linux/include/crypto
David Howells cdfbabfb2f net: Work around lockdep limitation in sockets that use sockets
Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.

The theory lockdep comes up with is as follows:

 (1) If the pagefault handler decides it needs to read pages from AFS, it
     calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
     creating a call requires the socket lock:

	mmap_sem must be taken before sk_lock-AF_RXRPC

 (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
     binds the underlying UDP socket whilst holding its socket lock.
     inet_bind() takes its own socket lock:

	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET

 (3) Reading from a TCP socket into a userspace buffer might cause a fault
     and thus cause the kernel to take the mmap_sem, but the TCP socket is
     locked whilst doing this:

	sk_lock-AF_INET must be taken before mmap_sem

However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks.  The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace.  This is
a limitation in the design of lockdep.

Fix the general case by:

 (1) Double up all the locking keys used in sockets so that one set are
     used if the socket is created by userspace and the other set is used
     if the socket is created by the kernel.

 (2) Store the kern parameter passed to sk_alloc() in a variable in the
     sock struct (sk_kern_sock).  This informs sock_lock_init(),
     sock_init_data() and sk_clone_lock() as to the lock keys to be used.

     Note that the child created by sk_clone_lock() inherits the parent's
     kern setting.

 (3) Add a 'kern' parameter to ->accept() that is analogous to the one
     passed in to ->create() that distinguishes whether kernel_accept() or
     sys_accept4() was the caller and can be passed to sk_alloc().

     Note that a lot of accept functions merely dequeue an already
     allocated socket.  I haven't touched these as the new socket already
     exists before we get the parameter.

     Note also that there are a couple of places where I've made the accepted
     socket unconditionally kernel-based:

	irda_accept()
	rds_rcp_accept_one()
	tcp_accept_from_sock()

     because they follow a sock_create_kern() and accept off of that.

Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal.  I wonder if these should do that so
that they use the new set of lock keys.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-09 18:23:27 -08:00
..
internal crypto: skcipher - introduce walksize attribute for SIMD algos 2016-12-30 19:52:47 +08:00
ablk_helper.h crypto: create generic version of ablk_helper 2013-09-24 06:02:24 +10:00
acompress.h crypto: acomp - add driver-side scomp interface 2016-10-25 11:08:31 +08:00
aead.h crypto: doc - clarify AEAD memory structure 2016-12-13 16:38:06 -07:00
aes.h crypto: aes - Move key_length in struct crypto_aes_ctx to be the last field 2009-02-18 16:48:04 +08:00
akcipher.h crypto: doc - add akcipher API 2016-02-17 04:07:53 +08:00
algapi.h crypto: api - Add crypto_requires_off helper 2017-02-27 18:09:39 +08:00
authenc.h crypto: authenc - Export key parsing helper function 2013-10-16 20:56:25 +08:00
b128ops.h [CRYPTO] lib: some common 128-bit block operations, nicely centralized 2006-12-06 18:38:55 -08:00
blowfish.h crypto: blowfish - split generic and common c code 2011-09-22 21:25:25 +10:00
cast5.h crypto: cast5/cast6 - move lookup tables to shared module 2012-12-06 17:16:26 +08:00
cast6.h crypto: cast5/cast6 - move lookup tables to shared module 2012-12-06 17:16:26 +08:00
cast_common.h crypto: cast5/cast6 - move lookup tables to shared module 2012-12-06 17:16:26 +08:00
cbc.h crypto: cbc - Export CBC implementation 2016-11-28 21:23:21 +08:00
chacha20.h crypto: chacha20 - convert generic and x86 versions to skcipher 2016-12-27 17:47:31 +08:00
cryptd.h crypto: cryptd - Add support for skcipher 2016-11-28 21:23:18 +08:00
crypto_wq.h crypto: api - Use dedicated workqueue for crypto subsystem 2009-02-19 14:33:40 +08:00
ctr.h [CRYPTO] ctr: Refactor into ctr and rfc3686 2008-01-11 08:16:41 +11:00
des.h crypto: des_3des - add x86-64 assembly implementation 2014-06-20 21:27:58 +08:00
dh.h crypto: doc - add KPP documentation 2016-12-13 16:38:06 -07:00
drbg.h crypto: drbg - prevent invalid SG mappings 2016-11-30 19:46:44 +08:00
ecdh.h crypto: doc - add KPP documentation 2016-12-13 16:38:06 -07:00
engine.h crypto: engine - Handle the kthread worker using the new API 2016-10-25 11:08:25 +08:00
gf128mul.h crypto: gf128mul - Zero memory when freeing multiplication table 2016-11-17 23:34:59 +08:00
ghash.h crypto: ghash-generic - move common definitions to a new header file 2016-10-02 22:26:40 +08:00
hash.h crypto: doc - Fix hash export state information 2017-02-03 18:16:11 +08:00
hash_info.h keys, trusted: select hash algorithm for TPM2 chips 2015-12-20 15:27:12 +02:00
if_alg.h net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
kpp.h crypto: doc - add KPP documentation 2016-12-13 16:38:06 -07:00
lrw.h crypto: lrw - add interface for parallelized cipher implementions 2011-11-09 11:50:31 +08:00
mcryptd.h crypto: sha1-mb - async implementation for sha1-mb 2016-06-23 18:29:55 +08:00
md5.h crypto: hash - add zero length message hash for shax and md5 2015-12-22 20:43:35 +08:00
null.h crypto: null - Remove default null blkcipher 2016-07-18 17:35:44 +08:00
padlock.h crypto: padlock - Move padlock.h into include/crypto 2011-01-07 14:52:00 +11:00
pcrypt.h crypto: pcrypt - Add pcrypt crypto parallelization wrapper 2010-01-07 15:57:19 +11:00
pkcs7.h PKCS#7: Make trust determination dependent on contents of trust keyring 2016-04-06 16:14:24 +01:00
poly1305.h crypto: poly1305 - Export common Poly1305 helpers 2015-07-17 21:20:26 +08:00
public_key.h KEYS: Move the point of trust determination to __key_link() 2016-04-11 22:43:43 +01:00
rng.h crypto: doc - Fix typo in crypto-API.xml 2015-06-04 15:05:08 +08:00
scatterwalk.h crypto: scatterwalk - Inline start/map/done 2016-07-18 17:35:50 +08:00
serpent.h crypto: serpent-sse2 - add lrw support 2011-11-21 16:13:24 +08:00
sha.h crypto: hash - add zero length message hash for shax and md5 2015-12-22 20:43:35 +08:00
sha1_base.h crypto: sha1 - implement base layer for SHA-1 2015-04-10 21:39:39 +08:00
sha3.h crypto: sha3 - Add SHA-3 hash algorithm 2016-06-20 19:25:01 +08:00
sha256_base.h crypto: sha256 - implement base layer for SHA-256 2015-04-10 21:39:39 +08:00
sha512_base.h crypto: sha512 - implement base layer for SHA-512 2015-04-10 21:39:39 +08:00
skcipher.h crypto: skcipher - introduce walksize attribute for SIMD algos 2016-12-30 19:52:47 +08:00
twofish.h crypto: twofish-x86_64-3way - add lrw support 2011-11-09 11:53:32 +08:00
vmac.h crypto: vmac - Make VMAC work when blocks aren't aligned 2012-10-15 22:33:20 +08:00
xts.h crypto: xts - Convert to skcipher 2016-11-28 21:23:18 +08:00