/*
 * linux/net/sunrpc/svcauth.c
 *
 * The generic interface for RPC authentication on the server side.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 *
 * CHANGES
 * 19-Apr-2000 Chris Evans      - Security fix
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/err.h>
#include <linux/hash.h>

#define RPCDBG_FACILITY	RPCDBG_AUTH


/*
 * Table of authenticators
 */
extern struct auth_ops svcauth_null;
extern struct auth_ops svcauth_unix;

static DEFINE_SPINLOCK(authtab_lock);
static struct auth_ops	*authtab[RPC_AUTH_MAXFLAVOR] = {
	[0] = &svcauth_null,
	[1] = &svcauth_unix,
};

int
svc_authenticate(struct svc_rqst *rqstp, __be32 *authp)
{
	rpc_authflavor_t	flavor;
	struct auth_ops		*aops;

	*authp = rpc_auth_ok;

	flavor = svc_getnl(&rqstp->rq_arg.head[0]);

	dprintk("svc: svc_authenticate (%d)\n", flavor);

	spin_lock(&authtab_lock);
	if (flavor >= RPC_AUTH_MAXFLAVOR || !(aops = authtab[flavor]) ||
	    !try_module_get(aops->owner)) {
		spin_unlock(&authtab_lock);
		*authp = rpc_autherr_badcred;
		return SVC_DENIED;
	}
	spin_unlock(&authtab_lock);

	rqstp->rq_auth_slack = 0;
	init_svc_cred(&rqstp->rq_cred);

	rqstp->rq_authop = aops;
	return aops->accept(rqstp, authp);
}
EXPORT_SYMBOL_GPL(svc_authenticate);

int svc_set_client(struct svc_rqst *rqstp)
{
	rqstp->rq_client = NULL;
	return rqstp->rq_authop->set_client(rqstp);
}
EXPORT_SYMBOL_GPL(svc_set_client);

/* A request, which was authenticated, has now executed.
 * Time to finalise the credentials and verifier
 * and release and resources
 */
int svc_authorise(struct svc_rqst *rqstp)
{
	struct auth_ops *aops = rqstp->rq_authop;
	int rv = 0;

	rqstp->rq_authop = NULL;

	if (aops) {
		rv = aops->release(rqstp);
		module_put(aops->owner);
	}
	return rv;
}

int
svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
{
	int rv = -EINVAL;
	spin_lock(&authtab_lock);
	if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
		authtab[flavor] = aops;
		rv = 0;
	}
	spin_unlock(&authtab_lock);
	return rv;
}
EXPORT_SYMBOL_GPL(svc_auth_register);

void
svc_auth_unregister(rpc_authflavor_t flavor)
{
	spin_lock(&authtab_lock);
	if (flavor < RPC_AUTH_MAXFLAVOR)
		authtab[flavor] = NULL;
	spin_unlock(&authtab_lock);
}
EXPORT_SYMBOL_GPL(svc_auth_unregister);

/**************************************************
 * 'auth_domains' are stored in a hash table indexed by name.
 * When the last reference to an 'auth_domain' is dropped,
 * the object is unhashed and freed.
 * If auth_domain_lookup fails to find an entry, it will return
 * it's second argument 'new'.  If this is non-null, it will
 * have been atomically linked into the table.
 */

#define	DN_HASHBITS	6
#define	DN_HASHMAX	(1<<DN_HASHBITS)

static struct hlist_head	auth_domain_table[DN_HASHMAX];
static DEFINE_SPINLOCK(auth_domain_lock);

void auth_domain_put(struct auth_domain *dom)
{
	if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
		hlist_del(&dom->hash);
		dom->flavour->domain_release(dom);
		spin_unlock(&auth_domain_lock);
	}
}
EXPORT_SYMBOL_GPL(auth_domain_put);

struct auth_domain *
auth_domain_lookup(char *name, struct auth_domain *new)
{
	struct auth_domain *hp;
	struct hlist_head *head;

	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];

	spin_lock(&auth_domain_lock);

	hlist_for_each_entry(hp, head, hash) {
		if (strcmp(hp->name, name)==0) {
			kref_get(&hp->ref);
			spin_unlock(&auth_domain_lock);
			return hp;
		}
	}
	if (new)
		hlist_add_head(&new->hash, head);
	spin_unlock(&auth_domain_lock);
	return new;
}
EXPORT_SYMBOL_GPL(auth_domain_lookup);

struct auth_domain *auth_domain_find(char *name)
{
	return auth_domain_lookup(name, NULL);
}
EXPORT_SYMBOL_GPL(auth_domain_find);
e='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Iago Abal &lt;mail@iagoabal.eu&gt;</td><td class='right'>2017-01-11 14:00:21 +0100</td></tr>
<tr><th>committer</th><td>Vinod Koul &lt;vinod.koul@intel.com&gt;</td><td class='right'>2017-01-25 15:35:11 +0530</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/core/seq/seq_timer.h?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>91539eb1fda2d530d3b268eef542c5414e54bf1a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/core/seq/seq_timer.h?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>960f5ca6342ad20837aff18aad6e8ecd7da32fd6</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/core/seq/seq_timer.h?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>sound/core/seq/seq_timer.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/core/seq/seq_timer.h?id=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>6610d0edf6dc7ee97e46ab3a538a565c79d26199</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/core/seq/seq_timer.h?id=91539eb1fda2d530d3b268eef542c5414e54bf1a&amp;id2=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>diff</a>)</td></tr></table>
<div class='commit-subject'>dmaengine: pl330: fix double lock</div><div class='commit-msg'>The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the
following double-lock bug:

    Double lock:
    1. spin_lock_irqsave(pch-&gt;lock, flags) at pl330_free_chan_resources:2236;
    2. call to function `pl330_release_channel' immediately after;
    3. call to function `dma_pl330_rqcb' in line 1753;
    4. spin_lock_irqsave(pch-&gt;lock, flags) at dma_pl330_rqcb:1505.

I have fixed it as suggested by Marek Szyprowski.

First, I have replaced `pch-&gt;lock' with `pl330-&gt;lock' in functions
`pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids
the double-lock by acquiring a different lock than `dma_pl330_rqcb'.

NOTE that, as a result, `pl330_free_chan_resources' executes
`list_splice_tail_init' on `pch-&gt;work_list' under lock `pl330-&gt;lock',
whereas in the rest of the code `pch-&gt;work_list' is protected by
`pch-&gt;lock'. I don't know if this may cause race conditions. Similarly
`pch-&gt;cyclic' is written by `pl330_alloc_chan_resources' under
`pl330-&gt;lock' but read by `pl330_tx_submit' under `pch-&gt;lock'.

Second, I have removed locking from `pl330_request_channel' and
`pl330_release_channel' functions. Function `pl330_request_channel' is
only called from `pl330_alloc_chan_resources', so the lock is already
held. Function `pl330_release_channel' is called from
`pl330_free_chan_resources', which already holds the lock, and from
`pl330_del'. Function `pl330_del' is called in an error path of
`pl330_probe' and at the end of `pl330_remove', but I assume that there
cannot be concurrent accesses to the protected data at those points.

Signed-off-by: Iago Abal &lt;mail@iagoabal.eu&gt;
Reviewed-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>Diffstat</a> (limited to 'sound/core/seq/seq_timer.h')</div><table summary='diffstat' class='diffstat'>