04 Apr, 2014
1 commit
-
Pull security subsystem updates from James Morris:
"Apart from reordering the SELinux mmap code to ensure DAC is called
before MAC, these are minor maintenance updates"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
selinux: correctly label /proc inodes in use before the policy is loaded
selinux: put the mmap() DAC controls before the MAC controls
selinux: fix the output of ./scripts/get_maintainer.pl for SELinux
evm: enable key retention service automatically
ima: skip memory allocation for empty files
evm: EVM does not use MD5
ima: return d_name.name if d_path fails
integrity: fix checkpatch errors
ima: fix erroneous removal of security.ima xattr
security: integrity: Use a more current logging style
MAINTAINERS: email updates and other misc. changes
ima: reduce memory usage when a template containing the n field is used
ima: restore the original behavior for sending data with ima template
Integrity: Pass commname via get_task_comm()
fs: move i_readcount
ima: use static const char array definitions
security: have cap_dentry_init_security return error
ima: new helper: file_inode(file)
kernel: Mark function as static in kernel/seccomp.c
capability: Use current logging styles
...
01 Apr, 2014
1 commit
-
Pull s390 compat wrapper rework from Heiko Carstens:
"S390 compat system call wrapper simplification work.The intention of this work is to get rid of all hand written assembly
compat system call wrappers on s390, which perform proper sign or zero
extension, or pointer conversion of compat system call parameters.
Instead all of this should be done with C code eg by using Al's
COMPAT_SYSCALL_DEFINEx() macro.Therefore all common code and s390 specific compat system calls have
been converted to the COMPAT_SYSCALL_DEFINEx() macro.In order to generate correct code all compat system calls may only
have eg compat_ulong_t parameters, but no unsigned long parameters.
Those patches which change parameter types from unsigned long to
compat_ulong_t parameters are separate in this series, but shouldn't
cause any harm.The only compat system calls which intentionally have 64 bit
parameters (preadv64 and pwritev64) in support of the x86/32 ABI
haven't been changed, but are now only available if an architecture
defines __ARCH_WANT_COMPAT_SYS_PREADV64/PWRITEV64.System calls which do not have a compat variant but still need proper
zero extension on s390, like eg "long sys_brk(unsigned long brk)" will
get a proper wrapper function with the new s390 specific
COMPAT_SYSCALL_WRAPx() macro:COMPAT_SYSCALL_WRAP1(brk, unsigned long, brk);
which generates the following code (simplified):
asmlinkage long sys_brk(unsigned long brk);
asmlinkage long compat_sys_brk(long brk)
{
return sys_brk((u32)brk);
}Given that the C file which contains all the COMPAT_SYSCALL_WRAP lines
includes both linux/syscall.h and linux/compat.h, it will generate
build errors, if the declaration of sys_brk() doesn't match, or if
there exists a non-matching compat_sys_brk() declaration.In addition this will intentionally result in a link error if
somewhere else a compat_sys_brk() function exists, which probably
should have been used instead. Two more BUILD_BUG_ONs make sure the
size and type of each compat syscall parameter can be handled
correctly with the s390 specific macros.I converted the compat system calls step by step to verify the
generated code is correct and matches the previous code. In fact it
did not always match, however that was always a bug in the hand
written asm code.In result we get less code, less bugs, and much more sanity checking"
* 'compat' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (44 commits)
s390/compat: add copyright statement
compat: include linux/unistd.h within linux/compat.h
s390/compat: get rid of compat wrapper assembly code
s390/compat: build error for large compat syscall args
mm/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
kexec/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
net/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
ipc/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
fs/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types
ipc/compat: convert to COMPAT_SYSCALL_DEFINE
fs/compat: convert to COMPAT_SYSCALL_DEFINE
security/compat: convert to COMPAT_SYSCALL_DEFINE
mm/compat: convert to COMPAT_SYSCALL_DEFINE
net/compat: convert to COMPAT_SYSCALL_DEFINE
kernel/compat: convert to COMPAT_SYSCALL_DEFINE
fs/compat: optional preadv64/pwrite64 compat system calls
ipc/compat_sys_msgrcv: change msgtyp type from long to compat_long_t
s390/compat: partial parameter conversion within syscall wrappers
s390/compat: automatic zero, sign and pointer conversion of syscalls
s390/compat: add sync_file_range and fallocate compat syscalls
...
10 Mar, 2014
1 commit
-
This fixes CVE-2014-0102.
The following command sequence produces an oops:
keyctl new_session
i=`keyctl newring _ses @s`
keyctl link @s $iThe problem is that search_nested_keyrings() sees two keyrings that have
matching type and description, so keyring_compare_object() returns true.
s_n_k() then passes the key to the iterator function -
keyring_detect_cycle_iterator() - which *should* check to see whether this is
the keyring of interest, not just one with the same name.Because assoc_array_find() will return one and only one match, I assumed that
the iterator function would only see an exact match or never be called - but
the iterator isn't only called from assoc_array_find()...The oops looks something like this:
kernel BUG at /data/fs/linux-2.6-fscache/security/keys/keyring.c:1003!
invalid opcode: 0000 [#1] SMP
...
RIP: keyring_detect_cycle_iterator+0xe/0x1f
...
Call Trace:
search_nested_keyrings+0x76/0x2aa
__key_link_check_live_key+0x50/0x5f
key_link+0x4e/0x85
keyctl_keyring_link+0x60/0x81
SyS_keyctl+0x65/0xe4
tracesys+0xdd/0xe2The fix is to make keyring_detect_cycle_iterator() check that the key it
has is the key it was actually looking for rather than calling BUG_ON().A testcase has been included in the keyutils testsuite for this:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=891f3365d07f1996778ade0e3428f01878a1790b
Reported-by: Tommi Rantala
Signed-off-by: David Howells
Acked-by: James Morris
Signed-off-by: Linus Torvalds
06 Mar, 2014
1 commit
-
Convert all compat system call functions where all parameter types
have a size of four or less than four bytes, or are pointer types
to COMPAT_SYSCALL_DEFINE.
The implicit casts within COMPAT_SYSCALL_DEFINE will perform proper
zero and sign extension to 64 bit of all parameters if needed.Signed-off-by: Heiko Carstens
06 Feb, 2014
1 commit
-
The usage of strict_strto*() is not preferred, because
strict_strto*() is obsolete. Thus, kstrto*() should be
used.Signed-off-by: Jingoo Han
Signed-off-by: James Morris
02 Dec, 2013
5 commits
-
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
Signed-off-by: David Howells
cc: Hugh Dickins
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
Tested-by: Stephen Gallagher -
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; idiff_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: [] hash_key_type_and_desc+0x18/0xb0
...
RIP: 0010:[] hash_key_type_and_desc+0x18/0xb0
...
Call Trace:
[] keyring_diff_objects+0x21/0xd2
[] assoc_array_insert+0x3b6/0x908
[] __key_link_begin+0x78/0xe5
[] key_create_or_update+0x17d/0x36a
[] SyS_add_key+0x123/0x183
[] tracesys+0xdd/0xe2Signed-off-by: David Howells
Tested-by: Stephen Gallagher -
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
Signed-off-by: David Howells
Tested-by: Stephen Gallagher -
The second word of key->payload does not get initialised in key_alloc(), but
the big_key type is relying on it having been cleared. The problem comes when
big_key fails to instantiate a large key and doesn't then set the payload. The
big_key_destroy() op is called from the garbage collector and this assumes that
the dentry pointer stored in the second word will be NULL if instantiation did
not complete.Therefore just pre-clear the entire struct key on allocation rather than trying
to be clever and only initialising to 0 only those bits that aren't otherwise
initialised.The lack of initialisation can lead to a bug report like the following if
big_key failed to initialise its file:general protection fault: 0000 [#1] SMP
Modules linked in: ...
CPU: 0 PID: 51 Comm: kworker/0:1 Not tainted 3.10.0-53.el7.x86_64 #1
Hardware name: Dell Inc. PowerEdge 1955/0HC513, BIOS 1.4.4 12/09/2008
Workqueue: events key_garbage_collector
task: ffff8801294f5680 ti: ffff8801296e2000 task.ti: ffff8801296e2000
RIP: 0010:[] dput+0x21/0x2d0
...
Call Trace:
[] path_put+0x16/0x30
[] big_key_destroy+0x44/0x60
[] key_gc_unused_keys.constprop.2+0x5b/0xe0
[] key_garbage_collector+0x1df/0x3c0
[] process_one_work+0x17b/0x460
[] worker_thread+0x11b/0x400
[] ? rescuer_thread+0x3e0/0x3e0
[] kthread+0xc0/0xd0
[] ? kthread_create_on_node+0x110/0x110
[] ret_from_fork+0x7c/0xb0
[] ? kthread_create_on_node+0x110/0x110Reported-by: Patrik Kis
Signed-off-by: David Howells
Reviewed-by: Stephen Gallagher
14 Nov, 2013
2 commits
-
Key pointers stored in the keyring are marked in bit 1 to indicate if they
point to a keyring. We need to strip off this bit before using the pointer
when iterating over the keyring for the purpose of looking for links to garbage
collect.This means that expirable keyrings aren't correctly expiring because the
checker is seeing their key pointer with 2 added to it.Since the fix for this involves knowing about the internals of the keyring,
key_gc_keyring() is moved to keyring.c and merged into keyring_gc().This can be tested by:
echo 2 >/proc/sys/kernel/keys/gc_delay
keyctl timeout `keyctl add keyring qwerty "" @s` 2
cat /proc/keys
sleep 5; cat /proc/keyswhich should see a keyring called "qwerty" appear in the session keyring and
then disappear after it expires, and:echo 2 >/proc/sys/kernel/keys/gc_delay
a=`keyctl get_persistent @s`
b=`keyctl add keyring 0 "" $a`
keyctl add user a a $b
keyctl timeout $b 2
cat /proc/keys
sleep 5; cat /proc/keyswhich should see a keyring called "0" with a key called "a" in it appear in the
user's persistent keyring (which will be attached to the session keyring) and
then both the "0" keyring and the "a" key should disappear when the "0" keyring
expires.Signed-off-by: David Howells
Acked-by: Simo Sorce -
In the big_key_instantiate() function we return 0 if kernel_write() returns us
an error rather than returning an error. This can potentially lead to
dentry_open() giving a BUG when called from big_key_read() with an unset
tmpfile path.------------[ cut here ]------------
kernel BUG at fs/open.c:798!
...
RIP: 0010:[] dentry_open+0xd1/0xe0
...
Call Trace:
[] big_key_read+0x55/0x100
[] keyctl_read_key+0xb4/0xe0
[] SyS_keyctl+0xf8/0x1d0
[] system_call_fastpath+0x16/0x1bSigned-off-by: David Howells
Reviewed-by: Stephen Gallagher
06 Nov, 2013
1 commit
-
If the UID is specified by userspace when calling the KEYCTL_GET_PERSISTENT
function and the process does not have the CAP_SETUID capability, then the
function will return -EPERM if the current process's uid, suid, euid and fsuid
all match the requested UID. This is incorrect.Fix it such that when a non-privileged caller requests a persistent keyring by
a specific UID they can only request their own (ie. the specified UID matches
either then process's UID or the process's EUID).This can be tested by logging in as the user and doing:
keyctl get_persistent @p
keyctl get_persistent @p `id -u`
keyctl get_persistent @p 0The first two should successfully print the same key ID. The third should do
the same if called by UID 0 or indicate Operation Not Permitted otherwise.Signed-off-by: David Howells
Acked-by: Stephen Gallagher
30 Oct, 2013
4 commits
-
Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.Signed-off-by: Wei Yongjun
Signed-off-by: David Howells -
If a key is displaced from a keyring by a matching one, then four more bytes
of quota are allocated to the keyring - despite the fact that the keyring does
not change in size.Further, when a key is unlinked from a keyring, the four bytes of quota
allocated the link isn't recovered and returned to the user's pool.The first can be tested by repeating:
keyctl add big_key a fred @s
cat /proc/key-users(Don't put it in a shell loop otherwise the garbage collector won't have time
to clear the displaced keys, thus affecting the result).This was causing the kerberos keyring to run out of room fairly quickly.
The second can be tested by:
cat /proc/key-users
a=`keyctl add user a a @s`
cat /proc/key-users
keyctl unlink $a
sleep 1 # Give RCU a chance to delete the key
cat /proc/key-usersassuming no system activity that otherwise adds/removes keys, the amount of
key data allocated should go up (say 40/20000 -> 47/20000) and then return to
the original value at the end.Reported-by: Stephen Gallagher
Signed-off-by: David Howells -
key_reject_and_link() marking a key as negative and setting the error with
which it was negated races with keyring searches and other things that read
that error.The fix is to switch the order in which the assignments are done in
key_reject_and_link() and to use memory barriers.Kudos to Dave Wysochanski and Scott Mayhew
for tracking this down.This may be the cause of:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
IP: [] wait_for_key_construction+0x31/0x80
PGD c6b2c3067 PUD c59879067 PMD 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map
CPU 0
Modules linked in: ...Pid: 13359, comm: amqzxma0 Not tainted 2.6.32-358.20.1.el6.x86_64 #1 IBM System x3650 M3 -[7945PSJ]-/00J6159
RIP: 0010:[] wait_for_key_construction+0x31/0x80
RSP: 0018:ffff880c6ab33758 EFLAGS: 00010246
RAX: ffffffff81219080 RBX: 0000000000000000 RCX: 0000000000000002
RDX: ffffffff81219060 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff880c6ab33768 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff880adfcbce40
R13: ffffffffa03afb84 R14: ffff880adfcbce40 R15: ffff880adfcbce43
FS: 00007f29b8042700(0000) GS:ffff880028200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000070 CR3: 0000000c613dc000 CR4: 00000000000007f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process amqzxma0 (pid: 13359, threadinfo ffff880c6ab32000, task ffff880c610deae0)
Stack:
ffff880adfcbce40 0000000000000000 ffff880c6ab337b8 ffffffff81219695
0000000000000000 ffff880a000000d0 ffff880c6ab337a8 000000000000000f
ffffffffa03afb93 000000000000000f ffff88186c7882c0 0000000000000014
Call Trace:
[] request_key+0x65/0xa0
[] nfs_idmap_request_key+0xc5/0x170 [nfs]
[] nfs_idmap_lookup_id+0x34/0x80 [nfs]
[] nfs_map_group_to_gid+0x75/0xa0 [nfs]
[] decode_getfattr_attrs+0xbdd/0xfb0 [nfs]
[] ? __dequeue_entity+0x30/0x50
[] ? __switch_to+0x26e/0x320
[] decode_getfattr+0x83/0xe0 [nfs]
[] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs]
[] nfs4_xdr_dec_getattr+0x8f/0xa0 [nfs]
[] rpcauth_unwrap_resp+0x84/0xb0 [sunrpc]
[] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs]
[] call_decode+0x1b3/0x800 [sunrpc]
[] ? wake_bit_function+0x0/0x50
[] ? call_decode+0x0/0x800 [sunrpc]
[] __rpc_execute+0x77/0x350 [sunrpc]
[] ? bit_waitqueue+0x17/0xd0
[] rpc_execute+0x61/0xa0 [sunrpc]
[] rpc_run_task+0x75/0x90 [sunrpc]
[] rpc_call_sync+0x42/0x70 [sunrpc]
[] _nfs4_call_sync+0x30/0x40 [nfs]
[] _nfs4_proc_getattr+0xac/0xc0 [nfs]
[] ? futex_wait+0x227/0x380
[] nfs4_proc_getattr+0x56/0x80 [nfs]
[] __nfs_revalidate_inode+0xe3/0x220 [nfs]
[] nfs_revalidate_mapping+0x4e/0x170 [nfs]
[] nfs_file_read+0x77/0x130 [nfs]
[] do_sync_read+0xfa/0x140
[] ? autoremove_wake_function+0x0/0x40
[] ? apic_timer_interrupt+0xe/0x20
[] ? common_interrupt+0xe/0x13
[] ? selinux_file_permission+0xfb/0x150
[] ? security_file_permission+0x16/0x20
[] vfs_read+0xb5/0x1a0
[] sys_read+0x51/0x90
[] ? __audit_syscall_exit+0x265/0x290
[] system_call_fastpath+0x16/0x1bSigned-off-by: David Howells
cc: Dave Wysochanski
cc: Scott Mayhew -
Having the big_keys functionality as a module is very marginally useful.
The userspace code that would use this functionality will get odd error
messages from the keys layer if the module isn't loaded. The code itself
is fairly small, so just have this as a boolean option and not a tristate.Signed-off-by: Josh Boyer
Signed-off-by: David Howells
26 Sep, 2013
2 commits
-
In order to create the integrity keyrings (eg. _evm, _ima), root's
uid and session keyrings need to be initialized early.Signed-off-by: Mimi Zohar
Signed-off-by: David Howells -
Add KEY_FLAG_TRUSTED to indicate that a key either comes from a trusted source
or had a cryptographic signature chain that led back to a trusted key the
kernel already possessed.Add KEY_FLAGS_TRUSTED_ONLY to indicate that a keyring will only accept links to
keys marked with KEY_FLAGS_TRUSTED.Signed-off-by: David Howells
Reviewed-by: Kees Cook
24 Sep, 2013
11 commits
-
Add support for per-user_namespace registers of persistent per-UID kerberos
caches held within the kernel.This allows the kerberos cache to be retained beyond the life of all a user's
processes so that the user's cron jobs can work.The kerberos cache is envisioned as a keyring/key tree looking something like:
struct user_namespace
\___ .krb_cache keyring - The register
\___ _krb.0 keyring - Root's Kerberos cache
\___ _krb.5000 keyring - User 5000's Kerberos cache
\___ _krb.5001 keyring - User 5001's Kerberos cache
\___ tkt785 big_key - A ccache blob
\___ tkt12345 big_key - Another ccache blobOr possibly:
struct user_namespace
\___ .krb_cache keyring - The register
\___ _krb.0 keyring - Root's Kerberos cache
\___ _krb.5000 keyring - User 5000's Kerberos cache
\___ _krb.5001 keyring - User 5001's Kerberos cache
\___ tkt785 keyring - A ccache
\___ krbtgt/REDHAT.COM@REDHAT.COM big_key
\___ http/REDHAT.COM@REDHAT.COM user
\___ afs/REDHAT.COM@REDHAT.COM user
\___ nfs/REDHAT.COM@REDHAT.COM user
\___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key
\___ http/KERNEL.ORG@KERNEL.ORG big_keyWhat goes into a particular Kerberos cache is entirely up to userspace. Kernel
support is limited to giving you the Kerberos cache keyring that you want.The user asks for their Kerberos cache by:
krb_cache = keyctl_get_krbcache(uid, dest_keyring);
The uid is -1 or the user's own UID for the user's own cache or the uid of some
other user's cache (requires CAP_SETUID). This permits rpc.gssd or whatever to
mess with the cache.The cache returned is a keyring named "_krb." that the possessor can read,
search, clear, invalidate, unlink from and add links to. Active LSMs get a
chance to rule on whether the caller is permitted to make a link.Each uid's cache keyring is created when it first accessed and is given a
timeout that is extended each time this function is called so that the keyring
goes away after a while. The timeout is configurable by sysctl but defaults to
three days.Each user_namespace struct gets a lazily-created keyring that serves as the
register. The cache keyrings are added to it. This means that standard key
search and garbage collection facilities are available.The user_namespace struct's register goes away when it does and anything left
in it is then automatically gc'd.Signed-off-by: David Howells
Tested-by: Simo Sorce
cc: Serge E. Hallyn
cc: Eric W. Biederman -
Implement a big key type that can save its contents to tmpfs and thus
swapspace when memory is tight. This is useful for Kerberos ticket caches.Signed-off-by: David Howells
Tested-by: Simo Sorce -
Expand the capacity of a keyring to be able to hold a lot more keys by using
the previously added associative array implementation. Currently the maximum
capacity is:(PAGE_SIZE - sizeof(header)) / sizeof(struct key *)
which, on a 64-bit system, is a little more 500. However, since this is being
used for the NFS uid mapper, we need more than that. The new implementation
gives us effectively unlimited capacity.With some alterations, the keyutils testsuite runs successfully to completion
after this patch is applied. The alterations are because (a) keyrings that
are simply added to no longer appear ordered and (b) some of the errors have
changed a bit.Signed-off-by: David Howells
-
Drop the permissions argument from __keyring_search_one() as the only caller
passes 0 here - which causes all checks to be skipped.Signed-off-by: David Howells
-
Define a __key_get() wrapper to use rather than atomic_inc() on the key usage
count as this makes it easier to hook in refcount error debugging.Signed-off-by: David Howells
-
Search for auth-key by name rather than by target key ID as, in a future
patch, we'll by searching directly by index key in preference to iteration
over all keys.Signed-off-by: David Howells
-
Search functions pass around a bunch of arguments, each of which gets copied
with each call. Introduce a search context structure to hold these.Whilst we're at it, create a search flag that indicates whether the search
should be directly to the description or whether it should iterate through all
keys looking for a non-description match.This will be useful when keyrings use a generic data struct with generic
routines to manage their content as the search terms can just be passed
through to the iterator callback function.Also, for future use, the data to be supplied to the match function is
separated from the description pointer in the search context. This makes it
clear which is being supplied.Signed-off-by: David Howells
-
Consolidate the concept of an 'index key' for accessing keys. The index key
is the search term needed to find a key directly - basically the key type and
the key description. We can add to that the description length.This will be useful when turning a keyring into an associative array rather
than just a pointer block.Signed-off-by: David Howells
-
key_is_dead() should take a const key pointer argument as it doesn't modify
what it points to.Signed-off-by: David Howells
-
Make make_key_ref() take a bool possession parameter and make
is_key_possessed() return a bool.Signed-off-by: David Howells
-
Skip key state checks (invalidation, revocation and expiration) when checking
for possession. Without this, keys that have been marked invalid, revoked
keys and expired keys are not given a possession attribute - which means the
possessor is not granted any possession permits and cannot do anything with
them unless they also have one a user, group or other permit.This causes failures in the keyutils test suite's revocation and expiration
tests now that commit 96b5c8fea6c0861621051290d705ec2e971963f1 reduced the
initial permissions granted to a key.The failures are due to accesses to revoked and expired keys being given
EACCES instead of EKEYREVOKED or EKEYEXPIRED.Signed-off-by: David Howells
08 May, 2013
1 commit
-
Faster kernel compiles by way of fewer unnecessary includes.
[akpm@linux-foundation.org: fix fallout]
[akpm@linux-foundation.org: fix build]
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 May, 2013
1 commit
-
Use call_usermodehelper_setup() + call_usermodehelper_exec() instead of
calling call_usermodehelper_fns(). In case there's an OOM in this last
function the cleanup function may not be called - in this case we would
miss a call to key_put().Signed-off-by: Lucas De Marchi
Cc: Oleg Nesterov
Acked-by: David Howells
Acked-by: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Mar, 2013
1 commit
-
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
compat_process_vm_rw() shows that the compatibility code requires an
explicit "access_ok()" check before calling
compat_rw_copy_check_uvector(). The same difference seems to appear when
we compare fs/read_write.c:do_readv_writev() to
fs/compat.c:compat_do_readv_writev().This subtle difference between the compat and non-compat requirements
should probably be debated, as it seems to be error-prone. In fact,
there are two others sites that use this function in the Linux kernel,
and they both seem to get it wrong:Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
also ends up calling compat_rw_copy_check_uvector() through
aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
be missing. Same situation for
security/keys/compat.c:compat_keyctl_instantiate_key_iov().I propose that we add the access_ok() check directly into
compat_rw_copy_check_uvector(), so callers don't have to worry about it,
and it therefore makes the compat call code similar to its non-compat
counterpart. Place the access_ok() check in the same location where
copy_from_user() can trigger a -EFAULT error in the non-compat code, so
the ABI behaviors are alike on both compat and non-compat.While we are here, fix compat_do_readv_writev() so it checks for
compat_rw_copy_check_uvector() negative return values.And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
handling.Acked-by: Linus Torvalds
Acked-by: Al Viro
Signed-off-by: Mathieu Desnoyers
Signed-off-by: Linus Torvalds
12 Mar, 2013
1 commit
-
This fixes CVE-2013-1792.
There is a race in install_user_keyrings() that can cause a NULL pointer
dereference when called concurrently for the same user if the uid and
uid-session keyrings are not yet created. It might be possible for an
unprivileged user to trigger this by calling keyctl() from userspace in
parallel immediately after logging in.Assume that we have two threads both executing lookup_user_key(), both
looking for KEY_SPEC_USER_SESSION_KEYRING.THREAD A THREAD B
=============================== ===============================
==>call install_user_keyrings();
if (!cred->user->session_keyring)
==>call install_user_keyrings()
...
user->uid_keyring = uid_keyring;
if (user->uid_keyring)
return 0;
user->session_keyring [== NULL]
user->session_keyring = session_keyring;
atomic_inc(&key->usage); [oops]At the point thread A dereferences cred->user->session_keyring, thread B
hasn't updated user->session_keyring yet, but thread A assumes it is
populated because install_user_keyrings() returned ok.The race window is really small but can be exploited if, for example,
thread B is interrupted or preempted after initializing uid_keyring, but
before doing setting session_keyring.This couldn't be reproduced on a stock kernel. However, after placing
systemtap probe on 'user->session_keyring = session_keyring;' that
introduced some delay, the kernel could be crashed reliably.Fix this by checking both pointers before deciding whether to return.
Alternatively, the test could be done away with entirely as it is checked
inside the mutex - but since the mutex is global, that may not be the best
way.Signed-off-by: David Howells
Reported-by: Mateusz Guzik
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: James Morris
04 Mar, 2013
1 commit
-
Dave Jones writes:
> Just hit this on Linus' current tree.
>
> [ 89.621770] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8
> [ 89.623111] IP: [] commit_creds+0x250/0x2f0
> [ 89.624062] PGD 122bfd067 PUD 122bfe067 PMD 0
> [ 89.624901] Oops: 0000 [#1] PREEMPT SMP
> [ 89.625678] Modules linked in: caif_socket caif netrom bridge hidp 8021q garp stp mrp rose llc2 af_rxrpc phonet af_key binfmt_misc bnep l2tp_ppp can_bcm l2tp_core pppoe pppox can_raw scsi_transport_iscsi ppp_generic slhc nfnetlink can ipt_ULOG ax25 decnet irda nfc rds x25 crc_ccitt appletalk atm ipx p8023 psnap p8022 llc lockd sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack nf_conntrack ip6table_filter ip6_tables btusb bluetooth snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_pcm vhost_net snd_page_alloc snd_timer tun macvtap usb_debug snd rfkill microcode macvlan edac_core pcspkr serio_raw kvm_amd soundcore kvm r8169 mii
> [ 89.637846] CPU 2
> [ 89.638175] Pid: 782, comm: trinity-main Not tainted 3.8.0+ #63 Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H
> [ 89.639850] RIP: 0010:[] [] commit_creds+0x250/0x2f0
> [ 89.641161] RSP: 0018:ffff880115657eb8 EFLAGS: 00010207
> [ 89.641984] RAX: 00000000000003e8 RBX: ffff88012688b000 RCX: 0000000000000000
> [ 89.643069] RDX: 0000000000000000 RSI: ffffffff81c32960 RDI: ffff880105839600
> [ 89.644167] RBP: ffff880115657ed8 R08: 0000000000000000 R09: 0000000000000000
> [ 89.645254] R10: 0000000000000001 R11: 0000000000000246 R12: ffff880105839600
> [ 89.646340] R13: ffff88011beea490 R14: ffff88011beea490 R15: 0000000000000000
> [ 89.647431] FS: 00007f3ac063b740(0000) GS:ffff88012b200000(0000) knlGS:0000000000000000
> [ 89.648660] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 89.649548] CR2: 00000000000000c8 CR3: 0000000122bfc000 CR4: 00000000000007e0
> [ 89.650635] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 89.651723] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 89.652812] Process trinity-main (pid: 782, threadinfo ffff880115656000, task ffff88011beea490)
> [ 89.654128] Stack:
> [ 89.654433] 0000000000000000 ffff8801058396a0 ffff880105839600 ffff88011beeaa78
> [ 89.655769] ffff880115657ef8 ffffffff812c7d9b ffffffff82079be0 0000000000000000
> [ 89.657073] ffff880115657f28 ffffffff8106c665 0000000000000002 ffff880115657f58
> [ 89.658399] Call Trace:
> [ 89.658822] [] key_change_session_keyring+0xfb/0x140
> [ 89.659845] [] task_work_run+0xa5/0xd0
> [ 89.660698] [] do_notify_resume+0x71/0xb0
> [ 89.661581] [] int_signal+0x12/0x17
> [ 89.662385] Code: 24 90 00 00 00 48 8b b3 90 00 00 00 49 8b 4c 24 40 48 39 f2 75 08 e9 83 00 00 00 48 89 ca 48 81 fa 60 29 c3 81 0f 84 41 fe ff ff 8b 8a c8 00 00 00 48 39 ce 75 e4 3b 82 d0 00 00 00 0f 84 4b
> [ 89.667778] RIP [] commit_creds+0x250/0x2f0
> [ 89.668733] RSP
> [ 89.669301] CR2: 00000000000000c8
>
> My fastest trinity induced oops yet!
>
>
> Appears to be..
>
> if ((set_ns == subset_ns->parent) &&
> 850: 48 8b 8a c8 00 00 00 mov 0xc8(%rdx),%rcx
>
> from the inlined cred_cap_issubsetBy historical accident we have been reading trying to set new->user_ns
from new->user_ns. Which is totally silly as new->user_ns is NULL (as
is every other field in new except session_keyring at that point).The intent is clearly to copy all of the fields from old to new so copy
old->user_ns into into new->user_ns.Cc: stable@vger.kernel.org
Reported-by: Dave Jones
Tested-by: Dave Jones
Acked-by: Serge Hallyn
Signed-off-by: "Eric W. Biederman"
21 Feb, 2013
1 commit
-
A patch to fix some unreachable code in search_my_process_keyrings() got
applied twice by two different routes upstream as commits e67eab39bee2
and b010520ab3d2 (both "fix unreachable code").Unfortunately, the second application removed something it shouldn't
have and this wasn't detected by GIT. This is due to the patch not
having sufficient lines of context to distinguish the two places of
application.The effect of this is relatively minor: inside the kernel, the keyring
search routines may search multiple keyrings and then prioritise the
errors if no keys or negative keys are found in any of them. With the
extra deletion, the presence of a negative key in the thread keyring
(causing ENOKEY) is incorrectly overridden by an error searching the
process keyring.So revert the second application of the patch.
Signed-off-by: David Howells
Cc: Jiri Kosina
Cc: Andrew Morton
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds
21 Dec, 2012
1 commit
-
We set ret to NULL then test it. Remove the bogus test
Signed-off-by: Alan Cox
Signed-off-by: David Howells
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Dec, 2012
1 commit
-
Pull security subsystem updates from James Morris:
"A quiet cycle for the security subsystem with just a few maintenance
updates."* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
Smack: create a sysfs mount point for smackfs
Smack: use select not depends in Kconfig
Yama: remove locking from delete path
Yama: add RCU to drop read locking
drivers/char/tpm: remove tasklet and cleanup
KEYS: Use keyring_alloc() to create special keyrings
KEYS: Reduce initial permissions on keys
KEYS: Make the session and process keyrings per-thread
seccomp: Make syscall skipping and nr changes more consistent
key: Fix resource leak
keys: Fix unreachable code
KEYS: Add payload preparsing opportunity prior to key instantiate or update
29 Oct, 2012
1 commit
-
Sync up with Linus' tree to be able to apply Cesar's patch
against newer version of the code.Signed-off-by: Jiri Kosina
26 Oct, 2012
1 commit
-
We set ret to NULL then test it. Remove the bogus test
Signed-off-by: Alan Cox
Signed-off-by: Jiri Kosina