Currently a number of Crypto API operations may fail when a signal
occurs.  This causes nasty problems as the caller of those operations
are often not in a good position to restart the operation.

In fact there is currently no need for those operations to be
interrupted by user signals at all.  All we need is for them to
be killable.

This patch replaces the relevant calls of signal_pending with
fatal_signal_pending, and wait_for_completion_interruptible with
wait_for_completion_killable, respectively.

Cc: stable@vger.kernel.org
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Several hardware related cipher implementations are implemented as
follows: a "helper" cipher implementation is registered with the
kernel crypto API.

Such helper ciphers are never intended to be called by normal users. In
some cases, calling them via the normal crypto API may even cause
failures including kernel crashes. In a normal case, the "wrapping"
ciphers that use the helpers ensure that these helpers are invoked
such that they cannot cause any calamity.

Considering the AF_ALG user space interface, unprivileged users can
call all ciphers registered with the crypto API, including these
helper ciphers that are not intended to be called directly. That
means, with AF_ALG user space may invoke these helper ciphers
and may cause undefined states or side effects.

To avoid any potential side effects with such helpers, the patch
prevents the helpers to be called directly. A new cipher type
flag is added: CRYPTO_ALG_INTERNAL. This flag shall be used
to mark helper ciphers. These ciphers can only be used if the
caller invoke the cipher with CRYPTO_ALG_INTERNAL in the type and
mask field.
Signed-off-by: NStephan Mueller <smueller@chronox.de>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This prefixes all crypto module loading with "crypto-" so we never run
the risk of exposing module auto-loading to userspace via a crypto API,
as demonstrated by Mathias Krause:

https://lkml.org/lkml/2013/3/4/70Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

crypto_larval_lookup should only return a larval if it created one.
Any larval created by another entity must be processed through
crypto_larval_wait before being returned.

Otherwise this will lead to a larval being killed twice, which
will most likely lead to a crash.

Cc: stable@vger.kernel.org
Reported-by: NKees Cook <keescook@chromium.org>
Tested-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: NCristian Stoica <cristian.stoica@freescale.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

On Thu, Jun 20, 2013 at 10:00:21AM +0200, Daniel Borkmann wrote:
> After having fixed a NULL pointer dereference in SCTP 1abd165e ("net:
> sctp: fix NULL pointer dereference in socket destruction"), I ran into
> the following NULL pointer dereference in the crypto subsystem with
> the same reproducer, easily hit each time:
> 
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffff81070321>] __wake_up_common+0x31/0x90
> PGD 0
> Oops: 0000 [#1] SMP
> Modules linked in: padlock_sha(F-) sha256_generic(F) sctp(F) libcrc32c(F) [..]
> CPU: 6 PID: 3326 Comm: cryptomgr_probe Tainted: GF            3.10.0-rc5+ #1
> Hardware name: Dell Inc. PowerEdge T410/0H19HD, BIOS 1.6.3 02/01/2011
> task: ffff88007b6cf4e0 ti: ffff88007b7cc000 task.ti: ffff88007b7cc000
> RIP: 0010:[<ffffffff81070321>]  [<ffffffff81070321>] __wake_up_common+0x31/0x90
> RSP: 0018:ffff88007b7cde08  EFLAGS: 00010082
> RAX: ffffffffffffffe8 RBX: ffff88003756c130 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff88003756c130
> RBP: ffff88007b7cde48 R08: 0000000000000000 R09: ffff88012b173200
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000282
> R13: ffff88003756c138 R14: 0000000000000000 R15: 0000000000000000
> FS:  0000000000000000(0000) GS:ffff88012fc60000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> CR2: 0000000000000000 CR3: 0000000001a0b000 CR4: 00000000000007e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Stack:
>  ffff88007b7cde28 0000000300000000 ffff88007b7cde28 ffff88003756c130
>  0000000000000282 ffff88003756c128 ffffffff81227670 0000000000000000
>  ffff88007b7cde78 ffffffff810722b7 ffff88007cdcf000 ffffffff81a90540
> Call Trace:
>  [<ffffffff81227670>] ? crypto_alloc_pcomp+0x20/0x20
>  [<ffffffff810722b7>] complete_all+0x47/0x60
>  [<ffffffff81227708>] cryptomgr_probe+0x98/0xc0
>  [<ffffffff81227670>] ? crypto_alloc_pcomp+0x20/0x20
>  [<ffffffff8106760e>] kthread+0xce/0xe0
>  [<ffffffff81067540>] ? kthread_freezable_should_stop+0x70/0x70
>  [<ffffffff815450dc>] ret_from_fork+0x7c/0xb0
>  [<ffffffff81067540>] ? kthread_freezable_should_stop+0x70/0x70
> Code: 41 56 41 55 41 54 53 48 83 ec 18 66 66 66 66 90 89 75 cc 89 55 c8
>       4c 8d 6f 08 48 8b 57 08 41 89 cf 4d 89 c6 48 8d 42 e
> RIP  [<ffffffff81070321>] __wake_up_common+0x31/0x90
>  RSP <ffff88007b7cde08>
> CR2: 0000000000000000
> ---[ end trace b495b19270a4d37e ]---
> 
> My assumption is that the following is happening: the minimal SCTP
> tool runs under ``echo 1 > /proc/sys/net/sctp/auth_enable'', hence
> it's making use of crypto_alloc_hash() via sctp_auth_init_hmacs().
> It forks itself, heavily allocates, binds, listens and waits in
> accept on sctp sockets, and then randomly kills some of them (no
> need for an actual client in this case to hit this). Then, again,
> allocating, binding, etc, and then killing child processes.
> 
> The problem that might be happening here is that cryptomgr requests
> the module to probe/load through cryptomgr_schedule_probe(), but
> before the thread handler cryptomgr_probe() returns, we return from
> the wait_for_completion_interruptible() function and probably already
> have cleared up larval, thus we run into a NULL pointer dereference
> when in cryptomgr_probe() complete_all() is being called.
> 
> If we wait with wait_for_completion() instead, this panic will not
> occur anymore. This is valid, because in case a signal is pending,
> cryptomgr_probe() returns from probing anyway with properly calling
> complete_all().

The use of wait_for_completion_interruptible is intentional so that
we don't lock up the thread if a bug causes us to never wake up.

This bug is caused by the helper thread using the larval without
holding a reference count on it.  If the helper thread completes
after the original thread requesting for help has gone away and
destroyed the larval, then we get the crash above.

So the fix is to hold a reference count on the larval.

Cc: <stable@vger.kernel.org> # 3.6+
Reported-by: NDaniel Borkmann <dborkman@redhat.com>
Tested-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: NRichard Hartmann <richih.mailinglist@gmail.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

As the extsize and init_tfm functions belong to the frontend the
frontend argument is superfluous.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch removes the implementation of hash and digest now that
no algorithms use them anymore.  The interface though will remain
until the users are converted across.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds the helper crypto_attr_alg2 which is similar to
crypto_attr_alg but takes an extra frontend argument.  This is
intended to be used by new style algorithm types such as shash.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Besdies, for the old code, gcc-4.3.3 produced this warning:
  "format not a string literal and no format arguments"
Signed-off-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Use kzfree() instead of memset() + kfree().
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The commit a760a665 (crypto:
api - Fix module load deadlock with fallback algorithms) broke
the auto-loading of algorithms that require fallbacks.  The
problem is that the fallback mask check is missing an and which
cauess bits that should be considered to interfere with the
result.
Reported-by: NChuck Ebbert <cebbert@redhat.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

With the mandatory algorithm testing at registration, we have
now created a deadlock with algorithms requiring fallbacks.
This can happen if the module containing the algorithm requiring
fallback is loaded first, without the fallback module being loaded
first.  The system will then try to test the new algorithm, find
that it needs to load a fallback, and then try to load that.

As both algorithms share the same module alias, it can attempt
to load the original algorithm again and block indefinitely.

As algorithms requiring fallbacks are a special case, we can fix
this by giving them a different module alias than the rest.  Then
it's just a matter of using the right aliases according to what
algorithms we're trying to find.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This is based on a report and patch by Geert Uytterhoeven.

The functions crypto_alloc_tfm and create_create_tfm return a
pointer that needs to be adjusted by the caller when successful
and otherwise an error value.  This means that the caller has
to check for the error and only perform the adjustment if the
pointer returned is valid.

Since all callers want to make the adjustment and we know how
to adjust it ourselves, it's much easier to just return adjusted
pointer directly.

The only caveat is that we have to return a void * instead of
struct crypto_tfm *.  However, this isn't that bad because both
of these functions are for internal use only (by types code like
shash.c, not even algorithms code).

This patch also moves crypto_alloc_tfm into crypto/internal.h
(crypto_create_tfm is already there) to reflect this.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

As it stands crypto_alg_mod_lookup will search either tested or
untested algorithms, but never both at the same time.  However,
we need exactly that when constructing givcipher and aead so
this patch adds support for that by setting the tested bit in
type but clearing it in mask.  This combination is currently
unused.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Geert Uytterhoeven pointed out that we're not zeroing all the
memory when freeing a transform.  This patch fixes it by calling
ksize to ensure that we zero everything in sight.
Reported-by: NGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch reintroduces a completely revamped crypto_alloc_tfm.
The biggest change is that we now take two crypto_type objects
when allocating a tfm, a frontend and a backend.  In fact this
simply formalises what we've been doing behind the API's back.

For example, as it stands crypto_alloc_ahash may use an
actual ahash algorithm or a crypto_hash algorithm.  Putting
this in the API allows us to do this much more cleanly.

The existing types will be converted across gradually.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The type exit function needs to undo any allocations done by the type
init function.  However, the type init function may differ depending
on the upper-level type of the transform (e.g., a crypto_blkcipher
instantiated as a crypto_ablkcipher).

So we need to move the exit function out of the lower-level
structure and into crypto_tfm itself.

As it stands this is a no-op since nobody uses exit functions at
all.  However, all cases where a lower-level type is instantiated
as a different upper-level type (such as blkcipher as ablkcipher)
will be converted such that they allocate the underlying transform
and use that instead of casting (e.g., crypto_ablkcipher casted
into crypto_blkcipher).  That will need to use a different exit
function depending on the upper-level type.

This patch also allows the type init/exit functions to call (or not)
cra_init/cra_exit instead of always calling them from the top level.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch makes use of the new testing infrastructure by requiring
algorithms to pass a run-time test before they're made available to
users.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Since the only user of __crypto_alg_lookup is doing exactly what
crypto_alg_lookup does, we can now the latter in lieu of the former.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds asynchronous hash and digest support.
Signed-off-by: NLoc Ho <lho@amcc.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: NSebastian Siewior <sebastian@breakpoint.cc>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch makes crypto_alloc_ablkcipher/crypto_grab_skcipher always
return algorithms that are capable of generating their own IVs through
givencrypt and givdecrypt.  Each algorithm may specify its default IV
generator through the geniv field.

For algorithms that do not set the geniv field, the blkcipher layer will
pick a default.  Currently it's chainiv for synchronous algorithms and
eseqiv for asynchronous algorithms.  Note that if these wrappers do not
work on an algorithm then that algorithm must specify its own geniv or
it can't be used at all.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Convert the subdirectory "crypto" to UTF-8. The files changed are
<crypto/fcrypt.c> and <crypto/api.c>.
Signed-off-by: NJohn Anthony Kazos Jr. <jakj@j-a-k-j.com>
Signed-off-by: NAdrian Bunk <bunk@kernel.org>

Right now when a larval matures or when it dies of an error we
only wake up one waiter.  This would cause other waiters to timeout
unnecessarily.  This patch changes it to use complete_all to wake
up all waiters.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The function crypto_mod_put first frees the algorithm and then drops
the reference to its module.  Unfortunately we read the module pointer
which after freeing the algorithm and that pointer sits inside the
object that we just freed.

So this patch reads the module pointer out before we free the object.

Thanks to Luca Tettamanti for reporting this.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds support for multiple frontend types for each backend
algorithm by passing the type and mask through to the backend type
init function.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch removes the old cipher interface and related code.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch removes the following no longer used functions:
- api.c: crypto_alg_available()
- digest.c: crypto_digest_init()
- digest.c: crypto_digest_update()
- digest.c: crypto_digest_final()
- digest.c: crypto_digest_digest()
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch makes crypto_alloc_base() return proper return value.

- If kzalloc() failure happens within __crypto_alloc_tfm(),
  crypto_alloc_base() returns NULL. But crypto_alloc_base()
  is supposed to return error code as pointer. So this patch
  makes it return -ENOMEM in that case.

- crypto_alloc_base() is suppose to return -EINTR, if it is
  interrupted by signal. But it may not return -EINTR.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds the crypto_comp type to complete the compile-time checking
conversion.  The functions crypto_has_alg and crypto_has_cipher, etc. are
also added to replace crypto_alg_available.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds the crypto_type structure which will be used for all new
crypto algorithm types, beginning with block ciphers.

The primary purpose of this abstraction is to allow different crypto_type
objects for crypto algorithms of the same type, in particular, there will
be a different crypto_type objects for asynchronous algorithms.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Up until now all crypto transforms have been of the same type, struct
crypto_tfm, regardless of whether they are ciphers, digests, or other
types.  As a result of that, we check the types at run-time before
each crypto operation.

This is rather cumbersome.  We could instead use different C types for
each crypto type to ensure that the correct types are used at compile
time.  That is, we would have crypto_cipher/crypto_digest instead of
just crypto_tfm.  The appropriate type would then be required for the
actual operations such as crypto_digest_digest.

Now that we have the type/mask fields when looking up algorithms, it
is easy to request for an algorithm of the precise type that the user
wants.  However, crypto_alloc_tfm currently does not expose these new
attributes.

This patch introduces the function crypto_alloc_base which will carry
these new parameters.  It will be renamed to crypto_alloc_tfm once
all existing users have been converted.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds the asynchronous flag and changes all existing users to
only look up algorithms that are synchronous.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Spawns lock a specific crypto algorithm in place.  They can then be used
with crypto_spawn_tfm to allocate a tfm for that algorithm.  When the base
algorithm of a spawn is deregistered, all its spawns will be automatically
removed.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch also adds the infrastructure to pick an algorithm based on
their type.  For example, this allows you to select the encryption
algorithm "aes", instead of any algorithm registered under the name
"aes".  For now this is only accessible internally.  Eventually it
will be made available through crypto_alloc_tfm.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The cryptomgr module is a simple manager of crypto algorithm instances.
It ensures that parameterised algorithms of the type tmpl(alg) (e.g.,
cbc(aes)) are always created.

This is meant to satisfy the needs for most users.  For more complex
cases such as deeper combinations or multiple parameters, a netlink
module will be created which allows arbitrary expressions to be parsed
in user-space.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a notifier chain for algorithm/template registration events.
This will be used to register compound algorithms such as cbc(aes).  In
future this will also be passed onto user-space through netlink.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The crypto API is made up of the part facing users such as IPsec and the
low-level part which is used by cryptographic entities such as algorithms.
This patch splits out the latter so that the two APIs are more clearly
delineated.  As a bonus the low-level API can now be modularised if all
algorithms are built as modules.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>