linux-kernel - [PATCH 2.2] CAP_FS_MASK: add CAP_LINUX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Wed, 25 Mar 2009 12:39:04 -0500
From:	"Serge E. Hallyn" <serue@...ibm.com>
To:	Marc-Christian Petersen <m.c.p@...k-project.de>
Cc:	mtk.manpages@...il.com, Stephen Smalley <sds@...ch.ncsc.mil>,
	Andrew Morgan <morgan@...nel.org>,
	linux-security-module@...r.kernel.org,
	lkml <linux-kernel@...r.kernel.org>, linux-nfs@...r.kernel.org,
	Igor Zhbanov <izh1979@...il.com>, stable@...nel.org,
	linux-api@...r.kernel.org, Chris Wright <chrisw@...s-sol.org>
Subject: [PATCH 2.2] CAP_FS_MASK: add CAP_LINUX_IMMUTABLE

When POSIX capabilities were introduced during the 2.1 Linux
cycle, the fs mask, which represents the capabilities which having
fsuid==0 is supposed to grant, did not include CAP_MKNOD and
CAP_LINUX_IMMUTABLE.  However, before capabilities the privilege
to call these did in fact depend upon fsuid==0.

However, 2.2 does not have CAP_MKNOD, instead using CAP_SYS_ADMIN
to authorize sys_mknod.  We don't want to put CAP_SYS_ADMIN in
CAP_FS_MASK because it carries too many non-fs implications.

This patch introduces CAP_LINUX_IMMUTABLE into the fsmask.

See the thread starting at http://lkml.org/lkml/2009/3/11/157 for
reference.

Reported-by: Igor Zhbanov <izh1979@...il.com>
Signed-off-by: Serge E. Hallyn <serue@...ibm.com>
Cc: stable@...nel.org
---
 include/linux/capability.h |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff -Nrup linux-2.2.26/include/linux/capability.h linux-2.2.26.new/include/linux/capability.h
--- linux-2.2.26/include/linux/capability.h	2004-02-23 07:44:47.000000000 -0600
+++ linux-2.2.26.new/include/linux/capability.h	2009-03-25 11:12:08.000000000 -0500
@@ -98,10 +98,6 @@ typedef __u32 kernel_cap_t;
 
 #define CAP_FSETID           4
 
-/* Used to decide between falling back on the old suser() or fsuser(). */
-
-#define CAP_FS_MASK          0x1f
-
 /* Overrides the restriction that the real or effective user ID of a
    process sending a signal must match the real or effective user ID
    of the process receiving the signal. */
@@ -288,6 +284,15 @@ extern kernel_cap_t cap_bset;
 
 #endif
 
+/* Used to decide between falling back on the old suser() or fsuser(). */
+
+#define CAP_FS_MASK	(CAP_TO_MASK(CAP_CHOWN)			\
+			| CAP_TO_MASK(CAP_DAC_OVERRIDE)		\
+			| CAP_TO_MASK(CAP_DAC_READ_SEARCH)	\
+			| CAP_TO_MASK(CAP_FOWNER)		\
+			| CAP_TO_MASK(CAP_FSETID)		\
+			| CAP_TO_MASK(CAP_LINUX_IMMUTABLE))
+
 #define CAP_EMPTY_SET       to_cap_t(0)
 #define CAP_FULL_SET        to_cap_t(~0)
 #define CAP_INIT_EFF_SET    to_cap_t(~0 & ~CAP_TO_MASK(CAP_SETPCAP))
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/