svcauth_gss.c

omap3 linux 2.6 用nocc去除了冗余代码

		/* number of additional gid's */
		if (get_int(&mesg, &N))
			goto out;
		status = -ENOMEM;
		rsci.cred.cr_group_info = groups_alloc(N);
		if (rsci.cred.cr_group_info == NULL)
			goto out;

		/* gid's */
		status = -EINVAL;
		for (i=0; i<N; i++) {
			gid_t gid;
			if (get_int(&mesg, &gid))
				goto out;
			GROUP_AT(rsci.cred.cr_group_info, i) = gid;
		}

		/* mech name */
		len = qword_get(&mesg, buf, mlen);
		if (len < 0)
			goto out;
		gm = gss_mech_get_by_name(buf);
		status = -EOPNOTSUPP;
		if (!gm)
			goto out;

		status = -EINVAL;
		/* mech-specific data: */
		len = qword_get(&mesg, buf, mlen);
		if (len < 0)
			goto out;
		status = gss_import_sec_context(buf, len, gm, &rsci.mechctx);
		if (status)
			goto out;
	}
	rsci.h.expiry_time = expiry;
	rscp = rsc_update(&rsci, rscp);
	status = 0;
out:
	gss_mech_put(gm);
	rsc_free(&rsci);
	if (rscp)
		cache_put(&rscp->h, &rsc_cache);
	else
		status = -ENOMEM;
	return status;
}

static struct cache_detail rsc_cache = {
	.owner		= THIS_MODULE,
	.hash_size	= RSC_HASHMAX,
	.hash_table	= rsc_table,
	.name		= "auth.rpcsec.context",
	.cache_put	= rsc_put,
	.cache_parse	= rsc_parse,
	.match		= rsc_match,
	.init		= rsc_init,
	.update		= update_rsc,
	.alloc		= rsc_alloc,
};

static struct rsc *rsc_lookup(struct rsc *item)
{
	struct cache_head *ch;
	int hash = rsc_hash(item);

	ch = sunrpc_cache_lookup(&rsc_cache, &item->h, hash);
	if (ch)
		return container_of(ch, struct rsc, h);
	else
		return NULL;
}

static struct rsc *rsc_update(struct rsc *new, struct rsc *old)
{
	struct cache_head *ch;
	int hash = rsc_hash(new);

	ch = sunrpc_cache_update(&rsc_cache, &new->h,
				 &old->h, hash);
	if (ch)
		return container_of(ch, struct rsc, h);
	else
		return NULL;
}


static struct rsc *
gss_svc_searchbyctx(struct xdr_netobj *handle)
{
	struct rsc rsci;
	struct rsc *found;

	memset(&rsci, 0, sizeof(rsci));
	if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
		return NULL;
	found = rsc_lookup(&rsci);
	rsc_free(&rsci);
	if (!found)
		return NULL;
	if (cache_check(&rsc_cache, &found->h, NULL))
		return NULL;
	return found;
}

/* Implements sequence number algorithm as specified in RFC 2203. */
static int
gss_check_seq_num(struct rsc *rsci, int seq_num)
{
	struct gss_svc_seq_data *sd = &rsci->seqdata;

	spin_lock(&sd->sd_lock);
	if (seq_num > sd->sd_max) {
		if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
			memset(sd->sd_win,0,sizeof(sd->sd_win));
			sd->sd_max = seq_num;
		} else while (sd->sd_max < seq_num) {
			sd->sd_max++;
			__clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
		}
		__set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
		goto ok;
	} else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) {
		goto drop;
	}
	/* sd_max - GSS_SEQ_WIN < seq_num <= sd_max */
	if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
		goto drop;
ok:
	spin_unlock(&sd->sd_lock);
	return 1;
drop:
	spin_unlock(&sd->sd_lock);
	return 0;
}

static inline u32 round_up_to_quad(u32 i)
{
	return (i + 3 ) & ~3;
}

static inline int
svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o)
{
	int l;

	if (argv->iov_len < 4)
		return -1;
	o->len = svc_getnl(argv);
	l = round_up_to_quad(o->len);
	if (argv->iov_len < l)
		return -1;
	o->data = argv->iov_base;
	argv->iov_base += l;
	argv->iov_len -= l;
	return 0;
}

static inline int
svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
{
	u8 *p;

	if (resv->iov_len + 4 > PAGE_SIZE)
		return -1;
	svc_putnl(resv, o->len);
	p = resv->iov_base + resv->iov_len;
	resv->iov_len += round_up_to_quad(o->len);
	if (resv->iov_len > PAGE_SIZE)
		return -1;
	memcpy(p, o->data, o->len);
	memset(p + o->len, 0, round_up_to_quad(o->len) - o->len);
	return 0;
}

/* Verify the checksum on the header and return SVC_OK on success.
 * Otherwise, return SVC_DROP (in the case of a bad sequence number)
 * or return SVC_DENIED and indicate error in authp.
 */
static int
gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
		  __be32 *rpcstart, struct rpc_gss_wire_cred *gc, __be32 *authp)
{
	struct gss_ctx		*ctx_id = rsci->mechctx;
	struct xdr_buf		rpchdr;
	struct xdr_netobj	checksum;
	u32			flavor = 0;
	struct kvec		*argv = &rqstp->rq_arg.head[0];
	struct kvec		iov;

	/* data to compute the checksum over: */
	iov.iov_base = rpcstart;
	iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart;
	xdr_buf_from_iov(&iov, &rpchdr);

	*authp = rpc_autherr_badverf;
	if (argv->iov_len < 4)
		return SVC_DENIED;
	flavor = svc_getnl(argv);
	if (flavor != RPC_AUTH_GSS)
		return SVC_DENIED;
	if (svc_safe_getnetobj(argv, &checksum))
		return SVC_DENIED;

	if (rqstp->rq_deferred) /* skip verification of revisited request */
		return SVC_OK;
	if (gss_verify_mic(ctx_id, &rpchdr, &checksum) != GSS_S_COMPLETE) {
		*authp = rpcsec_gsserr_credproblem;
		return SVC_DENIED;
	}

	if (gc->gc_seq > MAXSEQ) {
		dprintk("RPC:       svcauth_gss: discarding request with "
				"large sequence number %d\n", gc->gc_seq);
		*authp = rpcsec_gsserr_ctxproblem;
		return SVC_DENIED;
	}
	if (!gss_check_seq_num(rsci, gc->gc_seq)) {
		dprintk("RPC:       svcauth_gss: discarding request with "
				"old sequence number %d\n", gc->gc_seq);
		return SVC_DROP;
	}
	return SVC_OK;
}

static int
gss_write_null_verf(struct svc_rqst *rqstp)
{
	__be32     *p;

	svc_putnl(rqstp->rq_res.head, RPC_AUTH_NULL);
	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
	/* don't really need to check if head->iov_len > PAGE_SIZE ... */
	*p++ = 0;
	if (!xdr_ressize_check(rqstp, p))
		return -1;
	return 0;
}

static int
gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
{
	__be32			xdr_seq;
	u32			maj_stat;
	struct xdr_buf		verf_data;
	struct xdr_netobj	mic;
	__be32			*p;
	struct kvec		iov;

	svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
	xdr_seq = htonl(seq);

	iov.iov_base = &xdr_seq;
	iov.iov_len = sizeof(xdr_seq);
	xdr_buf_from_iov(&iov, &verf_data);
	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
	mic.data = (u8 *)(p + 1);
	maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
	if (maj_stat != GSS_S_COMPLETE)
		return -1;
	*p++ = htonl(mic.len);
	memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
	p += XDR_QUADLEN(mic.len);
	if (!xdr_ressize_check(rqstp, p))
		return -1;
	return 0;
}

struct gss_domain {
	struct auth_domain	h;
	u32			pseudoflavor;
};

static struct auth_domain *
find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
{
	char *name;

	name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
	if (!name)
		return NULL;
	return auth_domain_find(name);
}

static struct auth_ops svcauthops_gss;

int
svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
{
	struct gss_domain	*new;
	struct auth_domain	*test;
	int			stat = -ENOMEM;

	new = kmalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
		goto out;
	kref_init(&new->h.ref);
	new->h.name = kstrdup(name, GFP_KERNEL);
	if (!new->h.name)
		goto out_free_dom;
	new->h.flavour = &svcauthops_gss;
	new->pseudoflavor = pseudoflavor;

	stat = 0;
	test = auth_domain_lookup(name, &new->h);
	if (test != &new->h) { /* Duplicate registration */
		auth_domain_put(test);
		kfree(new->h.name);
		goto out_free_dom;
	}
	return 0;

out_free_dom:
	kfree(new);
out:
	return stat;
}

EXPORT_SYMBOL(svcauth_gss_register_pseudoflavor);

static inline int
read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
{
	__be32  raw;
	int     status;

	status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
	if (status)
		return status;
	*obj = ntohl(raw);
	return 0;
}

/* It would be nice if this bit of code could be shared with the client.
 * Obstacles:
 *	The client shouldn't malloc(), would have to pass in own memory.
 *	The server uses base of head iovec as read pointer, while the
 *	client uses separate pointer. */
static int
unwrap_integ_data(struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
{
	int stat = -EINVAL;
	u32 integ_len, maj_stat;
	struct xdr_netobj mic;
	struct xdr_buf integ_buf;

	integ_len = svc_getnl(&buf->head[0]);
	if (integ_len & 3)
		return stat;
	if (integ_len > buf->len)
		return stat;
	if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len))
		BUG();
	/* copy out mic... */
	if (read_u32_from_xdr_buf(buf, integ_len, &mic.len))
		BUG();
	if (mic.len > RPC_MAX_AUTH_SIZE)
		return stat;
	mic.data = kmalloc(mic.len, GFP_KERNEL);
	if (!mic.data)
		return stat;
	if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len))
		goto out;
	maj_stat = gss_verify_mic(ctx, &integ_buf, &mic);
	if (maj_stat != GSS_S_COMPLETE)
		goto out;
	if (svc_getnl(&buf->head[0]) != seq)
		goto out;
	stat = 0;
out:
	kfree(mic.data);
	return stat;
}

static inline int
total_buf_len(struct xdr_buf *buf)
{
	return buf->head[0].iov_len + buf->page_len + buf->tail[0].iov_len;
}

static void
fix_priv_head(struct xdr_buf *buf, int pad)
{
	if (buf->page_len == 0) {
		/* We need to adjust head and buf->len in tandem in this
		 * case to make svc_defer() work--it finds the original
		 * buffer start using buf->len - buf->head[0].iov_len. */
		buf->head[0].iov_len -= pad;
	}
}

static int
unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
{
	u32 priv_len, maj_stat;
	int pad, saved_len, remaining_len, offset;

	rqstp->rq_sendfile_ok = 0;

	priv_len = svc_getnl(&buf->head[0]);
	if (rqstp->rq_deferred) {
		/* Already decrypted last time through! The sequence number
		 * check at out_seq is unnecessary but harmless: */
		goto out_seq;
	}
	/* buf->len is the number of bytes from the original start of the
	 * request to the end, where head[0].iov_len is just the bytes
	 * not yet read from the head, so these two values are different: */
	remaining_len = total_buf_len(buf);
	if (priv_len > remaining_len)
		return -EINVAL;
	pad = remaining_len - priv_len;
	buf->len -= pad;
	fix_priv_head(buf, pad);

	/* Maybe it would be better to give gss_unwrap a length parameter: */
	saved_len = buf->len;
	buf->len = priv_len;
	maj_stat = gss_unwrap(ctx, 0, buf);
	pad = priv_len - buf->len;
	buf->len = saved_len;
	buf->len -= pad;
	/* The upper layers assume the buffer is aligned on 4-byte boundaries.
	 * In the krb5p case, at least, the data ends up offset, so we need to
	 * move it around. */
	/* XXX: This is very inefficient.  It would be better to either do
	 * this while we encrypt, or maybe in the receive code, if we can peak
	 * ahead and work out the service and mechanism there. */
	offset = buf->head[0].iov_len % 4;
	if (offset) {
		buf->buflen = RPCSVC_MAXPAYLOAD;
		xdr_shift_buf(buf, offset);
		fix_priv_head(buf, pad);
	}
	if (maj_stat != GSS_S_COMPLETE)
		return -EINVAL;
out_seq:
	if (svc_getnl(&buf->head[0]) != seq)
		return -EINVAL;
	return 0;
}

struct gss_svc_data {
	/* decoded gss client cred: */
	struct rpc_gss_wire_cred	clcred;
	/* save a pointer to the beginning of the encoded verifier,
	 * for use in encryption/checksumming in svcauth_gss_release: */
	__be32				*verf_start;
	struct rsc			*rsci;
};

static int
svcauth_gss_set_client(struct svc_rqst *rqstp)
{
	struct gss_svc_data *svcdata = rqstp->rq_auth_data;