Between checkpatch changes (eg. sizeof) and inconsistencies between
Lindent and checkpatch, unfixed checkpatch errors make it difficult
to see new errors. This patch fixes them. Some lines with over 80 chars
remained unchanged to improve code readability.
The "extern" keyword is removed from internal evm.h to make it consistent
with internal ima.h.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
ima_inode_post_setattr() calls ima_must_appraise() to check if the
file needs to be appraised. If it does not then it removes security.ima
xattr. With original policy matching code it might happen that even
file needs to be appraised with FILE_CHECK hook, it might not be
for POST_SETATTR hook. 'security.ima' might be erronously removed.
This patch treats POST_SETATTR as special wildcard function and will
cause ima_must_appraise() to be true if any of the hooks rules matches.
security.ima will not be removed if any of the hooks would require
appraisal.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Before this change, to correctly calculate the template digest for the
'ima' template, the event name field (id: 'n') length was set to the fixed
size of 256 bytes.
This patch reduces the length of the event name field to the string
length incremented of one (to make room for the termination character '\0')
and handles the specific case of the digest calculation for the 'ima'
template directly in ima_calc_field_array_hash_tfm().
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
With the new template mechanism introduced in IMA since kernel 3.13,
the format of data sent through the binary_runtime_measurements interface
is slightly changed. Now, for a generic measurement, the format of
template data (after the template name) is:
template_len | field1_len | field1 | ... | fieldN_len | fieldN
In addition, fields containing a string now include the '\0' termination
character.
Instead, the format for the 'ima' template should be:
SHA1 digest | event name length | event name
It must be noted that while in the IMA 3.13 code 'event name length' is
'IMA_EVENT_NAME_LEN_MAX + 1' (256 bytes), so that the template digest
is calculated correctly, and 'event name' contains '\0', in the pre 3.13
code 'event name length' is exactly the string length and 'event name'
does not contain the termination character.
The patch restores the behavior of the IMA code pre 3.13 for the 'ima'
template so that legacy userspace tools obtain a consistent behavior
when receiving data from the binary_runtime_measurements interface
regardless of which kernel version is used.
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Cc: <stable@vger.kernel.org> # 3.3.13: 3ce1217 ima: define template fields library
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
When we pass task->comm to audit_log_untrustedstring(), we need to pass it
via get_task_comm() because task->comm can be changed to contain untrusted
string by other threads after audit_log_untrustedstring() confirmed that
task->comm does not contain untrusted string.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
A const char pointer allocates memory for a pointer as well as for
a string, This patch replaces a number of the const char pointers
throughout IMA, with a static const char array.
Suggested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
The Makefiles in security/ uses a non-standard way to
specify sub-directories for building.
Fix it up so the normal (and documented) approach is used.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: James Morris <james.l.morris@oracle.com>
The usage of strict_strto*() is not preferred, because
strict_strto*() is obsolete. Thus, kstrto*() should be
used.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Hello.
I got below leak with linux-3.10.0-54.0.1.el7.x86_64 .
[ 681.903890] kmemleak: 5538 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
Below is a patch, but I don't know whether we need special handing for undoing
ebitmap_set_bit() call.
----------
>>From fe97527a90fe95e2239dfbaa7558f0ed559c0992 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Mon, 6 Jan 2014 16:30:21 +0900
Subject: [PATCH] SELinux: Fix memory leak upon loading policy
Commit 2463c26d "SELinux: put name based create rules in a hashtable" did not
check return value from hashtab_insert() in filename_trans_read(). It leaks
memory if hashtab_insert() returns error.
unreferenced object 0xffff88005c9160d0 (size 8):
comm "systemd", pid 1, jiffies 4294688674 (age 235.265s)
hex dump (first 8 bytes):
57 0b 00 00 6b 6b 6b a5 W...kkk.
backtrace:
[<ffffffff816604ae>] kmemleak_alloc+0x4e/0xb0
[<ffffffff811cba5e>] kmem_cache_alloc_trace+0x12e/0x360
[<ffffffff812aec5d>] policydb_read+0xd1d/0xf70
[<ffffffff812b345c>] security_load_policy+0x6c/0x500
[<ffffffff812a623c>] sel_write_load+0xac/0x750
[<ffffffff811eb680>] vfs_write+0xc0/0x1f0
[<ffffffff811ec08c>] SyS_write+0x4c/0xa0
[<ffffffff81690419>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
However, we should not return EEXIST error to the caller, or the systemd will
show below message and the boot sequence freezes.
systemd[1]: Failed to load SELinux policy. Freezing.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Eric Paris <eparis@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
This patch removes the 'size_limit' argument from
ima_eventdigest_init_common(). Since the 'd' field will never include
the hash algorithm as prefix and the 'd-ng' will always have it, we can
use the hash algorithm to differentiate the two cases in the modified
function (it is equal to HASH_ALGO__LAST in the first case, the opposite
in the second).
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Replace the '-1' value with HASH_ALGO__LAST in ima_eventdigest_init()
as the called function ima_eventdigest_init_common() expects an unsigned
char.
Fix commit:
4d7aeee ima: define new template ima-ng and template fields d-ng and n-ng
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Replace HASH_ALGO__LAST with HASH_ALGO_SHA1 as the initial value of
the hash algorithm so that the prefix 'sha1:' is added to violation
digests.
Fix commit:
4d7aeee ima: define new template ima-ng and template fields d-ng and n-ng
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Cc: <stable@vger.kernel.org> # 3.13.x
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Eric Paris politely points out:
Inside smack_file_receive() it seems like you are initting the audit
field with LSM_AUDIT_DATA_TASK. And then use
smk_ad_setfield_u_fs_path().
Seems like LSM_AUDIT_DATA_PATH would make more sense. (and depending
on how it's used fix a crash...)
He is correct. This puts things in order.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
The mount restrictions imposed by Smack rely heavily on the
use of the filesystem "floor", which is the label that all
processes writing to the filesystem must have access to. It
turns out that while the "floor" notion is sound, it has yet
to be fully implemented and has never been used.
The sb_mount and sb_umount hooks only make sense if the
filesystem floor is used actively, and it isn't. They can
be reintroduced if a rational restriction comes up. Until
then, they get removed.
The sb_kern_mount hook is required for the option processing.
It is too permissive in the case of unprivileged mounts,
effectively bypassing the CAP_MAC_ADMIN restrictions if
any of the smack options are specified. Unprivileged mounts
are no longer allowed to set Smack filesystem options.
Additionally, the root and default values are set to the
label of the caller, in keeping with the policy that objects
get the label of their creator.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
smk_write_change_rule() is calling capable rather than
the more correct smack_privileged(). This allows for setting
rules in violation of the onlycap facility. This is the
simple repair.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
The syslog control requires that the calling proccess
have the floor ("_") Smack label. Tizen does not run any
processes except for kernel helpers with the floor label.
This changes allows the admin to configure a specific
label for syslog. The default value is the star ("*")
label, effectively removing the restriction. The value
can be set using smackfs/syslog for anyone who wants
a more restrictive behavior.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
selinux_setprocattr() does ptrace_parent(p) under task_lock(p),
but task_struct->alloc_lock doesn't pin ->parent or ->ptrace,
this looks confusing and triggers the "suspicious RCU usage"
warning because ptrace_parent() does rcu_dereference_check().
And in theory this is wrong, spin_lock()->preempt_disable()
doesn't necessarily imply rcu_read_lock() we need to access
the ->parent.
Reported-by: Evan McNabb <emcnabb@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Fix a broken networking check. Return an error if peer recv fails. If
secmark is active and the packet recv succeeds the peer recv error is
ignored.
Signed-off-by: Chad Hanson <chanson@trustedcs.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Smack prohibits processes from using the star ("*") and web ("@") labels
because we don't want files with those labels getting created implicitly.
All setting of those labels should be done explicitly. The trouble is that
there is no check for these labels in the processing of SMACK64EXEC. That
is repaired.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
selinux_setprocattr() does ptrace_parent(p) under task_lock(p),
but task_struct->alloc_lock doesn't pin ->parent or ->ptrace,
this looks confusing and triggers the "suspicious RCU usage"
warning because ptrace_parent() does rcu_dereference_check().
And in theory this is wrong, spin_lock()->preempt_disable()
doesn't necessarily imply rcu_read_lock() we need to access
the ->parent.
Reported-by: Evan McNabb <emcnabb@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Pull SELinux fixes from James Morris.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute()
selinux: look for IPsec labels on both inbound and outbound packets
selinux: handle TCP SYN-ACK packets correctly in selinux_ip_postroute()
selinux: handle TCP SYN-ACK packets correctly in selinux_ip_output()
selinux: fix possible memory leak
This reverts commit 102aefdda4.
Tom London reports that it causes sync() to hang on Fedora rawhide:
https://bugzilla.redhat.com/show_bug.cgi?id=1033965
and Josh Boyer bisected it down to this commit. Reverting the commit in
the rawhide kernel fixes the problem.
Eric Paris root-caused it to incorrect subtype matching in that commit
breaking fuse, and has a tentative patch, but by now we're better off
retrying this in 3.14 rather than playing with it any more.
Reported-by: Tom London <selinux@gmail.com>
Bisected-by: Josh Boyer <jwboyer@fedoraproject.org>
Acked-by: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Anand Avati <avati@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert "selinux: consider filesystem subtype in policies"
This reverts commit 102aefdda4.
Explanation from Eric Paris:
SELinux policy can specify if it should use a filesystem's
xattrs or not. In current policy we have a specification that
fuse should not use xattrs but fuse.glusterfs should use
xattrs. This patch has a bug in which non-glusterfs
filesystems would match the rule saying fuse.glusterfs should
use xattrs. If both fuse and the particular filesystem in
question are not written to handle xattr calls during the mount
command, they will deadlock.
I have fixed the bug to do proper matching, however I believe a
revert is still the correct solution. The reason I believe
that is because the code still does not work. The s_subtype is
not set until after the SELinux hook which attempts to match on
the ".gluster" portion of the rule. So we cannot match on the
rule in question. The code is useless.
Signed-off-by: Paul Moore <pmoore@redhat.com>
Due to difficulty in arriving at the proper security label for
TCP SYN-ACK packets in selinux_ip_postroute(), we need to check packets
while/before they are undergoing XFRM transforms instead of waiting
until afterwards so that we can determine the correct security label.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Previously selinux_skb_peerlbl_sid() would only check for labeled
IPsec security labels on inbound packets, this patch enables it to
check both inbound and outbound traffic for labeled IPsec security
labels.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
In selinux_ip_postroute() we perform access checks based on the
packet's security label. For locally generated traffic we get the
packet's security label from the associated socket; this works in all
cases except for TCP SYN-ACK packets. In the case of SYN-ACK packet's
the correct security label is stored in the connection's request_sock,
not the server's socket. Unfortunately, at the point in time when
selinux_ip_postroute() is called we can't query the request_sock
directly, we need to recreate the label using the same logic that
originally labeled the associated request_sock.
See the inline comments for more explanation.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Tested-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
In selinux_ip_output() we always label packets based on the parent
socket. While this approach works in almost all cases, it doesn't
work in the case of TCP SYN-ACK packets when the correct label is not
the label of the parent socket, but rather the label of the larval
socket represented by the request_sock struct.
Unfortunately, since the request_sock isn't queued on the parent
socket until *after* the SYN-ACK packet is sent, we can't lookup the
request_sock to determine the correct label for the packet; at this
point in time the best we can do is simply pass/NF_ACCEPT the packet.
It must be said that simply passing the packet without any explicit
labeling action, while far from ideal, is not terrible as the SYN-ACK
packet will inherit any IP option based labeling from the initial
connection request so the label *should* be correct and all our
access controls remain in place so we shouldn't have to worry about
information leaks.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Tested-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
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Merge tag 'keys-devel-20131210' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull misc keyrings fixes from David Howells:
"These break down into five sets:
- A patch to error handling in the big_key type for huge payloads.
If the payload is larger than the "low limit" and the backing store
allocation fails, then big_key_instantiate() doesn't clear the
payload pointers in the key, assuming them to have been previously
cleared - but only one of them is.
Unfortunately, the garbage collector still calls big_key_destroy()
when sees one of the pointers with a weird value in it (and not
NULL) which it then tries to clean up.
- Three patches to fix the keyring type:
* A patch to fix the hash function to correctly divide keyrings off
from keys in the topology of the tree inside the associative
array. This is only a problem if searching through nested
keyrings - and only if the hash function incorrectly puts the a
keyring outside of the 0 branch of the root node.
* A patch to fix keyrings' use of the associative array. The
__key_link_begin() function initially passes a NULL key pointer
to assoc_array_insert() on the basis that it's holding a place in
the tree whilst it does more allocation and stuff.
This is only a problem when a node contains 16 keys that match at
that level and we want to add an also matching 17th. This should
easily be manufactured with a keyring full of keyrings (without
chucking any other sort of key into the mix) - except for (a)
above which makes it on average adding the 65th keyring.
* A patch to fix searching down through nested keyrings, where any
keyring in the set has more than 16 keyrings and none of the
first keyrings we look through has a match (before the tree
iteration needs to step to a more distal node).
Test in keyutils test suite:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=8b4ae963ed92523aea18dfbb8cab3f4979e13bd1
- A patch to fix the big_key type's use of a shmem file as its
backing store causing audit messages and LSM check failures. This
is done by setting S_PRIVATE on the file to avoid LSM checks on the
file (access to the shmem file goes through the keyctl() interface
and so is gated by the LSM that way).
This isn't normally a problem if a key is used by the context that
generated it - and it's currently only used by libkrb5.
Test in keyutils test suite:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=d9a53cbab42c293962f2f78f7190253fc73bd32e
- A patch to add a generated file to .gitignore.
- A patch to fix the alignment of the system certificate data such
that it it works on s390. As I understand it, on the S390 arch,
symbols must be 2-byte aligned because loading the address discards
the least-significant bit"
* tag 'keys-devel-20131210' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
KEYS: correct alignment of system_certificate_list content in assembly file
Ignore generated file kernel/x509_certificate_list
security: shmem: implement kernel private shmem inodes
KEYS: Fix searching of nested keyrings
KEYS: Fix multiple key add into associative array
KEYS: Fix the keyring hash function
KEYS: Pre-clear struct key on allocation
Fix a broken networking check. Return an error if peer recv fails. If
secmark is active and the packet recv succeeds the peer recv error is
ignored.
Signed-off-by: Chad Hanson <chanson@trustedcs.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
This is a regression caused by f7112e6c. When either subject or
object is not found the answer for access should be no. This
patch fixes the situation. '0' is written back instead of failing
with -EINVAL.
v2: cosmetic style fixes
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Due to difficulty in arriving at the proper security label for
TCP SYN-ACK packets in selinux_ip_postroute(), we need to check packets
while/before they are undergoing XFRM transforms instead of waiting
until afterwards so that we can determine the correct security label.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Previously selinux_skb_peerlbl_sid() would only check for labeled
IPsec security labels on inbound packets, this patch enables it to
check both inbound and outbound traffic for labeled IPsec security
labels.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
We don't need to inspect the packet to determine if the packet is an
IPv4 packet arriving on an IPv6 socket when we can query the
request_sock directly.
Signed-off-by: Paul Moore <pmoore@redhat.com>
In selinux_netlbl_skbuff_setsid() we leverage a cached NetLabel
secattr whenever possible. However, we never check to ensure that
the desired SID matches the cached NetLabel secattr. This patch
checks the SID against the secattr before use and only uses the
cached secattr when the SID values match.
Signed-off-by: Paul Moore <pmoore@redhat.com>
In selinux_ip_postroute() we perform access checks based on the
packet's security label. For locally generated traffic we get the
packet's security label from the associated socket; this works in all
cases except for TCP SYN-ACK packets. In the case of SYN-ACK packet's
the correct security label is stored in the connection's request_sock,
not the server's socket. Unfortunately, at the point in time when
selinux_ip_postroute() is called we can't query the request_sock
directly, we need to recreate the label using the same logic that
originally labeled the associated request_sock.
See the inline comments for more explanation.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Tested-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
In selinux_ip_output() we always label packets based on the parent
socket. While this approach works in almost all cases, it doesn't
work in the case of TCP SYN-ACK packets when the correct label is not
the label of the parent socket, but rather the label of the larval
socket represented by the request_sock struct.
Unfortunately, since the request_sock isn't queued on the parent
socket until *after* the SYN-ACK packet is sent, we can't lookup the
request_sock to determine the correct label for the packet; at this
point in time the best we can do is simply pass/NF_ACCEPT the packet.
It must be said that simply passing the packet without any explicit
labeling action, while far from ideal, is not terrible as the SYN-ACK
packet will inherit any IP option based labeling from the initial
connection request so the label *should* be correct and all our
access controls remain in place so we shouldn't have to worry about
information leaks.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Tested-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
The new templates management mechanism records information associated
to an event into an array of 'ima_field_data' structures and makes it
available through the 'template_data' field of the 'ima_template_entry'
structure (the element of the measurements list created by IMA).
Since 'ima_field_data' contains dynamically allocated data (which length
varies depending on the data associated to a selected template field),
it is not enough to just free the memory reserved for a
'ima_template_entry' structure if something goes wrong.
This patch creates the new function ima_free_template_entry() which
walks the array of 'ima_field_data' structures, frees the memory
referenced by the 'data' pointer and finally the space reserved for
the 'ima_template_entry' structure. Further, it replaces existing kfree()
that have a pointer to an 'ima_template_entry' structure as argument
with calls to the new function.
Fixes: a71dc65: ima: switch to new template management mechanism
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
7bc5f447ce (ima: define new function ima_alloc_init_template() to
API) moved the initialization of 'entry' in ima_add_boot_aggregate() a
bit more below, after the if (ima_used_chip).
So, 'entry' is not initialized while being inside this if-block. So, we
should not attempt to free it.
Found by Coverity (CID: 1131971)
Fixes: 7bc5f447ce (ima: define new function ima_alloc_init_template() to API)
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
We have a problem where the big_key key storage implementation uses a
shmem backed inode to hold the key contents. Because of this detail of
implementation LSM checks are being done between processes trying to
read the keys and the tmpfs backed inode. The LSM checks are already
being handled on the key interface level and should not be enforced at
the inode level (since the inode is an implementation detail, not a
part of the security model)
This patch implements a new function shmem_kernel_file_setup() which
returns the equivalent to shmem_file_setup() only the underlying inode
has S_PRIVATE set. This means that all LSM checks for the inode in
question are skipped. It should only be used for kernel internal
operations where the inode is not exposed to userspace without proper
LSM checking. It is possible that some other users of
shmem_file_setup() should use the new interface, but this has not been
explored.
Reproducing this bug is a little bit difficult. The steps I used on
Fedora are:
(1) Turn off selinux enforcing:
setenforce 0
(2) Create a huge key
k=`dd if=/dev/zero bs=8192 count=1 | keyctl padd big_key test-key @s`
(3) Access the key in another context:
runcon system_u:system_r:httpd_t:s0-s0:c0.c1023 keyctl print $k >/dev/null
(4) Examine the audit logs:
ausearch -m AVC -i --subject httpd_t | audit2allow
If the last command's output includes a line that looks like:
allow httpd_t user_tmpfs_t:file { open read };
There was an inode check between httpd and the tmpfs filesystem. With
this patch no such denial will be seen. (NOTE! you should clear your
audit log if you have tested for this previously)
(Please return you box to enforcing)
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hugh Dickins <hughd@google.com>
cc: linux-mm@kvack.org
If a keyring contains more than 16 keyrings (the capacity of a single node in
the associative array) then those keyrings are split over multiple nodes
arranged as a tree.
If search_nested_keyrings() is called to search the keyring then it will
attempt to manually walk over just the 0 branch of the associative array tree
where all the keyring links are stored. This works provided the key is found
before the algorithm steps from one node containing keyrings to a child node
or if there are sufficiently few keyring links that the keyrings are all in
one node.
However, if the algorithm does need to step from a node to a child node, it
doesn't change the node pointer unless a shortcut also gets transited. This
means that the algorithm will keep scanning the same node over and over again
without terminating and without returning.
To fix this, move the internal-pointer-to-node translation from inside the
shortcut transit handler so that it applies it to node arrival as well.
This can be tested by:
r=`keyctl newring sandbox @s`
for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done
for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done
for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done
for ((i=17; i<=20; i++)); do keyctl search $r user a$i; done
The searches should all complete successfully (or with an error for 17-20),
but instead one or more of them will hang.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Stephen Gallagher <sgallagh@redhat.com>
If sufficient keys (or keyrings) are added into a keyring such that a node in
the associative array's tree overflows (each node has a capacity N, currently
16) and such that all N+1 keys have the same index key segment for that level
of the tree (the level'th nibble of the index key), then assoc_array_insert()
calls ops->diff_objects() to indicate at which bit position the two index keys
vary.
However, __key_link_begin() passes a NULL object to assoc_array_insert() with
the intention of supplying the correct pointer later before we commit the
change. This means that keyring_diff_objects() is given a NULL pointer as one
of its arguments which it does not expect. This results in an oops like the
attached.
With the previous patch to fix the keyring hash function, this can be forced
much more easily by creating a keyring and only adding keyrings to it. Add any
other sort of key and a different insertion path is taken - all 16+1 objects
must want to cluster in the same node slot.
This can be tested by:
r=`keyctl newring sandbox @s`
for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done
This should work fine, but oopses when the 17th keyring is added.
Since ops->diff_objects() is always called with the first pointer pointing to
the object to be inserted (ie. the NULL pointer), we can fix the problem by
changing the to-be-inserted object pointer to point to the index key passed
into assoc_array_insert() instead.
Whilst we're at it, we also switch the arguments so that they are the same as
for ->compare_object().
BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
IP: [<ffffffff81191ee4>] hash_key_type_and_desc+0x18/0xb0
...
RIP: 0010:[<ffffffff81191ee4>] hash_key_type_and_desc+0x18/0xb0
...
Call Trace:
[<ffffffff81191f9d>] keyring_diff_objects+0x21/0xd2
[<ffffffff811f09ef>] assoc_array_insert+0x3b6/0x908
[<ffffffff811929a7>] __key_link_begin+0x78/0xe5
[<ffffffff81191a2e>] key_create_or_update+0x17d/0x36a
[<ffffffff81192e0a>] SyS_add_key+0x123/0x183
[<ffffffff81400ddb>] tracesys+0xdd/0xe2
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Stephen Gallagher <sgallagh@redhat.com>
The keyring hash function (used by the associative array) is supposed to clear
the bottommost nibble of the index key (where the hash value resides) for
keyrings and make sure it is non-zero for non-keyrings. This is done to make
keyrings cluster together on one branch of the tree separately to other keys.
Unfortunately, the wrong mask is used, so only the bottom two bits are
examined and cleared and not the whole bottom nibble. This means that keys
and keyrings can still be successfully searched for under most circumstances
as the hash is consistent in its miscalculation, but if a keyring's
associative array bottom node gets filled up then approx 75% of the keyrings
will not be put into the 0 branch.
The consequence of this is that a key in a keyring linked to by another
keyring, ie.
keyring A -> keyring B -> key
may not be found if the search starts at keyring A and then descends into
keyring B because search_nested_keyrings() only searches up the 0 branch (as it
"knows" all keyrings must be there and not elsewhere in the tree).
The fix is to use the right mask.
This can be tested with:
r=`keyctl newring sandbox @s`
for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done
for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done
for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done
This creates a sandbox keyring, then creates 17 keyrings therein (labelled
ring0..ring16). This causes the root node of the sandbox's associative array
to overflow and for the tree to have extra nodes inserted.
Each keyring then is given a user key (labelled aN for ringN) for us to search
for.
We then search for the user keys we added, starting from the sandbox. If
working correctly, it should return the same ordered list of key IDs as
for...keyctl add... did. Without this patch, it reports ENOKEY "Required key
not available" for some of the keys. Just which keys get this depends as the
kernel pointer to the key type forms part of the hash function.
Reported-by: Nalin Dahyabhai <nalin@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Stephen Gallagher <sgallagh@redhat.com>
