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linux-next/arch/s390/crypto/prng.c
Greg Kroah-Hartman 20a884f5e0 s390: crypto: add SPDX identifiers to the remaining files
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the arch/s390/crypto/ files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-24 15:37:14 +01:00

876 lines
22 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2006, 2015
* Author(s): Jan Glauber <jan.glauber@de.ibm.com>
* Harald Freudenberger <freude@de.ibm.com>
* Driver for the s390 pseudo random number generator
*/
#define KMSG_COMPONENT "prng"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/fs.h>
#include <linux/fips.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/cpufeature.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <asm/debug.h>
#include <linux/uaccess.h>
#include <asm/timex.h>
#include <asm/cpacf.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("s390 PRNG interface");
#define PRNG_MODE_AUTO 0
#define PRNG_MODE_TDES 1
#define PRNG_MODE_SHA512 2
static unsigned int prng_mode = PRNG_MODE_AUTO;
module_param_named(mode, prng_mode, int, 0);
MODULE_PARM_DESC(prng_mode, "PRNG mode: 0 - auto, 1 - TDES, 2 - SHA512");
#define PRNG_CHUNKSIZE_TDES_MIN 8
#define PRNG_CHUNKSIZE_TDES_MAX (64*1024)
#define PRNG_CHUNKSIZE_SHA512_MIN 64
#define PRNG_CHUNKSIZE_SHA512_MAX (64*1024)
static unsigned int prng_chunk_size = 256;
module_param_named(chunksize, prng_chunk_size, int, 0);
MODULE_PARM_DESC(prng_chunk_size, "PRNG read chunk size in bytes");
#define PRNG_RESEED_LIMIT_TDES 4096
#define PRNG_RESEED_LIMIT_TDES_LOWER 4096
#define PRNG_RESEED_LIMIT_SHA512 100000
#define PRNG_RESEED_LIMIT_SHA512_LOWER 10000
static unsigned int prng_reseed_limit;
module_param_named(reseed_limit, prng_reseed_limit, int, 0);
MODULE_PARM_DESC(prng_reseed_limit, "PRNG reseed limit");
/*
* Any one who considers arithmetical methods of producing random digits is,
* of course, in a state of sin. -- John von Neumann
*/
static int prng_errorflag;
#define PRNG_GEN_ENTROPY_FAILED 1
#define PRNG_SELFTEST_FAILED 2
#define PRNG_INSTANTIATE_FAILED 3
#define PRNG_SEED_FAILED 4
#define PRNG_RESEED_FAILED 5
#define PRNG_GEN_FAILED 6
struct prng_ws_s {
u8 parm_block[32];
u32 reseed_counter;
u64 byte_counter;
};
struct prno_ws_s {
u32 res;
u32 reseed_counter;
u64 stream_bytes;
u8 V[112];
u8 C[112];
};
struct prng_data_s {
struct mutex mutex;
union {
struct prng_ws_s prngws;
struct prno_ws_s prnows;
};
u8 *buf;
u32 rest;
u8 *prev;
};
static struct prng_data_s *prng_data;
/* initial parameter block for tdes mode, copied from libica */
static const u8 initial_parm_block[32] __initconst = {
0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 };
/*** helper functions ***/
/*
* generate_entropy:
* This algorithm produces 64 bytes of entropy data based on 1024
* individual stckf() invocations assuming that each stckf() value
* contributes 0.25 bits of entropy. So the caller gets 256 bit
* entropy per 64 byte or 4 bits entropy per byte.
*/
static int generate_entropy(u8 *ebuf, size_t nbytes)
{
int n, ret = 0;
u8 *pg, *h, hash[64];
/* allocate 2 pages */
pg = (u8 *) __get_free_pages(GFP_KERNEL, 1);
if (!pg) {
prng_errorflag = PRNG_GEN_ENTROPY_FAILED;
return -ENOMEM;
}
while (nbytes) {
/* fill pages with urandom bytes */
get_random_bytes(pg, 2*PAGE_SIZE);
/* exor pages with 1024 stckf values */
for (n = 0; n < 2 * PAGE_SIZE / sizeof(u64); n++) {
u64 *p = ((u64 *)pg) + n;
*p ^= get_tod_clock_fast();
}
n = (nbytes < sizeof(hash)) ? nbytes : sizeof(hash);
if (n < sizeof(hash))
h = hash;
else
h = ebuf;
/* hash over the filled pages */
cpacf_kimd(CPACF_KIMD_SHA_512, h, pg, 2*PAGE_SIZE);
if (n < sizeof(hash))
memcpy(ebuf, hash, n);
ret += n;
ebuf += n;
nbytes -= n;
}
free_pages((unsigned long)pg, 1);
return ret;
}
/*** tdes functions ***/
static void prng_tdes_add_entropy(void)
{
__u64 entropy[4];
unsigned int i;
for (i = 0; i < 16; i++) {
cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
(char *) entropy, (char *) entropy,
sizeof(entropy));
memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy));
}
}
static void prng_tdes_seed(int nbytes)
{
char buf[16];
int i = 0;
BUG_ON(nbytes > sizeof(buf));
get_random_bytes(buf, nbytes);
/* Add the entropy */
while (nbytes >= 8) {
*((__u64 *)prng_data->prngws.parm_block) ^= *((__u64 *)(buf+i));
prng_tdes_add_entropy();
i += 8;
nbytes -= 8;
}
prng_tdes_add_entropy();
prng_data->prngws.reseed_counter = 0;
}
static int __init prng_tdes_instantiate(void)
{
int datalen;
pr_debug("prng runs in TDES mode with "
"chunksize=%d and reseed_limit=%u\n",
prng_chunk_size, prng_reseed_limit);
/* memory allocation, prng_data struct init, mutex init */
datalen = sizeof(struct prng_data_s) + prng_chunk_size;
prng_data = kzalloc(datalen, GFP_KERNEL);
if (!prng_data) {
prng_errorflag = PRNG_INSTANTIATE_FAILED;
return -ENOMEM;
}
mutex_init(&prng_data->mutex);
prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
memcpy(prng_data->prngws.parm_block, initial_parm_block, 32);
/* initialize the PRNG, add 128 bits of entropy */
prng_tdes_seed(16);
return 0;
}
static void prng_tdes_deinstantiate(void)
{
pr_debug("The prng module stopped "
"after running in triple DES mode\n");
kzfree(prng_data);
}
/*** sha512 functions ***/
static int __init prng_sha512_selftest(void)
{
/* NIST DRBG testvector for Hash Drbg, Sha-512, Count #0 */
static const u8 seed[] __initconst = {
0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a,
0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22,
0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b,
0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c,
0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa,
0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25 };
static const u8 V0[] __initconst = {
0x00, 0xad, 0xe3, 0x6f, 0x9a, 0x01, 0xc7, 0x76,
0x61, 0x34, 0x35, 0xf5, 0x4e, 0x24, 0x74, 0x22,
0x21, 0x9a, 0x29, 0x89, 0xc7, 0x93, 0x2e, 0x60,
0x1e, 0xe8, 0x14, 0x24, 0x8d, 0xd5, 0x03, 0xf1,
0x65, 0x5d, 0x08, 0x22, 0x72, 0xd5, 0xad, 0x95,
0xe1, 0x23, 0x1e, 0x8a, 0xa7, 0x13, 0xd9, 0x2b,
0x5e, 0xbc, 0xbb, 0x80, 0xab, 0x8d, 0xe5, 0x79,
0xab, 0x5b, 0x47, 0x4e, 0xdd, 0xee, 0x6b, 0x03,
0x8f, 0x0f, 0x5c, 0x5e, 0xa9, 0x1a, 0x83, 0xdd,
0xd3, 0x88, 0xb2, 0x75, 0x4b, 0xce, 0x83, 0x36,
0x57, 0x4b, 0xf1, 0x5c, 0xca, 0x7e, 0x09, 0xc0,
0xd3, 0x89, 0xc6, 0xe0, 0xda, 0xc4, 0x81, 0x7e,
0x5b, 0xf9, 0xe1, 0x01, 0xc1, 0x92, 0x05, 0xea,
0xf5, 0x2f, 0xc6, 0xc6, 0xc7, 0x8f, 0xbc, 0xf4 };
static const u8 C0[] __initconst = {
0x00, 0xf4, 0xa3, 0xe5, 0xa0, 0x72, 0x63, 0x95,
0xc6, 0x4f, 0x48, 0xd0, 0x8b, 0x5b, 0x5f, 0x8e,
0x6b, 0x96, 0x1f, 0x16, 0xed, 0xbc, 0x66, 0x94,
0x45, 0x31, 0xd7, 0x47, 0x73, 0x22, 0xa5, 0x86,
0xce, 0xc0, 0x4c, 0xac, 0x63, 0xb8, 0x39, 0x50,
0xbf, 0xe6, 0x59, 0x6c, 0x38, 0x58, 0x99, 0x1f,
0x27, 0xa7, 0x9d, 0x71, 0x2a, 0xb3, 0x7b, 0xf9,
0xfb, 0x17, 0x86, 0xaa, 0x99, 0x81, 0xaa, 0x43,
0xe4, 0x37, 0xd3, 0x1e, 0x6e, 0xe5, 0xe6, 0xee,
0xc2, 0xed, 0x95, 0x4f, 0x53, 0x0e, 0x46, 0x8a,
0xcc, 0x45, 0xa5, 0xdb, 0x69, 0x0d, 0x81, 0xc9,
0x32, 0x92, 0xbc, 0x8f, 0x33, 0xe6, 0xf6, 0x09,
0x7c, 0x8e, 0x05, 0x19, 0x0d, 0xf1, 0xb6, 0xcc,
0xf3, 0x02, 0x21, 0x90, 0x25, 0xec, 0xed, 0x0e };
static const u8 random[] __initconst = {
0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57,
0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6,
0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d,
0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf,
0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26,
0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64,
0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55,
0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a,
0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78,
0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e,
0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb,
0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30,
0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19,
0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f,
0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d,
0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a,
0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2,
0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd,
0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd,
0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2,
0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b,
0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1,
0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99,
0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e,
0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3,
0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67,
0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3,
0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d,
0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b,
0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13,
0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c,
0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 };
u8 buf[sizeof(random)];
struct prno_ws_s ws;
memset(&ws, 0, sizeof(ws));
/* initial seed */
cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
&ws, NULL, 0, seed, sizeof(seed));
/* check working states V and C */
if (memcmp(ws.V, V0, sizeof(V0)) != 0
|| memcmp(ws.C, C0, sizeof(C0)) != 0) {
pr_err("The prng self test state test "
"for the SHA-512 mode failed\n");
prng_errorflag = PRNG_SELFTEST_FAILED;
return -EIO;
}
/* generate random bytes */
cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
&ws, buf, sizeof(buf), NULL, 0);
cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
&ws, buf, sizeof(buf), NULL, 0);
/* check against expected data */
if (memcmp(buf, random, sizeof(random)) != 0) {
pr_err("The prng self test data test "
"for the SHA-512 mode failed\n");
prng_errorflag = PRNG_SELFTEST_FAILED;
return -EIO;
}
return 0;
}
static int __init prng_sha512_instantiate(void)
{
int ret, datalen;
u8 seed[64 + 32 + 16];
pr_debug("prng runs in SHA-512 mode "
"with chunksize=%d and reseed_limit=%u\n",
prng_chunk_size, prng_reseed_limit);
/* memory allocation, prng_data struct init, mutex init */
datalen = sizeof(struct prng_data_s) + prng_chunk_size;
if (fips_enabled)
datalen += prng_chunk_size;
prng_data = kzalloc(datalen, GFP_KERNEL);
if (!prng_data) {
prng_errorflag = PRNG_INSTANTIATE_FAILED;
return -ENOMEM;
}
mutex_init(&prng_data->mutex);
prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
/* selftest */
ret = prng_sha512_selftest();
if (ret)
goto outfree;
/* generate initial seed bytestring, with 256 + 128 bits entropy */
ret = generate_entropy(seed, 64 + 32);
if (ret != 64 + 32)
goto outfree;
/* followed by 16 bytes of unique nonce */
get_tod_clock_ext(seed + 64 + 32);
/* initial seed of the prno drng */
cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
&prng_data->prnows, NULL, 0, seed, sizeof(seed));
/* if fips mode is enabled, generate a first block of random
bytes for the FIPS 140-2 Conditional Self Test */
if (fips_enabled) {
prng_data->prev = prng_data->buf + prng_chunk_size;
cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
&prng_data->prnows,
prng_data->prev, prng_chunk_size, NULL, 0);
}
return 0;
outfree:
kfree(prng_data);
return ret;
}
static void prng_sha512_deinstantiate(void)
{
pr_debug("The prng module stopped after running in SHA-512 mode\n");
kzfree(prng_data);
}
static int prng_sha512_reseed(void)
{
int ret;
u8 seed[64];
/* fetch 256 bits of fresh entropy */
ret = generate_entropy(seed, sizeof(seed));
if (ret != sizeof(seed))
return ret;
/* do a reseed of the prno drng with this bytestring */
cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
&prng_data->prnows, NULL, 0, seed, sizeof(seed));
return 0;
}
static int prng_sha512_generate(u8 *buf, size_t nbytes)
{
int ret;
/* reseed needed ? */
if (prng_data->prnows.reseed_counter > prng_reseed_limit) {
ret = prng_sha512_reseed();
if (ret)
return ret;
}
/* PRNO generate */
cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
&prng_data->prnows, buf, nbytes, NULL, 0);
/* FIPS 140-2 Conditional Self Test */
if (fips_enabled) {
if (!memcmp(prng_data->prev, buf, nbytes)) {
prng_errorflag = PRNG_GEN_FAILED;
return -EILSEQ;
}
memcpy(prng_data->prev, buf, nbytes);
}
return nbytes;
}
/*** file io functions ***/
static int prng_open(struct inode *inode, struct file *file)
{
return nonseekable_open(inode, file);
}
static ssize_t prng_tdes_read(struct file *file, char __user *ubuf,
size_t nbytes, loff_t *ppos)
{
int chunk, n, ret = 0;
/* lock prng_data struct */
if (mutex_lock_interruptible(&prng_data->mutex))
return -ERESTARTSYS;
while (nbytes) {
if (need_resched()) {
if (signal_pending(current)) {
if (ret == 0)
ret = -ERESTARTSYS;
break;
}
/* give mutex free before calling schedule() */
mutex_unlock(&prng_data->mutex);
schedule();
/* occopy mutex again */
if (mutex_lock_interruptible(&prng_data->mutex)) {
if (ret == 0)
ret = -ERESTARTSYS;
return ret;
}
}
/*
* we lose some random bytes if an attacker issues
* reads < 8 bytes, but we don't care
*/
chunk = min_t(int, nbytes, prng_chunk_size);
/* PRNG only likes multiples of 8 bytes */
n = (chunk + 7) & -8;
if (prng_data->prngws.reseed_counter > prng_reseed_limit)
prng_tdes_seed(8);
/* if the CPU supports PRNG stckf is present too */
*((unsigned long long *)prng_data->buf) = get_tod_clock_fast();
/*
* Beside the STCKF the input for the TDES-EDE is the output
* of the last operation. We differ here from X9.17 since we
* only store one timestamp into the buffer. Padding the whole
* buffer with timestamps does not improve security, since
* successive stckf have nearly constant offsets.
* If an attacker knows the first timestamp it would be
* trivial to guess the additional values. One timestamp
* is therefore enough and still guarantees unique input values.
*
* Note: you can still get strict X9.17 conformity by setting
* prng_chunk_size to 8 bytes.
*/
cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
prng_data->buf, prng_data->buf, n);
prng_data->prngws.byte_counter += n;
prng_data->prngws.reseed_counter += n;
if (copy_to_user(ubuf, prng_data->buf, chunk)) {
ret = -EFAULT;
break;
}
nbytes -= chunk;
ret += chunk;
ubuf += chunk;
}
/* unlock prng_data struct */
mutex_unlock(&prng_data->mutex);
return ret;
}
static ssize_t prng_sha512_read(struct file *file, char __user *ubuf,
size_t nbytes, loff_t *ppos)
{
int n, ret = 0;
u8 *p;
/* if errorflag is set do nothing and return 'broken pipe' */
if (prng_errorflag)
return -EPIPE;
/* lock prng_data struct */
if (mutex_lock_interruptible(&prng_data->mutex))
return -ERESTARTSYS;
while (nbytes) {
if (need_resched()) {
if (signal_pending(current)) {
if (ret == 0)
ret = -ERESTARTSYS;
break;
}
/* give mutex free before calling schedule() */
mutex_unlock(&prng_data->mutex);
schedule();
/* occopy mutex again */
if (mutex_lock_interruptible(&prng_data->mutex)) {
if (ret == 0)
ret = -ERESTARTSYS;
return ret;
}
}
if (prng_data->rest) {
/* push left over random bytes from the previous read */
p = prng_data->buf + prng_chunk_size - prng_data->rest;
n = (nbytes < prng_data->rest) ?
nbytes : prng_data->rest;
prng_data->rest -= n;
} else {
/* generate one chunk of random bytes into read buf */
p = prng_data->buf;
n = prng_sha512_generate(p, prng_chunk_size);
if (n < 0) {
ret = n;
break;
}
if (nbytes < prng_chunk_size) {
n = nbytes;
prng_data->rest = prng_chunk_size - n;
} else {
n = prng_chunk_size;
prng_data->rest = 0;
}
}
if (copy_to_user(ubuf, p, n)) {
ret = -EFAULT;
break;
}
ubuf += n;
nbytes -= n;
ret += n;
}
/* unlock prng_data struct */
mutex_unlock(&prng_data->mutex);
return ret;
}
/*** sysfs stuff ***/
static const struct file_operations prng_sha512_fops = {
.owner = THIS_MODULE,
.open = &prng_open,
.release = NULL,
.read = &prng_sha512_read,
.llseek = noop_llseek,
};
static const struct file_operations prng_tdes_fops = {
.owner = THIS_MODULE,
.open = &prng_open,
.release = NULL,
.read = &prng_tdes_read,
.llseek = noop_llseek,
};
static struct miscdevice prng_sha512_dev = {
.name = "prandom",
.minor = MISC_DYNAMIC_MINOR,
.mode = 0644,
.fops = &prng_sha512_fops,
};
static struct miscdevice prng_tdes_dev = {
.name = "prandom",
.minor = MISC_DYNAMIC_MINOR,
.mode = 0644,
.fops = &prng_tdes_fops,
};
/* chunksize attribute (ro) */
static ssize_t prng_chunksize_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "%u\n", prng_chunk_size);
}
static DEVICE_ATTR(chunksize, 0444, prng_chunksize_show, NULL);
/* counter attribute (ro) */
static ssize_t prng_counter_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
u64 counter;
if (mutex_lock_interruptible(&prng_data->mutex))
return -ERESTARTSYS;
if (prng_mode == PRNG_MODE_SHA512)
counter = prng_data->prnows.stream_bytes;
else
counter = prng_data->prngws.byte_counter;
mutex_unlock(&prng_data->mutex);
return snprintf(buf, PAGE_SIZE, "%llu\n", counter);
}
static DEVICE_ATTR(byte_counter, 0444, prng_counter_show, NULL);
/* errorflag attribute (ro) */
static ssize_t prng_errorflag_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", prng_errorflag);
}
static DEVICE_ATTR(errorflag, 0444, prng_errorflag_show, NULL);
/* mode attribute (ro) */
static ssize_t prng_mode_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
if (prng_mode == PRNG_MODE_TDES)
return snprintf(buf, PAGE_SIZE, "TDES\n");
else
return snprintf(buf, PAGE_SIZE, "SHA512\n");
}
static DEVICE_ATTR(mode, 0444, prng_mode_show, NULL);
/* reseed attribute (w) */
static ssize_t prng_reseed_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
if (mutex_lock_interruptible(&prng_data->mutex))
return -ERESTARTSYS;
prng_sha512_reseed();
mutex_unlock(&prng_data->mutex);
return count;
}
static DEVICE_ATTR(reseed, 0200, NULL, prng_reseed_store);
/* reseed limit attribute (rw) */
static ssize_t prng_reseed_limit_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "%u\n", prng_reseed_limit);
}
static ssize_t prng_reseed_limit_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
unsigned limit;
if (sscanf(buf, "%u\n", &limit) != 1)
return -EINVAL;
if (prng_mode == PRNG_MODE_SHA512) {
if (limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
return -EINVAL;
} else {
if (limit < PRNG_RESEED_LIMIT_TDES_LOWER)
return -EINVAL;
}
prng_reseed_limit = limit;
return count;
}
static DEVICE_ATTR(reseed_limit, 0644,
prng_reseed_limit_show, prng_reseed_limit_store);
/* strength attribute (ro) */
static ssize_t prng_strength_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "256\n");
}
static DEVICE_ATTR(strength, 0444, prng_strength_show, NULL);
static struct attribute *prng_sha512_dev_attrs[] = {
&dev_attr_errorflag.attr,
&dev_attr_chunksize.attr,
&dev_attr_byte_counter.attr,
&dev_attr_mode.attr,
&dev_attr_reseed.attr,
&dev_attr_reseed_limit.attr,
&dev_attr_strength.attr,
NULL
};
static struct attribute *prng_tdes_dev_attrs[] = {
&dev_attr_chunksize.attr,
&dev_attr_byte_counter.attr,
&dev_attr_mode.attr,
NULL
};
static struct attribute_group prng_sha512_dev_attr_group = {
.attrs = prng_sha512_dev_attrs
};
static struct attribute_group prng_tdes_dev_attr_group = {
.attrs = prng_tdes_dev_attrs
};
/*** module init and exit ***/
static int __init prng_init(void)
{
int ret;
/* check if the CPU has a PRNG */
if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG))
return -EOPNOTSUPP;
/* choose prng mode */
if (prng_mode != PRNG_MODE_TDES) {
/* check for MSA5 support for PRNO operations */
if (!cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN)) {
if (prng_mode == PRNG_MODE_SHA512) {
pr_err("The prng module cannot "
"start in SHA-512 mode\n");
return -EOPNOTSUPP;
}
prng_mode = PRNG_MODE_TDES;
} else
prng_mode = PRNG_MODE_SHA512;
}
if (prng_mode == PRNG_MODE_SHA512) {
/* SHA512 mode */
if (prng_chunk_size < PRNG_CHUNKSIZE_SHA512_MIN
|| prng_chunk_size > PRNG_CHUNKSIZE_SHA512_MAX)
return -EINVAL;
prng_chunk_size = (prng_chunk_size + 0x3f) & ~0x3f;
if (prng_reseed_limit == 0)
prng_reseed_limit = PRNG_RESEED_LIMIT_SHA512;
else if (prng_reseed_limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
return -EINVAL;
ret = prng_sha512_instantiate();
if (ret)
goto out;
ret = misc_register(&prng_sha512_dev);
if (ret) {
prng_sha512_deinstantiate();
goto out;
}
ret = sysfs_create_group(&prng_sha512_dev.this_device->kobj,
&prng_sha512_dev_attr_group);
if (ret) {
misc_deregister(&prng_sha512_dev);
prng_sha512_deinstantiate();
goto out;
}
} else {
/* TDES mode */
if (prng_chunk_size < PRNG_CHUNKSIZE_TDES_MIN
|| prng_chunk_size > PRNG_CHUNKSIZE_TDES_MAX)
return -EINVAL;
prng_chunk_size = (prng_chunk_size + 0x07) & ~0x07;
if (prng_reseed_limit == 0)
prng_reseed_limit = PRNG_RESEED_LIMIT_TDES;
else if (prng_reseed_limit < PRNG_RESEED_LIMIT_TDES_LOWER)
return -EINVAL;
ret = prng_tdes_instantiate();
if (ret)
goto out;
ret = misc_register(&prng_tdes_dev);
if (ret) {
prng_tdes_deinstantiate();
goto out;
}
ret = sysfs_create_group(&prng_tdes_dev.this_device->kobj,
&prng_tdes_dev_attr_group);
if (ret) {
misc_deregister(&prng_tdes_dev);
prng_tdes_deinstantiate();
goto out;
}
}
out:
return ret;
}
static void __exit prng_exit(void)
{
if (prng_mode == PRNG_MODE_SHA512) {
sysfs_remove_group(&prng_sha512_dev.this_device->kobj,
&prng_sha512_dev_attr_group);
misc_deregister(&prng_sha512_dev);
prng_sha512_deinstantiate();
} else {
sysfs_remove_group(&prng_tdes_dev.this_device->kobj,
&prng_tdes_dev_attr_group);
misc_deregister(&prng_tdes_dev);
prng_tdes_deinstantiate();
}
}
module_cpu_feature_match(MSA, prng_init);
module_exit(prng_exit);