glibc/sunrpc/svcauth_des.c
2017-08-31 15:59:02 +02:00

592 lines
16 KiB
C

/*
* Copyright (c) 2010, Oracle America, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of the "Oracle America, Inc." 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 BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT HOLDER 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.
*
* svcauth_des.c, server-side des authentication
*
* We insure for the service the following:
* (1) The timestamp microseconds do not exceed 1 million.
* (2) The timestamp plus the window is less than the current time.
* (3) The timestamp is not less than the one previously
* seen in the current session.
*
* It is up to the server to determine if the window size is
* too small .
*
*/
#include <limits.h>
#include <string.h>
#include <stdint.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <rpc/rpc.h>
#include <rpc/xdr.h>
#include <rpc/auth.h>
#include <rpc/auth_des.h>
#include <rpc/svc_auth.h>
#include <rpc/svc.h>
#include <rpc/des_crypt.h>
#include <shlib-compat.h>
#define debug(msg) /*printf("svcauth_des: %s\n", msg) */
#define USEC_PER_SEC ((uint32_t) 1000000L)
#define BEFORE(t1, t2) timercmp(t1, t2, <)
/*
* LRU cache of conversation keys and some other useful items.
*/
#define AUTHDES_CACHESZ 64
struct cache_entry
{
des_block key; /* conversation key */
char *rname; /* client's name */
u_int window; /* credential lifetime window */
struct rpc_timeval laststamp; /* detect replays of creds */
char *localcred; /* generic local credential */
};
#ifdef _RPC_THREAD_SAFE_
#define authdes_cache RPC_THREAD_VARIABLE(authdes_cache_s)
#define authdes_lru RPC_THREAD_VARIABLE(authdes_lru_s)
#else
static struct cache_entry *authdes_cache;
static int *authdes_lru;
#endif
static void cache_init (void); /* initialize the cache */
static short cache_spot (des_block *, char *, struct rpc_timeval *);
/* find an entry in the cache */
static void cache_ref (uint32_t sid); /* note that sid was ref'd */
static void invalidate (char *cred); /* invalidate entry in cache */
/*
* cache statistics
*/
struct
{
u_long ncachehits; /* times cache hit, and is not replay */
u_long ncachereplays; /* times cache hit, and is replay */
u_long ncachemisses; /* times cache missed */
}
svcauthdes_stats;
/*
* Service side authenticator for AUTH_DES
*/
enum auth_stat
_svcauth_des (register struct svc_req *rqst, register struct rpc_msg *msg)
{
register uint32_t *ixdr;
des_block cryptbuf[2];
register struct authdes_cred *cred;
struct authdes_verf verf;
int status;
register struct cache_entry *entry;
uint32_t sid = 0;
des_block *sessionkey;
des_block ivec;
u_int window;
struct rpc_timeval timestamp;
uint32_t namelen;
struct area
{
struct authdes_cred area_cred;
char area_netname[MAXNETNAMELEN + 1];
}
*area;
if (authdes_cache == NULL)
cache_init ();
if (authdes_cache == NULL) /* No free memory */
return AUTH_FAILED;
area = (struct area *) rqst->rq_clntcred;
cred = (struct authdes_cred *) &area->area_cred;
/*
* Get the credential
*/
if (msg->rm_call.cb_cred.oa_length <= 0 ||
msg->rm_call.cb_cred.oa_length > MAX_AUTH_BYTES)
return AUTH_BADCRED;
ixdr = (uint32_t *) msg->rm_call.cb_cred.oa_base;
cred->adc_namekind = IXDR_GET_ENUM (ixdr, enum authdes_namekind);
switch (cred->adc_namekind)
{
case ADN_FULLNAME:
namelen = IXDR_GET_U_INT32 (ixdr);
if (namelen > MAXNETNAMELEN)
{
return AUTH_BADCRED;
}
cred->adc_fullname.name = area->area_netname;
memcpy (cred->adc_fullname.name, (char *) ixdr, namelen);
cred->adc_fullname.name[namelen] = 0;
ixdr += (RNDUP (namelen) / BYTES_PER_XDR_UNIT);
cred->adc_fullname.key.key.high = *ixdr++;
cred->adc_fullname.key.key.low = *ixdr++;
cred->adc_fullname.window = *ixdr++;
break;
case ADN_NICKNAME:
cred->adc_nickname = *ixdr++;
break;
default:
return AUTH_BADCRED;
}
/*
* Get the verifier
*/
if (msg->rm_call.cb_verf.oa_length <= 0 ||
msg->rm_call.cb_verf.oa_length > MAX_AUTH_BYTES)
return AUTH_BADCRED;
ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
verf.adv_xtimestamp.key.high = *ixdr++;
verf.adv_xtimestamp.key.low = *ixdr++;
verf.adv_int_u = *ixdr++;
/*
* Get the conversation key
*/
if (cred->adc_namekind == ADN_FULLNAME)
{
netobj pkey;
char pkey_data[1024];
sessionkey = &cred->adc_fullname.key;
if (!getpublickey (cred->adc_fullname.name, pkey_data))
{
debug("getpublickey");
return AUTH_BADCRED;
}
pkey.n_bytes = pkey_data;
pkey.n_len = strlen (pkey_data) + 1;
if (key_decryptsession_pk (cred->adc_fullname.name, &pkey,
sessionkey) < 0)
{
debug ("decryptsessionkey");
return AUTH_BADCRED; /* key not found */
}
}
else
{ /* ADN_NICKNAME */
if (cred->adc_nickname >= AUTHDES_CACHESZ)
{
debug ("bad nickname");
return AUTH_BADCRED; /* garbled credential */
}
else
sid = cred->adc_nickname;
/* XXX This could be wrong, but else we have a
security problem */
if (authdes_cache[sid].rname == NULL)
return AUTH_BADCRED;
sessionkey = &authdes_cache[sid].key;
}
/*
* Decrypt the timestamp
*/
cryptbuf[0] = verf.adv_xtimestamp;
if (cred->adc_namekind == ADN_FULLNAME)
{
cryptbuf[1].key.high = cred->adc_fullname.window;
cryptbuf[1].key.low = verf.adv_winverf;
ivec.key.high = ivec.key.low = 0;
status = cbc_crypt ((char *) sessionkey, (char *) cryptbuf,
2 * sizeof (des_block), DES_DECRYPT | DES_HW,
(char *) &ivec);
}
else
status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
sizeof (des_block), DES_DECRYPT | DES_HW);
if (DES_FAILED (status))
{
debug ("decryption failure");
return AUTH_FAILED; /* system error */
}
/*
* XDR the decrypted timestamp
*/
ixdr = (uint32_t *) cryptbuf;
timestamp.tv_sec = IXDR_GET_INT32 (ixdr);
timestamp.tv_usec = IXDR_GET_INT32 (ixdr);
/*
* Check for valid credentials and verifiers.
* They could be invalid because the key was flushed
* out of the cache, and so a new session should begin.
* Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case.
*/
{
struct timeval current;
int nick;
u_int winverf;
if (cred->adc_namekind == ADN_FULLNAME)
{
short tmp_spot;
window = IXDR_GET_U_INT32 (ixdr);
winverf = IXDR_GET_U_INT32 (ixdr);
if (winverf != window - 1)
{
debug ("window verifier mismatch");
return AUTH_BADCRED; /* garbled credential */
}
tmp_spot = cache_spot (sessionkey, cred->adc_fullname.name,
&timestamp);
if (tmp_spot < 0 || tmp_spot > AUTHDES_CACHESZ)
{
debug ("replayed credential");
return AUTH_REJECTEDCRED; /* replay */
}
sid = tmp_spot;
nick = 0;
}
else
{ /* ADN_NICKNAME */
window = authdes_cache[sid].window;
nick = 1;
}
if (timestamp.tv_usec >= USEC_PER_SEC)
{
debug ("invalid usecs");
/* cached out (bad key), or garbled verifier */
return nick ? AUTH_REJECTEDVERF : AUTH_BADVERF;
}
if (nick && BEFORE (&timestamp, &authdes_cache[sid].laststamp))
{
debug ("timestamp before last seen");
return AUTH_REJECTEDVERF; /* replay */
}
__gettimeofday (&current, (struct timezone *) NULL);
current.tv_sec -= window; /* allow for expiration */
if (!BEFORE (&current, &timestamp))
{
debug ("timestamp expired");
/* replay, or garbled credential */
return nick ? AUTH_REJECTEDVERF : AUTH_BADCRED;
}
}
/*
* Set up the reply verifier
*/
verf.adv_nickname = sid;
/*
* xdr the timestamp before encrypting
*/
ixdr = (uint32_t *) cryptbuf;
IXDR_PUT_INT32 (ixdr, timestamp.tv_sec - 1);
IXDR_PUT_INT32 (ixdr, timestamp.tv_usec);
/*
* encrypt the timestamp
*/
status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
sizeof (des_block), DES_ENCRYPT | DES_HW);
if (DES_FAILED (status))
{
debug ("encryption failure");
return AUTH_FAILED; /* system error */
}
verf.adv_xtimestamp = cryptbuf[0];
/*
* Serialize the reply verifier, and update rqst
*/
ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
*ixdr++ = verf.adv_xtimestamp.key.high;
*ixdr++ = verf.adv_xtimestamp.key.low;
*ixdr++ = verf.adv_int_u;
rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES;
rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base;
rqst->rq_xprt->xp_verf.oa_length =
(char *) ixdr - msg->rm_call.cb_verf.oa_base;
/*
* We succeeded, commit the data to the cache now and
* finish cooking the credential.
*/
entry = &authdes_cache[sid];
entry->laststamp = timestamp;
cache_ref (sid);
if (cred->adc_namekind == ADN_FULLNAME)
{
size_t full_len;
cred->adc_fullname.window = window;
cred->adc_nickname = sid; /* save nickname */
if (entry->rname != NULL)
mem_free (entry->rname, strlen (entry->rname) + 1);
full_len = strlen (cred->adc_fullname.name) + 1;
entry->rname = mem_alloc ((u_int) full_len);
if (entry->rname != NULL)
memcpy (entry->rname, cred->adc_fullname.name, full_len);
else
{
debug ("out of memory");
return AUTH_FAILED; /* out of memory is bad */
}
entry->key = *sessionkey;
entry->window = window;
invalidate (entry->localcred); /* mark any cached cred invalid */
}
else
{ /* ADN_NICKNAME */
/*
* nicknames are cooked into fullnames
*/
cred->adc_namekind = ADN_FULLNAME;
cred->adc_fullname.name = entry->rname;
cred->adc_fullname.key = entry->key;
cred->adc_fullname.window = entry->window;
}
return AUTH_OK; /* we made it! */
}
/*
* Initialize the cache
*/
static void
cache_init (void)
{
register int i;
authdes_cache = (struct cache_entry *)
calloc (sizeof (struct cache_entry) * AUTHDES_CACHESZ, 1);
if (authdes_cache == NULL)
return;
authdes_lru = (int *) mem_alloc (sizeof (int) * AUTHDES_CACHESZ);
/*
* Initialize the lru list
*/
for (i = 0; i < AUTHDES_CACHESZ; ++i)
authdes_lru[i] = i;
}
/*
* Find the lru victim
*/
static short
cache_victim (void)
{
return authdes_lru[AUTHDES_CACHESZ - 1];
}
/*
* Note that sid was referenced
*/
static void
cache_ref (register uint32_t sid)
{
register int i;
register int curr;
register int prev;
prev = authdes_lru[0];
authdes_lru[0] = sid;
for (i = 1; prev != sid; ++i)
{
curr = authdes_lru[i];
authdes_lru[i] = prev;
prev = curr;
}
}
/*
* Find a spot in the cache for a credential containing
* the items given. Return -1 if a replay is detected, otherwise
* return the spot in the cache.
*/
static short
cache_spot (register des_block *key, char *name,
struct rpc_timeval *timestamp)
{
register struct cache_entry *cp;
register int i;
register uint32_t hi;
hi = key->key.high;
for (cp = authdes_cache, i = 0; i < AUTHDES_CACHESZ; ++i, ++cp)
{
if (cp->key.key.high == hi &&
cp->key.key.low == key->key.low &&
cp->rname != NULL &&
memcmp (cp->rname, name, strlen (name) + 1) == 0)
{
if (BEFORE (timestamp, &cp->laststamp))
{
++svcauthdes_stats.ncachereplays;
return -1; /* replay */
}
++svcauthdes_stats.ncachehits;
return i; /* refresh */
}
}
++svcauthdes_stats.ncachemisses;
return cache_victim (); /* new credential */
}
/*
* Local credential handling stuff.
* NOTE: bsd unix dependent.
* Other operating systems should put something else here.
*/
#define UNKNOWN -2 /* grouplen, if cached cred is unknown user */
#define INVALID -1 /* grouplen, if cache entry is invalid */
struct bsdcred
{
uid_t uid; /* cached uid */
gid_t gid; /* cached gid */
int grouplen; /* length of cached groups */
int grouplen_max; /* length of allocated cached groups */
gid_t groups[0]; /* cached groups */
};
/*
* Map a des credential into a unix cred.
* We cache the credential here so the application does
* not have to make an rpc call every time to interpret
* the credential.
*/
int
authdes_getucred (const struct authdes_cred *adc, uid_t * uid, gid_t * gid,
short *grouplen, gid_t * groups)
{
unsigned sid;
register int i;
uid_t i_uid;
gid_t i_gid;
int i_grouplen;
struct bsdcred *cred;
sid = adc->adc_nickname;
if (sid >= AUTHDES_CACHESZ)
{
debug ("invalid nickname");
return 0;
}
cred = (struct bsdcred *) authdes_cache[sid].localcred;
if (cred == NULL || cred->grouplen == INVALID)
{
/*
* not in cache: lookup
*/
if (!netname2user (adc->adc_fullname.name, &i_uid, &i_gid,
&i_grouplen, groups))
{
debug ("unknown netname");
if (cred != NULL)
cred->grouplen = UNKNOWN; /* mark as lookup up, but not found */
return 0;
}
if (cred != NULL && cred->grouplen_max < i_grouplen)
{
/* We already have an allocated data structure. But it is
too small. */
free (cred);
authdes_cache[sid].localcred = NULL;
cred = NULL;
}
if (cred == NULL)
{
/* We should allocate room for at least NGROUPS groups. */
int ngroups_max = MAX (i_grouplen, NGROUPS);
cred = (struct bsdcred *) mem_alloc (sizeof (struct bsdcred)
+ ngroups_max * sizeof (gid_t));
if (cred == NULL)
return 0;
authdes_cache[sid].localcred = (char *) cred;
cred->grouplen = INVALID;
cred->grouplen_max = ngroups_max;
}
debug ("missed ucred cache");
*uid = cred->uid = i_uid;
*gid = cred->gid = i_gid;
cred->grouplen = i_grouplen;
for (i = i_grouplen - 1; i >= 0; --i)
cred->groups[i] = groups[i];
/* Make sure no too large values are reported. */
*grouplen = MIN (SHRT_MAX, i_grouplen);
return 1;
}
else if (cred->grouplen == UNKNOWN)
{
/*
* Already lookup up, but no match found
*/
return 0;
}
/*
* cached credentials
*/
*uid = cred->uid;
*gid = cred->gid;
/* Another stupidity in the interface: *grouplen is of type short.
So we might have to cut the information passed up short. */
int grouplen_copy = MIN (SHRT_MAX, cred->grouplen);
*grouplen = grouplen_copy;
for (i = grouplen_copy - 1; i >= 0; --i)
groups[i] = cred->groups[i];
return 1;
}
libc_hidden_nolink_sunrpc (authdes_getucred, GLIBC_2_1)
static void
invalidate (char *cred)
{
if (cred == NULL)
return;
((struct bsdcred *) cred)->grouplen = INVALID;
}