auth_generic.c 7.51 KB
Newer Older
1 2 3 4 5 6 7
/*
 * Generic RPC credential
 *
 * Copyright (C) 2008, Trond Myklebust <Trond.Myklebust@netapp.com>
 */

#include <linux/err.h>
8
#include <linux/slab.h>
9 10 11 12 13 14 15 16
#include <linux/types.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/sched.h>

Jeff Layton's avatar
Jeff Layton committed
17
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
18 19 20
# define RPCDBG_FACILITY	RPCDBG_AUTH
#endif

21 22
#define RPC_MACHINE_CRED_USERID		GLOBAL_ROOT_UID
#define RPC_MACHINE_CRED_GROUPID	GLOBAL_ROOT_GID
23

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
struct generic_cred {
	struct rpc_cred gc_base;
	struct auth_cred acred;
};

static struct rpc_auth generic_auth;
static const struct rpc_credops generic_credops;

/*
 * Public call interface
 */
struct rpc_cred *rpc_lookup_cred(void)
{
	return rpcauth_lookupcred(&generic_auth, 0);
}
EXPORT_SYMBOL_GPL(rpc_lookup_cred);

41 42 43 44 45 46
struct rpc_cred *rpc_lookup_cred_nonblock(void)
{
	return rpcauth_lookupcred(&generic_auth, RPCAUTH_LOOKUP_RCU);
}
EXPORT_SYMBOL_GPL(rpc_lookup_cred_nonblock);

47 48 49
/*
 * Public call interface for looking up machine creds.
 */
50
struct rpc_cred *rpc_lookup_machine_cred(const char *service_name)
51 52
{
	struct auth_cred acred = {
53 54
		.uid = RPC_MACHINE_CRED_USERID,
		.gid = RPC_MACHINE_CRED_GROUPID,
55
		.principal = service_name,
56 57 58
		.machine_cred = 1,
	};

59 60
	dprintk("RPC:       looking up machine cred for service %s\n",
			service_name);
61 62 63 64
	return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
}
EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);

65 66
static struct rpc_cred *generic_bind_cred(struct rpc_task *task,
		struct rpc_cred *cred, int lookupflags)
67 68 69 70
{
	struct rpc_auth *auth = task->tk_client->cl_auth;
	struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;

71
	return auth->au_ops->lookup_cred(auth, acred, lookupflags);
72 73
}

74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97
/*
 * Lookup generic creds for current process
 */
static struct rpc_cred *
generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
	return rpcauth_lookup_credcache(&generic_auth, acred, flags);
}

static struct rpc_cred *
generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
	struct generic_cred *gcred;

	gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
	if (gcred == NULL)
		return ERR_PTR(-ENOMEM);

	rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
	gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;

	gcred->acred.uid = acred->uid;
	gcred->acred.gid = acred->gid;
	gcred->acred.group_info = acred->group_info;
98
	gcred->acred.ac_flags = 0;
99 100
	if (gcred->acred.group_info != NULL)
		get_group_info(gcred->acred.group_info);
101
	gcred->acred.machine_cred = acred->machine_cred;
102
	gcred->acred.principal = acred->principal;
103

104 105
	dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
			gcred->acred.machine_cred ? "machine" : "generic",
106 107 108
			gcred,
			from_kuid(&init_user_ns, acred->uid),
			from_kgid(&init_user_ns, acred->gid));
109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
	return &gcred->gc_base;
}

static void
generic_free_cred(struct rpc_cred *cred)
{
	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);

	dprintk("RPC:       generic_free_cred %p\n", gcred);
	if (gcred->acred.group_info != NULL)
		put_group_info(gcred->acred.group_info);
	kfree(gcred);
}

static void
generic_free_cred_callback(struct rcu_head *head)
{
	struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
	generic_free_cred(cred);
}

static void
generic_destroy_cred(struct rpc_cred *cred)
{
	call_rcu(&cred->cr_rcu, generic_free_cred_callback);
}

136 137 138 139 140
static int
machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flags)
{
	if (!gcred->acred.machine_cred ||
	    gcred->acred.principal != acred->principal ||
141 142
	    !uid_eq(gcred->acred.uid, acred->uid) ||
	    !gid_eq(gcred->acred.gid, acred->gid))
143 144 145 146
		return 0;
	return 1;
}

147 148 149 150 151 152 153
/*
 * Match credentials against current process creds.
 */
static int
generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
{
	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
154
	int i;
155

156 157 158
	if (acred->machine_cred)
		return machine_cred_match(acred, gcred, flags);

159 160
	if (!uid_eq(gcred->acred.uid, acred->uid) ||
	    !gid_eq(gcred->acred.gid, acred->gid) ||
161
	    gcred->acred.machine_cred != 0)
162 163 164 165 166 167 168 169 170 171
		goto out_nomatch;

	/* Optimisation in the case where pointers are identical... */
	if (gcred->acred.group_info == acred->group_info)
		goto out_match;

	/* Slow path... */
	if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
		goto out_nomatch;
	for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
172 173
		if (!gid_eq(GROUP_AT(gcred->acred.group_info, i),
				GROUP_AT(acred->group_info, i)))
174 175 176
			goto out_nomatch;
	}
out_match:
177
	return 1;
178 179
out_nomatch:
	return 0;
180 181
}

182
int __init rpc_init_generic_auth(void)
183
{
184
	return rpcauth_init_credcache(&generic_auth);
185 186
}

187
void rpc_destroy_generic_auth(void)
188
{
189
	rpcauth_destroy_credcache(&generic_auth);
190 191
}

192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247
/*
 * Test the the current time (now) against the underlying credential key expiry
 * minus a timeout and setup notification.
 *
 * The normal case:
 * If 'now' is before the key expiry minus RPC_KEY_EXPIRE_TIMEO, set
 * the RPC_CRED_NOTIFY_TIMEOUT flag to setup the underlying credential
 * rpc_credops crmatch routine to notify this generic cred when it's key
 * expiration is within RPC_KEY_EXPIRE_TIMEO, and return 0.
 *
 * The error case:
 * If the underlying cred lookup fails, return -EACCES.
 *
 * The 'almost' error case:
 * If 'now' is within key expiry minus RPC_KEY_EXPIRE_TIMEO, but not within
 * key expiry minus RPC_KEY_EXPIRE_FAIL, set the RPC_CRED_EXPIRE_SOON bit
 * on the acred ac_flags and return 0.
 */
static int
generic_key_timeout(struct rpc_auth *auth, struct rpc_cred *cred)
{
	struct auth_cred *acred = &container_of(cred, struct generic_cred,
						gc_base)->acred;
	struct rpc_cred *tcred;
	int ret = 0;


	/* Fast track for non crkey_timeout (no key) underlying credentials */
	if (test_bit(RPC_CRED_NO_CRKEY_TIMEOUT, &acred->ac_flags))
		return 0;

	/* Fast track for the normal case */
	if (test_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags))
		return 0;

	/* lookup_cred either returns a valid referenced rpc_cred, or PTR_ERR */
	tcred = auth->au_ops->lookup_cred(auth, acred, 0);
	if (IS_ERR(tcred))
		return -EACCES;

	if (!tcred->cr_ops->crkey_timeout) {
		set_bit(RPC_CRED_NO_CRKEY_TIMEOUT, &acred->ac_flags);
		ret = 0;
		goto out_put;
	}

	/* Test for the almost error case */
	ret = tcred->cr_ops->crkey_timeout(tcred);
	if (ret != 0) {
		set_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
		ret = 0;
	} else {
		/* In case underlying cred key has been reset */
		if (test_and_clear_bit(RPC_CRED_KEY_EXPIRE_SOON,
					&acred->ac_flags))
			dprintk("RPC:        UID %d Credential key reset\n",
248
				from_kuid(&init_user_ns, tcred->cr_uid));
249 250 251 252 253 254 255 256 257
		/* set up fasttrack for the normal case */
		set_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags);
	}

out_put:
	put_rpccred(tcred);
	return ret;
}

258 259 260 261 262
static const struct rpc_authops generic_auth_ops = {
	.owner = THIS_MODULE,
	.au_name = "Generic",
	.lookup_cred = generic_lookup_cred,
	.crcreate = generic_create_cred,
263
	.key_timeout = generic_key_timeout,
264 265 266 267 268 269 270
};

static struct rpc_auth generic_auth = {
	.au_ops = &generic_auth_ops,
	.au_count = ATOMIC_INIT(0),
};

271 272 273 274
static bool generic_key_to_expire(struct rpc_cred *cred)
{
	struct auth_cred *acred = &container_of(cred, struct generic_cred,
						gc_base)->acred;
275
	return test_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
276 277
}

278 279 280
static const struct rpc_credops generic_credops = {
	.cr_name = "Generic cred",
	.crdestroy = generic_destroy_cred,
281
	.crbind = generic_bind_cred,
282
	.crmatch = generic_match,
283
	.crkey_to_expire = generic_key_to_expire,
284
};