linux/net/sunrpc/svcauth_unix.c
NeilBrown 1f1e030bf7 [PATCH] knfsd: fix hash function for IP addresses on 64bit little-endian machines.
The hash.h hash_long function, when used on a 64 bit machine, ignores many
of the middle-order bits.  (The prime chosen it too bit-sparse).

IP addresses for clients of an NFS server are very likely to differ only in
the low-order bits.  As addresses are stored in network-byte-order, these
bits become middle-order bits in a little-endian 64bit 'long', and so do
not contribute to the hash.  Thus you can have the situation where all
clients appear on one hash chain.

So, until hash_long is fixed (or maybe forever), us a hash function that
works well on IP addresses - xor the bytes together.

Thanks to "Iozone" <capps@iozone.org> for identifying this problem.

Cc: "Iozone" <capps@iozone.org>

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:21 -08:00

508 lines
11 KiB
C

#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/err.h>
#include <linux/seq_file.h>
#include <linux/hash.h>
#include <linux/string.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 */
};
struct auth_domain *unix_domain_find(char *name)
{
struct auth_domain *rv, ud;
struct unix_domain *new;
ud.name = name;
rv = auth_domain_lookup(&ud, 0);
foundit:
if (rv && rv->flavour != RPC_AUTH_UNIX) {
auth_domain_put(rv);
return NULL;
}
if (rv)
return rv;
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (new == NULL)
return NULL;
cache_init(&new->h.h);
new->h.name = kstrdup(name, GFP_KERNEL);
new->h.flavour = RPC_AUTH_UNIX;
new->addr_changes = 0;
new->h.h.expiry_time = NEVER;
rv = auth_domain_lookup(&new->h, 2);
if (rv == &new->h) {
if (atomic_dec_and_test(&new->h.h.refcnt)) BUG();
} else {
auth_domain_put(&new->h);
goto foundit;
}
return rv;
}
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 cache_head *item, struct cache_detail *cd)
{
struct ip_map *im = container_of(item, struct ip_map,h);
if (cache_put(item, cd)) {
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(unsigned long ip)
{
int hash = ip ^ (ip>>16);
return (hash ^ (hash>>8)) & 0xff;
}
#endif
static inline int ip_map_hash(struct ip_map *item)
{
return hash_str(item->m_class, IP_HASHBITS) ^
hash_ip((unsigned long)item->m_addr.s_addr);
}
static inline int ip_map_match(struct ip_map *item, struct ip_map *tmp)
{
return strcmp(tmp->m_class, item->m_class) == 0
&& tmp->m_addr.s_addr == item->m_addr.s_addr;
}
static inline void ip_map_init(struct ip_map *new, struct ip_map *item)
{
strcpy(new->m_class, item->m_class);
new->m_addr.s_addr = item->m_addr.s_addr;
}
static inline void ip_map_update(struct ip_map *new, struct ip_map *item)
{
cache_get(&item->m_client->h.h);
new->m_client = item->m_client;
new->m_add_change = item->m_add_change;
}
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);
__u32 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(struct ip_map *, int);
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;
struct ip_map ipm, *ipmp;
struct auth_domain *dom;
time_t expiry;
if (mesg[mlen-1] != '\n')
return -EINVAL;
mesg[mlen-1] = 0;
/* class */
len = qword_get(&mesg, ipm.m_class, sizeof(ipm.m_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;
ipm.m_addr.s_addr =
htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);
ipm.h.flags = 0;
if (dom) {
ipm.m_client = container_of(dom, struct unix_domain, h);
ipm.m_add_change = ipm.m_client->addr_changes;
} else
set_bit(CACHE_NEGATIVE, &ipm.h.flags);
ipm.h.expiry_time = expiry;
ipmp = ip_map_lookup(&ipm, 1);
if (ipmp)
ip_map_put(&ipmp->h, &ip_map_cache);
if (dom)
auth_domain_put(dom);
if (!ipmp)
return -ENOMEM;
cache_flush();
return 0;
}
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,
htonl(addr.s_addr) >> 24 & 0xff,
htonl(addr.s_addr) >> 16 & 0xff,
htonl(addr.s_addr) >> 8 & 0xff,
htonl(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,
};
static DefineSimpleCacheLookup(ip_map, 0)
int auth_unix_add_addr(struct in_addr addr, struct auth_domain *dom)
{
struct unix_domain *udom;
struct ip_map ip, *ipmp;
if (dom->flavour != RPC_AUTH_UNIX)
return -EINVAL;
udom = container_of(dom, struct unix_domain, h);
strcpy(ip.m_class, "nfsd");
ip.m_addr = addr;
ip.m_client = udom;
ip.m_add_change = udom->addr_changes+1;
ip.h.flags = 0;
ip.h.expiry_time = NEVER;
ipmp = ip_map_lookup(&ip, 1);
if (ipmp) {
ip_map_put(&ipmp->h, &ip_map_cache);
return 0;
} else
return -ENOMEM;
}
int auth_unix_forget_old(struct auth_domain *dom)
{
struct unix_domain *udom;
if (dom->flavour != RPC_AUTH_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 key, *ipm;
struct auth_domain *rv;
strcpy(key.m_class, "nfsd");
key.m_addr = addr;
ipm = ip_map_lookup(&key, 0);
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;
cache_get(&rv->h);
}
ip_map_put(&ipm->h, &ip_map_cache);
return rv;
}
void svcauth_unix_purge(void)
{
cache_purge(&ip_map_cache);
cache_purge(&auth_domain_cache);
}
static int
svcauth_unix_set_client(struct svc_rqst *rqstp)
{
struct ip_map key, *ipm;
rqstp->rq_client = NULL;
if (rqstp->rq_proc == 0)
return SVC_OK;
strcpy(key.m_class, rqstp->rq_server->sv_program->pg_class);
key.m_addr = rqstp->rq_addr.sin_addr;
ipm = ip_map_lookup(&key, 0);
if (ipm == NULL)
return SVC_DENIED;
switch (cache_check(&ip_map_cache, &ipm->h, &rqstp->rq_chandle)) {
default:
BUG();
case -EAGAIN:
return SVC_DROP;
case -ENOENT:
return SVC_DENIED;
case 0:
rqstp->rq_client = &ipm->m_client->h;
cache_get(&rqstp->rq_client->h);
ip_map_put(&ipm->h, &ip_map_cache);
break;
}
return SVC_OK;
}
static int
svcauth_null_accept(struct svc_rqst *rqstp, u32 *authp)
{
struct kvec *argv = &rqstp->rq_arg.head[0];
struct kvec *resv = &rqstp->rq_res.head[0];
struct svc_cred *cred = &rqstp->rq_cred;
cred->cr_group_info = NULL;
rqstp->rq_client = NULL;
if (argv->iov_len < 3*4)
return SVC_GARBAGE;
if (svc_getu32(argv) != 0) {
dprintk("svc: bad null cred\n");
*authp = rpc_autherr_badcred;
return SVC_DENIED;
}
if (svc_getu32(argv) != RPC_AUTH_NULL || svc_getu32(argv) != 0) {
dprintk("svc: bad null verf\n");
*authp = rpc_autherr_badverf;
return SVC_DENIED;
}
/* Signal that mapping to nobody uid/gid is required */
cred->cr_uid = (uid_t) -1;
cred->cr_gid = (gid_t) -1;
cred->cr_group_info = groups_alloc(0);
if (cred->cr_group_info == NULL)
return SVC_DROP; /* kmalloc failure - client must retry */
/* Put NULL verifier */
svc_putu32(resv, RPC_AUTH_NULL);
svc_putu32(resv, 0);
return SVC_OK;
}
static int
svcauth_null_release(struct svc_rqst *rqstp)
{
if (rqstp->rq_client)
auth_domain_put(rqstp->rq_client);
rqstp->rq_client = NULL;
if (rqstp->rq_cred.cr_group_info)
put_group_info(rqstp->rq_cred.cr_group_info);
rqstp->rq_cred.cr_group_info = NULL;
return 0; /* don't drop */
}
struct auth_ops svcauth_null = {
.name = "null",
.owner = THIS_MODULE,
.flavour = RPC_AUTH_NULL,
.accept = svcauth_null_accept,
.release = svcauth_null_release,
.set_client = svcauth_unix_set_client,
};
static int
svcauth_unix_accept(struct svc_rqst *rqstp, u32 *authp)
{
struct kvec *argv = &rqstp->rq_arg.head[0];
struct kvec *resv = &rqstp->rq_res.head[0];
struct svc_cred *cred = &rqstp->rq_cred;
u32 slen, i;
int len = argv->iov_len;
cred->cr_group_info = NULL;
rqstp->rq_client = NULL;
if ((len -= 3*4) < 0)
return SVC_GARBAGE;
svc_getu32(argv); /* length */
svc_getu32(argv); /* time stamp */
slen = XDR_QUADLEN(ntohl(svc_getu32(argv))); /* machname length */
if (slen > 64 || (len -= (slen + 3)*4) < 0)
goto badcred;
argv->iov_base = (void*)((u32*)argv->iov_base + slen); /* skip machname */
argv->iov_len -= slen*4;
cred->cr_uid = ntohl(svc_getu32(argv)); /* uid */
cred->cr_gid = ntohl(svc_getu32(argv)); /* gid */
slen = ntohl(svc_getu32(argv)); /* gids length */
if (slen > 16 || (len -= (slen + 2)*4) < 0)
goto badcred;
cred->cr_group_info = groups_alloc(slen);
if (cred->cr_group_info == NULL)
return SVC_DROP;
for (i = 0; i < slen; i++)
GROUP_AT(cred->cr_group_info, i) = ntohl(svc_getu32(argv));
if (svc_getu32(argv) != RPC_AUTH_NULL || svc_getu32(argv) != 0) {
*authp = rpc_autherr_badverf;
return SVC_DENIED;
}
/* Put NULL verifier */
svc_putu32(resv, RPC_AUTH_NULL);
svc_putu32(resv, 0);
return SVC_OK;
badcred:
*authp = rpc_autherr_badcred;
return SVC_DENIED;
}
static int
svcauth_unix_release(struct svc_rqst *rqstp)
{
/* Verifier (such as it is) is already in place.
*/
if (rqstp->rq_client)
auth_domain_put(rqstp->rq_client);
rqstp->rq_client = NULL;
if (rqstp->rq_cred.cr_group_info)
put_group_info(rqstp->rq_cred.cr_group_info);
rqstp->rq_cred.cr_group_info = NULL;
return 0;
}
struct auth_ops svcauth_unix = {
.name = "unix",
.owner = THIS_MODULE,
.flavour = RPC_AUTH_UNIX,
.accept = svcauth_unix_accept,
.release = svcauth_unix_release,
.domain_release = svcauth_unix_domain_release,
.set_client = svcauth_unix_set_client,
};