Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1183941 > unrolled thread

[PATCH v4 0/2] capabilities: Ambient capability patchset

Back to article view | Back to linux.kernel

Contents

  [PATCH v4 0/2] capabilities: Ambient capability patchset Andy Lutomirski <luto@kernel.org> - 2015-07-14 21:50 +0200
    [PATCH v4 2/2] capabilities: Add a securebit to disable PR_CAP_AMBIENT_RAISE Andy Lutomirski <luto@kernel.org> - 2015-07-14 21:50 +0200

#1183941 — [PATCH v4 0/2] capabilities: Ambient capability patchset

This adds ambient capabilities.  See the individual patch changelogs
for details.

Preliminary userspace code is here, but it needs updating:

https://git.kernel.org/cgit/linux/kernel/git/luto/util-linux-playground.git/commit/?h=cap_ambient&id=7f5afbd175d2

Changes from v3:
 - Rename PR_CAP_AMBIENT_READ to PR_CAP_AMBIENT_IS_SET (Michael Kerrisk)
 - Add PR_CAP_AMBIENT_CLEAR_ALL (Michael Kerrisk)
 - Add acks from v2

Changes from v2:
 - Improve the patch 1 changelog a bit.
 - Add acks.
 - Add comment clarifying the pE' rule.
 - s/except/expect

Changes from v1:
 - Lots of cleanups to the ambient cap code.
 - The securebit is new.
 
Andy Lutomirski (2):
  capabilities: Ambient capabilities
  capabilities: Add a securebit to disable PR_CAP_AMBIENT_RAISE

 fs/proc/array.c                 |   5 +-
 include/linux/cred.h            |   8 ++++
 include/uapi/linux/prctl.h      |   7 +++
 include/uapi/linux/securebits.h |  11 ++++-
 kernel/user_namespace.c         |   1 +
 security/commoncap.c            | 103 ++++++++++++++++++++++++++++++++++++----
 security/keys/process_keys.c    |   1 +
 7 files changed, 124 insertions(+), 12 deletions(-)

-- 
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1183944 — [PATCH v4 2/2] capabilities: Add a securebit to disable PR_CAP_AMBIENT_RAISE

Per Andrew Morgan's request, add a securebit to allow admins to
disable PR_CAP_AMBIENT_RAISE.  This securebit will prevent processes
from adding capabilities to their ambient set.

For simplicity, this disables PR_CAP_AMBIENT_RAISE entirely rather
than just disabling setting previously cleared bits.

Acked-By: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Aaron Jones <aaronmdjones@gmail.com>
CC: Ted Ts'o <tytso@mit.edu>
Cc: linux-security-module@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: akpm@linuxfoundation.org
Cc: Andrew G. Morgan <morgan@kernel.org>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Austin S Hemmelgarn <ahferroin7@gmail.com>
Cc: Markku Savela <msa@moth.iki.fi>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 include/uapi/linux/securebits.h | 11 ++++++++++-
 security/commoncap.c            |  3 ++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/securebits.h b/include/uapi/linux/securebits.h
index 985aac9e6bf8..35ac35cef217 100644
--- a/include/uapi/linux/securebits.h
+++ b/include/uapi/linux/securebits.h
@@ -43,9 +43,18 @@
 #define SECBIT_KEEP_CAPS	(issecure_mask(SECURE_KEEP_CAPS))
 #define SECBIT_KEEP_CAPS_LOCKED (issecure_mask(SECURE_KEEP_CAPS_LOCKED))
 
+/* When set, a process cannot add new capabilities to its ambient set. */
+#define SECURE_NO_CAP_AMBIENT_RAISE		6
+#define SECURE_NO_CAP_AMBIENT_RAISE_LOCKED	7  /* make bit-6 immutable */
+
+#define SECBIT_NO_CAP_AMBIENT_RAISE (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE))
+#define SECBIT_NO_CAP_AMBIENT_RAISE_LOCKED \
+			(issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE_LOCKED))
+
 #define SECURE_ALL_BITS		(issecure_mask(SECURE_NOROOT) | \
 				 issecure_mask(SECURE_NO_SETUID_FIXUP) | \
-				 issecure_mask(SECURE_KEEP_CAPS))
+				 issecure_mask(SECURE_KEEP_CAPS) | \
+				 issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE))
 #define SECURE_ALL_LOCKS	(SECURE_ALL_BITS << 1)
 
 #endif /* _UAPI_LINUX_SECUREBITS_H */
diff --git a/security/commoncap.c b/security/commoncap.c
index 1f74dde1063e..1832cf701c3d 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -993,7 +993,8 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			if (arg2 == PR_CAP_AMBIENT_RAISE &&
 			    (!cap_raised(current_cred()->cap_permitted, arg3) ||
 			     !cap_raised(current_cred()->cap_inheritable,
-					 arg3)))
+					 arg3) ||
+			     issecure(SECURE_NO_CAP_AMBIENT_RAISE)))
 				return -EPERM;
 
 			new = prepare_creds();
-- 
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web