Revision ec3937107ab43f3e8b2bc9dad95710043c462ff7 authored by Baoquan He on 04 April 2019, 02:03:13 UTC, committed by Borislav Petkov on 18 April 2019, 08:42:58 UTC
kernel_randomize_memory() uses __PHYSICAL_MASK_SHIFT to calculate
the maximum amount of system RAM supported. The size of the direct
mapping section is obtained from the smaller one of the below two
values:
(actual system RAM size + padding size) vs (max system RAM size supported)
This calculation is wrong since commit
b83ce5ee9147 ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52").
In it, __PHYSICAL_MASK_SHIFT was changed to be 52, regardless of whether
the kernel is using 4-level or 5-level page tables. Thus, it will always
use 4 PB as the maximum amount of system RAM, even in 4-level paging
mode where it should actually be 64 TB.
Thus, the size of the direct mapping section will always
be the sum of the actual system RAM size plus the padding size.
Even when the amount of system RAM is 64 TB, the following layout will
still be used. Obviously KALSR will be weakened significantly.
|____|_______actual RAM_______|_padding_|______the rest_______|
0 64TB ~120TB
Instead, it should be like this:
|____|_______actual RAM_______|_________the rest______________|
0 64TB ~120TB
The size of padding region is controlled by
CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING, which is 10 TB by default.
The above issue only exists when
CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING is set to a non-zero value,
which is the case when CONFIG_MEMORY_HOTPLUG is enabled. Otherwise,
using __PHYSICAL_MASK_SHIFT doesn't affect KASLR.
Fix it by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
[ bp: Massage commit message. ]
Fixes: b83ce5ee9147 ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52")
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: frank.ramsay@hpe.com
Cc: herbert@gondor.apana.org.au
Cc: kirill@shutemov.name
Cc: mike.travis@hpe.com
Cc: thgarnie@google.com
Cc: x86-ml <x86@kernel.org>
Cc: yamada.masahiro@socionext.com
Link: https://lkml.kernel.org/r/20190417083536.GE7065@MiWiFi-R3L-srv
1 parent a943245
rsa.c
/* RSA asymmetric public-key algorithm [RFC3447]
*
* Copyright (c) 2015, Intel Corporation
* Authors: Tadeusz Struk <tadeusz.struk@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/mpi.h>
#include <crypto/internal/rsa.h>
#include <crypto/internal/akcipher.h>
#include <crypto/akcipher.h>
#include <crypto/algapi.h>
struct rsa_mpi_key {
MPI n;
MPI e;
MPI d;
};
/*
* RSAEP function [RFC3447 sec 5.1.1]
* c = m^e mod n;
*/
static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
{
/* (1) Validate 0 <= m < n */
if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
return -EINVAL;
/* (2) c = m^e mod n */
return mpi_powm(c, m, key->e, key->n);
}
/*
* RSADP function [RFC3447 sec 5.1.2]
* m = c^d mod n;
*/
static int _rsa_dec(const struct rsa_mpi_key *key, MPI m, MPI c)
{
/* (1) Validate 0 <= c < n */
if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
return -EINVAL;
/* (2) m = c^d mod n */
return mpi_powm(m, c, key->d, key->n);
}
/*
* RSASP1 function [RFC3447 sec 5.2.1]
* s = m^d mod n
*/
static int _rsa_sign(const struct rsa_mpi_key *key, MPI s, MPI m)
{
/* (1) Validate 0 <= m < n */
if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
return -EINVAL;
/* (2) s = m^d mod n */
return mpi_powm(s, m, key->d, key->n);
}
/*
* RSAVP1 function [RFC3447 sec 5.2.2]
* m = s^e mod n;
*/
static int _rsa_verify(const struct rsa_mpi_key *key, MPI m, MPI s)
{
/* (1) Validate 0 <= s < n */
if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0)
return -EINVAL;
/* (2) m = s^e mod n */
return mpi_powm(m, s, key->e, key->n);
}
static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
{
return akcipher_tfm_ctx(tfm);
}
static int rsa_enc(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
MPI m, c = mpi_alloc(0);
int ret = 0;
int sign;
if (!c)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->e)) {
ret = -EINVAL;
goto err_free_c;
}
ret = -ENOMEM;
m = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!m)
goto err_free_c;
ret = _rsa_enc(pkey, c, m);
if (ret)
goto err_free_m;
ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign);
if (ret)
goto err_free_m;
if (sign < 0)
ret = -EBADMSG;
err_free_m:
mpi_free(m);
err_free_c:
mpi_free(c);
return ret;
}
static int rsa_dec(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
MPI c, m = mpi_alloc(0);
int ret = 0;
int sign;
if (!m)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->d)) {
ret = -EINVAL;
goto err_free_m;
}
ret = -ENOMEM;
c = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!c)
goto err_free_m;
ret = _rsa_dec(pkey, m, c);
if (ret)
goto err_free_c;
ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
if (ret)
goto err_free_c;
if (sign < 0)
ret = -EBADMSG;
err_free_c:
mpi_free(c);
err_free_m:
mpi_free(m);
return ret;
}
static int rsa_sign(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
MPI m, s = mpi_alloc(0);
int ret = 0;
int sign;
if (!s)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->d)) {
ret = -EINVAL;
goto err_free_s;
}
ret = -ENOMEM;
m = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!m)
goto err_free_s;
ret = _rsa_sign(pkey, s, m);
if (ret)
goto err_free_m;
ret = mpi_write_to_sgl(s, req->dst, req->dst_len, &sign);
if (ret)
goto err_free_m;
if (sign < 0)
ret = -EBADMSG;
err_free_m:
mpi_free(m);
err_free_s:
mpi_free(s);
return ret;
}
static int rsa_verify(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
MPI s, m = mpi_alloc(0);
int ret = 0;
int sign;
if (!m)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->e)) {
ret = -EINVAL;
goto err_free_m;
}
s = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!s) {
ret = -ENOMEM;
goto err_free_m;
}
ret = _rsa_verify(pkey, m, s);
if (ret)
goto err_free_s;
ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
if (ret)
goto err_free_s;
if (sign < 0)
ret = -EBADMSG;
err_free_s:
mpi_free(s);
err_free_m:
mpi_free(m);
return ret;
}
static void rsa_free_mpi_key(struct rsa_mpi_key *key)
{
mpi_free(key->d);
mpi_free(key->e);
mpi_free(key->n);
key->d = NULL;
key->e = NULL;
key->n = NULL;
}
static int rsa_check_key_length(unsigned int len)
{
switch (len) {
case 512:
case 1024:
case 1536:
case 2048:
case 3072:
case 4096:
return 0;
}
return -EINVAL;
}
static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
struct rsa_key raw_key = {0};
int ret;
/* Free the old MPI key if any */
rsa_free_mpi_key(mpi_key);
ret = rsa_parse_pub_key(&raw_key, key, keylen);
if (ret)
return ret;
mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
if (!mpi_key->e)
goto err;
mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
if (!mpi_key->n)
goto err;
if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
rsa_free_mpi_key(mpi_key);
return -EINVAL;
}
return 0;
err:
rsa_free_mpi_key(mpi_key);
return -ENOMEM;
}
static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
struct rsa_key raw_key = {0};
int ret;
/* Free the old MPI key if any */
rsa_free_mpi_key(mpi_key);
ret = rsa_parse_priv_key(&raw_key, key, keylen);
if (ret)
return ret;
mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
if (!mpi_key->d)
goto err;
mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
if (!mpi_key->e)
goto err;
mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
if (!mpi_key->n)
goto err;
if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
rsa_free_mpi_key(mpi_key);
return -EINVAL;
}
return 0;
err:
rsa_free_mpi_key(mpi_key);
return -ENOMEM;
}
static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
{
struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
return mpi_get_size(pkey->n);
}
static void rsa_exit_tfm(struct crypto_akcipher *tfm)
{
struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
rsa_free_mpi_key(pkey);
}
static struct akcipher_alg rsa = {
.encrypt = rsa_enc,
.decrypt = rsa_dec,
.sign = rsa_sign,
.verify = rsa_verify,
.set_priv_key = rsa_set_priv_key,
.set_pub_key = rsa_set_pub_key,
.max_size = rsa_max_size,
.exit = rsa_exit_tfm,
.base = {
.cra_name = "rsa",
.cra_driver_name = "rsa-generic",
.cra_priority = 100,
.cra_module = THIS_MODULE,
.cra_ctxsize = sizeof(struct rsa_mpi_key),
},
};
static int rsa_init(void)
{
int err;
err = crypto_register_akcipher(&rsa);
if (err)
return err;
err = crypto_register_template(&rsa_pkcs1pad_tmpl);
if (err) {
crypto_unregister_akcipher(&rsa);
return err;
}
return 0;
}
static void rsa_exit(void)
{
crypto_unregister_template(&rsa_pkcs1pad_tmpl);
crypto_unregister_akcipher(&rsa);
}
module_init(rsa_init);
module_exit(rsa_exit);
MODULE_ALIAS_CRYPTO("rsa");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RSA generic algorithm");
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