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This is from a Smatch check I'm writing.
strncpy_from_user() returns -EFAULT on error so the first change just
silences a warning but doesn't change how the code works.
The other change is a bug fix because install_thread_keyring_to_cred()
can return a variety of errors such as -EINVAL, -EEXIST, -ENOMEM or
-EKEYREVOKED.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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No functional changes.
keyctl_session_to_parent() is the only user of signal->count which needs
the correct value. Change it to use thread_group_empty() instead, this
must be strictly equivalent under tasklist, and imho looks better.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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call_usermodehelper_keys() uses call_usermodehelper_setkeys() to change
subprocess_info->cred in advance. Now that we have info->init() we can
change this code to set tgcred->session_keyring in context of execing
kernel thread.
Note: since currently call_usermodehelper_keys() is never called with
UMH_NO_WAIT, call_usermodehelper_keys()->key_get() and umh_keys_cleanup()
are not really needed, we could rely on install_session_keyring_to_cred()
which does key_get() on success.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SHRT_MAX and SHRT_MIN
- C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not
USHORT_MAX/SHORT_MAX/SHORT_MIN.
- Make SHRT_MIN of type s16, not int, for consistency.
[akpm@linux-foundation.org: fix drivers/dma/timb_dma.c]
[akpm@linux-foundation.org: fix security/keys/keyring.c]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We were using the wrong variable here so the error codes weren't being returned
properly. The original code returns -ENOKEY.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Do preallocation for __key_link() so that the various callers in request_key.c
can deal with any errors from this source before attempting to construct a key.
This allows them to assume that the actual linkage step is guaranteed to be
successful.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Conflicts:
security/keys/keyring.c
Resolved conflict with whitespace fix in find_keyring_by_name()
Signed-off-by: James Morris <jmorris@namei.org>
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Errors from construct_alloc_key() shouldn't just be ignored in the way they are
by construct_key_and_link(). The only error that can be ignored so is
EINPROGRESS as that is used to indicate that we've found a key and don't need
to construct one.
We don't, however, handle ENOMEM, EDQUOT or EACCES to indicate allocation
failures of one sort or another.
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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keyring_serialise_link_sem is only needed for keyring->keyring links as it's
used to prevent cycle detection from being avoided by parallel keyring
additions.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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call_sbin_request_key() creates a keyring and then attempts to insert a link to
the authorisation key into that keyring, but does so without holding a write
lock on the keyring semaphore.
It will normally get away with this because it hasn't told anyone that the
keyring exists yet. The new keyring, however, has had its serial number
published, which means it can be accessed directly by that handle.
This was found by a previous patch that adds RCU lockdep checks to the code
that reads the keyring payload pointer, which includes a check that the keyring
semaphore is actually locked.
Without this patch, the following command:
keyctl request2 user b a @s
will provoke the following lockdep warning is displayed in dmesg:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/keyring.c:727 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
2 locks held by keyctl/2076:
#0: (key_types_sem){.+.+.+}, at: [<ffffffff811a5b29>] key_type_lookup+0x1c/0x71
#1: (keyring_serialise_link_sem){+.+.+.}, at: [<ffffffff811a6d1e>] __key_link+0x4d/0x3c5
stack backtrace:
Pid: 2076, comm: keyctl Not tainted 2.6.34-rc6-cachefs #54
Call Trace:
[<ffffffff81051fdc>] lockdep_rcu_dereference+0xaa/0xb2
[<ffffffff811a6d1e>] ? __key_link+0x4d/0x3c5
[<ffffffff811a6e6f>] __key_link+0x19e/0x3c5
[<ffffffff811a5952>] ? __key_instantiate_and_link+0xb1/0xdc
[<ffffffff811a59bf>] ? key_instantiate_and_link+0x42/0x5f
[<ffffffff811aa0dc>] call_sbin_request_key+0xe7/0x33b
[<ffffffff8139376a>] ? mutex_unlock+0x9/0xb
[<ffffffff811a5952>] ? __key_instantiate_and_link+0xb1/0xdc
[<ffffffff811a59bf>] ? key_instantiate_and_link+0x42/0x5f
[<ffffffff811aa6fa>] ? request_key_auth_new+0x1c2/0x23c
[<ffffffff810aaf15>] ? cache_alloc_debugcheck_after+0x108/0x173
[<ffffffff811a9d00>] ? request_key_and_link+0x146/0x300
[<ffffffff810ac568>] ? kmem_cache_alloc+0xe1/0x118
[<ffffffff811a9e45>] request_key_and_link+0x28b/0x300
[<ffffffff811a89ac>] sys_request_key+0xf7/0x14a
[<ffffffff81052c0b>] ? trace_hardirqs_on_caller+0x10c/0x130
[<ffffffff81394fb9>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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The keyring key type code should use RCU dereference wrappers, even when it
holds the keyring's key semaphore.
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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find_keyring_by_name() can gain access to a keyring that has had its reference
count reduced to zero, and is thus ready to be freed. This then allows the
dead keyring to be brought back into use whilst it is being destroyed.
The following timeline illustrates the process:
|(cleaner) (user)
|
| free_user(user) sys_keyctl()
| | |
| key_put(user->session_keyring) keyctl_get_keyring_ID()
| || //=> keyring->usage = 0 |
| |schedule_work(&key_cleanup_task) lookup_user_key()
| || |
| kmem_cache_free(,user) |
| . |[KEY_SPEC_USER_KEYRING]
| . install_user_keyrings()
| . ||
| key_cleanup() [<= worker_thread()] ||
| | ||
| [spin_lock(&key_serial_lock)] |[mutex_lock(&key_user_keyr..mutex)]
| | ||
| atomic_read() == 0 ||
| |{ rb_ease(&key->serial_node,) } ||
| | ||
| [spin_unlock(&key_serial_lock)] |find_keyring_by_name()
| | |||
| keyring_destroy(keyring) ||[read_lock(&keyring_name_lock)]
| || |||
| |[write_lock(&keyring_name_lock)] ||atomic_inc(&keyring->usage)
| |. ||| *** GET freeing keyring ***
| |. ||[read_unlock(&keyring_name_lock)]
| || ||
| |list_del() |[mutex_unlock(&key_user_k..mutex)]
| || |
| |[write_unlock(&keyring_name_lock)] ** INVALID keyring is returned **
| | .
| kmem_cache_free(,keyring) .
| .
| atomic_dec(&keyring->usage)
v *** DESTROYED ***
TIME
If CONFIG_SLUB_DEBUG=y then we may see the following message generated:
=============================================================================
BUG key_jar: Poison overwritten
-----------------------------------------------------------------------------
INFO: 0xffff880197a7e200-0xffff880197a7e200. First byte 0x6a instead of 0x6b
INFO: Allocated in key_alloc+0x10b/0x35f age=25 cpu=1 pid=5086
INFO: Freed in key_cleanup+0xd0/0xd5 age=12 cpu=1 pid=10
INFO: Slab 0xffffea000592cb90 objects=16 used=2 fp=0xffff880197a7e200 flags=0x200000000000c3
INFO: Object 0xffff880197a7e200 @offset=512 fp=0xffff880197a7e300
Bytes b4 0xffff880197a7e1f0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
Object 0xffff880197a7e200: 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b jkkkkkkkkkkkkkkk
Alternatively, we may see a system panic happen, such as:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
IP: [<ffffffff810e61a3>] kmem_cache_alloc+0x5b/0xe9
PGD 6b2b4067 PUD 6a80d067 PMD 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/kernel/kexec_crash_loaded
CPU 1
...
Pid: 31245, comm: su Not tainted 2.6.34-rc5-nofixed-nodebug #2 D2089/PRIMERGY
RIP: 0010:[<ffffffff810e61a3>] [<ffffffff810e61a3>] kmem_cache_alloc+0x5b/0xe9
RSP: 0018:ffff88006af3bd98 EFLAGS: 00010002
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88007d19900b
RDX: 0000000100000000 RSI: 00000000000080d0 RDI: ffffffff81828430
RBP: ffffffff81828430 R08: ffff88000a293750 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000100000 R12: 00000000000080d0
R13: 00000000000080d0 R14: 0000000000000296 R15: ffffffff810f20ce
FS: 00007f97116bc700(0000) GS:ffff88000a280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000001 CR3: 000000006a91c000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process su (pid: 31245, threadinfo ffff88006af3a000, task ffff8800374414c0)
Stack:
0000000512e0958e 0000000000008000 ffff880037f8d180 0000000000000001
0000000000000000 0000000000008001 ffff88007d199000 ffffffff810f20ce
0000000000008000 ffff88006af3be48 0000000000000024 ffffffff810face3
Call Trace:
[<ffffffff810f20ce>] ? get_empty_filp+0x70/0x12f
[<ffffffff810face3>] ? do_filp_open+0x145/0x590
[<ffffffff810ce208>] ? tlb_finish_mmu+0x2a/0x33
[<ffffffff810ce43c>] ? unmap_region+0xd3/0xe2
[<ffffffff810e4393>] ? virt_to_head_page+0x9/0x2d
[<ffffffff81103916>] ? alloc_fd+0x69/0x10e
[<ffffffff810ef4ed>] ? do_sys_open+0x56/0xfc
[<ffffffff81008a02>] ? system_call_fastpath+0x16/0x1b
Code: 0f 1f 44 00 00 49 89 c6 fa 66 0f 1f 44 00 00 65 4c 8b 04 25 60 e8 00 00 48 8b 45 00 49 01 c0 49 8b 18 48 85 db 74 0d 48 63 45 18 <48> 8b 04 03 49 89 00 eb 14 4c 89 f9 83 ca ff 44 89 e6 48 89 ef
RIP [<ffffffff810e61a3>] kmem_cache_alloc+0x5b/0xe9
This problem is that find_keyring_by_name does not confirm that the keyring is
valid before accepting it.
Skipping keyrings that have been reduced to a zero count seems the way to go.
To this end, use atomic_inc_not_zero() to increment the usage count and skip
the candidate keyring if that returns false.
The following script _may_ cause the bug to happen, but there's no guarantee
as the window of opportunity is small:
#!/bin/sh
LOOP=100000
USER=dummy_user
/bin/su -c "exit;" $USER || { /usr/sbin/adduser -m $USER; add=1; }
for ((i=0; i<LOOP; i++))
do
/bin/su -c "echo '$i' > /dev/null" $USER
done
(( add == 1 )) && /usr/sbin/userdel -r $USER
exit
Note that the nominated user must not be in use.
An alternative way of testing this may be:
for ((i=0; i<100000; i++))
do
keyctl session foo /bin/true || break
done >&/dev/null
as that uses a keyring named "foo" rather than relying on the user and
user-session named keyrings.
Reported-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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key_gc_keyring() needs to either hold the RCU read lock or hold the keyring
semaphore if it's going to scan the keyring's list. Given that it only needs
to read the key list, and it's doing so under a spinlock, the RCU read lock is
the thing to use.
Furthermore, the RCU check added in e7b0a61b7929632d36cf052d9e2820ef0a9c1bfe is
incorrect as holding the spinlock on key_serial_lock is not grounds for
assuming a keyring's pointer list can be read safely. Instead, a simple
rcu_dereference() inside of the previously mentioned RCU read lock is what we
want.
Reported-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Fix an RCU warning in the reading of user keys:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/user_defined.c:202 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by keyctl/3637:
#0: (&key->sem){+++++.}, at: [<ffffffff811a80ae>] keyctl_read_key+0x9c/0xcf
stack backtrace:
Pid: 3637, comm: keyctl Not tainted 2.6.34-rc5-cachefs #18
Call Trace:
[<ffffffff81051f6c>] lockdep_rcu_dereference+0xaa/0xb2
[<ffffffff811aa55f>] user_read+0x47/0x91
[<ffffffff811a80be>] keyctl_read_key+0xac/0xcf
[<ffffffff811a8a06>] sys_keyctl+0x75/0xb7
[<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
keys: don't need to use RCU in keyring_read() as semaphore is held
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The request_key() system call and request_key_and_link() should make a
link from an existing key to the destination keyring (if supplied), not
just from a new key to the destination keyring.
This can be tested by:
ring=`keyctl newring fred @s`
keyctl request2 user debug:a a
keyctl request user debug:a $ring
keyctl list $ring
If it says:
keyring is empty
then it didn't work. If it shows something like:
1 key in keyring:
1070462727: --alswrv 0 0 user: debug:a
then it did.
request_key() system call is meant to recursively search all your keyrings for
the key you desire, and, optionally, if it doesn't exist, call out to userspace
to create one for you.
If request_key() finds or creates a key, it should, optionally, create a link
to that key from the destination keyring specified.
Therefore, if, after a successful call to request_key() with a desination
keyring specified, you see the destination keyring empty, the code didn't work
correctly.
If you see the found key in the keyring, then it did - which is what the patch
is required for.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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keyring_read() doesn't need to use rcu_dereference() to access the keyring
payload as the caller holds the key semaphore to prevent modifications
from happening whilst the data is read out.
This should solve the following warning:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/keyring.c:204 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by keyctl/2144:
#0: (&key->sem){+++++.}, at: [<ffffffff81177f7c>] keyctl_read_key+0x9c/0xcf
stack backtrace:
Pid: 2144, comm: keyctl Not tainted 2.6.34-rc2-cachefs #113
Call Trace:
[<ffffffff8105121f>] lockdep_rcu_dereference+0xaa/0xb2
[<ffffffff811762d5>] keyring_read+0x4d/0xe7
[<ffffffff81177f8c>] keyctl_read_key+0xac/0xcf
[<ffffffff811788d4>] sys_keyctl+0x75/0xb9
[<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>
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Fix the following RCU warning:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/request_key.c:116 invoked rcu_dereference_check() without protection!
This was caused by doing:
[root@andromeda ~]# keyctl newring fred @s
539196288
[root@andromeda ~]# keyctl request2 user a a 539196288
request_key: Required key not available
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Whitespace coding style fixes.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Unused hook. Remove.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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This fixes to include <linux/uaccess.h> instead <asm/uaccess.h> and some
code style issues like to put a else sentence below close brace '}' and
to replace a tab instead of some space characters.
Signed-off-by: Chihau Chau <chihau@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Fix some coding styles in security/keys/keyring.c
Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Apply lockdep-ified RCU primitives to key_gc_keyring() and
keyring_destroy().
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-12-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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As of commit ee18d64c1f632043a02e6f5ba5e045bb26a5465f ("KEYS: Add a keyctl to
install a process's session keyring on its parent [try #6]"), CONFIG_KEYS=y
fails to build on architectures that haven't implemented TIF_NOTIFY_RESUME yet:
security/keys/keyctl.c: In function 'keyctl_session_to_parent':
security/keys/keyctl.c:1312: error: 'TIF_NOTIFY_RESUME' undeclared (first use in this function)
security/keys/keyctl.c:1312: error: (Each undeclared identifier is reported only once
security/keys/keyctl.c:1312: error: for each function it appears in.)
Make KEYCTL_SESSION_TO_PARENT depend on TIF_NOTIFY_RESUME until
m68k, and xtensa have implemented it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
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Return the PTR_ERR of the correct pointer.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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For consistency drop & in front of every proc_handler. Explicity
taking the address is unnecessary and it prevents optimizations
like stubbing the proc_handlers to NULL.
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name
and .strategy members of sysctl tables are dead code. Remove them.
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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The destination keyring specified to request_key() and co. is made available to
the process that instantiates the key (the slave process started by
/sbin/request-key typically). This is passed in the request_key_auth struct as
the dest_keyring member.
keyctl_instantiate_key and keyctl_negate_key() call get_instantiation_keyring()
to get the keyring to attach the newly constructed key to at the end of
instantiation. This may be given a specific keyring into which a link will be
made later, or it may be asked to find the keyring passed to request_key(). In
the former case, it returns a keyring with the refcount incremented by
lookup_user_key(); in the latter case, it returns the keyring from the
request_key_auth struct - and does _not_ increment the refcount.
The latter case will eventually result in an oops when the keyring prematurely
runs out of references and gets destroyed. The effect may take some time to
show up as the key is destroyed lazily.
To fix this, the keyring returned by get_instantiation_keyring() must always
have its refcount incremented, no matter where it comes from.
This can be tested by setting /etc/request-key.conf to:
#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...
#====== ======= =============== =============== ===============================
create * test:* * |/bin/false %u %g %d %{user:_display}
negate * * * /bin/keyctl negate %k 10 @u
and then doing:
keyctl add user _display aaaaaaaa @u
while keyctl request2 user test:x test:x @u &&
keyctl list @u;
do
keyctl request2 user test:x test:x @u;
sleep 31;
keyctl list @u;
done
which will oops eventually. Changing the negate line to have @u rather than
%S at the end is important as that forces the latter case by passing a special
keyring ID rather than an actual keyring ID.
Reported-by: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The key garbage collector sets a timer to start a new collection cycle at the
point the earliest key to expire should be considered garbage. However, it
currently only does this if the key it is considering hasn't yet expired.
If the key being considering has expired, but hasn't yet reached the collection
time then it is ignored, and won't be collected until some other key provokes a
round of collection.
Make the garbage collector set the timer for the earliest key that hasn't yet
passed its collection time, rather than the earliest key that hasn't yet
expired.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Fix a number of problems with the new key garbage collector:
(1) A rogue semicolon in keyring_gc() was causing the initial count of dead
keys to be miscalculated.
(2) A missing return in keyring_gc() meant that under certain circumstances,
the keyring semaphore would be unlocked twice.
(3) The key serial tree iterator (key_garbage_collector()) part of the garbage
collector has been modified to:
(a) Complete each scan of the keyrings before setting the new timer.
(b) Only set the new timer for keys that have yet to expire. This means
that the new timer is now calculated correctly, and the gc doesn't
get into a loop continually scanning for keys that have expired, and
preventing other things from happening, like RCU cleaning up the old
keyring contents.
(c) Perform an extra scan if any keys were garbage collected in this one
as a key might become garbage during a scan, and (b) could mean we
don't set the timer again.
(4) Made key_schedule_gc() take the time at which to do a collection run,
rather than the time at which the key expires. This means the collection
of dead keys (key type unregistered) can happen immediately.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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When we exit early from keyctl_session_to_parent because of permissions or
because the session keyring is the same as the parent, we need to unlock the
tasklist.
The missing unlock causes the system to hang completely when using
keyctl(KEYCTL_SESSION_TO_PARENT) with a keyring shared with the parent.
Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Do some whitespace cleanups in the key management code.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Make the file position maintained by /proc/keys represent the ID of the key
just read rather than the number of keys read. This should make it faster to
perform a lookup as we don't have to scan the key ID tree from the beginning to
find the current position.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Add garbage collection for dead, revoked and expired keys. This involved
erasing all links to such keys from keyrings that point to them. At that
point, the key will be deleted in the normal manner.
Keyrings from which garbage collection occurs are shrunk and their quota
consumption reduced as appropriate.
Dead keys (for which the key type has been removed) will be garbage collected
immediately.
Revoked and expired keys will hang around for a number of seconds, as set in
/proc/sys/kernel/keys/gc_delay before being automatically removed. The default
is 5 minutes.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Set the KEY_FLAG_DEAD flag on keys for which the type has been removed. This
causes the key_permission() function to return EKEYREVOKED in response to
various commands. It does not, however, prevent unlinking or clearing of
keyrings from detaching the key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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[try #6]
Allow keyctl_revoke() to operate on keys that have SETATTR but not WRITE
permission, rather than only on keys that have WRITE permission.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Allow keys for which the key type has been removed to be unlinked. Currently
dead-type keys can only be disposed of by completely clearing the keyrings
that point to them.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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- is_single_threaded(task) is not safe unless task == current,
we can't use task->signal or task->mm.
- it doesn't make sense unless task == current, the task can
fork right after the check.
Rename it to current_is_single_threaded() and kill the argument.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Annotate seqfile ops with __releases and __acquires to stop sparse
complaining about unbalanced locking.
Signed-off-by: James Morris <jmorris@namei.org>
Reviewed-by: Serge Hallyn <serue@us.ibm.com>
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When request_key() is called, without there being any standard process
keyrings on which to fall back if a destination keyring is not specified, an
oops is liable to occur when construct_alloc_key() calls down_write() on
dest_keyring's semaphore.
Due to function inlining this may be seen as an oops in down_write() as called
from request_key_and_link().
This situation crops up during boot, where request_key() is called from within
the kernel (such as in CIFS mounts) where nobody is actually logged in, and so
PAM has not had a chance to create a session keyring and user keyrings to act
as the fallback.
To fix this, make construct_alloc_key() not attempt to cache a key if there is
no fallback key if no destination keyring is given specifically.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Restrict the /proc/keys and /proc/key-users output to keys
belonging to the same user namespace as the reading task.
We may want to make this more complicated - so that any
keys in a user-namespace which is belongs to the reading
task are also shown. But let's see if anyone wants that
first.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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When listing keys, do not return keys belonging to the
same uid in another user namespace. Otherwise uid 500
in another user namespace will return keyrings called
uid.500 for another user namespace.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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If a key is owned by another user namespace, then treat the
key as though it is owned by both another uid and gid.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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per-uid keys were looked by uid only. Use the user namespace
to distinguish the same uid in different namespaces.
This does not address key_permission. So a task can for instance
try to join a keyring owned by the same uid in another namespace.
That will be handled by a separate patch.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Plug this leak.
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: <stable@kernel.org>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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