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// SPDX-License-Identifier: BSD-3-Clause
/*
* linux/net/sunrpc/gss_krb5_mech.c
*
* Copyright (c) 2001-2008 The Regents of the University of Michigan.
* All rights reserved.
*
* Andy Adamson <andros@umich.edu>
* J. Bruce Fields <bfields@umich.edu>
*/
#include <crypto/hash.h>
#include <crypto/skcipher.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/gss_krb5_enctypes.h>
#include "auth_gss_internal.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static struct gss_api_mech gss_kerberos_mech; /* forward declaration */
static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
#ifndef CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES
/*
* DES (All DES enctypes are mapped to the same gss functionality)
*/
{
.etype = ENCTYPE_DES_CBC_RAW,
.ctype = CKSUMTYPE_RSA_MD5,
.name = "des-cbc-crc",
.encrypt_name = "cbc(des)",
.cksum_name = "md5",
.encrypt = krb5_encrypt,
.decrypt = krb5_decrypt,
.mk_key = NULL,
.signalg = SGN_ALG_DES_MAC_MD5,
.sealalg = SEAL_ALG_DES,
.keybytes = 7,
.keylength = 8,
.blocksize = 8,
.conflen = 8,
.cksumlength = 8,
.keyed_cksum = 0,
},
#endif /* CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES */
/*
* 3DES
*/
{
.etype = ENCTYPE_DES3_CBC_RAW,
.ctype = CKSUMTYPE_HMAC_SHA1_DES3,
.name = "des3-hmac-sha1",
.encrypt_name = "cbc(des3_ede)",
.cksum_name = "hmac(sha1)",
.encrypt = krb5_encrypt,
.decrypt = krb5_decrypt,
.mk_key = gss_krb5_des3_make_key,
.signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
.sealalg = SEAL_ALG_DES3KD,
.keybytes = 21,
.keylength = 24,
.blocksize = 8,
.conflen = 8,
.cksumlength = 20,
.keyed_cksum = 1,
},
/*
* AES128
*/
{
.etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
.ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
.name = "aes128-cts",
.encrypt_name = "cts(cbc(aes))",
.cksum_name = "hmac(sha1)",
.encrypt = krb5_encrypt,
.decrypt = krb5_decrypt,
.mk_key = gss_krb5_aes_make_key,
.encrypt_v2 = gss_krb5_aes_encrypt,
.decrypt_v2 = gss_krb5_aes_decrypt,
.signalg = -1,
.sealalg = -1,
.keybytes = 16,
.keylength = 16,
.blocksize = 16,
.conflen = 16,
.cksumlength = 12,
.keyed_cksum = 1,
},
/*
* AES256
*/
{
.etype = ENCTYPE_AES256_CTS_HMAC_SHA1_96,
.ctype = CKSUMTYPE_HMAC_SHA1_96_AES256,
.name = "aes256-cts",
.encrypt_name = "cts(cbc(aes))",
.cksum_name = "hmac(sha1)",
.encrypt = krb5_encrypt,
.decrypt = krb5_decrypt,
.mk_key = gss_krb5_aes_make_key,
.encrypt_v2 = gss_krb5_aes_encrypt,
.decrypt_v2 = gss_krb5_aes_decrypt,
.signalg = -1,
.sealalg = -1,
.keybytes = 32,
.keylength = 32,
.blocksize = 16,
.conflen = 16,
.cksumlength = 12,
.keyed_cksum = 1,
},
};
static const int num_supported_enctypes =
ARRAY_SIZE(supported_gss_krb5_enctypes);
static int
supported_gss_krb5_enctype(int etype)
{
int i;
for (i = 0; i < num_supported_enctypes; i++)
if (supported_gss_krb5_enctypes[i].etype == etype)
return 1;
return 0;
}
static const struct gss_krb5_enctype *
get_gss_krb5_enctype(int etype)
{
int i;
for (i = 0; i < num_supported_enctypes; i++)
if (supported_gss_krb5_enctypes[i].etype == etype)
return &supported_gss_krb5_enctypes[i];
return NULL;
}
static inline const void *
get_key(const void *p, const void *end,
struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)
{
struct xdr_netobj key;
int alg;
p = simple_get_bytes(p, end, &alg, sizeof(alg));
if (IS_ERR(p))
goto out_err;
switch (alg) {
case ENCTYPE_DES_CBC_CRC:
case ENCTYPE_DES_CBC_MD4:
case ENCTYPE_DES_CBC_MD5:
/* Map all these key types to ENCTYPE_DES_CBC_RAW */
alg = ENCTYPE_DES_CBC_RAW;
break;
}
if (!supported_gss_krb5_enctype(alg)) {
printk(KERN_WARNING "gss_kerberos_mech: unsupported "
"encryption key algorithm %d\n", alg);
p = ERR_PTR(-EINVAL);
goto out_err;
}
p = simple_get_netobj(p, end, &key);
if (IS_ERR(p))
goto out_err;
*res = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
if (IS_ERR(*res)) {
printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
*res = NULL;
goto out_err_free_key;
}
if (crypto_sync_skcipher_setkey(*res, key.data, key.len)) {
printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
goto out_err_free_tfm;
}
kfree(key.data);
return p;
out_err_free_tfm:
crypto_free_sync_skcipher(*res);
out_err_free_key:
kfree(key.data);
p = ERR_PTR(-EINVAL);
out_err:
return p;
}
static int
gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
{
u32 seq_send;
int tmp;
u32 time32;
p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
if (IS_ERR(p))
goto out_err;
/* Old format supports only DES! Any other enctype uses new format */
ctx->enctype = ENCTYPE_DES_CBC_RAW;
ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
if (ctx->gk5e == NULL) {
p = ERR_PTR(-EINVAL);
goto out_err;
}
/* The downcall format was designed before we completely understood
* the uses of the context fields; so it includes some stuff we
* just give some minimal sanity-checking, and some we ignore
* completely (like the next twenty bytes): */
if (unlikely(p + 20 > end || p + 20 < p)) {
p = ERR_PTR(-EFAULT);
goto out_err;
}
p += 20;
p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
if (IS_ERR(p))
goto out_err;
if (tmp != SGN_ALG_DES_MAC_MD5) {
p = ERR_PTR(-ENOSYS);
goto out_err;
}
p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
if (IS_ERR(p))
goto out_err;
if (tmp != SEAL_ALG_DES) {
p = ERR_PTR(-ENOSYS);
goto out_err;
}
p = simple_get_bytes(p, end, &time32, sizeof(time32));
if (IS_ERR(p))
goto out_err;
/* unsigned 32-bit time overflows in year 2106 */
ctx->endtime = (time64_t)time32;
p = simple_get_bytes(p, end, &seq_send, sizeof(seq_send));
if (IS_ERR(p))
goto out_err;
atomic_set(&ctx->seq_send, seq_send);
p = simple_get_netobj(p, end, &ctx->mech_used);
if (IS_ERR(p))
goto out_err;
p = get_key(p, end, ctx, &ctx->enc);
if (IS_ERR(p))
goto out_err_free_mech;
p = get_key(p, end, ctx, &ctx->seq);
if (IS_ERR(p))
goto out_err_free_key1;
if (p != end) {
p = ERR_PTR(-EFAULT);
goto out_err_free_key2;
}
return 0;
out_err_free_key2:
crypto_free_sync_skcipher(ctx->seq);
out_err_free_key1:
crypto_free_sync_skcipher(ctx->enc);
out_err_free_mech:
kfree(ctx->mech_used.data);
out_err:
return PTR_ERR(p);
}
static struct crypto_sync_skcipher *
context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
{
struct crypto_sync_skcipher *cp;
cp = crypto_alloc_sync_skcipher(cname, 0, 0);
if (IS_ERR(cp)) {
dprintk("gss_kerberos_mech: unable to initialize "
"crypto algorithm %s\n", cname);
return NULL;
}
if (crypto_sync_skcipher_setkey(cp, key, ctx->gk5e->keylength)) {
dprintk("gss_kerberos_mech: error setting key for "
"crypto algorithm %s\n", cname);
crypto_free_sync_skcipher(cp);
return NULL;
}
return cp;
}
static inline void
set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
{
cdata[0] = (usage>>24)&0xff;
cdata[1] = (usage>>16)&0xff;
cdata[2] = (usage>>8)&0xff;
cdata[3] = usage&0xff;
cdata[4] = seed;
}
static int
context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
{
struct xdr_netobj c, keyin, keyout;
u8 cdata[GSS_KRB5_K5CLENGTH];
u32 err;
c.len = GSS_KRB5_K5CLENGTH;
c.data = cdata;
keyin.data = ctx->Ksess;
keyin.len = ctx->gk5e->keylength;
keyout.len = ctx->gk5e->keylength;
/* seq uses the raw key */
ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
ctx->Ksess);
if (ctx->seq == NULL)
goto out_err;
ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
ctx->Ksess);
if (ctx->enc == NULL)
goto out_free_seq;
/* derive cksum */
set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
keyout.data = ctx->cksum;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving cksum key\n",
__func__, err);
goto out_free_enc;
}
return 0;
out_free_enc:
crypto_free_sync_skcipher(ctx->enc);
out_free_seq:
crypto_free_sync_skcipher(ctx->seq);
out_err:
return -EINVAL;
}
static int
context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
{
struct xdr_netobj c, keyin, keyout;
u8 cdata[GSS_KRB5_K5CLENGTH];
u32 err;
c.len = GSS_KRB5_K5CLENGTH;
c.data = cdata;
keyin.data = ctx->Ksess;
keyin.len = ctx->gk5e->keylength;
keyout.len = ctx->gk5e->keylength;
/* initiator seal encryption */
set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
keyout.data = ctx->initiator_seal;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving initiator_seal key\n",
__func__, err);
goto out_err;
}
ctx->initiator_enc = context_v2_alloc_cipher(ctx,
ctx->gk5e->encrypt_name,
ctx->initiator_seal);
if (ctx->initiator_enc == NULL)
goto out_err;
/* acceptor seal encryption */
set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
keyout.data = ctx->acceptor_seal;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving acceptor_seal key\n",
__func__, err);
goto out_free_initiator_enc;
}
ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
ctx->gk5e->encrypt_name,
ctx->acceptor_seal);
if (ctx->acceptor_enc == NULL)
goto out_free_initiator_enc;
/* initiator sign checksum */
set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
keyout.data = ctx->initiator_sign;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving initiator_sign key\n",
__func__, err);
goto out_free_acceptor_enc;
}
/* acceptor sign checksum */
set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
keyout.data = ctx->acceptor_sign;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving acceptor_sign key\n",
__func__, err);
goto out_free_acceptor_enc;
}
/* initiator seal integrity */
set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
keyout.data = ctx->initiator_integ;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving initiator_integ key\n",
__func__, err);
goto out_free_acceptor_enc;
}
/* acceptor seal integrity */
set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
keyout.data = ctx->acceptor_integ;
err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
if (err) {
dprintk("%s: Error %d deriving acceptor_integ key\n",
__func__, err);
goto out_free_acceptor_enc;
}
switch (ctx->enctype) {
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
ctx->initiator_enc_aux =
context_v2_alloc_cipher(ctx, "cbc(aes)",
ctx->initiator_seal);
if (ctx->initiator_enc_aux == NULL)
goto out_free_acceptor_enc;
ctx->acceptor_enc_aux =
context_v2_alloc_cipher(ctx, "cbc(aes)",
ctx->acceptor_seal);
if (ctx->acceptor_enc_aux == NULL) {
crypto_free_sync_skcipher(ctx->initiator_enc_aux);
goto out_free_acceptor_enc;
}
}
return 0;
out_free_acceptor_enc:
crypto_free_sync_skcipher(ctx->acceptor_enc);
out_free_initiator_enc:
crypto_free_sync_skcipher(ctx->initiator_enc);
out_err:
return -EINVAL;
}
static int
gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
gfp_t gfp_mask)
{
u64 seq_send64;
int keylen;
u32 time32;
p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
if (IS_ERR(p))
goto out_err;
ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
p = simple_get_bytes(p, end, &time32, sizeof(time32));
if (IS_ERR(p))
goto out_err;
/* unsigned 32-bit time overflows in year 2106 */
ctx->endtime = (time64_t)time32;
p = simple_get_bytes(p, end, &seq_send64, sizeof(seq_send64));
if (IS_ERR(p))
goto out_err;
atomic64_set(&ctx->seq_send64, seq_send64);
/* set seq_send for use by "older" enctypes */
atomic_set(&ctx->seq_send, seq_send64);
if (seq_send64 != atomic_read(&ctx->seq_send)) {
dprintk("%s: seq_send64 %llx, seq_send %x overflow?\n", __func__,
seq_send64, atomic_read(&ctx->seq_send));
p = ERR_PTR(-EINVAL);
goto out_err;
}
p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
if (IS_ERR(p))
goto out_err;
/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
ctx->enctype = ENCTYPE_DES3_CBC_RAW;
ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
if (ctx->gk5e == NULL) {
dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
ctx->enctype);
p = ERR_PTR(-EINVAL);
goto out_err;
}
keylen = ctx->gk5e->keylength;
p = simple_get_bytes(p, end, ctx->Ksess, keylen);
if (IS_ERR(p))
goto out_err;
if (p != end) {
p = ERR_PTR(-EINVAL);
goto out_err;
}
ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
gss_kerberos_mech.gm_oid.len, gfp_mask);
if (unlikely(ctx->mech_used.data == NULL)) {
p = ERR_PTR(-ENOMEM);
goto out_err;
}
ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
switch (ctx->enctype) {
case ENCTYPE_DES3_CBC_RAW:
return context_derive_keys_des3(ctx, gfp_mask);
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
return context_derive_keys_new(ctx, gfp_mask);
default:
return -EINVAL;
}
out_err:
return PTR_ERR(p);
}
static int
gss_import_sec_context_kerberos(const void *p, size_t len,
struct gss_ctx *ctx_id,
time64_t *endtime,
gfp_t gfp_mask)
{
const void *end = (const void *)((const char *)p + len);
struct krb5_ctx *ctx;
int ret;
ctx = kzalloc(sizeof(*ctx), gfp_mask);
if (ctx == NULL)
return -ENOMEM;
if (len == 85)
ret = gss_import_v1_context(p, end, ctx);
else
ret = gss_import_v2_context(p, end, ctx, gfp_mask);
if (ret == 0) {
ctx_id->internal_ctx_id = ctx;
if (endtime)
*endtime = ctx->endtime;
} else
kfree(ctx);
dprintk("RPC: %s: returning %d\n", __func__, ret);
return ret;
}
static void
gss_delete_sec_context_kerberos(void *internal_ctx) {
struct krb5_ctx *kctx = internal_ctx;
crypto_free_sync_skcipher(kctx->seq);
crypto_free_sync_skcipher(kctx->enc);
crypto_free_sync_skcipher(kctx->acceptor_enc);
crypto_free_sync_skcipher(kctx->initiator_enc);
crypto_free_sync_skcipher(kctx->acceptor_enc_aux);
crypto_free_sync_skcipher(kctx->initiator_enc_aux);
kfree(kctx->mech_used.data);
kfree(kctx);
}
static const struct gss_api_ops gss_kerberos_ops = {
.gss_import_sec_context = gss_import_sec_context_kerberos,
.gss_get_mic = gss_get_mic_kerberos,
.gss_verify_mic = gss_verify_mic_kerberos,
.gss_wrap = gss_wrap_kerberos,
.gss_unwrap = gss_unwrap_kerberos,
.gss_delete_sec_context = gss_delete_sec_context_kerberos,
};
static struct pf_desc gss_kerberos_pfs[] = {
[0] = {
.pseudoflavor = RPC_AUTH_GSS_KRB5,
.qop = GSS_C_QOP_DEFAULT,
.service = RPC_GSS_SVC_NONE,
.name = "krb5",
},
[1] = {
.pseudoflavor = RPC_AUTH_GSS_KRB5I,
.qop = GSS_C_QOP_DEFAULT,
.service = RPC_GSS_SVC_INTEGRITY,
.name = "krb5i",
.datatouch = true,
},
[2] = {
.pseudoflavor = RPC_AUTH_GSS_KRB5P,
.qop = GSS_C_QOP_DEFAULT,
.service = RPC_GSS_SVC_PRIVACY,
.name = "krb5p",
.datatouch = true,
},
};
MODULE_ALIAS("rpc-auth-gss-krb5");
MODULE_ALIAS("rpc-auth-gss-krb5i");
MODULE_ALIAS("rpc-auth-gss-krb5p");
MODULE_ALIAS("rpc-auth-gss-390003");
MODULE_ALIAS("rpc-auth-gss-390004");
MODULE_ALIAS("rpc-auth-gss-390005");
MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");
static struct gss_api_mech gss_kerberos_mech = {
.gm_name = "krb5",
.gm_owner = THIS_MODULE,
.gm_oid = { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
.gm_ops = &gss_kerberos_ops,
.gm_pf_num = ARRAY_SIZE(gss_kerberos_pfs),
.gm_pfs = gss_kerberos_pfs,
.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
};
static int __init init_kerberos_module(void)
{
int status;
status = gss_mech_register(&gss_kerberos_mech);
if (status)
printk("Failed to register kerberos gss mechanism!\n");
return status;
}
static void __exit cleanup_kerberos_module(void)
{
gss_mech_unregister(&gss_kerberos_mech);
}
MODULE_LICENSE("GPL");
module_init(init_kerberos_module);
module_exit(cleanup_kerberos_module);