svcauth_unix.c

linux 内核源代码

#include <linux/types.h>
#include <linux/sched.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/sunrpc/gss_api.h>
#include <linux/err.h>
#include <linux/seq_file.h>
#include <linux/hash.h>
#include <linux/string.h>
#include <net/sock.h>

#define RPCDBG_FACILITY	RPCDBG_AUTH


/*
 * AUTHUNIX and AUTHNULL credentials are both handled here.
 * AUTHNULL is treated just like AUTHUNIX except that the uid/gid
 * are always nobody (-2).  i.e. we do the same IP address checks for
 * AUTHNULL as for AUTHUNIX, and that is done here.
 */


struct unix_domain {
	struct auth_domain	h;
	int	addr_changes;
	/* other stuff later */
};

extern struct auth_ops svcauth_unix;

struct auth_domain *unix_domain_find(char *name)
{
	struct auth_domain *rv;
	struct unix_domain *new = NULL;

	rv = auth_domain_lookup(name, NULL);
	while(1) {
		if (rv) {
			if (new && rv != &new->h)
				auth_domain_put(&new->h);

			if (rv->flavour != &svcauth_unix) {
				auth_domain_put(rv);
				return NULL;
			}
			return rv;
		}

		new = kmalloc(sizeof(*new), GFP_KERNEL);
		if (new == NULL)
			return NULL;
		kref_init(&new->h.ref);
		new->h.name = kstrdup(name, GFP_KERNEL);
		if (new->h.name == NULL) {
			kfree(new);
			return NULL;
		}
		new->h.flavour = &svcauth_unix;
		new->addr_changes = 0;
		rv = auth_domain_lookup(name, &new->h);
	}
}

static void svcauth_unix_domain_release(struct auth_domain *dom)
{
	struct unix_domain *ud = container_of(dom, struct unix_domain, h);

	kfree(dom->name);
	kfree(ud);
}


/**************************************************
 * cache for IP address to unix_domain
 * as needed by AUTH_UNIX
 */
#define	IP_HASHBITS	8
#define	IP_HASHMAX	(1<<IP_HASHBITS)
#define	IP_HASHMASK	(IP_HASHMAX-1)

struct ip_map {
	struct cache_head	h;
	char			m_class[8]; /* e.g. "nfsd" */
	struct in_addr		m_addr;
	struct unix_domain	*m_client;
	int			m_add_change;
};
static struct cache_head	*ip_table[IP_HASHMAX];

static void ip_map_put(struct kref *kref)
{
	struct cache_head *item = container_of(kref, struct cache_head, ref);
	struct ip_map *im = container_of(item, struct ip_map,h);

	if (test_bit(CACHE_VALID, &item->flags) &&
	    !test_bit(CACHE_NEGATIVE, &item->flags))
		auth_domain_put(&im->m_client->h);
	kfree(im);
}

#if IP_HASHBITS == 8
/* hash_long on a 64 bit machine is currently REALLY BAD for
 * IP addresses in reverse-endian (i.e. on a little-endian machine).
 * So use a trivial but reliable hash instead
 */
static inline int hash_ip(__be32 ip)
{
	int hash = (__force u32)ip ^ ((__force u32)ip>>16);
	return (hash ^ (hash>>8)) & 0xff;
}
#endif
static int ip_map_match(struct cache_head *corig, struct cache_head *cnew)
{
	struct ip_map *orig = container_of(corig, struct ip_map, h);
	struct ip_map *new = container_of(cnew, struct ip_map, h);
	return strcmp(orig->m_class, new->m_class) == 0
		&& orig->m_addr.s_addr == new->m_addr.s_addr;
}
static void ip_map_init(struct cache_head *cnew, struct cache_head *citem)
{
	struct ip_map *new = container_of(cnew, struct ip_map, h);
	struct ip_map *item = container_of(citem, struct ip_map, h);

	strcpy(new->m_class, item->m_class);
	new->m_addr.s_addr = item->m_addr.s_addr;
}
static void update(struct cache_head *cnew, struct cache_head *citem)
{
	struct ip_map *new = container_of(cnew, struct ip_map, h);
	struct ip_map *item = container_of(citem, struct ip_map, h);

	kref_get(&item->m_client->h.ref);
	new->m_client = item->m_client;
	new->m_add_change = item->m_add_change;
}
static struct cache_head *ip_map_alloc(void)
{
	struct ip_map *i = kmalloc(sizeof(*i), GFP_KERNEL);
	if (i)
		return &i->h;
	else
		return NULL;
}

static void ip_map_request(struct cache_detail *cd,
				  struct cache_head *h,
				  char **bpp, int *blen)
{
	char text_addr[20];
	struct ip_map *im = container_of(h, struct ip_map, h);
	__be32 addr = im->m_addr.s_addr;

	snprintf(text_addr, 20, "%u.%u.%u.%u",
		 ntohl(addr) >> 24 & 0xff,
		 ntohl(addr) >> 16 & 0xff,
		 ntohl(addr) >>  8 & 0xff,
		 ntohl(addr) >>  0 & 0xff);

	qword_add(bpp, blen, im->m_class);
	qword_add(bpp, blen, text_addr);
	(*bpp)[-1] = '\n';
}

static struct ip_map *ip_map_lookup(char *class, struct in_addr addr);
static int ip_map_update(struct ip_map *ipm, struct unix_domain *udom, time_t expiry);

static int ip_map_parse(struct cache_detail *cd,
			  char *mesg, int mlen)
{
	/* class ipaddress [domainname] */
	/* should be safe just to use the start of the input buffer
	 * for scratch: */
	char *buf = mesg;
	int len;
	int b1,b2,b3,b4;
	char c;
	char class[8];
	struct in_addr addr;
	int err;

	struct ip_map *ipmp;
	struct auth_domain *dom;
	time_t expiry;

	if (mesg[mlen-1] != '\n')
		return -EINVAL;
	mesg[mlen-1] = 0;

	/* class */
	len = qword_get(&mesg, class, sizeof(class));
	if (len <= 0) return -EINVAL;

	/* ip address */
	len = qword_get(&mesg, buf, mlen);
	if (len <= 0) return -EINVAL;

	if (sscanf(buf, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
		return -EINVAL;

	expiry = get_expiry(&mesg);
	if (expiry ==0)
		return -EINVAL;

	/* domainname, or empty for NEGATIVE */
	len = qword_get(&mesg, buf, mlen);
	if (len < 0) return -EINVAL;

	if (len) {
		dom = unix_domain_find(buf);
		if (dom == NULL)
			return -ENOENT;
	} else
		dom = NULL;

	addr.s_addr =
		htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);

	ipmp = ip_map_lookup(class,addr);
	if (ipmp) {
		err = ip_map_update(ipmp,
			     container_of(dom, struct unix_domain, h),
			     expiry);
	} else
		err = -ENOMEM;

	if (dom)
		auth_domain_put(dom);

	cache_flush();
	return err;
}

static int ip_map_show(struct seq_file *m,
		       struct cache_detail *cd,
		       struct cache_head *h)
{
	struct ip_map *im;
	struct in_addr addr;
	char *dom = "-no-domain-";

	if (h == NULL) {
		seq_puts(m, "#class IP domain\n");
		return 0;
	}
	im = container_of(h, struct ip_map, h);
	/* class addr domain */
	addr = im->m_addr;

	if (test_bit(CACHE_VALID, &h->flags) &&
	    !test_bit(CACHE_NEGATIVE, &h->flags))
		dom = im->m_client->h.name;

	seq_printf(m, "%s %d.%d.%d.%d %s\n",
		   im->m_class,
		   ntohl(addr.s_addr) >> 24 & 0xff,
		   ntohl(addr.s_addr) >> 16 & 0xff,
		   ntohl(addr.s_addr) >>  8 & 0xff,
		   ntohl(addr.s_addr) >>  0 & 0xff,
		   dom
		   );
	return 0;
}


struct cache_detail ip_map_cache = {
	.owner		= THIS_MODULE,
	.hash_size	= IP_HASHMAX,
	.hash_table	= ip_table,
	.name		= "auth.unix.ip",
	.cache_put	= ip_map_put,
	.cache_request	= ip_map_request,
	.cache_parse	= ip_map_parse,
	.cache_show	= ip_map_show,
	.match		= ip_map_match,
	.init		= ip_map_init,
	.update		= update,
	.alloc		= ip_map_alloc,
};

static struct ip_map *ip_map_lookup(char *class, struct in_addr addr)
{
	struct ip_map ip;
	struct cache_head *ch;

	strcpy(ip.m_class, class);
	ip.m_addr = addr;
	ch = sunrpc_cache_lookup(&ip_map_cache, &ip.h,
				 hash_str(class, IP_HASHBITS) ^
				 hash_ip(addr.s_addr));

	if (ch)
		return container_of(ch, struct ip_map, h);
	else
		return NULL;
}

static int ip_map_update(struct ip_map *ipm, struct unix_domain *udom, time_t expiry)
{
	struct ip_map ip;
	struct cache_head *ch;

	ip.m_client = udom;
	ip.h.flags = 0;
	if (!udom)
		set_bit(CACHE_NEGATIVE, &ip.h.flags);
	else {
		ip.m_add_change = udom->addr_changes;
		/* if this is from the legacy set_client system call,
		 * we need m_add_change to be one higher
		 */
		if (expiry == NEVER)
			ip.m_add_change++;
	}
	ip.h.expiry_time = expiry;
	ch = sunrpc_cache_update(&ip_map_cache,
				 &ip.h, &ipm->h,
				 hash_str(ipm->m_class, IP_HASHBITS) ^
				 hash_ip(ipm->m_addr.s_addr));
	if (!ch)
		return -ENOMEM;
	cache_put(ch, &ip_map_cache);
	return 0;
}

int auth_unix_add_addr(struct in_addr addr, struct auth_domain *dom)
{
	struct unix_domain *udom;
	struct ip_map *ipmp;

	if (dom->flavour != &svcauth_unix)
		return -EINVAL;
	udom = container_of(dom, struct unix_domain, h);
	ipmp = ip_map_lookup("nfsd", addr);

	if (ipmp)
		return ip_map_update(ipmp, udom, NEVER);
	else
		return -ENOMEM;
}

int auth_unix_forget_old(struct auth_domain *dom)
{
	struct unix_domain *udom;

	if (dom->flavour != &svcauth_unix)
		return -EINVAL;
	udom = container_of(dom, struct unix_domain, h);
	udom->addr_changes++;
	return 0;
}

struct auth_domain *auth_unix_lookup(struct in_addr addr)
{
	struct ip_map *ipm;
	struct auth_domain *rv;

	ipm = ip_map_lookup("nfsd", addr);

	if (!ipm)
		return NULL;
	if (cache_check(&ip_map_cache, &ipm->h, NULL))
		return NULL;

	if ((ipm->m_client->addr_changes - ipm->m_add_change) >0) {
		if (test_and_set_bit(CACHE_NEGATIVE, &ipm->h.flags) == 0)
			auth_domain_put(&ipm->m_client->h);
		rv = NULL;
	} else {
		rv = &ipm->m_client->h;
		kref_get(&rv->ref);
	}
	cache_put(&ipm->h, &ip_map_cache);
	return rv;
}

void svcauth_unix_purge(void)
{
	cache_purge(&ip_map_cache);
}

static inline struct ip_map *
ip_map_cached_get(struct svc_rqst *rqstp)
{
	struct ip_map *ipm;
	struct svc_sock *svsk = rqstp->rq_sock;
	spin_lock(&svsk->sk_lock);
	ipm = svsk->sk_info_authunix;
	if (ipm != NULL) {
		if (!cache_valid(&ipm->h)) {
			/*
			 * The entry has been invalidated since it was
			 * remembered, e.g. by a second mount from the
			 * same IP address.
			 */
			svsk->sk_info_authunix = NULL;
			spin_unlock(&svsk->sk_lock);
			cache_put(&ipm->h, &ip_map_cache);
			return NULL;
		}
		cache_get(&ipm->h);
	}
	spin_unlock(&svsk->sk_lock);
	return ipm;
}

static inline void
ip_map_cached_put(struct svc_rqst *rqstp, struct ip_map *ipm)
{
	struct svc_sock *svsk = rqstp->rq_sock;