC7vPd2we
 84IacCRIE/DO1M1rmbNBSpeErmvkxRo00Qjupl0XGf7D4aazxnQl+RpaLdHAtBI1
 ubzU/76DCkaCO1x+3KPHyQUHZvXa3dt0/n4yEkOv01RIzivKZZz6jahsCrbX6lzX
 Dq4n0zg8sA7vh/T7aNX77z0FU1TuFBpiJ8dn/0vUgJPxDwt2V9F2k9jyV1pUeK1V
 yvSkIleIQmwmuT0p2nB/1g7yE5xkvWTM5WOy8/zIQj2aCvuo3ToY06Qc0rNOKTa8
 6Qi/Byi/5S1bBwYQqrAyrd5GhPVdZ8oNZyaUu8Mpm+4P0+2CquvDfN3ZHUxwILNX
 /TMVTVMu1PQQIltWANA0L0BjGIjSGxutisEUQL7o24566GXA3wTQd8HoKRBc6h+p
 DGeVMehPG7GIwoCIvuzdahSRdzzI/iBG3P10TZ5u+3BwTL0OUNY=
 =s2Jw
 -----END PGP SIGNATURE-----

Merge tag 'for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem updates from James Morris:
 "A couple of minor documentation updates only for this release"

* tag 'for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  LSM: drop duplicated words in header file comments
  Replace HTTP links with HTTPS ones: security
2020-08-11 14:30:36 -07:00
Waiman Long
453431a549 mm, treewide: rename kzfree() to kfree_sensitive()
As said by Linus:

  A symmetric naming is only helpful if it implies symmetries in use.
  Otherwise it's actively misleading.

  In "kzalloc()", the z is meaningful and an important part of what the
  caller wants.

  In "kzfree()", the z is actively detrimental, because maybe in the
  future we really _might_ want to use that "memfill(0xdeadbeef)" or
  something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

  git grep -w --name-only kzfree |\
  xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:22 -07:00
Alexander A. Klimov
c9fecf505a Replace HTTP links with HTTPS ones: security
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
          If both the HTTP and HTTPS versions
          return 200 OK and serve the same content:
            Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2020-08-06 12:00:05 -07:00
Richard Guy Briggs
f1d9b23cab audit: purge audit_log_string from the intra-kernel audit API
audit_log_string() was inteded to be an internal audit function and
since there are only two internal uses, remove them.  Purge all external
uses of it by restructuring code to use an existing audit_log_format()
or using audit_log_format().

Please see the upstream issue
https://github.com/linux-audit/audit-kernel/issues/84

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-21 11:12:31 -04:00
Linus Torvalds
595a56ac1b linux-kselftest-kunit-5.8-rc1
This Kunit update for Linux 5.8-rc1 consists of:
 
 - Several config fragment fixes from Anders Roxell to improve
   test coverage.
 - Improvements to kunit run script to use defconfig as default and
   restructure the code for config/build/exec/parse from Vitor Massaru Iha
   and David Gow.
 - Miscellaneous documentation warn fix.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEPZKym/RZuOCGeA/kCwJExA0NQxwFAl7etrcACgkQCwJExA0N
 QxzGYg/+KHpPhB31IAjNFKCRqwDooftst3dohhzguxJLpDHdEmVJ4moQhLr4gL+/
 qpi3T9hr4Rx++n/A5NoxDvyJvGr+FAL40U+Of7F2UyHpqQmfKPj37I+yvyeR1JEL
 z4+yXEpfQLZaQkmZ7f3GWHyqN3+xwvyTEy7NYUad7xMxLF/99No+I6RMD6yp3srS
 wUUeuBIesSFT0LXYrgI+wgsNGUESlj/McjiP5eMj6UtlMgKpzmfzH56Fia8uw1pw
 6QtpntxDHjtxVfp8YKM4qExI54YI2t6sgHTIoOUsMWD5Q2kHd8kNf1L+lb1sKYUF
 j7lzol5nuqqchAVQYjHzNHa8XKndvexGyWMsPz1gAnkpgVrvBTSFcavdDpDuDZ0T
 HoJZnk9XPsguBQjDxapzPYfAQ81Un/rEmZQ8/X2TaNjdSIH1hHljhaP2OZ6eND/Q
 iobq9x8nC9D95TIqjDbRw3Sp2na/pZLN8Gp27hmKlc+L1XzV8NuZe/WGOUe3lsrq
 fG1ZSLo/iRau8gHuF6fRSrGIzQSCEMGKl3jlQ28OT9HGMAgTlncEwVzQId48/AsS
 UOY+bIAnRZuK+B5F/vw6L3o1e3c17z5bruVlb0M0alP5b7P9/3WLNHsHA3r8haZF
 F6PwIWu41wdRjJf2HI7zD5LaQe/7oU3jfwvuA7n2z8Py+zGx7m4=
 =S+HY
 -----END PGP SIGNATURE-----

Merge tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kunit updates from Shuah Khan:
 "This consists of:

   - Several config fragment fixes from Anders Roxell to improve test
     coverage.

   - Improvements to kunit run script to use defconfig as default and
     restructure the code for config/build/exec/parse from Vitor Massaru
     Iha and David Gow.

   - Miscellaneous documentation warn fix"

* tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  security: apparmor: default KUNIT_* fragments to KUNIT_ALL_TESTS
  fs: ext4: default KUNIT_* fragments to KUNIT_ALL_TESTS
  drivers: base: default KUNIT_* fragments to KUNIT_ALL_TESTS
  lib: Kconfig.debug: default KUNIT_* fragments to KUNIT_ALL_TESTS
  kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS
  kunit: Kconfig: enable a KUNIT_ALL_TESTS fragment
  kunit: Fix TabError, remove defconfig code and handle when there is no kunitconfig
  kunit: use KUnit defconfig by default
  kunit: use --build_dir=.kunit as default
  Documentation: test.h - fix warnings
  kunit: kunit_tool: Separate out config/build/exec/parse
2020-06-09 10:04:47 -07:00
Linus Torvalds
a2b447066c Tag summary
+ Features
   - Replace zero-length array with flexible-array
   - add a valid state flags check
   - add consistency check between state and dfa diff encode flags
   - add apparmor subdir to proc attr interface
   - fail unpack if profile mode is unknown
   - add outofband transition and use it in xattr match
   - ensure that dfa state tables have entries
 
 + Cleanups
   - Use true and false for bool variable
   - Remove semicolon
   - Clean code by removing redundant instructions
   - Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
   - remove duplicate check of xattrs on profile attachment
   - remove useless aafs_create_symlink
 
 + Bug fixes
   - Fix memory leak of profile proxy
   - fix introspection of of task mode for unconfined tasks
   - fix nnp subset test for unconfined
   - check/put label on apparmor_sk_clone_security()
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEE7cSDD705q2rFEEf7BS82cBjVw9gFAl7dUf4ACgkQBS82cBjV
 w9j8rA//R3qbVeiN3SJtxLhiF3AAdP2cVbZ/mAhQLwYObI6flb1bliiahJHRf8Ey
 FaVb4srOH8NlmzNINZehXOvD3UDwX/sbpw8h0Y0JolO+v1m3UXkt/eRoMt6gRz7I
 jtaImY1/V+G4O5rV5fGA1HQI8Geg+W9Abt32d16vyKIIpnBS/Pfv8ppM0NcHCZ4G
 e8935T/dMNK5K0Y7HNb1nMjyzEr0LtEXvXznBOrGVpCtDQ45m0/NBvAqpfhuKsVm
 FE5Na8rgtiB9sU72LaoNXNr8Y5LVgkXPmBr/e1FqZtF01XEarKb7yJDGOLrLpp1o
 rGYpY9DQSBT/ZZrwMaLFqCd1XtnN1BAmhlM6TXfnm25ArEnQ49ReHFc7ZHZRSTZz
 LWVBD6atZbapvqckk1SU49eCLuGs5wmRj/CmwdoQUbZ+aOfR68zF+0PANbP5xDo4
 862MmeMsm8JHndeCelpZQRbhtXt0t9MDzwMBevKhxV9hbpt4g8DcnC5tNUc9AnJi
 qJDsMkytYhazIW+/4MsnLTo9wzhqzXq5kBeE++Xl7vDE/V+d5ocvQg73xtwQo9sx
 LzMlh3cPmBvOnlpYfnONZP8pJdjDAuESsi/H5+RKQL3cLz7NX31CLWR8dXLBHy80
 Dvxqvy84Cf7buigqwSzgAGKjDI5HmeOECAMjpLbEB2NS9xxQYuk=
 =U7d2
 -----END PGP SIGNATURE-----

Merge tag 'apparmor-pr-2020-06-07' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "Features:
   - Replace zero-length array with flexible-array
   - add a valid state flags check
   - add consistency check between state and dfa diff encode flags
   - add apparmor subdir to proc attr interface
   - fail unpack if profile mode is unknown
   - add outofband transition and use it in xattr match
   - ensure that dfa state tables have entries

  Cleanups:
   - Use true and false for bool variable
   - Remove semicolon
   - Clean code by removing redundant instructions
   - Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
   - remove duplicate check of xattrs on profile attachment
   - remove useless aafs_create_symlink

  Bug fixes:
   - Fix memory leak of profile proxy
   - fix introspection of of task mode for unconfined tasks
   - fix nnp subset test for unconfined
   - check/put label on apparmor_sk_clone_security()"

* tag 'apparmor-pr-2020-06-07' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
  apparmor: Fix memory leak of profile proxy
  apparmor: fix introspection of of task mode for unconfined tasks
  apparmor: check/put label on apparmor_sk_clone_security()
  apparmor: Use true and false for bool variable
  security/apparmor/label.c: Clean code by removing redundant instructions
  apparmor: Replace zero-length array with flexible-array
  apparmor: ensure that dfa state tables have entries
  apparmor: remove duplicate check of xattrs on profile attachment.
  apparmor: add outofband transition and use it in xattr match
  apparmor: fail unpack if profile mode is unknown
  apparmor: fix nnp subset test for unconfined
  apparmor: remove useless aafs_create_symlink
  apparmor: add proc subdir to attrs
  apparmor: add consistency check between state and dfa diff encode flags
  apparmor: add a valid state flags check
  AppArmor: Remove semicolon
  apparmor: Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
2020-06-07 16:04:49 -07:00
John Johansen
3622ad25d4 apparmor: Fix memory leak of profile proxy
When the proxy isn't replaced and the profile is removed, the proxy
is being leaked resulting in a kmemleak check message of

unreferenced object 0xffff888077a3a490 (size 16):
  comm "apparmor_parser", pid 128041, jiffies 4322684109 (age 1097.028s)
  hex dump (first 16 bytes):
    03 00 00 00 00 00 00 00 b0 92 fd 4b 81 88 ff ff  ...........K....
  backtrace:
    [<0000000084d5daf2>] aa_alloc_proxy+0x58/0xe0
    [<00000000ecc0e21a>] aa_alloc_profile+0x159/0x1a0
    [<000000004cc9ce15>] unpack_profile+0x275/0x1c40
    [<000000007332b3ca>] aa_unpack+0x1e7/0x7e0
    [<00000000e25e31bd>] aa_replace_profiles+0x18a/0x1d10
    [<00000000350d9415>] policy_update+0x237/0x650
    [<000000003fbf934e>] profile_load+0x122/0x160
    [<0000000047f7b781>] vfs_write+0x139/0x290
    [<000000008ad12358>] ksys_write+0xcd/0x170
    [<000000001a9daa7b>] do_syscall_64+0x70/0x310
    [<00000000b9efb0cf>] entry_SYSCALL_64_after_hwframe+0x49/0xb3

Make sure to cleanup the profile's embedded label which will result
on the proxy being properly freed.

Fixes: 637f688dc3 ("apparmor: switch from profiles to using labels on contexts")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-06-07 13:38:55 -07:00
John Johansen
dd2569fbb0 apparmor: fix introspection of of task mode for unconfined tasks
Fix two issues with introspecting the task mode.

1. If a task is attached to a unconfined profile that is not the
   ns->unconfined profile then. Mode the mode is always reported
   as -

      $ ps -Z
      LABEL                               PID TTY          TIME CMD
      unconfined                         1287 pts/0    00:00:01 bash
      test (-)                           1892 pts/0    00:00:00 ps

   instead of the correct value of (unconfined) as shown below

      $ ps -Z
      LABEL                               PID TTY          TIME CMD
      unconfined                         2483 pts/0    00:00:01 bash
      test (unconfined)                  3591 pts/0    00:00:00 ps

2. if a task is confined by a stack of profiles that are unconfined
   the output of label mode is again the incorrect value of (-) like
   above, instead of (unconfined). This is because the visibile
   profile count increment is skipped by the special casing of
   unconfined.

Fixes: f1bd904175 ("apparmor: add the base fns() for domain labels")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-06-07 13:38:55 -07:00
Mauricio Faria de Oliveira
3b646abc5b apparmor: check/put label on apparmor_sk_clone_security()
Currently apparmor_sk_clone_security() does not check for existing
label/peer in the 'new' struct sock; it just overwrites it, if any
(with another reference to the label of the source sock.)

    static void apparmor_sk_clone_security(const struct sock *sk,
                                           struct sock *newsk)
    {
            struct aa_sk_ctx *ctx = SK_CTX(sk);
            struct aa_sk_ctx *new = SK_CTX(newsk);

            new->label = aa_get_label(ctx->label);
            new->peer = aa_get_label(ctx->peer);
    }

This might leak label references, which might overflow under load.
Thus, check for and put labels, to prevent such errors.

Note this is similarly done on:

    static int apparmor_socket_post_create(struct socket *sock, ...)
    ...
            if (sock->sk) {
                    struct aa_sk_ctx *ctx = SK_CTX(sock->sk);

                    aa_put_label(ctx->label);
                    ctx->label = aa_get_label(label);
            }
    ...

Context:
-------

The label reference count leak is observed if apparmor_sock_graft()
is called previously: this sets the 'ctx->label' field by getting
a reference to the current label (later overwritten, without put.)

    static void apparmor_sock_graft(struct sock *sk, ...)
    {
            struct aa_sk_ctx *ctx = SK_CTX(sk);

            if (!ctx->label)
                    ctx->label = aa_get_current_label();
    }

And that is the case on crypto/af_alg.c:af_alg_accept():

    int af_alg_accept(struct sock *sk, struct socket *newsock, ...)
    ...
            struct sock *sk2;
            ...
            sk2 = sk_alloc(...);
            ...
            security_sock_graft(sk2, newsock);
            security_sk_clone(sk, sk2);
    ...

Apparently both calls are done on their own right, especially for
other LSMs, being introduced in 2010/2014, before apparmor socket
mediation in 2017 (see commits [1,2,3,4]).

So, it looks OK there! Let's fix the reference leak in apparmor.

Test-case:
---------

Exercise that code path enough to overflow label reference count.

    $ cat aa-refcnt-af_alg.c
    #include <stdio.h>
    #include <string.h>
    #include <unistd.h>
    #include <sys/socket.h>
    #include <linux/if_alg.h>

    int main() {
            int sockfd;
            struct sockaddr_alg sa;

            /* Setup the crypto API socket */
            sockfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
            if (sockfd < 0) {
                    perror("socket");
                    return 1;
            }

            memset(&sa, 0, sizeof(sa));
            sa.salg_family = AF_ALG;
            strcpy((char *) sa.salg_type, "rng");
            strcpy((char *) sa.salg_name, "stdrng");

            if (bind(sockfd, (struct sockaddr *) &sa, sizeof(sa)) < 0) {
                    perror("bind");
                    return 1;
            }

            /* Accept a "connection" and close it; repeat. */
            while (!close(accept(sockfd, NULL, 0)));

            return 0;
    }

    $ gcc -o aa-refcnt-af_alg aa-refcnt-af_alg.c

    $ ./aa-refcnt-af_alg
    <a few hours later>

    [ 9928.475953] refcount_t overflow at apparmor_sk_clone_security+0x37/0x70 in aa-refcnt-af_alg[1322], uid/euid: 1000/1000
    ...
    [ 9928.507443] RIP: 0010:apparmor_sk_clone_security+0x37/0x70
    ...
    [ 9928.514286]  security_sk_clone+0x33/0x50
    [ 9928.514807]  af_alg_accept+0x81/0x1c0 [af_alg]
    [ 9928.516091]  alg_accept+0x15/0x20 [af_alg]
    [ 9928.516682]  SYSC_accept4+0xff/0x210
    [ 9928.519609]  SyS_accept+0x10/0x20
    [ 9928.520190]  do_syscall_64+0x73/0x130
    [ 9928.520808]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Note that other messages may be seen, not just overflow, depending on
the value being incremented by kref_get(); on another run:

    [ 7273.182666] refcount_t: saturated; leaking memory.
    ...
    [ 7273.185789] refcount_t: underflow; use-after-free.

Kprobes:
-------

Using kprobe events to monitor sk -> sk_security -> label -> count (kref):

Original v5.7 (one reference leak every iteration)

 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd2
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd4
 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd3
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd5
 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd4
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd6

Patched v5.7 (zero reference leak per iteration)

 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594
 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594
 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594

Commits:
-------

[1] commit 507cad355f ("crypto: af_alg - Make sure sk_security is initialized on accept()ed sockets")
[2] commit 4c63f83c2c ("crypto: af_alg - properly label AF_ALG socket")
[3] commit 2acce6aa9f ("Networking") a.k.a ("crypto: af_alg - Avoid sock_graft call warning)
[4] commit 56974a6fcf ("apparmor: add base infastructure for socket mediation")

Fixes: 56974a6fcf ("apparmor: add base infastructure for socket mediation")
Reported-by: Brian Moyles <bmoyles@netflix.com>
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-06-07 13:38:56 -07:00
Linus Torvalds
15a2bc4dbb Merge branch 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull execve updates from Eric Biederman:
 "Last cycle for the Nth time I ran into bugs and quality of
  implementation issues related to exec that could not be easily be
  fixed because of the way exec is implemented. So I have been digging
  into exec and cleanup up what I can.

  I don't think I have exec sorted out enough to fix the issues I
  started with but I have made some headway this cycle with 4 sets of
  changes.

   - promised cleanups after introducing exec_update_mutex

   - trivial cleanups for exec

   - control flow simplifications

   - remove the recomputation of bprm->cred

  The net result is code that is a bit easier to understand and work
  with and a decrease in the number of lines of code (if you don't count
  the added tests)"

* 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits)
  exec: Compute file based creds only once
  exec: Add a per bprm->file version of per_clear
  binfmt_elf_fdpic: fix execfd build regression
  selftests/exec: Add binfmt_script regression test
  exec: Remove recursion from search_binary_handler
  exec: Generic execfd support
  exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC
  exec: Move the call of prepare_binprm into search_binary_handler
  exec: Allow load_misc_binary to call prepare_binprm unconditionally
  exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds
  exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
  exec: Teach prepare_exec_creds how exec treats uids & gids
  exec: Set the point of no return sooner
  exec: Move handling of the point of no return to the top level
  exec: Run sync_mm_rss before taking exec_update_mutex
  exec: Fix spelling of search_binary_handler in a comment
  exec: Move the comment from above de_thread to above unshare_sighand
  exec: Rename flush_old_exec begin_new_exec
  exec: Move most of setup_new_exec into flush_old_exec
  exec: In setup_new_exec cache current in the local variable me
  ...
2020-06-04 14:07:08 -07:00
Anders Roxell
6d6861d45e security: apparmor: default KUNIT_* fragments to KUNIT_ALL_TESTS
This makes it easier to enable all KUnit fragments.

Adding 'if !KUNIT_ALL_TESTS' so individual tests can not be turned off.
Therefore if KUNIT_ALL_TESTS is enabled that will hide the prompt in
menuconfig.

Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2020-06-01 14:25:15 -06:00
David S. Miller
13209a8f73 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
The MSCC bug fix in 'net' had to be slightly adjusted because the
register accesses are done slightly differently in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-24 13:47:27 -07:00
Navid Emamdoost
c54d481d71 apparmor: Fix use-after-free in aa_audit_rule_init
In the implementation of aa_audit_rule_init(), when aa_label_parse()
fails the allocated memory for rule is released using
aa_audit_rule_free(). But after this release, the return statement
tries to access the label field of the rule which results in
use-after-free. Before releasing the rule, copy errNo and return it
after release.

Fixes: 52e8c38001 ("apparmor: Fix memory leak of rule on error exit path")
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-05-21 15:25:51 -07:00
Xiyu Yang
c6b39f0707 apparmor: Fix aa_label refcnt leak in policy_update
policy_update() invokes begin_current_label_crit_section(), which
returns a reference of the updated aa_label object to "label" with
increased refcount.

When policy_update() returns, "label" becomes invalid, so the refcount
should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
policy_update(). When aa_may_manage_policy() returns not NULL, the
refcnt increased by begin_current_label_crit_section() is not decreased,
causing a refcnt leak.

Fix this issue by jumping to "end_section" label when
aa_may_manage_policy() returns not NULL.

Fixes: 5ac8c355ae ("apparmor: allow introspecting the loaded policy pre internal transform")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-05-21 15:25:51 -07:00
Xiyu Yang
a0b845ffa0 apparmor: fix potential label refcnt leak in aa_change_profile
aa_change_profile() invokes aa_get_current_label(), which returns
a reference of the current task's label.

According to the comment of aa_get_current_label(), the returned
reference must be put with aa_put_label().
However, when the original object pointed by "label" becomes
unreachable because aa_change_profile() returns or a new object
is assigned to "label", reference count increased by
aa_get_current_label() is not decreased, causing a refcnt leak.

Fix this by calling aa_put_label() before aa_change_profile() return
and dropping unnecessary aa_get_current_label().

Fixes: 9fcf78cca1 ("apparmor: update domain transitions that are subsets of confinement at nnp")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-05-21 15:25:51 -07:00
Eric W. Biederman
b8bff59926 exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
Today security_bprm_set_creds has several implementations:
apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds,
smack_bprm_set_creds, and tomoyo_bprm_set_creds.

Except for cap_bprm_set_creds they all test bprm->called_set_creds and
return immediately if it is true.  The function cap_bprm_set_creds
ignores bprm->calld_sed_creds entirely.

Create a new LSM hook security_bprm_creds_for_exec that is called just
before prepare_binprm in __do_execve_file, resulting in a LSM hook
that is called exactly once for the entire of exec.  Modify the bits
of security_bprm_set_creds that only want to be called once per exec
into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds
behind.

Remove bprm->called_set_creds all of it's former users have been moved
to security_bprm_creds_for_exec.

Add or upate comments a appropriate to bring them up to date and
to reflect this change.

Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-20 14:45:31 -05:00
Zou Wei
e37986097b apparmor: Use true and false for bool variable
Fixes coccicheck warnings:

security/apparmor/file.c:162:9-10: WARNING: return of 0/1 in function 'is_deleted' with return type bool
security/apparmor/file.c:362:9-10: WARNING: return of 0/1 in function 'xindex_is_subset' with return type bool
security/apparmor/policy_unpack.c:246:9-10: WARNING: return of 0/1 in function 'unpack_X' with return type bool
security/apparmor/policy_unpack.c:292:9-10: WARNING: return of 0/1 in function 'unpack_nameX' with return type bool
security/apparmor/policy_unpack.c:646:8-9: WARNING: return of 0/1 in function 'unpack_rlimits' with return type bool
security/apparmor/policy_unpack.c:604:8-9: WARNING: return of 0/1 in function 'unpack_secmark' with return type bool
security/apparmor/policy_unpack.c:538:8-9: WARNING: return of 0/1 in function 'unpack_trans_table' with return type bool
security/apparmor/policy_unpack.c:327:9-10: WARNING: return of 0/1 in function 'unpack_u32' with return type bool
security/apparmor/policy_unpack.c:345:9-10: WARNING: return of 0/1 in function 'unpack_u64' with return type bool
security/apparmor/policy_unpack.c:309:9-10: WARNING: return of 0/1 in function 'unpack_u8' with return type bool
security/apparmor/policy_unpack.c:568:8-9: WARNING: return of 0/1 in function 'unpack_xattrs' with return type bool
security/apparmor/policy_unpack.c:1007:10-11: WARNING: return of 0/1 in function 'verify_dfa_xindex' with return type bool
security/apparmor/policy_unpack.c:997:9-10: WARNING: return of 0/1 in function 'verify_xindex' with return type bool

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-05-15 14:26:33 -07:00
Mateusz Nosek
c84b80cd41 security/apparmor/label.c: Clean code by removing redundant instructions
Previously 'label->proxy->label' value checking
and conditional reassigning were done twice in the same function.
The second one is redundant and can be removed.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-05-15 14:22:40 -07:00
Gustavo A. R. Silva
fe9fd23e3b apparmor: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-05-15 13:04:55 -07:00
Christoph Hellwig
32927393dc sysctl: pass kernel pointers to ->proc_handler
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:07:40 -04:00
John Johansen
c27c6bd2c4 apparmor: ensure that dfa state tables have entries
Currently it is possible to specify a state machine table with 0 length,
this is not valid as optional tables are specified by not defining
the table as present. Further this allows by-passing the base tables
range check against the next/check tables.

Fixes: d901d6a298 ("apparmor: dfa split verification of table headers")
Reported-by: Mike Salvatore <mike.salvatore@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-04-08 04:42:48 -07:00
Masahiro Yamada
d198b34f38 .gitignore: add SPDX License Identifier
Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-25 11:50:48 +01:00
Masahiro Yamada
2985bed680 .gitignore: remove too obvious comments
Some .gitignore files have comments like "Generated files",
"Ignore generated files" at the header part, but they are
too obvious.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-25 11:50:28 +01:00
Linus Torvalds
08a3ef8f6b linux-kselftest-5.6-rc1-kunit
This kunit update for Linux 5.6-rc1 consists of:
 
 -- Support for building kunit as a module from Alan Maguire
 -- AppArmor KUnit tests for policy unpack from Mike Salvatore
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEPZKym/RZuOCGeA/kCwJExA0NQxwFAl4xz/wACgkQCwJExA0N
 Qxyg2A//X0bnhN82oCchkTRW3GyGi5wTR2wGhoNzMZD0XUtCvn+4BlCSP20ttYdT
 beiLCiewcuEdvXRyEV9Kikvet/67ovbjA/ce6ZrR7TlIHo8esKcy19/nu1OTvtI1
 8eji1q7NSEV9iswz1ZoBAw+MTDHZfOI9qYY2UPcwjy7xWN84z2X1w+8UQ3EamOKd
 6BfbohsYuuTTHhA2k1aUzvQcHqNz0YdH4yvNQpdunJXLUI04TeGZA6Ug66u6kWEd
 1f5SSAu6r1vnU7DADrb1QwEDuIwL4KBuaMg2Rj5GLxTNp3wxmW9M2Dit+iN7+vNH
 TS31kZW6KgxC5XuGVPENJaWlDX5Hm+5W8uiRZLNXsxDy927u53RzwrSZw/FbdbB1
 HuPZZCzE1soWHdPIQz44HCCAg9XddypYlC1o4IYL1JkJknqG12ky4xgM8GRNCZAB
 oUW3Ax3Lcr0EJALO/kFd/uEbl79PdmDk8uPMU1jtLyx5cs70yC3fsT2GB+DbP802
 i/FxTtrOMGjU2OWcYfQcXapvZdgImf9nPsSZe3FJXjHfytNRbVZOZ2rHAMh03Keu
 EBthDs6ejm6OUSGUXjngE9NaQKXsNSQ1Qor+6FrGnT4IxUMzWenudqHH7/dgF7Fr
 fHlZGBilKMc/EYKb/6hj4kvEChrSIXj6TFknmI28I/epPiOr2gU=
 =AFO4
 -----END PGP SIGNATURE-----

Merge tag 'linux-kselftest-5.6-rc1-kunit' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest kunit updates from Shuah Khan:
 "This kunit update consists of:

   - Support for building kunit as a module from Alan Maguire

   - AppArmor KUnit tests for policy unpack from Mike Salvatore"

* tag 'linux-kselftest-5.6-rc1-kunit' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: building kunit as a module breaks allmodconfig
  kunit: update documentation to describe module-based build
  kunit: allow kunit to be loaded as a module
  kunit: remove timeout dependence on sysctl_hung_task_timeout_seconds
  kunit: allow kunit tests to be loaded as a module
  kunit: hide unexported try-catch interface in try-catch-impl.h
  kunit: move string-stream.h to lib/kunit
  apparmor: add AppArmor KUnit tests for policy unpack
2020-01-29 15:25:34 -08:00
Linus Torvalds
6aee4badd8 Merge branch 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull openat2 support from Al Viro:
 "This is the openat2() series from Aleksa Sarai.

  I'm afraid that the rest of namei stuff will have to wait - it got
  zero review the last time I'd posted #work.namei, and there had been a
  leak in the posted series I'd caught only last weekend. I was going to
  repost it on Monday, but the window opened and the odds of getting any
  review during that... Oh, well.

  Anyway, openat2 part should be ready; that _did_ get sane amount of
  review and public testing, so here it comes"

From Aleksa's description of the series:
 "For a very long time, extending openat(2) with new features has been
  incredibly frustrating. This stems from the fact that openat(2) is
  possibly the most famous counter-example to the mantra "don't silently
  accept garbage from userspace" -- it doesn't check whether unknown
  flags are present[1].

  This means that (generally) the addition of new flags to openat(2) has
  been fraught with backwards-compatibility issues (O_TMPFILE has to be
  defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old
  kernels gave errors, since it's insecure to silently ignore the
  flag[2]). All new security-related flags therefore have a tough road
  to being added to openat(2).

  Furthermore, the need for some sort of control over VFS's path
  resolution (to avoid malicious paths resulting in inadvertent
  breakouts) has been a very long-standing desire of many userspace
  applications.

  This patchset is a revival of Al Viro's old AT_NO_JUMPS[3] patchset
  (which was a variant of David Drysdale's O_BENEATH patchset[4] which
  was a spin-off of the Capsicum project[5]) with a few additions and
  changes made based on the previous discussion within [6] as well as
  others I felt were useful.

  In line with the conclusions of the original discussion of
  AT_NO_JUMPS, the flag has been split up into separate flags. However,
  instead of being an openat(2) flag it is provided through a new
  syscall openat2(2) which provides several other improvements to the
  openat(2) interface (see the patch description for more details). The
  following new LOOKUP_* flags are added:

  LOOKUP_NO_XDEV:

     Blocks all mountpoint crossings (upwards, downwards, or through
     absolute links). Absolute pathnames alone in openat(2) do not
     trigger this. Magic-link traversal which implies a vfsmount jump is
     also blocked (though magic-link jumps on the same vfsmount are
     permitted).

  LOOKUP_NO_MAGICLINKS:

     Blocks resolution through /proc/$pid/fd-style links. This is done
     by blocking the usage of nd_jump_link() during resolution in a
     filesystem. The term "magic-links" is used to match with the only
     reference to these links in Documentation/, but I'm happy to change
     the name.

     It should be noted that this is different to the scope of
     ~LOOKUP_FOLLOW in that it applies to all path components. However,
     you can do openat2(NO_FOLLOW|NO_MAGICLINKS) on a magic-link and it
     will *not* fail (assuming that no parent component was a
     magic-link), and you will have an fd for the magic-link.

     In order to correctly detect magic-links, the introduction of a new
     LOOKUP_MAGICLINK_JUMPED state flag was required.

  LOOKUP_BENEATH:

     Disallows escapes to outside the starting dirfd's
     tree, using techniques such as ".." or absolute links. Absolute
     paths in openat(2) are also disallowed.

     Conceptually this flag is to ensure you "stay below" a certain
     point in the filesystem tree -- but this requires some additional
     to protect against various races that would allow escape using
     "..".

     Currently LOOKUP_BENEATH implies LOOKUP_NO_MAGICLINKS, because it
     can trivially beam you around the filesystem (breaking the
     protection). In future, there might be similar safety checks done
     as in LOOKUP_IN_ROOT, but that requires more discussion.

  In addition, two new flags are added that expand on the above ideas:

  LOOKUP_NO_SYMLINKS:

     Does what it says on the tin. No symlink resolution is allowed at
     all, including magic-links. Just as with LOOKUP_NO_MAGICLINKS this
     can still be used with NOFOLLOW to open an fd for the symlink as
     long as no parent path had a symlink component.

  LOOKUP_IN_ROOT:

     This is an extension of LOOKUP_BENEATH that, rather than blocking
     attempts to move past the root, forces all such movements to be
     scoped to the starting point. This provides chroot(2)-like
     protection but without the cost of a chroot(2) for each filesystem
     operation, as well as being safe against race attacks that
     chroot(2) is not.

     If a race is detected (as with LOOKUP_BENEATH) then an error is
     generated, and similar to LOOKUP_BENEATH it is not permitted to
     cross magic-links with LOOKUP_IN_ROOT.

     The primary need for this is from container runtimes, which
     currently need to do symlink scoping in userspace[7] when opening
     paths in a potentially malicious container.

     There is a long list of CVEs that could have bene mitigated by
     having RESOLVE_THIS_ROOT (such as CVE-2017-1002101,
     CVE-2017-1002102, CVE-2018-15664, and CVE-2019-5736, just to name a
     few).

  In order to make all of the above more usable, I'm working on
  libpathrs[8] which is a C-friendly library for safe path resolution.
  It features a userspace-emulated backend if the kernel doesn't support
  openat2(2). Hopefully we can get userspace to switch to using it, and
  thus get openat2(2) support for free once it's ready.

  Future work would include implementing things like
  RESOLVE_NO_AUTOMOUNT and possibly a RESOLVE_NO_REMOTE (to allow
  programs to be sure they don't hit DoSes though stale NFS handles)"

* 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  Documentation: path-lookup: include new LOOKUP flags
  selftests: add openat2(2) selftests
  open: introduce openat2(2) syscall
  namei: LOOKUP_{IN_ROOT,BENEATH}: permit limited ".." resolution
  namei: LOOKUP_IN_ROOT: chroot-like scoped resolution
  namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution
  namei: LOOKUP_NO_XDEV: block mountpoint crossing
  namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution
  namei: LOOKUP_NO_SYMLINKS: block symlink resolution
  namei: allow set_root() to produce errors
  namei: allow nd_jump_link() to produce errors
  nsfs: clean-up ns_get_path() signature to return int
  namei: only return -ECHILD from follow_dotdot_rcu()
2020-01-29 11:20:24 -08:00
John Johansen
01df52d726 apparmor: remove duplicate check of xattrs on profile attachment.
The second check to ensure the xattrs are present and checked is
unneeded as this is already done in the profile attachment xmatch.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-21 06:00:20 -08:00
John Johansen
0df34a645b apparmor: add outofband transition and use it in xattr match
There are cases where the a special out of band transition that can
not be triggered by input is useful in separating match conditions
in the dfa encoding.

The null_transition is currently used as an out of band transition
for match conditions that can not contain a \0 in their input
but apparmor needs an out of band transition for cases where
the match condition is allowed to contain any input character.

Achieve this by allowing for an explicit transition out of input
range that can only be triggered by code.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-21 06:00:20 -08:00
John Johansen
f05841a940 apparmor: fail unpack if profile mode is unknown
Profile unpack should fail if the profile mode is not a mode that the
kernel understands.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-21 05:58:53 -08:00
John Johansen
3ed4aaa94f apparmor: fix nnp subset test for unconfined
The subset test is not taking into account the unconfined exception
which will cause profile transitions in the stacked confinement
case to fail when no_new_privs is applied.

This fixes a regression introduced in the fix for
https://bugs.launchpad.net/bugs/1839037

BugLink: https://bugs.launchpad.net/bugs/1844186
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-21 05:58:04 -08:00
John Johansen
a68d59ff4d apparmor: remove useless aafs_create_symlink
commit 1180b4c757 ("apparmor: fix dangling symlinks to policy
rawdata after replacement") reworked how the rawdata symlink is
handled but failedto remove aafs_create_symlink which was reduced to a
useles stub.

Fixes: 1180b4c757 ("apparmor: fix dangling symlinks to policy rawdata after replacement")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-21 05:55:38 -08:00
John Johansen
dae6029325 apparmor: add consistency check between state and dfa diff encode flags
Check that a states diff encode flag is only set if diff encode is
enabled in the dfa header.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-18 15:37:49 -08:00
John Johansen
c659696964 apparmor: add a valid state flags check
Add a check to ensure only known state flags are set on each
state in the dfa.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-18 15:37:24 -08:00
Vasyl Gomonovych
e4f4e6ba5e AppArmor: Remove semicolon
Remove unneeded semicolon

Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-18 15:36:58 -08:00
Markus Elfring
278de07ef8 apparmor: Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
Two strings which did not contain a data format specification should be put
into a sequence. Thus use the corresponding function “seq_puts”.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-18 15:35:23 -08:00
Alan Maguire
35c57fc3f8 kunit: building kunit as a module breaks allmodconfig
kunit tests that do not support module build should depend
on KUNIT=y rather than just KUNIT in Kconfig, otherwise
they will trigger compilation errors for "make allmodconfig"
builds.

Fixes: 9fe124bf1b ("kunit: allow kunit to be loaded as a module")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2020-01-10 14:36:37 -07:00
Mike Salvatore
4d944bcd4e apparmor: add AppArmor KUnit tests for policy unpack
Add KUnit tests to test AppArmor unpacking of userspace policies.
AppArmor uses a serialized binary format for loading policies. To find
policy format documentation see
Documentation/admin-guide/LSM/apparmor.rst.

In order to write the tests against the policy unpacking code, some
static functions needed to be exposed for testing purposes. One of the
goals of this patch is to establish a pattern for which testing these
kinds of functions should be done in the future.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Mike Salvatore <mike.salvatore@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2020-01-09 16:27:43 -07:00
John Johansen
8c62ed27a1 apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock
aa_xattrs_match() is unfortunately calling vfs_getxattr_alloc() from a
context protected by an rcu_read_lock. This can not be done as
vfs_getxattr_alloc() may sleep regardles of the gfp_t value being
passed to it.

Fix this by breaking the rcu_read_lock on the policy search when the
xattr match feature is requested and restarting the search if a policy
changes occur.

Fixes: 8e51f9087f ("apparmor: Add support for attaching profiles via xattr, presence and value")
Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-04 15:56:44 -08:00
John Johansen
20d4e80d25 apparmor: only get a label reference if the fast path check fails
The common fast path check can be done under rcu_read_lock() and
doesn't need a reference count on the label. Only take a reference
count if entering the slow path.

Fixes reported hackbench regression
  - sha1 79e178a57d ("Merge tag 'apparmor-pr-2019-12-03' of
    git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor")

  hackbench -l (256000/#grp) -g #grp
   128 groups     19.679 ±0.90%

  - previous sha1 01d1dff646 ("Merge tag 's390-5.5-2' of
    git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux")

  hackbench -l (256000/#grp) -g #grp
   128 groups     3.1689 ±3.04%

Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Fixes: bce4e7e9c4 ("apparmor: reduce rcu_read_lock scope for aa_file_perm mediation")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-02 05:31:40 -08:00
Patrick Steinhardt
9c95a278ba apparmor: fix bind mounts aborting with -ENOMEM
With commit df323337e5 ("apparmor: Use a memory pool instead per-CPU
caches, 2019-05-03"), AppArmor code was converted to use memory pools. In
that conversion, a bug snuck into the code that polices bind mounts that
causes all bind mounts to fail with -ENOMEM, as we erroneously error out
if `aa_get_buffer` returns a pointer instead of erroring out when it
does _not_ return a valid pointer.

Fix the issue by correctly checking for valid pointers returned by
`aa_get_buffer` to fix bind mounts with AppArmor.

Fixes: df323337e5 ("apparmor: Use a memory pool instead per-CPU caches")
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-01-02 05:31:40 -08:00
Aleksa Sarai
1bc82070fa namei: allow nd_jump_link() to produce errors
In preparation for LOOKUP_NO_MAGICLINKS, it's necessary to add the
ability for nd_jump_link() to return an error which the corresponding
get_link() caller must propogate back up to the VFS.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-08 19:09:38 -05:00