auth_gss.c

linux-2.6.15.6

/*
 * linux/net/sunrpc/auth_gss.c
 *
 * RPCSEC_GSS client authentication.
 * 
 *  Copyright (c) 2000 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Dug Song       <[e-mail]>
 *  Andy Adamson   <[e-mail]>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $Id$
 */


#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/auth_gss.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/gss_err.h>
#include <linux/workqueue.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/sunrpc/gss_api.h>
#include <asm/uaccess.h>

static struct rpc_authops authgss_ops;

static struct rpc_credops gss_credops;

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY	RPCDBG_AUTH
#endif

#define NFS_NGROUPS	16

#define GSS_CRED_EXPIRE		(60 * HZ)	/* XXX: reasonable? */
#define GSS_CRED_SLACK		1024		/* XXX: unused */
/* length of a krb5 verifier (48), plus data added before arguments when
 * using integrity (two 4-byte integers): */
#define GSS_VERF_SLACK		56

/* XXX this define must match the gssd define
* as it is passed to gssd to signal the use of
* machine creds should be part of the shared rpc interface */

#define CA_RUN_AS_MACHINE  0x00000200 

/* dump the buffer in `emacs-hexl' style */
#define isprint(c)      ((c > 0x1f) && (c < 0x7f))

static DEFINE_RWLOCK(gss_ctx_lock);

struct gss_auth {
	struct rpc_auth rpc_auth;
	struct gss_api_mech *mech;
	enum rpc_gss_svc service;
	struct list_head upcalls;
	struct rpc_clnt *client;
	struct dentry *dentry;
	char path[48];
	spinlock_t lock;
};

static void gss_destroy_ctx(struct gss_cl_ctx *);
static struct rpc_pipe_ops gss_upcall_ops;

void
print_hexl(u32 *p, u_int length, u_int offset)
{
	u_int i, j, jm;
	u8 c, *cp;
	
	dprintk("RPC: print_hexl: length %d\n",length);
	dprintk("\n");
	cp = (u8 *) p;
	
	for (i = 0; i < length; i += 0x10) {
		dprintk("  %04x: ", (u_int)(i + offset));
		jm = length - i;
		jm = jm > 16 ? 16 : jm;
		
		for (j = 0; j < jm; j++) {
			if ((j % 2) == 1)
				dprintk("%02x ", (u_int)cp[i+j]);
			else
				dprintk("%02x", (u_int)cp[i+j]);
		}
		for (; j < 16; j++) {
			if ((j % 2) == 1)
				dprintk("   ");
			else
				dprintk("  ");
		}
		dprintk(" ");
		
		for (j = 0; j < jm; j++) {
			c = cp[i+j];
			c = isprint(c) ? c : '.';
			dprintk("%c", c);
		}
		dprintk("\n");
	}
}

EXPORT_SYMBOL(print_hexl);

static inline struct gss_cl_ctx *
gss_get_ctx(struct gss_cl_ctx *ctx)
{
	atomic_inc(&ctx->count);
	return ctx;
}

static inline void
gss_put_ctx(struct gss_cl_ctx *ctx)
{
	if (atomic_dec_and_test(&ctx->count))
		gss_destroy_ctx(ctx);
}

static void
gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
{
	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
	struct gss_cl_ctx *old;
	write_lock(&gss_ctx_lock);
	old = gss_cred->gc_ctx;
	gss_cred->gc_ctx = ctx;
	cred->cr_flags |= RPCAUTH_CRED_UPTODATE;
	write_unlock(&gss_ctx_lock);
	if (old)
		gss_put_ctx(old);
}

static int
gss_cred_is_uptodate_ctx(struct rpc_cred *cred)
{
	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
	int res = 0;

	read_lock(&gss_ctx_lock);
	if ((cred->cr_flags & RPCAUTH_CRED_UPTODATE) && gss_cred->gc_ctx)
		res = 1;
	read_unlock(&gss_ctx_lock);
	return res;
}

static const void *
simple_get_bytes(const void *p, const void *end, void *res, size_t len)
{
	const void *q = (const void *)((const char *)p + len);
	if (unlikely(q > end || q < p))
		return ERR_PTR(-EFAULT);
	memcpy(res, p, len);
	return q;
}

static inline const void *
simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
{
	const void *q;
	unsigned int len;

	p = simple_get_bytes(p, end, &len, sizeof(len));
	if (IS_ERR(p))
		return p;
	q = (const void *)((const char *)p + len);
	if (unlikely(q > end || q < p))
		return ERR_PTR(-EFAULT);
	dest->data = kmalloc(len, GFP_KERNEL);
	if (unlikely(dest->data == NULL))
		return ERR_PTR(-ENOMEM);
	dest->len = len;
	memcpy(dest->data, p, len);
	return q;
}

static struct gss_cl_ctx *
gss_cred_get_ctx(struct rpc_cred *cred)
{
	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
	struct gss_cl_ctx *ctx = NULL;

	read_lock(&gss_ctx_lock);
	if (gss_cred->gc_ctx)
		ctx = gss_get_ctx(gss_cred->gc_ctx);
	read_unlock(&gss_ctx_lock);
	return ctx;
}

static struct gss_cl_ctx *
gss_alloc_context(void)
{
	struct gss_cl_ctx *ctx;

	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
	if (ctx != NULL) {
		memset(ctx, 0, sizeof(*ctx));
		ctx->gc_proc = RPC_GSS_PROC_DATA;
		ctx->gc_seq = 1;	/* NetApp 6.4R1 doesn't accept seq. no. 0 */
		spin_lock_init(&ctx->gc_seq_lock);
		atomic_set(&ctx->count,1);
	}
	return ctx;
}

#define GSSD_MIN_TIMEOUT (60 * 60)
static const void *
gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
{
	const void *q;
	unsigned int seclen;
	unsigned int timeout;
	u32 window_size;
	int ret;

	/* First unsigned int gives the lifetime (in seconds) of the cred */
	p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
	if (IS_ERR(p))
		goto err;
	if (timeout == 0)
		timeout = GSSD_MIN_TIMEOUT;
	ctx->gc_expiry = jiffies + (unsigned long)timeout * HZ * 3 / 4;
	/* Sequence number window. Determines the maximum number of simultaneous requests */
	p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
	if (IS_ERR(p))
		goto err;
	ctx->gc_win = window_size;
	/* gssd signals an error by passing ctx->gc_win = 0: */
	if (ctx->gc_win == 0) {
		/* in which case, p points to  an error code which we ignore */
		p = ERR_PTR(-EACCES);
		goto err;
	}
	/* copy the opaque wire context */
	p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
	if (IS_ERR(p))
		goto err;
	/* import the opaque security context */
	p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
	if (IS_ERR(p))
		goto err;
	q = (const void *)((const char *)p + seclen);
	if (unlikely(q > end || q < p)) {
		p = ERR_PTR(-EFAULT);
		goto err;
	}
	ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx);
	if (ret < 0) {
		p = ERR_PTR(ret);
		goto err;
	}
	return q;
err:
	dprintk("RPC:      gss_fill_context returning %ld\n", -PTR_ERR(p));
	return p;
}


struct gss_upcall_msg {
	atomic_t count;
	uid_t	uid;
	struct rpc_pipe_msg msg;
	struct list_head list;
	struct gss_auth *auth;
	struct rpc_wait_queue rpc_waitqueue;
	wait_queue_head_t waitqueue;
	struct gss_cl_ctx *ctx;
};

static void
gss_release_msg(struct gss_upcall_msg *gss_msg)
{
	if (!atomic_dec_and_test(&gss_msg->count))
		return;
	BUG_ON(!list_empty(&gss_msg->list));
	if (gss_msg->ctx != NULL)
		gss_put_ctx(gss_msg->ctx);
	kfree(gss_msg);
}

static struct gss_upcall_msg *
__gss_find_upcall(struct gss_auth *gss_auth, uid_t uid)
{
	struct gss_upcall_msg *pos;
	list_for_each_entry(pos, &gss_auth->upcalls, list) {
		if (pos->uid != uid)
			continue;
		atomic_inc(&pos->count);
		dprintk("RPC:      gss_find_upcall found msg %p\n", pos);
		return pos;
	}
	dprintk("RPC:      gss_find_upcall found nothing\n");
	return NULL;
}

/* Try to add a upcall to the pipefs queue.
 * If an upcall owned by our uid already exists, then we return a reference
 * to that upcall instead of adding the new upcall.
 */
static inline struct gss_upcall_msg *
gss_add_msg(struct gss_auth *gss_auth, struct gss_upcall_msg *gss_msg)
{
	struct gss_upcall_msg *old;

	spin_lock(&gss_auth->lock);
	old = __gss_find_upcall(gss_auth, gss_msg->uid);
	if (old == NULL) {
		atomic_inc(&gss_msg->count);
		list_add(&gss_msg->list, &gss_auth->upcalls);
	} else
		gss_msg = old;
	spin_unlock(&gss_auth->lock);
	return gss_msg;
}

static void
__gss_unhash_msg(struct gss_upcall_msg *gss_msg)
{
	if (list_empty(&gss_msg->list))
		return;
	list_del_init(&gss_msg->list);
	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
	wake_up_all(&gss_msg->waitqueue);
	atomic_dec(&gss_msg->count);
}

static void
gss_unhash_msg(struct gss_upcall_msg *gss_msg)
{
	struct gss_auth *gss_auth = gss_msg->auth;

	spin_lock(&gss_auth->lock);
	__gss_unhash_msg(gss_msg);
	spin_unlock(&gss_auth->lock);
}

static void
gss_upcall_callback(struct rpc_task *task)
{
	struct gss_cred *gss_cred = container_of(task->tk_msg.rpc_cred,
			struct gss_cred, gc_base);
	struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;

	BUG_ON(gss_msg == NULL);
	if (gss_msg->ctx)
		gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_get_ctx(gss_msg->ctx));
	else
		task->tk_status = gss_msg->msg.errno;
	spin_lock(&gss_msg->auth->lock);
	gss_cred->gc_upcall = NULL;
	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
	spin_unlock(&gss_msg->auth->lock);
	gss_release_msg(gss_msg);
}

static inline struct gss_upcall_msg *
gss_alloc_msg(struct gss_auth *gss_auth, uid_t uid)
{
	struct gss_upcall_msg *gss_msg;

	gss_msg = kmalloc(sizeof(*gss_msg), GFP_KERNEL);
	if (gss_msg != NULL) {
		memset(gss_msg, 0, sizeof(*gss_msg));
		INIT_LIST_HEAD(&gss_msg->list);
		rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
		init_waitqueue_head(&gss_msg->waitqueue);
		atomic_set(&gss_msg->count, 1);
		gss_msg->msg.data = &gss_msg->uid;
		gss_msg->msg.len = sizeof(gss_msg->uid);
		gss_msg->uid = uid;
		gss_msg->auth = gss_auth;
	}
	return gss_msg;
}

static struct gss_upcall_msg *
gss_setup_upcall(struct rpc_clnt *clnt, struct gss_auth *gss_auth, struct rpc_cred *cred)
{
	struct gss_upcall_msg *gss_new, *gss_msg;

	gss_new = gss_alloc_msg(gss_auth, cred->cr_uid);
	if (gss_new == NULL)
		return ERR_PTR(-ENOMEM);
	gss_msg = gss_add_msg(gss_auth, gss_new);
	if (gss_msg == gss_new) {
		int res = rpc_queue_upcall(gss_auth->dentry->d_inode, &gss_new->msg);
		if (res) {
			gss_unhash_msg(gss_new);
			gss_msg = ERR_PTR(res);
		}
	} else
		gss_release_msg(gss_new);
	return gss_msg;
}

static inline int
gss_refresh_upcall(struct rpc_task *task)
{