Commit e3c4abbf authored by Dmitry Kasatkin's avatar Dmitry Kasatkin Committed by Mimi Zohar
Browse files

integrity: define a new function integrity_read_file() 



This patch defines a new function called integrity_read_file()
to read file from the kernel into a buffer. Subsequent patches
will read a file containing the public keys and load them onto
the IMA keyring.

This patch moves and renames ima_kernel_read(), the non-security
checking version of kernel_read(), to integrity_kernel_read().

Changes in v3:
* Patch descriptions improved (Mimi)
* Add missing cast (kbuild test robot)

Changes in v2:
* configuration option removed
* function declared as '__init'

Signed-off-by: default avatarDmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
parent c2426d2a

security/integrity/iint.c

+78 −0
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ 
#include <linux/module.h>

#include <linux/spinlock.h>

#include <linux/rbtree.h>

#include <linux/file.h>

#include <linux/uaccess.h>

#include "integrity.h"



static struct rb_root integrity_iint_tree = RB_ROOT;
@@ -167,3 +169,79 @@ static int __init integrity_iintcache_init(void) 
	return 0;

}

security_initcall(integrity_iintcache_init);





/*

 * integrity_kernel_read - read data from the file

 *

 * This is a function for reading file content instead of kernel_read().

 * It does not perform locking checks to ensure it cannot be blocked.

 * It does not perform security checks because it is irrelevant for IMA.

 *

 */

int integrity_kernel_read(struct file *file, loff_t offset,

			  char *addr, unsigned long count)

{

	mm_segment_t old_fs;

	char __user *buf = (char __user *)addr;

	ssize_t ret = -EINVAL;



	if (!(file->f_mode & FMODE_READ))

		return -EBADF;



	old_fs = get_fs();

	set_fs(get_ds());

	if (file->f_op->read)

		ret = file->f_op->read(file, buf, count, &offset);

	else if (file->f_op->aio_read)

		ret = do_sync_read(file, buf, count, &offset);

	else if (file->f_op->read_iter)

		ret = new_sync_read(file, buf, count, &offset);

	set_fs(old_fs);

	return ret;

}



/*

 * integrity_read_file - read entire file content into the buffer

 *

 * This is function opens a file, allocates the buffer of required

 * size, read entire file content to the buffer and closes the file

 *

 * It is used only by init code.

 *

 */

int __init integrity_read_file(const char *path, char **data)

{

	struct file *file;

	loff_t size;

	char *buf;

	int rc = -EINVAL;



	file = filp_open(path, O_RDONLY, 0);

	if (IS_ERR(file)) {

		rc = PTR_ERR(file);

		pr_err("Unable to open file: %s (%d)", path, rc);

		return rc;

	}



	size = i_size_read(file_inode(file));

	if (size <= 0)

		goto out;



	buf = kmalloc(size, GFP_KERNEL);

	if (!buf) {

		rc = -ENOMEM;

		goto out;

	}



	rc = integrity_kernel_read(file, 0, buf, size);

	if (rc < 0)

		kfree(buf);

	else if (rc != size)

		rc = -EIO;

	else

		*data = buf;

out:

	fput(file);

	return rc;

}

security/integrity/ima/ima_crypto.c

+3 −32
Original line number Diff line number Diff line
@@ -67,36 +67,6 @@ MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size"); 
static struct crypto_shash *ima_shash_tfm;

static struct crypto_ahash *ima_ahash_tfm;



/**

 * ima_kernel_read - read file content

 *

 * This is a function for reading file content instead of kernel_read().

 * It does not perform locking checks to ensure it cannot be blocked.

 * It does not perform security checks because it is irrelevant for IMA.

 *

 */

static int ima_kernel_read(struct file *file, loff_t offset,

			   char *addr, unsigned long count)

{

	mm_segment_t old_fs;

	char __user *buf = addr;

	ssize_t ret = -EINVAL;



	if (!(file->f_mode & FMODE_READ))

		return -EBADF;



	old_fs = get_fs();

	set_fs(get_ds());

	if (file->f_op->read)

		ret = file->f_op->read(file, buf, count, &offset);

	else if (file->f_op->aio_read)

		ret = do_sync_read(file, buf, count, &offset);

	else if (file->f_op->read_iter)

		ret = new_sync_read(file, buf, count, &offset);

	set_fs(old_fs);

	return ret;

}



int __init ima_init_crypto(void)

{

	long rc;
@@ -324,7 +294,8 @@ static int ima_calc_file_hash_atfm(struct file *file, 
		}

		/* read buffer */

		rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);

		rc = ima_kernel_read(file, offset, rbuf[active], rbuf_len);

		rc = integrity_kernel_read(file, offset, rbuf[active],

					   rbuf_len);

		if (rc != rbuf_len)

			goto out3;
@@ -417,7 +388,7 @@ static int ima_calc_file_hash_tfm(struct file *file, 
	while (offset < i_size) {

		int rbuf_len;



		rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE);

		rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);

		if (rbuf_len < 0) {

			rc = rbuf_len;

			break;

security/integrity/integrity.h

+4 −0
Original line number Diff line number Diff line
@@ -119,6 +119,10 @@ struct integrity_iint_cache { 
 */

struct integrity_iint_cache *integrity_iint_find(struct inode *inode);



int integrity_kernel_read(struct file *file, loff_t offset,

			  char *addr, unsigned long count);

int __init integrity_read_file(const char *path, char **data);



#define INTEGRITY_KEYRING_EVM		0

#define INTEGRITY_KEYRING_MODULE	1

#define INTEGRITY_KEYRING_IMA		2

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