openafs/src/afs/afs_osi_pag.c
Derrick Brashear a179e005df STABLE14-macos104-20051005
distill out chaskiel's tiger changes and pull them up. this should be fun.
wonder how broken it is.
2005-10-05 06:58:26 +00:00

532 lines
13 KiB
C

/*
* Copyright 2000, International Business Machines Corporation and others.
* All Rights Reserved.
*
* This software has been released under the terms of the IBM Public
* License. For details, see the LICENSE file in the top-level source
* directory or online at http://www.openafs.org/dl/license10.html
*/
/*
* Implements:
* genpag
* getpag
* afs_setpag
* AddPag
* afs_InitReq
* afs_get_pag_from_groups
* afs_get_groups_from_pag
* PagInCred
*/
#include <afsconfig.h>
#include "afs/param.h"
RCSID
("$Header$");
#include "afs/sysincludes.h" /* Standard vendor system headers */
#include "afsincludes.h" /* Afs-based standard headers */
#include "afs/afs_stats.h" /* statistics */
#include "afs/afs_cbqueue.h"
#include "afs/nfsclient.h"
#include "afs/afs_osidnlc.h"
/* Imported variables */
extern int afs_shuttingdown;
/* Exported variables */
afs_uint32 pag_epoch;
#if defined(UKERNEL) && defined(AFS_WEB_ENHANCEMENTS)
afs_uint32 pagCounter = 1;
#else
afs_uint32 pagCounter = 0;
#endif /* UKERNEL && AFS_WEB_ENHANCEMENTS */
/* Local variables */
/*
* Pags are implemented as follows: the set of groups whose long
* representation is '41XXXXXX' hex are used to represent the pags.
* Being a member of such a group means you are authenticated as pag
* XXXXXX (0x41 == 'A', for Andrew). You are never authenticated as
* multiple pags at once.
*
* The function afs_InitReq takes a credential field and formats the
* corresponding venus request structure. The uid field in the
* vrequest structure is set to the *pag* you are authenticated as, or
* the uid, if you aren't authenticated with a pag.
*
* The basic motivation behind pags is this: just because your unix
* uid is N doesn't mean that you should have the same privileges as
* anyone logged in on the machine as user N, since this would enable
* the superuser on the machine to sneak in and make use of anyone's
* authentication info, even that which is only accidentally left
* behind when someone leaves a public workstation.
*
* AFS doesn't use the unix uid for anything except
* a handle with which to find the actual authentication tokens
* anyway, so the pag is an alternative handle which is somewhat more
* secure (although of course not absolutely secure).
*/
#if !defined(UKERNEL) || !defined(AFS_WEB_ENHANCEMENTS)
afs_uint32
genpag(void)
{
AFS_STATCNT(genpag);
#ifdef AFS_LINUX20_ENV
/* Ensure unique PAG's (mod 200 days) when reloading the client. */
return (('A' << 24) + ((pag_epoch + pagCounter++) & 0xffffff));
#else /* AFS_LINUX20_ENV */
return (('A' << 24) + (pagCounter++ & 0xffffff));
#endif /* AFS_LINUX20_ENV */
}
afs_uint32
getpag(void)
{
AFS_STATCNT(getpag);
#ifdef AFS_LINUX20_ENV
/* Ensure unique PAG's (mod 200 days) when reloading the client. */
return (('A' << 24) + ((pag_epoch + pagCounter) & 0xffffff));
#else
return (('A' << 24) + (pagCounter & 0xffffff));
#endif
}
#else
/* Web enhancement: we don't need to restrict pags to 41XXXXXX since
* we are not sharing the space with anyone. So we use the full 32 bits. */
afs_uint32
genpag(void)
{
AFS_STATCNT(genpag);
#ifdef AFS_LINUX20_ENV
return (pag_epoch + pagCounter++);
#else
return (pagCounter++);
#endif /* AFS_LINUX20_ENV */
}
afs_uint32
getpag(void)
{
AFS_STATCNT(getpag);
#ifdef AFS_LINUX20_ENV
/* Ensure unique PAG's (mod 200 days) when reloading the client. */
return (pag_epoch + pagCounter);
#else
return (pagCounter);
#endif
}
#endif /* UKERNEL && AFS_WEB_ENHANCEMENTS */
/* used to require 10 seconds between each setpag to guarantee that
* PAGs never wrap - which would be a security hole. If we presume
* that in ordinary operation, the average rate of PAG allocation
* will not exceed one per second, the 24 bits provided will be
* sufficient for ~200 days. Unfortunately, if we merely assume that,
* there will be an opportunity for attack. So we must enforce it.
* If we need to increase the average rate of PAG allocation, we
* should increase the number of bits in a PAG, and/or reduce our
* window in which we guarantee that the PAG counter won't wrap.
* By permitting an average of one new PAG per second, new PAGs can
* be allocated VERY frequently over a short period relative to total uptime.
* Of course, there's only an issue here if one user stays logged (and re-
* activates tokens repeatedly) for that entire period.
*/
static int afs_pag_sleepcnt = 0;
static int
afs_pag_sleep(struct AFS_UCRED **acred)
{
int rv = 0;
if (!afs_suser(acred)) {
if(osi_Time() - pag_epoch < pagCounter) {
rv = 1;
}
}
return rv;
}
static int
afs_pag_wait(struct AFS_UCRED **acred)
{
if (afs_pag_sleep(acred)) {
if (!afs_pag_sleepcnt) {
printf("%s() PAG throttling triggered, pid %d... sleeping. sleepcnt %d\n",
"afs_pag_wait", osi_getpid(), afs_pag_sleepcnt);
}
afs_pag_sleepcnt++;
do {
/* XXX spins on EINTR */
afs_osi_Wait(1000, (struct afs_osi_WaitHandle *)0, 0);
} while (afs_pag_sleep(acred));
afs_pag_sleepcnt--;
}
return 0;
}
int
#if defined(AFS_SUN5_ENV)
afs_setpag(struct AFS_UCRED **credpp)
#elif defined(AFS_OSF_ENV) || defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
afs_setpag(struct proc *p, void *args, int *retval)
#else
afs_setpag(void)
#endif
{
#if defined(AFS_SUN5_ENV)
struct AFS_UCRED **acred = *credpp;
#elif defined(AFS_OBSD_ENV)
struct AFS_UCRED **acred = &p->p_ucred;
#else
struct AFS_UCRED **acred = NULL;
#endif
int code = 0;
#if defined(AFS_SGI53_ENV) && defined(MP)
/* This is our first chance to get the global lock. */
AFS_GLOCK();
#endif /* defined(AFS_SGI53_ENV) && defined(MP) */
AFS_STATCNT(afs_setpag);
afs_pag_wait(acred);
#if defined(AFS_SUN5_ENV)
code = AddPag(genpag(), credpp);
#elif defined(AFS_OSF_ENV) || defined(AFS_XBSD_ENV)
code = AddPag(p, genpag(), &p->p_rcred);
#elif defined(AFS_AIX41_ENV)
{
struct ucred *credp;
struct ucred *credp0;
credp = crref();
credp0 = credp;
code = AddPag(genpag(), &credp);
/* If AddPag() didn't make a new cred, then free our cred ref */
if (credp == credp0) {
crfree(credp);
}
}
#elif defined(AFS_HPUX110_ENV)
{
struct ucred *credp = p_cred(u.u_procp);
code = AddPag(genpag(), &credp);
}
#elif defined(AFS_SGI_ENV)
{
cred_t *credp;
credp = OSI_GET_CURRENT_CRED();
code = AddPag(genpag(), &credp);
}
#elif defined(AFS_LINUX20_ENV)
{
struct AFS_UCRED *credp = crref();
code = AddPag(genpag(), &credp);
crfree(credp);
}
#elif defined(AFS_DARWIN80_ENV)
{
struct ucred *credp = kauth_cred_proc_ref(p);
code = AddPag(p, genpag(), &credp);
kauth_cred_rele(credp);
}
#elif defined(AFS_DARWIN_ENV)
{
struct ucred *credp = crdup(p->p_cred->pc_ucred);
code = AddPag(p, genpag(), &credp);
crfree(credp);
}
#else
code = AddPag(genpag(), &u.u_cred);
#endif
afs_Trace1(afs_iclSetp, CM_TRACE_SETPAG, ICL_TYPE_INT32, code);
#if defined(KERNEL_HAVE_UERROR)
if (!getuerror())
setuerror(code);
#endif
#if defined(AFS_SGI53_ENV) && defined(MP)
AFS_GUNLOCK();
#endif /* defined(AFS_SGI53_ENV) && defined(MP) */
return (code);
}
#if defined(UKERNEL) && defined(AFS_WEB_ENHANCEMENTS)
/*
* afs_setpag_val
* This function is like setpag but sets the current thread's pag id to a
* caller-provided value instead of calling genpag(). This implements a
* form of token caching since the caller can recall a particular pag value
* for the thread to restore tokens, rather than reauthenticating.
*/
int
#if defined(AFS_SUN5_ENV)
afs_setpag_val(struct AFS_UCRED **credpp, int pagval)
#elif defined(AFS_OSF_ENV) || defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
afs_setpag_val(struct proc *p, void *args, int *retval, int pagval)
#else
afs_setpag_val(int pagval)
#endif
{
#if defined(AFS_SUN5_ENV)
struct AFS_UCRED **acred = *credp;
#elif defined(AFS_OBSD_ENV)
struct AFS_UCRED **acred = &p->p_ucred;
#else
struct AFS_UCRED **acred = NULL;
#endif
int code = 0;
#if defined(AFS_SGI53_ENV) && defined(MP)
/* This is our first chance to get the global lock. */
AFS_GLOCK();
#endif /* defined(AFS_SGI53_ENV) && defined(MP) */
AFS_STATCNT(afs_setpag);
afs_pag_wait(acred);
#if defined(AFS_SUN5_ENV)
code = AddPag(pagval, credpp);
#elif defined(AFS_OSF_ENV) || defined(AFS_XBSD_ENV)
code = AddPag(p, pagval, &p->p_rcred);
#elif defined(AFS_AIX41_ENV)
{
struct ucred *credp;
struct ucred *credp0;
credp = crref();
credp0 = credp;
code = AddPag(pagval, &credp);
/* If AddPag() didn't make a new cred, then free our cred ref */
if (credp == credp0) {
crfree(credp);
}
}
#elif defined(AFS_HPUX110_ENV)
{
struct ucred *credp = p_cred(u.u_procp);
code = AddPag(pagval, &credp);
}
#elif defined(AFS_SGI_ENV)
{
cred_t *credp;
credp = OSI_GET_CURRENT_CRED();
code = AddPag(pagval, &credp);
}
#elif defined(AFS_LINUX20_ENV)
{
struct AFS_UCRED *credp = crref();
code = AddPag(pagval, &credp);
crfree(credp);
}
#elif defined(AFS_DARWIN_ENV)
{
struct ucred *credp = crdup(p->p_cred->pc_ucred);
code = AddPag(p, pagval, &credp);
crfree(credp);
}
#else
code = AddPag(pagval, &u.u_cred);
#endif
afs_Trace1(afs_iclSetp, CM_TRACE_SETPAG, ICL_TYPE_INT32, code);
#if defined(KERNEL_HAVE_UERROR)
if (!getuerror())
setuerror(code);
#endif
#if defined(AFS_SGI53_ENV) && defined(MP)
AFS_GUNLOCK();
#endif /* defined(AFS_SGI53_ENV) && defined(MP) */
return (code);
}
int
afs_getpag_val()
{
int pagvalue;
struct AFS_UCRED *credp = u.u_cred;
int gidset0, gidset1;
gidset0 = credp->cr_groups[0];
gidset1 = credp->cr_groups[1];
pagvalue = afs_get_pag_from_groups(gidset0, gidset1);
return pagvalue;
}
#endif /* UKERNEL && AFS_WEB_ENHANCEMENTS */
/* Note - needs to be available on AIX, others can be static - rework this */
#if defined(AFS_OSF_ENV) || defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
int
AddPag(struct proc *p, afs_int32 aval, struct AFS_UCRED **credpp)
#else
int
AddPag(afs_int32 aval, struct AFS_UCRED **credpp)
#endif
{
afs_int32 newpag, code;
AFS_STATCNT(AddPag);
#if defined(AFS_OSF_ENV) || defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
if ((code = setpag(p, credpp, aval, &newpag, 0)))
#else
if ((code = setpag(credpp, aval, &newpag, 0)))
#endif
#if defined(KERNEL_HAVE_UERROR)
return (setuerror(code), code);
#else
return (code);
#endif
return 0;
}
int
afs_InitReq(register struct vrequest *av, struct AFS_UCRED *acred)
{
AFS_STATCNT(afs_InitReq);
if (afs_shuttingdown)
return EIO;
av->uid = PagInCred(acred);
if (av->uid == NOPAG) {
/* Afs doesn't use the unix uid for anuthing except a handle
* with which to find the actual authentication tokens so I
* think it's ok to use the real uid to make setuid
* programs (without setpag) to work properly.
*/
#if defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
if (acred == NOCRED)
av->uid = -2; /* XXX nobody... ? */
else
av->uid = acred->cr_uid; /* bsd creds don't have ruid */
#else
av->uid = acred->cr_ruid; /* default when no pag is set */
#endif
}
av->initd = 0;
return 0;
}
afs_uint32
afs_get_pag_from_groups(gid_t g0a, gid_t g1a)
{
afs_uint32 g0 = g0a;
afs_uint32 g1 = g1a;
afs_uint32 h, l, ret;
AFS_STATCNT(afs_get_pag_from_groups);
g0 -= 0x3f00;
g1 -= 0x3f00;
if (g0 < 0xc000 && g1 < 0xc000) {
l = ((g0 & 0x3fff) << 14) | (g1 & 0x3fff);
h = (g0 >> 14);
h = (g1 >> 14) + h + h + h;
ret = ((h << 28) | l);
#if defined(UKERNEL) && defined(AFS_WEB_ENHANCEMENTS)
return ret;
#else
/* Additional testing */
if (((ret >> 24) & 0xff) == 'A')
return ret;
else
return NOPAG;
#endif /* UKERNEL && AFS_WEB_ENHANCEMENTS */
}
return NOPAG;
}
void
afs_get_groups_from_pag(afs_uint32 pag, gid_t * g0p, gid_t * g1p)
{
unsigned short g0, g1;
AFS_STATCNT(afs_get_groups_from_pag);
#if !defined(UKERNEL) || !defined(AFS_WEB_ENHANCEMENTS)
pag &= 0x7fffffff;
#endif /* UKERNEL && AFS_WEB_ENHANCEMENTS */
g0 = 0x3fff & (pag >> 14);
g1 = 0x3fff & pag;
g0 |= ((pag >> 28) / 3) << 14;
g1 |= ((pag >> 28) % 3) << 14;
*g0p = g0 + 0x3f00;
*g1p = g1 + 0x3f00;
}
afs_int32
PagInCred(const struct AFS_UCRED *cred)
{
afs_int32 pag;
gid_t g0, g1;
AFS_STATCNT(PagInCred);
if (cred == NULL) {
return NOPAG;
}
#if defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
if (cred == NOCRED || cred == FSCRED) {
return NOPAG;
}
if (cred->cr_ngroups < 3)
return NOPAG;
/* gid is stored in cr_groups[0] */
g0 = cred->cr_groups[1];
g1 = cred->cr_groups[2];
#else
#if defined(AFS_AIX51_ENV)
if (kcred_getpag(cred, PAG_AFS, &pag) < 0 || pag == 0)
pag = NOPAG;
return pag;
#elif defined(AFS_AIX_ENV)
if (cred->cr_ngrps < 2) {
return NOPAG;
}
#elif defined(AFS_LINUX26_ENV)
if (cred->cr_group_info->ngroups < 2)
return NOPAG;
#elif defined(AFS_SGI_ENV) || defined(AFS_SUN5_ENV) || defined(AFS_DUX40_ENV) || defined(AFS_LINUX20_ENV) || defined(AFS_XBSD_ENV)
if (cred->cr_ngroups < 2)
return NOPAG;
#endif
#if defined(AFS_AIX51_ENV)
g0 = cred->cr_groupset.gs_union.un_groups[0];
g1 = cred->cr_groupset.gs_union.un_groups[1];
#elif defined(AFS_LINUX26_ENV)
g0 = GROUP_AT(cred->cr_group_info, 0);
g1 = GROUP_AT(cred->cr_group_info, 1);
#else
g0 = cred->cr_groups[0];
g1 = cred->cr_groups[1];
#endif
#endif
pag = (afs_int32) afs_get_pag_from_groups(g0, g1);
return pag;
}