diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/Makefile | 2 | ||||
| -rw-r--r-- | drivers/char/frandom.c | 415 |
2 files changed, 1 insertions, 416 deletions
diff --git a/drivers/char/Makefile b/drivers/char/Makefile index 82bebe8f3..7ff1d0d20 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -2,7 +2,7 @@ # Makefile for the kernel character device drivers. # -obj-y += mem.o random.o frandom.o +obj-y += mem.o random.o obj-$(CONFIG_TTY_PRINTK) += ttyprintk.o obj-y += misc.o obj-$(CONFIG_ATARI_DSP56K) += dsp56k.o diff --git a/drivers/char/frandom.c b/drivers/char/frandom.c deleted file mode 100644 index 54b98c53e..000000000 --- a/drivers/char/frandom.c +++ /dev/null @@ -1,415 +0,0 @@ -/* -** frandom.c -** Fast pseudo-random generator -** -** (c) Copyright 2003-2011 Eli Billauer -** http://www.billauer.co.il -** -** This program is free software; you can redistribute it and/or modify -** it under the terms of the GNU General Public License as published by -** the Free Software Foundation; either version 2 of the License, or -** (at your option) any later version. -** -** -*/ - -#include <linux/version.h> -#include <linux/module.h> -#include <linux/moduleparam.h> - -#include <linux/kernel.h> -#include <linux/init.h> -#include <linux/slab.h> -#include <linux/fs.h> -#include <linux/errno.h> -#include <linux/types.h> -#include <linux/random.h> - -#include <asm/uaccess.h> -#include <linux/cdev.h> -#include <linux/err.h> -#include <linux/device.h> - -#define INTERNAL_SEED 0 -#define EXTERNAL_SEED 1 - -#define FRANDOM_MAJOR 235 -#define FRANDOM_MINOR 11 -#define ERANDOM_MINOR 12 - -static struct file_operations frandom_fops; /* Values assigned below */ - -static int erandom_seeded = 0; /* Internal flag */ - -static int frandom_major = FRANDOM_MAJOR; -static int frandom_minor = FRANDOM_MINOR; -static int erandom_minor = ERANDOM_MINOR; -static int frandom_bufsize = 256; -static int frandom_chunklimit = 0; /* =0 means unlimited */ - -static struct cdev frandom_cdev; -static struct cdev erandom_cdev; -static struct class *frandom_class; -struct device *frandom_device; -struct device *erandom_device; - -MODULE_DESCRIPTION("Fast pseudo-random number generator"); -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Eli Billauer"); -module_param(frandom_major, int, 0); -module_param(frandom_minor, int, 0); -module_param(erandom_minor, int, 0); -module_param(frandom_bufsize, int, 0); -module_param(frandom_chunklimit, int, 0); - -MODULE_PARM_DESC(frandom_major,"Major number of /dev/frandom and /dev/erandom"); -MODULE_PARM_DESC(frandom_minor,"Minor number of /dev/frandom"); -MODULE_PARM_DESC(erandom_minor,"Minor number of /dev/erandom"); -MODULE_PARM_DESC(frandom_bufsize,"Internal buffer size in bytes. Default is 256. Must be >= 256"); -MODULE_PARM_DESC(frandom_chunklimit,"Limit for read() blocks size. 0 (default) is unlimited, otherwise must be >= 256"); - -struct frandom_state -{ - struct semaphore sem; /* Semaphore on the state structure */ - - u8 S[256]; /* The state array */ - u8 i; - u8 j; - - char *buf; -}; - -static struct frandom_state *erandom_state; - -static inline void swap_byte(u8 *a, u8 *b) -{ - u8 swapByte; - - swapByte = *a; - *a = *b; - *b = swapByte; -} - -static void init_rand_state(struct frandom_state *state, int seedflag); - -void erandom_get_random_bytes(char *buf, size_t count) -{ - struct frandom_state *state = erandom_state; - int k; - - unsigned int i; - unsigned int j; - u8 *S; - - /* If we fail to get the semaphore, we revert to external random data. - Since semaphore blocking is expected to be very rare, and interrupts - during these rare and very short periods of time even less frequent, - we take the better-safe-than-sorry approach, and fill the buffer - some expensive random data, in case the caller wasn't aware of this - possibility, and expects random data anyhow. - */ - - if (down_interruptible(&state->sem)) { - get_random_bytes(buf, count); - return; - } - - /* We seed erandom as late as possible, hoping that the kernel's main - RNG is already restored in the boot sequence (not critical, but - better. - */ - - if (!erandom_seeded) { - erandom_seeded = 1; - init_rand_state(state, EXTERNAL_SEED); - printk(KERN_INFO "frandom: Seeded global generator now (used by erandom)\n"); - } - - i = state->i; - j = state->j; - S = state->S; - - for (k=0; k<count; k++) { - i = (i + 1) & 0xff; - j = (j + S[i]) & 0xff; - swap_byte(&S[i], &S[j]); - *buf++ = S[(S[i] + S[j]) & 0xff]; - } - - state->i = i; - state->j = j; - - up(&state->sem); -} - -static void init_rand_state(struct frandom_state *state, int seedflag) -{ - unsigned int i, j, k; - u8 *S; - u8 *seed = state->buf; - - if (seedflag == INTERNAL_SEED) - erandom_get_random_bytes(seed, 256); - else - get_random_bytes(seed, 256); - - S = state->S; - for (i=0; i<256; i++) - *S++=i; - - j=0; - S = state->S; - - for (i=0; i<256; i++) { - j = (j + S[i] + *seed++) & 0xff; - swap_byte(&S[i], &S[j]); - } - - /* It's considered good practice to discard the first 256 bytes - generated. So we do it: - */ - - i=0; j=0; - for (k=0; k<256; k++) { - i = (i + 1) & 0xff; - j = (j + S[i]) & 0xff; - swap_byte(&S[i], &S[j]); - } - - state->i = i; /* Save state */ - state->j = j; -} - -static int frandom_open(struct inode *inode, struct file *filp) -{ - - struct frandom_state *state; - - int num = iminor(inode); - - /* This should never happen, now when the minors are regsitered - * explicitly - */ - if ((num != frandom_minor) && (num != erandom_minor)) return -ENODEV; - - state = kmalloc(sizeof(struct frandom_state), GFP_KERNEL); - if (!state) - return -ENOMEM; - - state->buf = kmalloc(frandom_bufsize, GFP_KERNEL); - if (!state->buf) { - kfree(state); - return -ENOMEM; - } - - sema_init(&state->sem, 1); /* Init semaphore as a mutex */ - - if (num == frandom_minor) - init_rand_state(state, EXTERNAL_SEED); - else - init_rand_state(state, INTERNAL_SEED); - - filp->private_data = state; - - return 0; /* Success */ -} - -static int frandom_release(struct inode *inode, struct file *filp) -{ - - struct frandom_state *state = filp->private_data; - - kfree(state->buf); - kfree(state); - - return 0; -} - -static ssize_t frandom_read(struct file *filp, char *buf, size_t count, - loff_t *f_pos) -{ - struct frandom_state *state = filp->private_data; - ssize_t ret; - int dobytes, k; - char *localbuf; - - unsigned int i; - unsigned int j; - u8 *S; - - if (down_interruptible(&state->sem)) - return -ERESTARTSYS; - - if ((frandom_chunklimit > 0) && (count > frandom_chunklimit)) - count = frandom_chunklimit; - - ret = count; /* It's either everything or an error... */ - - i = state->i; - j = state->j; - S = state->S; - - while (count) { - if (count > frandom_bufsize) - dobytes = frandom_bufsize; - else - dobytes = count; - - localbuf = state->buf; - - for (k=0; k<dobytes; k++) { - i = (i + 1) & 0xff; - j = (j + S[i]) & 0xff; - swap_byte(&S[i], &S[j]); - *localbuf++ = S[(S[i] + S[j]) & 0xff]; - } - - if (copy_to_user(buf, state->buf, dobytes)) { - ret = -EFAULT; - goto out; - } - - buf += dobytes; - count -= dobytes; - } - - out: - state->i = i; - state->j = j; - - up(&state->sem); - return ret; -} - -static struct file_operations frandom_fops = { - read: frandom_read, - open: frandom_open, - release: frandom_release, -}; - -static void frandom_cleanup_module(void) { - unregister_chrdev_region(MKDEV(frandom_major, erandom_minor), 1); - cdev_del(&erandom_cdev); - device_destroy(frandom_class, MKDEV(frandom_major, erandom_minor)); - - unregister_chrdev_region(MKDEV(frandom_major, frandom_minor), 1); - cdev_del(&frandom_cdev); - device_destroy(frandom_class, MKDEV(frandom_major, frandom_minor)); - class_destroy(frandom_class); - - kfree(erandom_state->buf); - kfree(erandom_state); -} - - -static int frandom_init_module(void) -{ - int result; - - /* The buffer size MUST be at least 256 bytes, because we assume that - minimal length in init_rand_state(). - */ - if (frandom_bufsize < 256) { - printk(KERN_ERR "frandom: Refused to load because frandom_bufsize=%d < 256\n",frandom_bufsize); - return -EINVAL; - } - if ((frandom_chunklimit != 0) && (frandom_chunklimit < 256)) { - printk(KERN_ERR "frandom: Refused to load because frandom_chunklimit=%d < 256 and != 0\n",frandom_chunklimit); - return -EINVAL; - } - - erandom_state = kmalloc(sizeof(struct frandom_state), GFP_KERNEL); - if (!erandom_state) - return -ENOMEM; - - /* This specific buffer is only used for seeding, so we need - 256 bytes exactly */ - erandom_state->buf = kmalloc(256, GFP_KERNEL); - if (!erandom_state->buf) { - kfree(erandom_state); - return -ENOMEM; - } - - sema_init(&erandom_state->sem, 1); /* Init semaphore as a mutex */ - - erandom_seeded = 0; - - frandom_class = class_create(THIS_MODULE, "fastrng"); - if (IS_ERR(frandom_class)) { - result = PTR_ERR(frandom_class); - printk(KERN_WARNING "frandom: Failed to register class fastrng\n"); - goto error0; - } - - /* - * Register your major, and accept a dynamic number. This is the - * first thing to do, in order to avoid releasing other module's - * fops in frandom_cleanup_module() - */ - - cdev_init(&frandom_cdev, &frandom_fops); - frandom_cdev.owner = THIS_MODULE; - result = cdev_add(&frandom_cdev, MKDEV(frandom_major, frandom_minor), 1); - if (result) { - printk(KERN_WARNING "frandom: Failed to add cdev for /dev/frandom\n"); - goto error1; - } - - result = register_chrdev_region(MKDEV(frandom_major, frandom_minor), 1, "/dev/frandom"); - if (result < 0) { - printk(KERN_WARNING "frandom: can't get major/minor %d/%d\n", frandom_major, frandom_minor); - goto error2; - } - - frandom_device = device_create(frandom_class, NULL, MKDEV(frandom_major, frandom_minor), NULL, "frandom"); - - if (IS_ERR(frandom_device)) { - printk(KERN_WARNING "frandom: Failed to create frandom device\n"); - goto error3; - } - - cdev_init(&erandom_cdev, &frandom_fops); - erandom_cdev.owner = THIS_MODULE; - result = cdev_add(&erandom_cdev, MKDEV(frandom_major, erandom_minor), 1); - if (result) { - printk(KERN_WARNING "frandom: Failed to add cdev for /dev/erandom\n"); - goto error4; - } - - result = register_chrdev_region(MKDEV(frandom_major, erandom_minor), 1, "/dev/erandom"); - if (result < 0) { - printk(KERN_WARNING "frandom: can't get major/minor %d/%d\n", frandom_major, erandom_minor); - goto error5; - } - - erandom_device = device_create(frandom_class, NULL, MKDEV(frandom_major, erandom_minor), NULL, "erandom"); - - if (IS_ERR(erandom_device)) { - printk(KERN_WARNING "frandom: Failed to create erandom device\n"); - goto error6; - } - return 0; /* succeed */ - - error6: - unregister_chrdev_region(MKDEV(frandom_major, erandom_minor), 1); - error5: - cdev_del(&erandom_cdev); - error4: - device_destroy(frandom_class, MKDEV(frandom_major, frandom_minor)); - error3: - unregister_chrdev_region(MKDEV(frandom_major, frandom_minor), 1); - error2: - cdev_del(&frandom_cdev); - error1: - class_destroy(frandom_class); - error0: - kfree(erandom_state->buf); - kfree(erandom_state); - - return result; -} - -module_init(frandom_init_module); -module_exit(frandom_cleanup_module); - -EXPORT_SYMBOL(erandom_get_random_bytes); |