hi all:
I built a module for calculate the SHA-1. The code is:
##################
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
MODULE_LICENSE("Dual BSD/GPL");
#define SHA1_LENGTH 20
static int hello_init(void)
{
/*
*/
struct scatterlist sg;
struct hash_desc desc;
//way 1
/*
char *plaintext = "c";
size_t len = strlen(plaintext);
*/
//way 2
/*
char *plaintext = kmalloc(sizeof(char), GFP_KERNEL);
plaintext = "c";
size_t len = 1;
*/
// way 3.
/*
char plaintext[1] = {'c'};
size_t len = 1;
*/
// way 4.
/*
char *plaintext = (char *)__get_free_page(GFP_KERNEL);
memcpy(plaintext, "c", 1);
size_t len = 1;
*/
int rc = 0;
int i;
char hashtext[SHA1_LENGTH];
memset(hashtext, 0x00, SHA1_LENGTH);
printk(KERN_INFO "sha1: %s\n", __FUNCTION__);
sg_init_one(&sg, plaintext, len);
desc.tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
desc.flags = 0;
rc = crypto_hash_init(&desc);
if (rc) {
printk(KERN_ERR "%s: Error initializing crypto hash; rc = [%d]\n", __func__, rc);
goto out;
}
rc = crypto_hash_update(&desc, &sg, len);
if (rc) {
printk(KERN_ERR "%s: Error updating crypto hash; rc = [%d]\n", __func__, rc);
goto out;
}
rc = crypto_hash_final(&desc, hashtext);
if (rc) {
printk(KERN_ERR "%s: Error finalizing crypto hash; rc = [%d]\n", __func__, rc);
goto out;
}
crypto_free_hash(desc.tfm);
for (i = 0; i < 20; i++) {
printk(KERN_INFO "%02x-%d\n", hashtext[i]&0xff, i);
}
out:
printk(KERN_INFO "end\n");
return rc;
}
static void hello_exit(void)
{
printk(KERN_ALERT "Goodbye, cruel world\n");
}
module_init(hello_init);
module_exit(hello_exit);
##################
I can just get the right result by way 3 and 4, In way 1 and 2 , I get the wrong result,
I check the result by link: http://www.xorbin.com/tools/sha1-hash-calculator .
Please tell me why? Thank you.
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