* SHA-1 hash calculate in Kernel.
@ 2015-08-28 7:36 lx
2015-08-28 8:27 ` Bjørn Mork
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: lx @ 2015-08-28 7:36 UTC (permalink / raw)
To: kernelnewbies
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)
{
/*
* http://lxr.oss.org.cn/source/fs/ecryptfs/crypto.c?v=2.6.30
*/
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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^ permalink raw reply [flat|nested] 5+ messages in thread* SHA-1 hash calculate in Kernel.
2015-08-28 7:36 SHA-1 hash calculate in Kernel lx
@ 2015-08-28 8:27 ` Bjørn Mork
2015-08-28 17:04 ` Jeff Haran
2015-08-29 11:49 ` Bernd Petrovitsch
2 siblings, 0 replies; 5+ messages in thread
From: Bjørn Mork @ 2015-08-28 8:27 UTC (permalink / raw)
To: kernelnewbies
lx <lxlenovostar@gmail.com> writes:
> 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)
> {
> /*
> * http://lxr.oss.org.cn/source/fs/ecryptfs/crypto.c?v=2.6.30
> */
> 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 suggest you add something like this:
printk(KERN_INFO "plaintext='%c', len=%zu, valid=%s\n", *plaintext, len, virt_addr_valid(plaintext) ? "true" : "false");
and then go figure out the relationship between that and the correct
result :)
Bj?rn
^ permalink raw reply [flat|nested] 5+ messages in thread* SHA-1 hash calculate in Kernel.
2015-08-28 7:36 SHA-1 hash calculate in Kernel lx
2015-08-28 8:27 ` Bjørn Mork
@ 2015-08-28 17:04 ` Jeff Haran
2015-08-29 11:49 ` Bernd Petrovitsch
2 siblings, 0 replies; 5+ messages in thread
From: Jeff Haran @ 2015-08-28 17:04 UTC (permalink / raw)
To: kernelnewbies
From: kernelnewbies-bounces@kernelnewbies.org [mailto:kernelnewbies-bounces at kernelnewbies.org] On Behalf Of lx
Sent: Friday, August 28, 2015 12:36 AM
To: kernelnewbies
Subject: SHA-1 hash calculate in Kernel.
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)
{
/*
* http://lxr.oss.org.cn/source/fs/ecryptfs/crypto.c?v=2.6.30
*/
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.
I don?t know why the crypto function isn?t generating the right result in the first two cases. Just pointing out that way 1 and way 2 are identical except that way 2 leaks the memory that was kmalloc()?ed. This in way 2 is a pointer assignment, not a buffer copy:
plaintext = "c";
The big difference it seems between ways 1 and 2 and ways 3 and 4 is in the former, plaintext points to a string constant that I believe is going to be read only whereas in the latter, plaintext points to r/w memory. Maybe the crypto functions need r/w access?
Jeff Haran
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^ permalink raw reply [flat|nested] 5+ messages in thread* SHA-1 hash calculate in Kernel.
2015-08-28 7:36 SHA-1 hash calculate in Kernel lx
2015-08-28 8:27 ` Bjørn Mork
2015-08-28 17:04 ` Jeff Haran
@ 2015-08-29 11:49 ` Bernd Petrovitsch
2015-10-22 8:24 ` lx
2 siblings, 1 reply; 5+ messages in thread
From: Bernd Petrovitsch @ 2015-08-29 11:49 UTC (permalink / raw)
To: kernelnewbies
On Fre, 2015-08-28 at 15:36 +0800, lx wrote:
[...]
> //way 2
> /*
> char *plaintext = kmalloc(sizeof(char), GFP_KERNEL);
> plaintext = "c";
I don't think that this line doesn't give any warning ...
Kind regards,
Bernd
--
"I dislike type abstraction if it has no real reason. And saving
on typing is not a good reason - if your typing speed is the main
issue when you're coding, you're doing something seriously wrong."
- Linus Torvalds
^ permalink raw reply [flat|nested] 5+ messages in thread* SHA-1 hash calculate in Kernel.
2015-08-29 11:49 ` Bernd Petrovitsch
@ 2015-10-22 8:24 ` lx
0 siblings, 0 replies; 5+ messages in thread
From: lx @ 2015-10-22 8:24 UTC (permalink / raw)
To: kernelnewbies
hi all:
I finally implement it by learning form the function of tcp md5
checksum. This is the relative kernel source
<http://lxr.oss.org.cn/source/net/ipv4/tcp.c?v=2.6.30#L2667>. The SHA-1
implement is here
<https://github.com/lxlenovostar/kernel_test/blob/master/model/kernel_hash/sha.c>.But
I still have a question about __virt_addr_valid.
##############################
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <linux/mm.h>
#define SHA1_LENGTH 20
static inline int phys_addr_valid(resource_size_t addr)
{
#ifdef CONFIG_PHYS_ADDR_T_64BIT
return !(addr >> boot_cpu_data.x86_phys_bits);
#else
return 1;
#endif
}
bool __virt_addr_valid(unsigned long x)
{
unsigned long old_x;
old_x = x;
//The kernel text is mapped into the region starting
from__START_KERNEL_MAP
if (x >= __START_KERNEL_map) {
if (x >= MODULES_VADDR && x <= MODULES_END) {
printk(KERN_INFO "right here");
}
x -= __START_KERNEL_map;
if (x >= KERNEL_IMAGE_SIZE) {
printk(KERN_INFO "error1");
return false;
}
x += phys_base;
} else {
if (x < PAGE_OFFSET) {
printk(KERN_INFO "error2");
return false;
}
x -= PAGE_OFFSET;
if (!phys_addr_valid(x)) {
printk(KERN_INFO "error3");
return false;
}
}
return pfn_valid(x >> PAGE_SHIFT);
}
static int minit(void)
{
/*
* http://lxr.oss.org.cn/source/fs/ecryptfs/crypto.c?v=2.6.30
*/
struct scatterlist sg;
struct hash_desc desc;
int rc = 0;
int i;
char hashtext[SHA1_LENGTH];
char *plaintext = NULL;
printk(KERN_INFO "valid=%s\n", virt_addr_valid(plaintext) ? "true" :
"false");
plaintext = "c";
printk(KERN_INFO "valid=%s\n", virt_addr_valid(plaintext) ? "true" :
"false");
size_t len = strlen(plaintext);
sg_init_one(&sg, (u8 *)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:
return rc;
}
static void mexit(void)
{
printk("Exit %s.\n", THIS_MODULE->name);
}
##############################
I make and insmod it. the log is:
##############################
[root at localhost sha]# dmesg -c
error2
valid=false
right here
error1
valid=false
##############################
I think plaintext is between MODULES_VADDR and MODULES_END, So why the
address in
MODULES not a valid virtual address?
Thank you.
2015-08-29 19:49 GMT+08:00 Bernd Petrovitsch <bernd@petrovitsch.priv.at>:
> On Fre, 2015-08-28 at 15:36 +0800, lx wrote:
> [...]
> > //way 2
> > /*
> > char *plaintext = kmalloc(sizeof(char), GFP_KERNEL);
> > plaintext = "c";
>
> I don't think that this line doesn't give any warning ...
>
> Kind regards,
> Bernd
> --
> "I dislike type abstraction if it has no real reason. And saving
> on typing is not a good reason - if your typing speed is the main
> issue when you're coding, you're doing something seriously wrong."
> - Linus Torvalds
>
>
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2015-08-28 7:36 SHA-1 hash calculate in Kernel lx
2015-08-28 8:27 ` Bjørn Mork
2015-08-28 17:04 ` Jeff Haran
2015-08-29 11:49 ` Bernd Petrovitsch
2015-10-22 8:24 ` lx
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