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srandom.c
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srandom.c
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#include <linux/ctype.h>
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/fcntl.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/wait.h>
#include <linux/random.h>
#include <linux/signal.h>
//#include "mix.h"
//#include "sha1.h"
#include <linux/ioctl.h>
#include <linux/types.h> /* for __u32, size_t */
#include <linux/string.h>
#define POOL_SIZE 512
#define WRITE_CHUNK_SIZE 64
#define READ_CHUNK_SIZE 20
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Omri&Or");
ssize_t device_read(struct file *, char * buffer, size_t n, loff_t *);
ssize_t device_write(struct file *, const char* buffer, size_t n, loff_t *);
int device_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg);
int init_module(void);
void cleanup_module(void);
void mix(const void *in, size_t nbytes, void *pooldata);
void hash_pool(const void *pooldata, void *out);
int rndaddentropy(struct rand_pool_info *p);
int rndclearpool();
int rndgetentcnt(int* p);
struct file_operations fops = {
.open = NULL,
.release = NULL,
.read = device_read,
.write = device_write,
.llseek = NULL,
.ioctl = device_ioctl,
.owner = THIS_MODULE,
};
char entropy_pool[POOL_SIZE];
int entropy_count=0;
DECLARE_WAIT_QUEUE_HEAD(wait_list);
int init_module(void)
{
int i;
//SET_MODULE_OWNER(&fops);
int retval = register_chrdev(62,"srandom",&fops);
if (retval < 0)
return retval;
for (i = 0; i < POOL_SIZE; i++) {
entropy_pool[i] = 0;
}
return 0;
}
void cleanup_module(void)
{
unregister_chrdev(62, "srandom");
return;
}
/*static int device_open(struct inode *, struct file *) {
return 0;
}
static int device_release(struct inode *, struct file *) {
return 0;
}
*/
ssize_t device_read(struct file * flip, char * buffer, size_t n, loff_t * f_pos) {
if (n == 0) {
return 0;
}
if (buffer == NULL) {
return -EINVAL;
}
while (entropy_count < 8) {
wait_event_interruptible(wait_list, entropy_count >= 8);
}
if (signal_pending(current) != 0) {
return -ERESTARTSYS;
}
int E = entropy_count / 8;
if (n > E) {
n = E;
}
entropy_count -= 8 * n;
int i;
int retval=0;
char* tmp = kmalloc(READ_CHUNK_SIZE, GFP_KERNEL);
if (tmp == NULL) {
return -ENOMEM;
}
int last_size = n % READ_CHUNK_SIZE;
for (i = 0;i < n / READ_CHUNK_SIZE; i++) {
hash_pool(entropy_pool, tmp);
mix(tmp, READ_CHUNK_SIZE, entropy_pool);
retval = copy_to_user(buffer, tmp, READ_CHUNK_SIZE);
if (retval > 0) {
kfree(tmp);
return -EFAULT;
}
buffer += READ_CHUNK_SIZE;
}
if (last_size != 0) {
hash_pool(entropy_pool, tmp);
mix(tmp, READ_CHUNK_SIZE, entropy_pool);
retval = copy_to_user(buffer, tmp, last_size);
if (retval > 0) {
kfree(tmp);
return -EFAULT;
}
}
kfree(tmp);
return n;
}
ssize_t device_write(struct file * flip, const char* buffer, size_t n, loff_t * f_pos) {
if (buffer == NULL) {
return -EFAULT;
}
int full_amount = n / WRITE_CHUNK_SIZE;
int last_size = n % WRITE_CHUNK_SIZE;
int retval = 0;
int i;
char* chunk = kmalloc(n, GFP_KERNEL);
if (chunk == NULL) {
return -ENOMEM;
}
retval = copy_from_user((void*)chunk, buffer, n);
if (retval > 0) {
kfree(chunk);
return -EFAULT;
}
for ( i = 0;i < full_amount;i++) {
mix(chunk+i*WRITE_CHUNK_SIZE, WRITE_CHUNK_SIZE, entropy_pool);
}
mix(chunk+ i*WRITE_CHUNK_SIZE, last_size, entropy_pool);
kfree(chunk);
return n;
}
int device_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) {
switch (cmd) {
case RNDGETENTCNT:
return rndgetentcnt((int*)arg);
break;
case RNDCLEARPOOL:
return rndclearpool();
break;
case RNDADDENTROPY:
return rndaddentropy((struct rand_pool_info*)arg);
break;
default: return -EINVAL;
}
return 0;
}
int rndgetentcnt(int* p) {
if (p == NULL) {
return -EFAULT;
}
int retval = copy_to_user(p, &entropy_count, sizeof(int));
if (retval != 0) {
return -EFAULT;
}
return 0;
}
int rndclearpool() {
int retval = capable(CAP_SYS_ADMIN);
if (retval == 0) {
return -EPERM;
}
entropy_count = 0;
return 0;
}
int rndaddentropy(struct rand_pool_info *p) { int retval = capable(CAP_SYS_ADMIN);
if (retval == 0) {
return -EPERM;
} struct rand_pool_info* tmp_p = kmalloc(sizeof(struct rand_pool_info), GFP_KERNEL); if (tmp_p==NULL) {
return -ENOMEM;
} if (copy_from_user(tmp_p, p, sizeof(struct rand_pool_info)) != 0) {
kfree(tmp_p);
return -EFAULT;
} if (tmp_p->entropy_count < 0 || tmp_p->buf_size<=0) { kfree(tmp_p); return -EINVAL; } retval = 0; retval =device_write(NULL,(char*)(p->buf),(size_t) p->buf_size, NULL); if (retval < 0) { kfree(tmp_p); return retval; } entropy_count += p->entropy_count; if (entropy_count > 4096) { entropy_count = 4096; } wake_up_interruptible(&wait_list); kfree(tmp_p); return 0;}/*
* Public Domain SHA-1 implementation by Steve Reid <[email protected]>
*
* Taken from:
* http://download.redis.io/redis-stable/src/sha1.c
*/
typedef struct {
__u32 state[5];
__u32 count[2];
unsigned char buffer[64];
} SHA1_CTX;
#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
|(rol(block->l[i],8)&0x00FF00FF))
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
^block->l[(i+2)&15]^block->l[i&15],1))
/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
/* Hash a single 512-bit block. This is the core of the algorithm. */
void SHA1Transform(__u32 state[5], const unsigned char buffer[64])
{
__u32 a, b, c, d, e;
typedef union {
unsigned char c[64];
__u32 l[16];
} CHAR64LONG16;
CHAR64LONG16 block[1]; /* use array to appear as a pointer */
memcpy(block, buffer, 64);
/* Copy context->state[] to working vars */
a = state[0];
b = state[1];
c = state[2];
d = state[3];
e = state[4];
/* 4 rounds of 20 operations each. Loop unrolled. */
R0(a, b, c, d, e, 0); R0(e, a, b, c, d, 1); R0(d, e, a, b, c, 2); R0(c, d, e, a, b, 3);
R0(b, c, d, e, a, 4); R0(a, b, c, d, e, 5); R0(e, a, b, c, d, 6); R0(d, e, a, b, c, 7);
R0(c, d, e, a, b, 8); R0(b, c, d, e, a, 9); R0(a, b, c, d, e, 10); R0(e, a, b, c, d, 11);
R0(d, e, a, b, c, 12); R0(c, d, e, a, b, 13); R0(b, c, d, e, a, 14); R0(a, b, c, d, e, 15);
R1(e, a, b, c, d, 16); R1(d, e, a, b, c, 17); R1(c, d, e, a, b, 18); R1(b, c, d, e, a, 19);
R2(a, b, c, d, e, 20); R2(e, a, b, c, d, 21); R2(d, e, a, b, c, 22); R2(c, d, e, a, b, 23);
R2(b, c, d, e, a, 24); R2(a, b, c, d, e, 25); R2(e, a, b, c, d, 26); R2(d, e, a, b, c, 27);
R2(c, d, e, a, b, 28); R2(b, c, d, e, a, 29); R2(a, b, c, d, e, 30); R2(e, a, b, c, d, 31);
R2(d, e, a, b, c, 32); R2(c, d, e, a, b, 33); R2(b, c, d, e, a, 34); R2(a, b, c, d, e, 35);
R2(e, a, b, c, d, 36); R2(d, e, a, b, c, 37); R2(c, d, e, a, b, 38); R2(b, c, d, e, a, 39);
R3(a, b, c, d, e, 40); R3(e, a, b, c, d, 41); R3(d, e, a, b, c, 42); R3(c, d, e, a, b, 43);
R3(b, c, d, e, a, 44); R3(a, b, c, d, e, 45); R3(e, a, b, c, d, 46); R3(d, e, a, b, c, 47);
R3(c, d, e, a, b, 48); R3(b, c, d, e, a, 49); R3(a, b, c, d, e, 50); R3(e, a, b, c, d, 51);
R3(d, e, a, b, c, 52); R3(c, d, e, a, b, 53); R3(b, c, d, e, a, 54); R3(a, b, c, d, e, 55);
R3(e, a, b, c, d, 56); R3(d, e, a, b, c, 57); R3(c, d, e, a, b, 58); R3(b, c, d, e, a, 59);
R4(a, b, c, d, e, 60); R4(e, a, b, c, d, 61); R4(d, e, a, b, c, 62); R4(c, d, e, a, b, 63);
R4(b, c, d, e, a, 64); R4(a, b, c, d, e, 65); R4(e, a, b, c, d, 66); R4(d, e, a, b, c, 67);
R4(c, d, e, a, b, 68); R4(b, c, d, e, a, 69); R4(a, b, c, d, e, 70); R4(e, a, b, c, d, 71);
R4(d, e, a, b, c, 72); R4(c, d, e, a, b, 73); R4(b, c, d, e, a, 74); R4(a, b, c, d, e, 75);
R4(e, a, b, c, d, 76); R4(d, e, a, b, c, 77); R4(c, d, e, a, b, 78); R4(b, c, d, e, a, 79);
/* Add the working vars back into context.state[] */
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
state[4] += e;
/* Wipe variables */
a = b = c = d = e = 0;
memset(block, '\0', sizeof(block));
}
/* SHA1Init - Initialize new context */
void SHA1Init(SHA1_CTX* context)
{
/* SHA1 initialization constants */
context->state[0] = 0x67452301;
context->state[1] = 0xEFCDAB89;
context->state[2] = 0x98BADCFE;
context->state[3] = 0x10325476;
context->state[4] = 0xC3D2E1F0;
context->count[0] = context->count[1] = 0;
}
/* Run your data through this. */
void SHA1Update(SHA1_CTX* context, const unsigned char* data, __u32 len)
{
__u32 i, j;
j = context->count[0];
if ((context->count[0] += len << 3) < j)
context->count[1]++;
context->count[1] += (len >> 29);
j = (j >> 3) & 63;
if ((j + len) > 63) {
memcpy(&context->buffer[j], data, (i = 64 - j));
SHA1Transform(context->state, context->buffer);
for (; i + 63 < len; i += 64) {
SHA1Transform(context->state, &data[i]);
}
j = 0;
}
else i = 0;
memcpy(&context->buffer[j], &data[i], len - i);
}
/* Add padding and return the message digest. */
void SHA1Final(unsigned char digest[20], SHA1_CTX* context)
{
unsigned i;
unsigned char finalcount[8];
unsigned char c;
for (i = 0; i < 8; i++) {
finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
>> ((3 - (i & 3)) * 8)) & 255); /* Endian independent */
}
c = 0200;
SHA1Update(context, &c, 1);
while ((context->count[0] & 504) != 448) {
c = 0000;
SHA1Update(context, &c, 1);
}
SHA1Update(context, finalcount, 8); /* Should cause a SHA1Transform() */
for (i = 0; i < 20; i++) {
digest[i] = (unsigned char)
((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
}
/* Wipe variables */
memset(context, '\0', sizeof(*context));
memset(&finalcount, '\0', sizeof(finalcount));
}
void hash_pool(const void *pooldata, void *out)
{
SHA1_CTX ctx;
SHA1Init(&ctx);
SHA1Update(&ctx, pooldata, 512);
SHA1Final(out, &ctx);
}
/*mix*/
static inline __u32 rol32(__u32 word, unsigned int shift)
{
return (word << shift) | (word >> ((-shift) & 31));
}
static unsigned short rotate_bits = 0;
static unsigned short pool_index = 0;
static const __u32 twist_table[8] = {
0x00000000,
0x3b6e20c8,
0x76dc4190,
0x4db26158,
0xedb88320,
0xd6d6a3e8,
0x9b64c2b0,
0xa00ae278
};
void mix(const void *in, size_t nbytes, void *pooldata)
{
__u32 *pool = pooldata;
const char *bytes = in;
while (nbytes--) {
__u32 w = rol32(*bytes++, rotate_bits);
pool_index = (pool_index - 1) & 127;
w ^= pool[pool_index];
w ^= pool[(pool_index + 104) & 127];
w ^= pool[(pool_index + 76) & 127];
w ^= pool[(pool_index + 51) & 127];
w ^= pool[(pool_index + 25) & 127];
w ^= pool[(pool_index + 1) & 127];
pool[pool_index] = (w >> 3) ^ twist_table[w & 7];
rotate_bits = (rotate_bits + (pool_index ? 7 : 14)) & 31;
}
}