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Cache the hash of the key's type and description in the index key so that
we're not recalculating it every time we look at a key during a search.
The hash function does a bunch of multiplications, so evading those is
probably worthwhile - especially as this is done for every key examined
during a search.
This also allows the methods used by assoc_array to get chunks of index-key
to be simplified.
Signed-off-by: David Howells <dhowells@redhat.com>
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Simplify key description management by cramming the word containing the
length with the first few chars of the description also. This simplifies
the code that generates the index-key used by assoc_array. It should speed
up key searching a bit too.
Signed-off-by: David Howells <dhowells@redhat.com>
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Invalidate used request_key authentication keys rather than revoking them
so that they get cleaned up immediately rather than potentially hanging
around. There doesn't seem any need to keep the revoked keys around.
Signed-off-by: David Howells <dhowells@redhat.com>
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Hoist the locking of out of __key_link_begin() and into its callers. This
is necessary to allow the upcoming key_move() operation to correctly order
taking of the source keyring semaphore, the destination keyring semaphore
and the keyring serialisation lock.
Signed-off-by: David Howells <dhowells@redhat.com>
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Set the timestamp on new keys rather than leaving it unset.
Fixes: 31d5a79d7f3d ("KEYS: Do LRU discard in full keyrings")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
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If the sysctl 'kernel.keys.maxkeys' is set to some number n, then
actually users can only add up to 'n - 1' keys. Likewise for
'kernel.keys.maxbytes' and the root_* versions of these sysctls. But
these sysctls are apparently supposed to be *maximums*, as per their
names and all documentation I could find -- the keyrings(7) man page,
Documentation/security/keys/core.rst, and all the mentions of EDQUOT
meaning that the key quota was *exceeded* (as opposed to reached).
Thus, fix the code to allow reaching the quotas exactly.
Fixes: 0b77f5bfb45c ("keys: make the keyring quotas controllable through /proc/sys")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
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Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.
The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.
Since module.h might have been the implicit source for init.h
(for __init) and for export.h (for EXPORT_SYMBOL) we consider each
instance for the presence of either and replace as needed.
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: linux-security-module@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: keyrings@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
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Variable key_ref is being assigned a value that is never read;
key_ref is being re-assigned a few statements later. Hence this
assignment is redundant and can be removed.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
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The 'struct key_preparsed_payload' will use 'time_t' which we will
try to remove in the kernel, since 'time_t' is not year 2038 safe on
32bits systems.
Thus this patch replaces 'time_t' with 'time64_t' which is year 2038
safe on 32 bits system for 'struct key_preparsed_payload', moreover
we should use the 'TIME64_MAX' macro to initialize the 'time64_t'
type variable.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
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The 'struct key' will use 'time_t' which we try to remove in the
kernel, since 'time_t' is not year 2038 safe on 32bit systems.
Also the 'struct keyring_search_context' will use 'timespec' type
to record current time, which is also not year 2038 safe on 32bit
systems.
Thus this patch replaces 'time_t' with 'time64_t' which is year 2038
safe for 'struct key', and replace 'timespec' with 'time64_t' for the
'struct keyring_search_context', since we only look at the the seconds
part of 'timespec' variable. Moreover we also change the codes where
using the 'time_t' and 'timespec', and we can get current time by
ktime_get_real_seconds() instead of current_kernel_time(), and use
'TIME64_MAX' macro to initialize the 'time64_t' type variable.
Especially in proc.c file, we have replaced 'unsigned long' and 'timespec'
type with 'u64' and 'time64_t' type to save the timeout value, which means
user will get one 'u64' type timeout value by issuing proc_keys_show()
function.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
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Currently, when passed a key that already exists, add_key() will call the
key's ->update() method if such exists. But this is heavily broken in the
case where the key is uninstantiated because it doesn't call
__key_instantiate_and_link(). Consequently, it doesn't do most of the
things that are supposed to happen when the key is instantiated, such as
setting the instantiation state, clearing KEY_FLAG_USER_CONSTRUCT and
awakening tasks waiting on it, and incrementing key->user->nikeys.
It also never takes key_construction_mutex, which means that
->instantiate() can run concurrently with ->update() on the same key. In
the case of the "user" and "logon" key types this causes a memory leak, at
best. Maybe even worse, the ->update() methods of the "encrypted" and
"trusted" key types actually just dereference a NULL pointer when passed an
uninstantiated key.
Change key_create_or_update() to wait interruptibly for the key to finish
construction before continuing.
This patch only affects *uninstantiated* keys. For now we still allow a
negatively instantiated key to be updated (thereby positively
instantiating it), although that's broken too (the next patch fixes it)
and I'm not sure that anyone actually uses that functionality either.
Here is a simple reproducer for the bug using the "encrypted" key type
(requires CONFIG_ENCRYPTED_KEYS=y), though as noted above the bug
pertained to more than just the "encrypted" key type:
#include <stdlib.h>
#include <unistd.h>
#include <keyutils.h>
int main(void)
{
int ringid = keyctl_join_session_keyring(NULL);
if (fork()) {
for (;;) {
const char payload[] = "update user:foo 32";
usleep(rand() % 10000);
add_key("encrypted", "desc", payload, sizeof(payload), ringid);
keyctl_clear(ringid);
}
} else {
for (;;)
request_key("encrypted", "desc", "callout_info", ringid);
}
}
It causes:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
IP: encrypted_update+0xb0/0x170
PGD 7a178067 P4D 7a178067 PUD 77269067 PMD 0
PREEMPT SMP
CPU: 0 PID: 340 Comm: reproduce Tainted: G D 4.14.0-rc1-00025-g428490e38b2e #796
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff8a467a39a340 task.stack: ffffb15c40770000
RIP: 0010:encrypted_update+0xb0/0x170
RSP: 0018:ffffb15c40773de8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8a467a275b00 RCX: 0000000000000000
RDX: 0000000000000005 RSI: ffff8a467a275b14 RDI: ffffffffb742f303
RBP: ffffb15c40773e20 R08: 0000000000000000 R09: ffff8a467a275b17
R10: 0000000000000020 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8a4677057180 R15: ffff8a467a275b0f
FS: 00007f5d7fb08700(0000) GS:ffff8a467f200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000018 CR3: 0000000077262005 CR4: 00000000001606f0
Call Trace:
key_create_or_update+0x2bc/0x460
SyS_add_key+0x10c/0x1d0
entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x7f5d7f211259
RSP: 002b:00007ffed03904c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8
RAX: ffffffffffffffda RBX: 000000003b2a7955 RCX: 00007f5d7f211259
RDX: 00000000004009e4 RSI: 00000000004009ff RDI: 0000000000400a04
RBP: 0000000068db8bad R08: 000000003b2a7955 R09: 0000000000000004
R10: 000000000000001a R11: 0000000000000246 R12: 0000000000400868
R13: 00007ffed03905d0 R14: 0000000000000000 R15: 0000000000000000
Code: 77 28 e8 64 34 1f 00 45 31 c0 31 c9 48 8d 55 c8 48 89 df 48 8d 75 d0 e8 ff f9 ff ff 85 c0 41 89 c4 0f 88 84 00 00 00 4c 8b 7d c8 <49> 8b 75 18 4c 89 ff e8 24 f8 ff ff 85 c0 41 89 c4 78 6d 49 8b
RIP: encrypted_update+0xb0/0x170 RSP: ffffb15c40773de8
CR2: 0000000000000018
Cc: <stable@vger.kernel.org> # v2.6.12+
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Biggers <ebiggers@google.com>
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Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection
error into one field such that:
(1) The instantiation state can be modified/read atomically.
(2) The error can be accessed atomically with the state.
(3) The error isn't stored unioned with the payload pointers.
This deals with the problem that the state is spread over three different
objects (two bits and a separate variable) and reading or updating them
atomically isn't practical, given that not only can uninstantiated keys
change into instantiated or rejected keys, but rejected keys can also turn
into instantiated keys - and someone accessing the key might not be using
any locking.
The main side effect of this problem is that what was held in the payload
may change, depending on the state. For instance, you might observe the
key to be in the rejected state. You then read the cached error, but if
the key semaphore wasn't locked, the key might've become instantiated
between the two reads - and you might now have something in hand that isn't
actually an error code.
The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error
code if the key is negatively instantiated. The key_is_instantiated()
function is replaced with key_is_positive() to avoid confusion as negative
keys are also 'instantiated'.
Additionally, barriering is included:
(1) Order payload-set before state-set during instantiation.
(2) Order state-read before payload-read when using the key.
Further separate barriering is necessary if RCU is being used to access the
payload content after reading the payload pointers.
Fixes: 146aa8b1453b ("KEYS: Merge the type-specific data with the payload data")
Cc: stable@vger.kernel.org # v4.4+
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
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In key_user_lookup(), if there is no key_user for the given uid, we drop
key_user_lock, allocate a new key_user, and search the tree again. But
we failed to set 'parent' to NULL at the beginning of the second search.
If the tree were to be empty for the second search, the insertion would
be done with an invalid 'parent', scribbling over freed memory.
Fortunately this can't actually happen currently because the tree always
contains at least the root_key_user. But it still should be fixed to
make the code more robust.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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It was possible for an unprivileged user to create the user and user
session keyrings for another user. For example:
sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u
keyctl add keyring _uid_ses.4000 "" @u
sleep 15' &
sleep 1
sudo -u '#4000' keyctl describe @u
sudo -u '#4000' keyctl describe @us
This is problematic because these "fake" keyrings won't have the right
permissions. In particular, the user who created them first will own
them and will have full access to them via the possessor permissions,
which can be used to compromise the security of a user's keys:
-4: alswrv-----v------------ 3000 0 keyring: _uid.4000
-5: alswrv-----v------------ 3000 0 keyring: _uid_ses.4000
Fix it by marking user and user session keyrings with a flag
KEY_FLAG_UID_KEYRING. Then, when searching for a user or user session
keyring by name, skip all keyrings that don't have the flag set.
Fixes: 69664cf16af4 ("keys: don't generate user and user session keyrings unless they're accessed")
Cc: <stable@vger.kernel.org> [v2.6.26+]
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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If a key's refcount is dropped to zero between key_lookup() peeking at
the refcount and subsequently attempting to increment it, refcount_inc()
will see a zero refcount. Here, refcount_inc() will WARN_ONCE(), and
will *not* increment the refcount, which will remain zero.
Once key_lookup() drops key_serial_lock, it is possible for the key to
be freed behind our back.
This patch uses refcount_inc_not_zero() to perform the peek and increment
atomically.
Fixes: fff292914d3a2f1e ("security, keys: convert key.usage from atomic_t to refcount_t")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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key_update() freed the key_preparsed_payload even if it was not
initialized first. This would cause a crash if userspace called
keyctl_update() on a key with type like "asymmetric" that has a
->preparse() method but not an ->update() method. Possibly it could
even be triggered for other key types by racing with keyctl_setperm() to
make the KEY_NEED_WRITE check fail (the permission was already checked,
so normally it wouldn't fail there).
Reproducer with key type "asymmetric", given a valid cert.der:
keyctl new_session
keyid=$(keyctl padd asymmetric desc @s < cert.der)
keyctl setperm $keyid 0x3f000000
keyctl update $keyid data
[ 150.686666] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
[ 150.687601] IP: asymmetric_key_free_kids+0x12/0x30
[ 150.688139] PGD 38a3d067
[ 150.688141] PUD 3b3de067
[ 150.688447] PMD 0
[ 150.688745]
[ 150.689160] Oops: 0000 [#1] SMP
[ 150.689455] Modules linked in:
[ 150.689769] CPU: 1 PID: 2478 Comm: keyctl Not tainted 4.11.0-rc4-xfstests-00187-ga9f6b6b8cd2f #742
[ 150.690916] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
[ 150.692199] task: ffff88003b30c480 task.stack: ffffc90000350000
[ 150.692952] RIP: 0010:asymmetric_key_free_kids+0x12/0x30
[ 150.693556] RSP: 0018:ffffc90000353e58 EFLAGS: 00010202
[ 150.694142] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000004
[ 150.694845] RDX: ffffffff81ee3920 RSI: ffff88003d4b0700 RDI: 0000000000000001
[ 150.697569] RBP: ffffc90000353e60 R08: ffff88003d5d2140 R09: 0000000000000000
[ 150.702483] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 150.707393] R13: 0000000000000004 R14: ffff880038a4d2d8 R15: 000000000040411f
[ 150.709720] FS: 00007fcbcee35700(0000) GS:ffff88003fd00000(0000) knlGS:0000000000000000
[ 150.711504] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 150.712733] CR2: 0000000000000001 CR3: 0000000039eab000 CR4: 00000000003406e0
[ 150.714487] Call Trace:
[ 150.714975] asymmetric_key_free_preparse+0x2f/0x40
[ 150.715907] key_update+0xf7/0x140
[ 150.716560] ? key_default_cmp+0x20/0x20
[ 150.717319] keyctl_update_key+0xb0/0xe0
[ 150.718066] SyS_keyctl+0x109/0x130
[ 150.718663] entry_SYSCALL_64_fastpath+0x1f/0xc2
[ 150.719440] RIP: 0033:0x7fcbce75ff19
[ 150.719926] RSP: 002b:00007ffd5d167088 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa
[ 150.720918] RAX: ffffffffffffffda RBX: 0000000000404d80 RCX: 00007fcbce75ff19
[ 150.721874] RDX: 00007ffd5d16785e RSI: 000000002866cd36 RDI: 0000000000000002
[ 150.722827] RBP: 0000000000000006 R08: 000000002866cd36 R09: 00007ffd5d16785e
[ 150.723781] R10: 0000000000000004 R11: 0000000000000206 R12: 0000000000404d80
[ 150.724650] R13: 00007ffd5d16784d R14: 00007ffd5d167238 R15: 000000000040411f
[ 150.725447] Code: 83 c4 08 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 ff 74 23 55 48 89 e5 53 48 89 fb <48> 8b 3f e8 06 21 c5 ff 48 8b 7b 08 e8 fd 20 c5 ff 48 89 df e8
[ 150.727489] RIP: asymmetric_key_free_kids+0x12/0x30 RSP: ffffc90000353e58
[ 150.728117] CR2: 0000000000000001
[ 150.728430] ---[ end trace f7f8fe1da2d5ae8d ]---
Fixes: 4d8c0250b841 ("KEYS: Call ->free_preparse() even after ->preparse() returns an error")
Cc: stable@vger.kernel.org # 3.17+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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The keyring restrict callback was sometimes called before
__key_link_begin and sometimes after, which meant that the keyring
semaphores were not always held during the restrict callback.
If the semaphores are consistently acquired before checking link
restrictions, keyring contents cannot be changed after the restrict
check is complete but before the evaluated key is linked to the keyring.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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Replace struct key's restrict_link function pointer with a pointer to
the new struct key_restriction. The structure contains pointers to the
restriction function as well as relevant data for evaluating the
restriction.
The garbage collector checks restrict_link->keytype when key types are
unregistered. Restrictions involving a removed key type are converted
to use restrict_link_reject so that restrictions cannot be removed by
unregistering key types.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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The first argument to the restrict_link_func_t functions was a keyring
pointer. These functions are called by the key subsystem with this
argument set to the destination keyring, but restrict_link_by_signature
expects a pointer to the relevant trusted keyring.
Restrict functions may need something other than a single struct key
pointer to allow or reject key linkage, so the data used to make that
decision (such as the trust keyring) is moved to a new, fourth
argument. The first argument is now always the destination keyring.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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This pointer type needs to be returned from a lookup function, and
without a typedef the syntax gets cumbersome.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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If __key_link_begin() failed then "edit" would be uninitialized. I've
added a check to fix that.
This allows a random user to crash the kernel, though it's quite
difficult to achieve. There are three ways it can be done as the user
would have to cause an error to occur in __key_link():
(1) Cause the kernel to run out of memory. In practice, this is difficult
to achieve without ENOMEM cropping up elsewhere and aborting the
attempt.
(2) Revoke the destination keyring between the keyring ID being looked up
and it being tested for revocation. In practice, this is difficult to
time correctly because the KEYCTL_REJECT function can only be used
from the request-key upcall process. Further, users can only make use
of what's in /sbin/request-key.conf, though this does including a
rejection debugging test - which means that the destination keyring
has to be the caller's session keyring in practice.
(3) Have just enough key quota available to create a key, a new session
keyring for the upcall and a link in the session keyring, but not then
sufficient quota to create a link in the nominated destination keyring
so that it fails with EDQUOT.
The bug can be triggered using option (3) above using something like the
following:
echo 80 >/proc/sys/kernel/keys/root_maxbytes
keyctl request2 user debug:fred negate @t
The above sets the quota to something much lower (80) to make the bug
easier to trigger, but this is dependent on the system. Note also that
the name of the keyring created contains a random number that may be
between 1 and 10 characters in size, so may throw the test off by
changing the amount of quota used.
Assuming the failure occurs, something like the following will be seen:
kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b68h
------------[ cut here ]------------
kernel BUG at ../mm/slab.c:2821!
...
RIP: 0010:[<ffffffff811600f9>] kfree_debugcheck+0x20/0x25
RSP: 0018:ffff8804014a7de8 EFLAGS: 00010092
RAX: 0000000000000034 RBX: 6b6b6b6b6b6b6b68 RCX: 0000000000000000
RDX: 0000000000040001 RSI: 00000000000000f6 RDI: 0000000000000300
RBP: ffff8804014a7df0 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8804014a7e68 R11: 0000000000000054 R12: 0000000000000202
R13: ffffffff81318a66 R14: 0000000000000000 R15: 0000000000000001
...
Call Trace:
kfree+0xde/0x1bc
assoc_array_cancel_edit+0x1f/0x36
__key_link_end+0x55/0x63
key_reject_and_link+0x124/0x155
keyctl_reject_key+0xb6/0xe0
keyctl_negate_key+0x10/0x12
SyS_keyctl+0x9f/0xe7
do_syscall_64+0x63/0x13a
entry_SYSCALL64_slow_path+0x25/0x25
Fixes: f70e2e06196a ('KEYS: Do preallocation for __key_link()')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer
meaningful. Also we can drop the trusted flag from the preparse structure.
Given this, we no longer need to pass the key flags through to
restrict_link().
Further, we can now get rid of keyring_restrict_trusted_only() also.
Signed-off-by: David Howells <dhowells@redhat.com>
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Add a facility whereby proposed new links to be added to a keyring can be
vetted, permitting them to be rejected if necessary. This can be used to
block public keys from which the signature cannot be verified or for which
the signature verification fails. It could also be used to provide
blacklisting.
This affects operations like add_key(), KEYCTL_LINK and KEYCTL_INSTANTIATE.
To this end:
(1) A function pointer is added to the key struct that, if set, points to
the vetting function. This is called as:
int (*restrict_link)(struct key *keyring,
const struct key_type *key_type,
unsigned long key_flags,
const union key_payload *key_payload),
where 'keyring' will be the keyring being added to, key_type and
key_payload will describe the key being added and key_flags[*] can be
AND'ed with KEY_FLAG_TRUSTED.
[*] This parameter will be removed in a later patch when
KEY_FLAG_TRUSTED is removed.
The function should return 0 to allow the link to take place or an
error (typically -ENOKEY, -ENOPKG or -EKEYREJECTED) to reject the
link.
The pointer should not be set directly, but rather should be set
through keyring_alloc().
Note that if called during add_key(), preparse is called before this
method, but a key isn't actually allocated until after this function
is called.
(2) KEY_ALLOC_BYPASS_RESTRICTION is added. This can be passed to
key_create_or_update() or key_instantiate_and_link() to bypass the
restriction check.
(3) KEY_FLAG_TRUSTED_ONLY is removed. The entire contents of a keyring
with this restriction emplaced can be considered 'trustworthy' by
virtue of being in the keyring when that keyring is consulted.
(4) key_alloc() and keyring_alloc() take an extra argument that will be
used to set restrict_link in the new key. This ensures that the
pointer is set before the key is published, thus preventing a window
of unrestrictedness. Normally this argument will be NULL.
(5) As a temporary affair, keyring_restrict_trusted_only() is added. It
should be passed to keyring_alloc() as the extra argument instead of
setting KEY_FLAG_TRUSTED_ONLY on a keyring. This will be replaced in
a later patch with functions that look in the appropriate places for
authoritative keys.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
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Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN
set rather than setting it after the fact.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
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KEY_FLAG_KEEP should only be applied to a key if the keyring it is being
linked into has KEY_FLAG_KEEP set.
To this end, partially revert the following patch:
commit 1d6d167c2efcfe9539d9cffb1a1be9c92e39c2c0
Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
Date: Thu Jan 7 07:46:36 2016 -0500
KEYS: refcount bug fix
to undo the change that made it unconditional (Mimi got it right the first
time).
Without undoing this change, it becomes impossible to delete, revoke or
invalidate keys added to keyrings through __key_instantiate_and_link()
where the keyring has itself been linked to. To test this, run the
following command sequence:
keyctl newring foo @s
keyctl add user a a %:foo
keyctl unlink %user:a %:foo
keyctl clear %:foo
With the commit mentioned above the third and fourth commands fail with
EPERM when they should succeed.
Reported-by: Stephen Gallager <sgallagh@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: keyrings@vger.kernel.org
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
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This patch fixes the key_ref leak, removes the unnecessary KEY_FLAG_KEEP
test before setting the flag, and cleans up the if/then brackets style
introduced in commit:
d3600bc KEYS: prevent keys from being removed from specified keyrings
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
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Userspace should not be allowed to remove keys from certain keyrings
(eg. blacklist), though the keys themselves can expire.
This patch defines a new key flag named KEY_FLAG_KEEP to prevent
userspace from being able to unlink, revoke, invalidate or timed
out a key on a keyring. When this flag is set on the keyring, all
keys subsequently added are flagged.
In addition, when this flag is set, the keyring itself can not be
cleared.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
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Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.
Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net
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key->description and key->index_key.description are same because
they are unioned. But, for readability, using same name for
duplication and validation seems better.
Signed-off-by: Insu Yun <wuninsu@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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We already checked if "desc" was NULL at the beginning of the function
and we've dereferenced it so this causes a static checker warning.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris.
Mostly ima, selinux, smack and key handling updates.
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (65 commits)
integrity: do zero padding of the key id
KEYS: output last portion of fingerprint in /proc/keys
KEYS: strip 'id:' from ca_keyid
KEYS: use swapped SKID for performing partial matching
KEYS: Restore partial ID matching functionality for asymmetric keys
X.509: If available, use the raw subjKeyId to form the key description
KEYS: handle error code encoded in pointer
selinux: normalize audit log formatting
selinux: cleanup error reporting in selinux_nlmsg_perm()
KEYS: Check hex2bin()'s return when generating an asymmetric key ID
ima: detect violations for mmaped files
ima: fix race condition on ima_rdwr_violation_check and process_measurement
ima: added ima_policy_flag variable
ima: return an error code from ima_add_boot_aggregate()
ima: provide 'ima_appraise=log' kernel option
ima: move keyring initialization to ima_init()
PKCS#7: Handle PKCS#7 messages that contain no X.509 certs
PKCS#7: Better handling of unsupported crypto
KEYS: Overhaul key identification when searching for asymmetric keys
KEYS: Implement binary asymmetric key ID handling
...
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A previous patch added a ->match_preparse() method to the key type. This is
allowed to override the function called by the iteration algorithm.
Therefore, we can just set a default that simply checks for an exact match of
the key description with the original criterion data and allow match_preparse
to override it as needed.
The key_type::match op is then redundant and can be removed, as can the
user_match() function.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
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Now that NFS client uses the kernel key ring facility to store the NFSv4
id/gid mappings, the defaults for root_maxkeys and root_maxbytes need to be
substantially increased.
These values have been soak tested:
https://bugzilla.redhat.com/show_bug.cgi?id=1033708#c73
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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Call the ->free_preparse() key type op even after ->preparse() returns an
error as it does cleaning up type stuff.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
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Allow a key type's preparsing routine to set the expiry time for a key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
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struct key_preparsed_payload should have two payload pointers to correspond
with those in struct key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
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Provide a generic instantiation function for key types that use the preparse
hook. This makes it easier to prereserve key quota before keyrings get locked
to retain the new key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Sage Weil <sage@redhat.com>
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Move the flags representing required permission to linux/key.h as the perm
parameter of security_key_permission() is in terms of them - and not the
permissions mask flags used in key->perm.
Whilst we're at it:
(1) Rename them to be KEY_NEED_xxx rather than KEY_xxx to avoid collisions
with symbols in uapi/linux/input.h.
(2) Don't use key_perm_t for a mask of required permissions, but rather limit
it to the permissions mask attached to the key and arguments related
directly to that.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
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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:[<ffffffff811b4a51>] dput+0x21/0x2d0
...
Call Trace:
[<ffffffff811a7b06>] path_put+0x16/0x30
[<ffffffff81235604>] big_key_destroy+0x44/0x60
[<ffffffff8122dc4b>] key_gc_unused_keys.constprop.2+0x5b/0xe0
[<ffffffff8122df2f>] key_garbage_collector+0x1df/0x3c0
[<ffffffff8107759b>] process_one_work+0x17b/0x460
[<ffffffff8107834b>] worker_thread+0x11b/0x400
[<ffffffff81078230>] ? rescuer_thread+0x3e0/0x3e0
[<ffffffff8107eb00>] kthread+0xc0/0xd0
[<ffffffff8107ea40>] ? kthread_create_on_node+0x110/0x110
[<ffffffff815c4bec>] ret_from_fork+0x7c/0xb0
[<ffffffff8107ea40>] ? kthread_create_on_node+0x110/0x110
Reported-by: Patrik Kis <pkis@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Stephen Gallagher <sgallagh@redhat.com>
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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 <dwysocha@redhat.com> and Scott Mayhew
<smayhew@redhat.com> for tracking this down.
This may be the cause of:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
IP: [<ffffffff81219011>] 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:[<ffffffff81219011>] 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
<d> 0000000000000000 ffff880a000000d0 ffff880c6ab337a8 000000000000000f
<d> ffffffffa03afb93 000000000000000f ffff88186c7882c0 0000000000000014
Call Trace:
[<ffffffff81219695>] request_key+0x65/0xa0
[<ffffffffa03a0885>] nfs_idmap_request_key+0xc5/0x170 [nfs]
[<ffffffffa03a0eb4>] nfs_idmap_lookup_id+0x34/0x80 [nfs]
[<ffffffffa03a1255>] nfs_map_group_to_gid+0x75/0xa0 [nfs]
[<ffffffffa039a9ad>] decode_getfattr_attrs+0xbdd/0xfb0 [nfs]
[<ffffffff81057310>] ? __dequeue_entity+0x30/0x50
[<ffffffff8100988e>] ? __switch_to+0x26e/0x320
[<ffffffffa039ae03>] decode_getfattr+0x83/0xe0 [nfs]
[<ffffffffa039b610>] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs]
[<ffffffffa039b69f>] nfs4_xdr_dec_getattr+0x8f/0xa0 [nfs]
[<ffffffffa02dada4>] rpcauth_unwrap_resp+0x84/0xb0 [sunrpc]
[<ffffffffa039b610>] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs]
[<ffffffffa02cf923>] call_decode+0x1b3/0x800 [sunrpc]
[<ffffffff81096de0>] ? wake_bit_function+0x0/0x50
[<ffffffffa02cf770>] ? call_decode+0x0/0x800 [sunrpc]
[<ffffffffa02d99a7>] __rpc_execute+0x77/0x350 [sunrpc]
[<ffffffff81096c67>] ? bit_waitqueue+0x17/0xd0
[<ffffffffa02d9ce1>] rpc_execute+0x61/0xa0 [sunrpc]
[<ffffffffa02d03a5>] rpc_run_task+0x75/0x90 [sunrpc]
[<ffffffffa02d04c2>] rpc_call_sync+0x42/0x70 [sunrpc]
[<ffffffffa038ff80>] _nfs4_call_sync+0x30/0x40 [nfs]
[<ffffffffa038836c>] _nfs4_proc_getattr+0xac/0xc0 [nfs]
[<ffffffff810aac87>] ? futex_wait+0x227/0x380
[<ffffffffa038b856>] nfs4_proc_getattr+0x56/0x80 [nfs]
[<ffffffffa0371403>] __nfs_revalidate_inode+0xe3/0x220 [nfs]
[<ffffffffa037158e>] nfs_revalidate_mapping+0x4e/0x170 [nfs]
[<ffffffffa036f147>] nfs_file_read+0x77/0x130 [nfs]
[<ffffffff811811aa>] do_sync_read+0xfa/0x140
[<ffffffff81096da0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff8100bb8e>] ? apic_timer_interrupt+0xe/0x20
[<ffffffff8100b9ce>] ? common_interrupt+0xe/0x13
[<ffffffff81228ffb>] ? selinux_file_permission+0xfb/0x150
[<ffffffff8121bed6>] ? security_file_permission+0x16/0x20
[<ffffffff81181a95>] vfs_read+0xb5/0x1a0
[<ffffffff81181bd1>] sys_read+0x51/0x90
[<ffffffff810dc685>] ? __audit_syscall_exit+0x265/0x290
[<ffffffff8100b072>] system_call_fastpath+0x16/0x1b
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Dave Wysochanski <dwysocha@redhat.com>
cc: Scott Mayhew <smayhew@redhat.com>
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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 <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
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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 <dhowells@redhat.com>
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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 <dhowells@redhat.com>
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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 <dhowells@redhat.com>
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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 <dhowells@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
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
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git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module signing support from Rusty Russell:
"module signing is the highlight, but it's an all-over David Howells frenzy..."
Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG.
* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits)
X.509: Fix indefinite length element skip error handling
X.509: Convert some printk calls to pr_devel
asymmetric keys: fix printk format warning
MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
MODSIGN: Make mrproper should remove generated files.
MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs
MODSIGN: Use the same digest for the autogen key sig as for the module sig
MODSIGN: Sign modules during the build process
MODSIGN: Provide a script for generating a key ID from an X.509 cert
MODSIGN: Implement module signature checking
MODSIGN: Provide module signing public keys to the kernel
MODSIGN: Automatically generate module signing keys if missing
MODSIGN: Provide Kconfig options
MODSIGN: Provide gitignore and make clean rules for extra files
MODSIGN: Add FIPS policy
module: signature checking hook
X.509: Add a crypto key parser for binary (DER) X.509 certificates
MPILIB: Provide a function to read raw data into an MPI
X.509: Add an ASN.1 decoder
X.509: Add simple ASN.1 grammar compiler
...
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Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called. This is done with the
provision of two new key type operations:
int (*preparse)(struct key_preparsed_payload *prep);
void (*free_preparse)(struct key_preparsed_payload *prep);
If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases). The second operation is called to clean up if the first
was called.
preparse() is given the opportunity to fill in the following structure:
struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};
Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.
The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.
The preparser may also propose a description for the key by attaching it as a
string to the description field. This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function. This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.
This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.
The instantiate() and update() operations are then modified to look like this:
int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
int (*update)(struct key *key, struct key_preparsed_payload *prep);
and the new payload data is passed in *prep, whether or not it was preparsed.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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