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On Tue, 2009-05-19 at 00:05 -0400, Eamon Walsh wrote:
> Recent versions of coreutils have bumped the read buffer size from 4K to
> 32K in several of the utilities.
>
> This means that "cat /selinux/booleans/xserver_object_manager" no longer
> works, it returns "Invalid argument" on F11. getsebool works fine.
>
> sel_read_bool has a check for "count > PAGE_SIZE" that doesn't seem to
> be present in the other read functions. Maybe it could be removed?
Yes, that check is obsoleted by the conversion of those functions to
using simple_read_from_buffer(), which will reduce count if necessary to
what is available in the buffer.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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This patch enables applications to handle permissive domain correctly.
Since the v2.6.26 kernel, SELinux has supported an idea of permissive
domain which allows certain processes to work as if permissive mode,
even if the global setting is enforcing mode.
However, we don't have an application program interface to inform
what domains are permissive one, and what domains are not.
It means applications focuses on SELinux (XACE/SELinux, SE-PostgreSQL
and so on) cannot handle permissive domain correctly.
This patch add the sixth field (flags) on the reply of the /selinux/access
interface which is used to make an access control decision from userspace.
If the first bit of the flags field is positive, it means the required
access control decision is on permissive domain, so application should
allow any required actions, as the kernel doing.
This patch also has a side benefit. The av_decision.flags is set at
context_struct_compute_av(). It enables to check required permissions
without read_lock(&policy_rwlock).
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@redhat.com>
--
security/selinux/avc.c | 2 +-
security/selinux/include/security.h | 4 +++-
security/selinux/selinuxfs.c | 4 ++--
security/selinux/ss/services.c | 30 +++++-------------------------
4 files changed, 11 insertions(+), 29 deletions(-)
Signed-off-by: James Morris <jmorris@namei.org>
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The SELinux "compat_net" is marked as deprecated, the time has come to
finally remove it from the kernel. Further code simplifications are
likely in the future, but this patch was intended to be a simple,
straight-up removal of the compat_net code.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
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It appears there was an intention to have the security server only decide
certain permissions and leave other for later as some sort of a portential
performance win. We are currently always deciding all 32 bits of
permissions and this is a useless couple of branches and wasted space.
This patch completely drops the av.decided concept.
This in a 17% reduction in the time spent in avc_has_perm_noaudit
based on oprofile sampling of a tbench benchmark.
Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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... and don't bother in callers. Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.
i_mode is not worth the effort; it has no common default value.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Impact: cleanup
In future, all cpumask ops will only be valid (in general) for bit
numbers < nr_cpu_ids. So use that instead of NR_CPUS in iterators
and other comparisons.
This is always safe: no cpu number can be >= nr_cpu_ids, and
nr_cpu_ids is initialized to NR_CPUS at boot.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: James Morris <jmorris@namei.org>
Cc: Eric Biederman <ebiederm@xmission.com>
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This patch is the first step towards removing the old "compat_net" code from
the kernel. Secmark, the "compat_net" replacement was first introduced in
2.6.18 (September 2006) and the major Linux distributions with SELinux support
have transitioned to Secmark so it is time to start deprecating the "compat_net"
mechanism. Testing a patched version of 2.6.28-rc6 with the initial release of
Fedora Core 5 did not show any problems when running in enforcing mode.
This patch adds an entry to the feature-removal-schedule.txt file and removes
the SECURITY_SELINUX_ENABLE_SECMARK_DEFAULT configuration option, forcing
Secmark on by default although it can still be disabled at runtime. The patch
also makes the Secmark permission checks "dynamic" in the sense that they are
only executed when Secmark is configured; this should help prevent problems
with older distributions that have not yet migrated to Secmark.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: James Morris <jmorris@namei.org>
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Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Separate the task security context from task_struct. At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.
Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.
With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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I've gotten complaints and reports about people not understanding the
meaning of the current unknown class/perm handling the kernel emits on
every policy load. Hopefully this will make make it clear to everyone
the meaning of the message and won't waste a printk the user won't care
about anyway on systems where the kernel and the policy agree on
everything.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Formatting and syntax changes
whitespace, tabs to spaces, trailing space
put open { on same line as struct def
remove unneeded {} after if statements
change printk("Lu") to printk("llu")
convert asm/uaccess.h to linux/uaacess.h includes
remove unnecessary asm/bug.h includes
convert all users of simple_strtol to strict_strtol
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6:
SELinux: one little, two little, three little whitespaces, the avc.c saga.
SELinux: cleanup on isle selinuxfs.c
changing whitespace for fun and profit: policydb.c
SELinux: whitespace and formating fixes for hooks.c
SELinux: clean up printks
SELinux: sidtab.c whitespace, syntax, and static declaraction cleanups
SELinux: services.c whitespace, syntax, and static declaraction cleanups
SELinux: mls.c whitespace, syntax, and static declaraction cleanups
SELinux: hashtab.c whitespace, syntax, and static declaraction cleanups
SELinux: ebitmap.c whitespace, syntax, and static declaraction cleanups
SELinux: conditional.c whitespace, syntax, and static declaraction cleanups
SELinux: avtab.c whitespace, syntax, and static declaraction cleanups
SELinux: xfrm.c whitespace, syntax, and static declaraction cleanups
SELinux: nlmsgtab.c whitespace, syntax, and static declaraction cleanups
SELinux: netnode.c whitespace, syntax, and static declaraction cleanups
SELinux: netlink.c whitespace, syntax, and static declaraction cleanups
SELinux: netlabel.c whitespace, syntax, and static declaraction cleanups
SELinux: netif.c whitespace, syntax, and static declaraction cleanups
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Why would anyone just clean up white space all day? Because they were
out too late last night and don't want to think for a day. So here is a
nice clean selinuxfs.c patch.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Make sure all printk start with KERN_*
Make sure all printk end with \n
Make sure all printk have the word 'selinux' in them
Change "function name" to "%s", __func__ (found 2 wrong)
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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None of these files use any of the functionality promised by
asm/semaphore.h.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
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__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>
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Adds a new open permission inside SELinux when 'opening' a file. The idea
is that opening a file and reading/writing to that file are not the same
thing. Its different if a program had its stdout redirected to /tmp/output
than if the program tried to directly open /tmp/output. This should allow
policy writers to more liberally give read/write permissions across the
policy while still blocking many design and programing flaws SELinux is so
good at catching today.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
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In order to correlate audit records to an individual login add a session
id. This is incremented every time a user logs in and is included in
almost all messages which currently output the auid. The field is
labeled ses= or oses=
Signed-off-by: Eric Paris <eparis@redhat.com>
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all callers pass something->audit_context
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Add a new policy capabilities bitmap to SELinux policy version 22. This bitmap
will enable the security server to query the policy to determine which features
it supports.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Constify function pointer tables and fields.
Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: James Morris <jmorris@namei.org>
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Instead of using f_op to detect dead booleans, check the inode index
against the number of booleans and check the dentry name against the
boolean name for that index on reads and writes. This prevents
incorrect use of a boolean file opened prior to a policy reload while
allowing valid use of it as long as it still corresponds to the same
boolean in the policy.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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Do not clear f_op when removing entries since it isn't safe to do.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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Allow policy to select, in much the same way as it selects MLS support, how
the kernel should handle access decisions which contain either unknown
classes or unknown permissions in known classes. The three choices for the
policy flags are
0 - Deny unknown security access. (default)
2 - reject loading policy if it does not contain all definitions
4 - allow unknown security access
The policy's choice is exported through 2 booleans in
selinuxfs. /selinux/deny_unknown and /selinux/reject_unknown.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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The structure is as follows (relative to selinuxfs root):
/class/file/index
/class/file/perms/read
/class/file/perms/write
...
Each class is allocated 33 inodes, 1 for the class index and 32 for
permissions. Relative to SEL_CLASS_INO_OFFSET, the inode of the index file
DIV 33 is the class number. The inode of the permission file % 33 is the
index of the permission for that class.
Signed-off-by: Christopher J. PeBenito <cpebenito@tresys.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Specify the inode counter explicitly in sel_make_dir(), rather than always
using sel_last_ino.
Signed-off-by: Christopher J. PeBenito <cpebenito@tresys.com>
Signed-off-by: James Morris <jmorris@namei.org>
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sel_remove_bools() will also be used by the object class discovery, rename
it for more general use.
Signed-off-by: Christopher J. PeBenito <cpebenito@tresys.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Change the numbering of the booleans directory inodes in selinuxfs to
provide more room for new inodes without a conflict in inode numbers and
to be consistent with how inode numbering is done in the
initial_contexts directory.
Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@parisplace.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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Remove the unused enumeration constant, SEL_AVC, from the sel_inos
enumeration in selinuxfs.
Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@parisplace.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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Explicitly number all selinuxfs inodes to prevent a conflict between
inodes numbered using last_ino when created with new_inode() and those
labeled explicitly.
Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@parisplace.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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Make the initial SID contexts accessible to userspace via selinuxfs.
An initial use of this support will be to make the unlabeled context
available to libselinux for use for invalidated userspace SIDs.
Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
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Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This is mostly included for parity with dec_nlink(), where we will have some
more hooks. This one should stay pretty darn straightforward for now.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This eliminates the i_blksize field from struct inode. Filesystems that want
to provide a per-inode st_blksize can do so by providing their own getattr
routine instead of using the generic_fillattr() function.
Note that some filesystems were providing pretty much random (and incorrect)
values for i_blksize.
[bunk@stusta.de: cleanup]
[akpm@osdl.org: generic_fillattr() fix]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.
The filesystem is then required to manually set the superblock and root dentry
pointers. For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).
The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.
This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing. In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.
The patch also makes the following changes:
(*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
pointer argument and return an integer, so most filesystems have to change
very little.
(*) If one of the convenience function is not used, then get_sb() should
normally call simple_set_mnt() to instantiate the vfsmount. This will
always return 0, and so can be tail-called from get_sb().
(*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
dcache upon superblock destruction rather than shrink_dcache_anon().
This is required because the superblock may now have multiple trees that
aren't actually bound to s_root, but that still need to be cleaned up. The
currently called functions assume that the whole tree is rooted at s_root,
and that anonymous dentries are not the roots of trees which results in
dentries being left unculled.
However, with the way NFS superblock sharing are currently set to be
implemented, these assumptions are violated: the root of the filesystem is
simply a dummy dentry and inode (the real inode for '/' may well be
inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
with child trees.
[*] Anonymous until discovered from another tree.
(*) The documentation has been adjusted, including the additional bit of
changing ext2_* into foo_* in the documentation.
[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: (22 commits)
[PATCH] fix audit_init failure path
[PATCH] EXPORT_SYMBOL patch for audit_log, audit_log_start, audit_log_end and audit_format
[PATCH] sem2mutex: audit_netlink_sem
[PATCH] simplify audit_free() locking
[PATCH] Fix audit operators
[PATCH] promiscuous mode
[PATCH] Add tty to syscall audit records
[PATCH] add/remove rule update
[PATCH] audit string fields interface + consumer
[PATCH] SE Linux audit events
[PATCH] Minor cosmetic cleanups to the code moved into auditfilter.c
[PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL
[PATCH] Fix IA64 success/failure indication in syscall auditing.
[PATCH] Miscellaneous bug and warning fixes
[PATCH] Capture selinux subject/object context information.
[PATCH] Exclude messages by message type
[PATCH] Collect more inode information during syscall processing.
[PATCH] Pass dentry, not just name, in fsnotify creation hooks.
[PATCH] Define new range of userspace messages.
[PATCH] Filter rule comparators
...
Fixed trivial conflict in security/selinux/hooks.c
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A further fix is needed for selinuxfs link count management, to ensure that
the count is correct for the parent directory when a subdirectory is
created. This is only required for the root directory currently, but the
code has been updated for the general case.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Fix copy & paste error in sel_make_avc_files(), removing a supurious call to
d_genocide() in the error path. All of this will be cleaned up by
kill_litter_super().
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove the call to sel_make_bools() from sel_fill_super(), as policy needs to
be loaded before the boolean files can be created. Policy will never be
loaded during sel_fill_super() as selinuxfs is kernel mounted during init and
the only means to load policy is via selinuxfs.
Also, the call to d_genocide() on the error path of sel_make_bools() is
incorrect and replaced with sel_remove_bools().
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Unify the error path of sel_fill_super() so that all errors pass through the
same point and generate an error message. Also, removes a spurious dput() in
the error path which breaks the refcounting for the filesystem
(litter_kill_super() will correctly clean things up itself on error).
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Use existing sel_make_dir() helper to create booleans directory rather than
duplicating the logic.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Fix the hard link count for selinuxfs directories, which are currently one
short.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Simplify sel_read_bool to use the simple_read_from_buffer helper, like the
other selinuxfs functions.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Stephen Smalley <sds@epoch.ncsc.mil>
Cc: James Morris <jmorris@namei.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Attached is a patch that hardwires important SE Linux events to the audit
system. Please Apply.
Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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Some long time ago, dentry struct was carefully tuned so that on 32 bits
UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple
of memory cache lines.
Then RCU was added and dentry struct enlarged by two pointers, with nice
results for SMP, but not so good on UP, because breaking the above tuning
(128 + 8 = 136 bytes)
This patch reverts this unwanted side effect, by using an union (d_u),
where d_rcu and d_child are placed so that these two fields can share their
memory needs.
At the time d_free() is called (and d_rcu is really used), d_child is known
to be empty and not touched by the dentry freeing.
Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so
the previous content of d_child is not needed if said dentry was unhashed
but still accessed by a CPU because of RCU constraints)
As dentry cache easily contains millions of entries, a size reduction is
worth the extra complexity of the ugly C union.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Paul Jackson <pj@sgi.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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