linux-toradex.git/net/sunrpc/auth.c, branch v4.8

sunrpc: Fix bit count when setting hashtable size to power-of-two

2016-07-19T20:23:26+00:00

Author: Frank Sorenson 
Date:   2016-06-27 13:55:48 -0500

    sunrpc: Fix bit count when setting hashtable size to power-of-two

    The hashtable size is incorrectly calculated as the next higher
    power-of-two when being set to a power-of-two.  fls() returns the
    bit number of the most significant set bit, with the least
    significant bit being numbered '1'.  For a power-of-two, fls()
    will return a bit number which is one higher than the number of bits
    required, leading to a hashtable which is twice the requested size.

    In addition, the value of (1 << nbits) will always be at least num,
    so the test will never be true.

    Fix the hash table size calculation to correctly set hashtable
    size, and eliminate the unnecessary check.

    Signed-off-by: Frank Sorenson 

Signed-off-by: Trond Myklebust

sunrpc: move NO_CRKEY_TIMEOUT to the auth->au_flags

2016-07-19T20:23:24+00:00

A generic_cred can be used to look up a unx_cred or a gss_cred, so it's
not really safe to use the the generic_cred->acred->ac_flags to store
the NO_CRKEY_TIMEOUT flag.  A lookup for a unx_cred triggered while the
KEY_EXPIRE_SOON flag is already set will cause both NO_CRKEY_TIMEOUT and
KEY_EXPIRE_SOON to be set in the ac_flags, leaving the user associated
with the auth_cred to be in a state where they're perpetually doing 4K
NFS_FILE_SYNC writes.

This can be reproduced as follows:

1. Mount two NFS filesystems, one with sec=krb5 and one with sec=sys.
They do not need to be the same export, nor do they even need to be from
the same NFS server.  Also, v3 is fine.
$ sudo mount -o v3,sec=krb5 server1:/export /mnt/krb5
$ sudo mount -o v3,sec=sys server2:/export /mnt/sys

2. As the normal user, before accessing the kerberized mount, kinit with
a short lifetime (but not so short that renewing the ticket would leave
you within the 4-minute window again by the time the original ticket
expires), e.g.
$ kinit -l 10m -r 60m

3. Do some I/O to the kerberized mount and verify that the writes are
wsize, UNSTABLE:
$ dd if=/dev/zero of=/mnt/krb5/file bs=1M count=1

4. Wait until you're within 4 minutes of key expiry, then do some more
I/O to the kerberized mount to ensure that RPC_CRED_KEY_EXPIRE_SOON gets
set.  Verify that the writes are 4K, FILE_SYNC:
$ dd if=/dev/zero of=/mnt/krb5/file bs=1M count=1

5. Now do some I/O to the sec=sys mount.  This will cause
RPC_CRED_NO_CRKEY_TIMEOUT to be set:
$ dd if=/dev/zero of=/mnt/sys/file bs=1M count=1

6. Writes for that user will now be permanently 4K, FILE_SYNC for that
user, regardless of which mount is being written to, until you reboot
the client.  Renewing the kerberos ticket (assuming it hasn't already
expired) will have no effect.  Grabbing a new kerberos ticket at this
point will have no effect either.

Move the flag to the auth->au_flags field (which is currently unused)
and rename it slightly to reflect that it's no longer associated with
the auth_cred->ac_flags.  Add the rpc_auth to the arg list of
rpcauth_cred_key_to_expire and check the au_flags there too.  Finally,
add the inode to the arg list of nfs_ctx_key_to_expire so we can
determine the rpc_auth to pass to rpcauth_cred_key_to_expire.

Signed-off-by: Scott Mayhew 
Signed-off-by: Trond Myklebust

SUNRPC: Ensure get_rpccred() and put_rpccred() can take NULL arguments

2016-05-17T19:48:06+00:00

Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

sunrpc: plumb gfp_t parm into crcreate operation

2016-05-09T13:05:40+00:00

We need to be able to call the generic_cred creator from different
contexts. Add a gfp_t parm to the crcreate operation and to
rpcauth_lookup_credcache. For now, we just push the gfp_t parms up
one level to the *_lookup_cred functions.

Signed-off-by: Jeff Layton 
Signed-off-by: Anna Schumaker

kernel/params: constify struct kernel_param_ops uses

2015-05-28T02:02:10+00:00

Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.

In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.

Test compiled on x86_64 against:

	* allnoconfig
	* allmodconfig
	* allyesconfig

@ const_found @
identifier ops;
@@

const struct kernel_param_ops ops = {
};

@ const_not_found depends on !const_found @
identifier ops;
@@

-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};

Generated-by: Coccinelle SmPL
Cc: Rusty Russell 
Cc: Junio C Hamano 
Cc: Andrew Morton 
Cc: Kees Cook 
Cc: Tejun Heo 
Cc: Ingo Molnar 
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez 
Signed-off-by: Rusty Russell

sunrpc: eliminate RPC_DEBUG

2014-11-24T22:31:46+00:00

It's always set to whatever CONFIG_SUNRPC_DEBUG is, so just use that.

Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust

SUNRPC: remove all refcounting of groupinfo from rpcauth_lookupcred

2014-08-04T13:22:08+00:00

current_cred() can only be changed by 'current', and
cred->group_info is never changed.  If a new group_info is
needed, a new 'cred' is created.

Consequently it is always safe to access
   current_cred()->group_info

without taking any further references.
So drop the refcounting and the incorrect rcu_dereference().

Signed-off-by: NeilBrown 
Signed-off-by: Trond Myklebust

sunrpc/auth: allow lockless (rcu) lookup of credential cache.

2014-08-03T21:14:12+00:00

The new flag RPCAUTH_LOOKUP_RCU to credential lookup avoids locking,
does not take a reference on the returned credential, and returns
-ECHILD if a simple lookup was not possible.

The returned value can only be used within an rcu_read_lock protected
region.

The main user of this is the new rpc_lookup_cred_nonblock() which
returns a pointer to the current credential which is only rcu-safe (no
ref-count held), and might return -ECHILD if allocation was required.

Signed-off-by: NeilBrown 
Signed-off-by: Trond Myklebust

SUNRPC: Enforce an upper limit on the number of cached credentials

2014-08-03T20:02:50+00:00

In some cases where the credentials are not often reused, we may want
to limit their total number just in order to make the negative lookups
in the hash table more manageable.

Signed-off-by: Trond Myklebust

replace strict_strto calls

2014-07-12T22:45:49+00:00

Replace obsolete strict_strto calls with appropriate kstrto calls

Signed-off-by: Daniel Walter 
Signed-off-by: Trond Myklebust