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Commit b804defe authored by Mimi Zohar's avatar Mimi Zohar
Browse files

kexec: replace call to copy_file_from_fd() with kernel version 



Replace copy_file_from_fd() with kernel_read_file_from_fd().

Two new identifiers named READING_KEXEC_IMAGE and READING_KEXEC_INITRAMFS
are defined for measuring, appraising or auditing the kexec image and
initramfs.

Changelog v3:
- return -EBADF, not -ENOEXEC
- identifier change
- split patch, moving copy_file_from_fd() to a separate patch
- split patch, moving IMA changes to a separate patch
v0:
- use kstat file size type loff_t, not size_t
- Calculate the file hash from the in memory buffer - Dave Young

Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Acked-by: default avatarDave Young <dyoung@redhat.com>
parent c6af8efe

include/linux/fs.h

+2 −0
Original line number Diff line number Diff line
@@ -2579,6 +2579,8 @@ extern int do_pipe_flags(int *, int); 
enum kernel_read_file_id {

	READING_FIRMWARE = 1,

	READING_MODULE,

	READING_KEXEC_IMAGE,

	READING_KEXEC_INITRAMFS,

	READING_MAX_ID

};

kernel/kexec_file.c

+9 −64
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/kexec.h>

#include <linux/mutex.h>

#include <linux/list.h>

#include <linux/fs.h>

#include <crypto/hash.h>

#include <crypto/sha.h>

#include <linux/syscalls.h>
@@ -33,65 +34,6 @@ size_t __weak kexec_purgatory_size = 0; 


static int kexec_calculate_store_digests(struct kimage *image);



static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)

{

	struct fd f = fdget(fd);

	int ret;

	struct kstat stat;

	loff_t pos;

	ssize_t bytes = 0;



	if (!f.file)

		return -EBADF;



	ret = vfs_getattr(&f.file->f_path, &stat);

	if (ret)

		goto out;



	if (stat.size > INT_MAX) {

		ret = -EFBIG;

		goto out;

	}



	/* Don't hand 0 to vmalloc, it whines. */

	if (stat.size == 0) {

		ret = -EINVAL;

		goto out;

	}



	*buf = vmalloc(stat.size);

	if (!*buf) {

		ret = -ENOMEM;

		goto out;

	}



	pos = 0;

	while (pos < stat.size) {

		bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,

				    stat.size - pos);

		if (bytes < 0) {

			vfree(*buf);

			ret = bytes;

			goto out;

		}



		if (bytes == 0)

			break;

		pos += bytes;

	}



	if (pos != stat.size) {

		ret = -EBADF;

		vfree(*buf);

		goto out;

	}



	*buf_len = pos;

out:

	fdput(f);

	return ret;

}



/* Architectures can provide this probe function */

int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,

					 unsigned long buf_len)
@@ -182,16 +124,17 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, 
{

	int ret = 0;

	void *ldata;

	loff_t size;



	ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,

				&image->kernel_buf_len);

	ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,

				       &size, INT_MAX, READING_KEXEC_IMAGE);

	if (ret)

		return ret;

	image->kernel_buf_len = size;



	/* Call arch image probe handlers */

	ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,

					    image->kernel_buf_len);



	if (ret)

		goto out;
@@ -206,10 +149,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, 
#endif

	/* It is possible that there no initramfs is being loaded */

	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {

		ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,

					&image->initrd_buf_len);

		ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,

					       &size, INT_MAX,

					       READING_KEXEC_INITRAMFS);

		if (ret)

			goto out;

		image->initrd_buf_len = size;

	}



	if (cmdline_len) {