f05ef8db1a
Fix a regression in NFSD's permission checking introduced by the credentials
patches. There are two parts to the problem, both in nfsd_setuser():
(1) The return value of set_groups() is -ve if in error, not 0, and should be
checked appropriately. 0 indicates success.
(2) The UID to use for fs accesses is in new->fsuid, not new->uid (which is
0). This causes CAP_DAC_OVERRIDE to always be set, rather than being
cleared if the UID is anything other than 0 after squashing.
Reported-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
96 lines
2 KiB
C
96 lines
2 KiB
C
/*
|
|
* linux/fs/nfsd/auth.c
|
|
*
|
|
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sunrpc/svc.h>
|
|
#include <linux/sunrpc/svcauth.h>
|
|
#include <linux/nfsd/nfsd.h>
|
|
#include <linux/nfsd/export.h>
|
|
#include "auth.h"
|
|
|
|
int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
|
|
{
|
|
struct exp_flavor_info *f;
|
|
struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
|
|
|
|
for (f = exp->ex_flavors; f < end; f++) {
|
|
if (f->pseudoflavor == rqstp->rq_flavor)
|
|
return f->flags;
|
|
}
|
|
return exp->ex_flags;
|
|
|
|
}
|
|
|
|
int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
|
|
{
|
|
struct group_info *rqgi;
|
|
struct group_info *gi;
|
|
struct cred *new;
|
|
int i;
|
|
int flags = nfsexp_flags(rqstp, exp);
|
|
int ret;
|
|
|
|
/* discard any old override before preparing the new set */
|
|
revert_creds(get_cred(current->real_cred));
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
new->fsuid = rqstp->rq_cred.cr_uid;
|
|
new->fsgid = rqstp->rq_cred.cr_gid;
|
|
|
|
rqgi = rqstp->rq_cred.cr_group_info;
|
|
|
|
if (flags & NFSEXP_ALLSQUASH) {
|
|
new->fsuid = exp->ex_anon_uid;
|
|
new->fsgid = exp->ex_anon_gid;
|
|
gi = groups_alloc(0);
|
|
} else if (flags & NFSEXP_ROOTSQUASH) {
|
|
if (!new->fsuid)
|
|
new->fsuid = exp->ex_anon_uid;
|
|
if (!new->fsgid)
|
|
new->fsgid = exp->ex_anon_gid;
|
|
|
|
gi = groups_alloc(rqgi->ngroups);
|
|
if (!gi)
|
|
goto oom;
|
|
|
|
for (i = 0; i < rqgi->ngroups; i++) {
|
|
if (!GROUP_AT(rqgi, i))
|
|
GROUP_AT(gi, i) = exp->ex_anon_gid;
|
|
else
|
|
GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
|
|
}
|
|
} else {
|
|
gi = get_group_info(rqgi);
|
|
}
|
|
|
|
if (new->fsuid == (uid_t) -1)
|
|
new->fsuid = exp->ex_anon_uid;
|
|
if (new->fsgid == (gid_t) -1)
|
|
new->fsgid = exp->ex_anon_gid;
|
|
|
|
ret = set_groups(new, gi);
|
|
put_group_info(gi);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
if (new->fsuid)
|
|
new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
|
|
else
|
|
new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
|
|
new->cap_permitted);
|
|
put_cred(override_creds(new));
|
|
return 0;
|
|
|
|
oom:
|
|
ret = -ENOMEM;
|
|
error:
|
|
abort_creds(new);
|
|
return ret;
|
|
}
|
|
|