Date:   Thu, 28 Jun 2018 21:50:17 +0800
From:   Yu Chen <yu.c.chen@...el.com>
To:     joeyli <jlee@...e.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        Borislav Petkov <bp@...en8.de>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH 2/3][RFC] PM / Hibernate: Encrypt the snapshot pages
 before submitted to the block device

Hi,
On Thu, Jun 28, 2018 at 09:07:20PM +0800, joeyli wrote:
> Hi Chen Yu,
> 
> On Wed, Jun 20, 2018 at 05:40:32PM +0800, Chen Yu wrote:
> > Use the helper functions introduced previously to encrypt
> > the page data before they are submitted to the block device.
> > Besides, for the case of hibernation compression, the data
> > are firstly compressed and then encrypted, and vice versa
> > for the resume process.
> >
> 
> I want to suggest my solution that it direct signs/encrypts the
> memory snapshot image. This solution is already shipped with
> SLE12 a couple of years:
> 
> https://github.com/joeyli/linux-s4sign/commits/s4sign-hmac-encrypted-key-v0.2-v4.17-rc3
> 
I did not see image page encryption in above link, if I understand
correctly, your code focus on signation and encrypt the hidden data,
but not target for the whole snapshot data.
> The above patches still need to clean up. I am working on some
> other bugs, but I can clean up and send out it ASAP.
> 
> The advantage of this solution is that it produces a signed and
> encrypted image. Not just for writing to block device by kernel,
> it also can provide a signed/encrypted image to user space. User
> space can store the encrypted image to anywhere.
> 
> I am OK for your user space key generator because I didn't have
> similar solution yet. I am working on the EFI master key and also
> want to adapt hibernation to keyring. I will continue the works.
> 
The user space tool can easily add the keyring support besides
ioctl if needed.

Best,
Yu
> Thanks a lot!
> Joey Lee
>  
> > Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > Cc: Pavel Machek <pavel@....cz>
> > Cc: Len Brown <len.brown@...el.com>
> > Cc: Borislav Petkov <bp@...en8.de>
> > Cc: "Lee, Chun-Yi" <jlee@...e.com>
> > Cc: linux-pm@...r.kernel.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Chen Yu <yu.c.chen@...el.com>
> > ---
> >  kernel/power/power.h |   1 +
> >  kernel/power/swap.c  | 215 ++++++++++++++++++++++++++++++++++++++++++++++++---
> >  2 files changed, 205 insertions(+), 11 deletions(-)
> > 
> > diff --git a/kernel/power/power.h b/kernel/power/power.h
> > index 660aac3..637695c 100644
> > --- a/kernel/power/power.h
> > +++ b/kernel/power/power.h
> > @@ -207,6 +207,7 @@ extern int swsusp_swap_in_use(void);
> >  #define SF_PLATFORM_MODE	1
> >  #define SF_NOCOMPRESS_MODE	2
> >  #define SF_CRC32_MODE	        4
> > +#define SF_ENCRYPT_MODE		8
> >  
> >  /* kernel/power/hibernate.c */
> >  extern int swsusp_check(void);
> > diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> > index c2bcf97..2b6b3d0 100644
> > --- a/kernel/power/swap.c
> > +++ b/kernel/power/swap.c
> > @@ -102,14 +102,16 @@ struct swap_map_handle {
> >  	unsigned int k;
> >  	unsigned long reqd_free_pages;
> >  	u32 crc32;
> > +	bool crypto;
> >  };
> >  
> >  struct swsusp_header {
> >  	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
> > -	              sizeof(u32)];
> > +			sizeof(u32) - HIBERNATE_SALT_BYTES];
> >  	u32	crc32;
> >  	sector_t image;
> >  	unsigned int flags;	/* Flags to pass to the "boot" kernel */
> > +	char salt[HIBERNATE_SALT_BYTES];
> >  	char	orig_sig[10];
> >  	char	sig[10];
> >  } __packed;
> > @@ -127,6 +129,53 @@ struct swsusp_extent {
> >  	unsigned long end;
> >  };
> >  
> > +/* For encryption/decryption. */
> > +static struct hibernation_crypto *hibernation_crypto_ops;
> > +
> > +void set_hibernation_ops(struct hibernation_crypto *ops)
> > +{
> > +	hibernation_crypto_ops = ops;
> > +}
> > +EXPORT_SYMBOL_GPL(set_hibernation_ops);
> > +
> > +static int crypto_data(const char *inbuf,
> > +			    int inlen,
> > +			    char *outbuf,
> > +			    int outlen,
> > +			    bool encrypt,
> > +			    int page_idx)
> > +{
> > +	if (hibernation_crypto_ops &&
> > +	    hibernation_crypto_ops->crypto_data)
> > +		return hibernation_crypto_ops->crypto_data(inbuf,
> > +			inlen, outbuf, outlen, encrypt, page_idx);
> > +	else
> > +		return -EINVAL;
> > +}
> > +
> > +static void crypto_save(void *outbuf)
> > +{
> > +	if (hibernation_crypto_ops &&
> > +	    hibernation_crypto_ops->save)
> > +		hibernation_crypto_ops->save(outbuf);
> > +}
> > +
> > +static void crypto_restore(void *inbuf)
> > +{
> > +	if (hibernation_crypto_ops &&
> > +	    hibernation_crypto_ops->restore)
> > +		hibernation_crypto_ops->restore(inbuf);
> > +}
> > +
> > +static int crypto_init(bool suspend)
> > +{
> > +	if (hibernation_crypto_ops &&
> > +	    hibernation_crypto_ops->init)
> > +		return hibernation_crypto_ops->init(suspend);
> > +	else
> > +		return -EINVAL;
> > +}
> > +
> >  static struct rb_root swsusp_extents = RB_ROOT;
> >  
> >  static int swsusp_extents_insert(unsigned long swap_offset)
> > @@ -318,6 +367,10 @@ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
> >  		swsusp_header->flags = flags;
> >  		if (flags & SF_CRC32_MODE)
> >  			swsusp_header->crc32 = handle->crc32;
> > +		if (handle->crypto) {
> > +			swsusp_header->flags |= SF_ENCRYPT_MODE;
> > +			crypto_save((void *)swsusp_header->salt);
> > +		}
> >  		error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
> >  				      swsusp_resume_block, swsusp_header, NULL);
> >  	} else {
> > @@ -535,11 +588,12 @@ static int save_image(struct swap_map_handle *handle,
> >  {
> >  	unsigned int m;
> >  	int ret;
> > -	int nr_pages;
> > +	int nr_pages, crypto_page_idx;
> >  	int err2;
> >  	struct hib_bio_batch hb;
> >  	ktime_t start;
> >  	ktime_t stop;
> > +	void *tmp = NULL, *crypt_buf = NULL;
> >  
> >  	hib_init_batch(&hb);
> >  
> > @@ -549,12 +603,33 @@ static int save_image(struct swap_map_handle *handle,
> >  	if (!m)
> >  		m = 1;
> >  	nr_pages = 0;
> > +	crypto_page_idx = 0;
> > +	if (handle->crypto) {
> > +		crypt_buf = (void *)get_zeroed_page(GFP_KERNEL);
> > +		if (!crypt_buf)
> > +			return -ENOMEM;
> > +	}
> > +
> >  	start = ktime_get();
> >  	while (1) {
> >  		ret = snapshot_read_next(snapshot);
> >  		if (ret <= 0)
> >  			break;
> > -		ret = swap_write_page(handle, data_of(*snapshot), &hb);
> > +		tmp = data_of(*snapshot);
> > +		if (handle->crypto) {
> > +			/* Encryption before submit_io.*/
> > +			ret = crypto_data(data_of(*snapshot),
> > +					  PAGE_SIZE,
> > +					  crypt_buf,
> > +					  PAGE_SIZE,
> > +					  true,
> > +					  crypto_page_idx);
> > +			if (ret)
> > +				goto out;
> > +			crypto_page_idx++;
> > +			tmp = crypt_buf;
> > +		}
> > +		ret = swap_write_page(handle, tmp, &hb);
> >  		if (ret)
> >  			break;
> >  		if (!(nr_pages % m))
> > @@ -569,6 +644,9 @@ static int save_image(struct swap_map_handle *handle,
> >  	if (!ret)
> >  		pr_info("Image saving done\n");
> >  	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
> > + out:
> > +	if (crypt_buf)
> > +		free_page((unsigned long)crypt_buf);
> >  	return ret;
> >  }
> >  
> > @@ -671,7 +749,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
> >  {
> >  	unsigned int m;
> >  	int ret = 0;
> > -	int nr_pages;
> > +	int nr_pages, crypto_page_idx;
> >  	int err2;
> >  	struct hib_bio_batch hb;
> >  	ktime_t start;
> > @@ -767,6 +845,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
> >  	if (!m)
> >  		m = 1;
> >  	nr_pages = 0;
> > +	crypto_page_idx = 0;
> >  	start = ktime_get();
> >  	for (;;) {
> >  		for (thr = 0; thr < nr_threads; thr++) {
> > @@ -835,7 +914,25 @@ static int save_image_lzo(struct swap_map_handle *handle,
> >  			for (off = 0;
> >  			     off < LZO_HEADER + data[thr].cmp_len;
> >  			     off += PAGE_SIZE) {
> > -				memcpy(page, data[thr].cmp + off, PAGE_SIZE);
> > +				if (handle->crypto) {
> > +					/*
> > +					 * Encrypt the compressed data
> > +					 * before we write them to the
> > +					 * block device.
> > +					 */
> > +					ret = crypto_data(data[thr].cmp + off,
> > +							  PAGE_SIZE,
> > +							  page,
> > +							  PAGE_SIZE,
> > +							  true,
> > +							  crypto_page_idx);
> > +					if (ret)
> > +						goto out_finish;
> > +					crypto_page_idx++;
> > +				} else {
> > +					memcpy(page, data[thr].cmp + off,
> > +						PAGE_SIZE);
> > +				}
> >  
> >  				ret = swap_write_page(handle, page, &hb);
> >  				if (ret)
> > @@ -909,6 +1006,7 @@ int swsusp_write(unsigned int flags)
> >  	int error;
> >  
> >  	pages = snapshot_get_image_size();
> > +	memset(&handle, 0, sizeof(struct swap_map_handle));
> >  	error = get_swap_writer(&handle);
> >  	if (error) {
> >  		pr_err("Cannot get swap writer\n");
> > @@ -922,6 +1020,9 @@ int swsusp_write(unsigned int flags)
> >  		}
> >  	}
> >  	memset(&snapshot, 0, sizeof(struct snapshot_handle));
> > +	if (!crypto_init(true))
> > +		/* The image needs to be encrypted. */
> > +		handle.crypto = true;
> >  	error = snapshot_read_next(&snapshot);
> >  	if (error < PAGE_SIZE) {
> >  		if (error >= 0)
> > @@ -1059,7 +1160,8 @@ static int load_image(struct swap_map_handle *handle,
> >  	ktime_t stop;
> >  	struct hib_bio_batch hb;
> >  	int err2;
> > -	unsigned nr_pages;
> > +	unsigned nr_pages, crypto_page_idx;
> > +	void *crypt_buf = NULL;
> >  
> >  	hib_init_batch(&hb);
> >  
> > @@ -1069,18 +1171,42 @@ static int load_image(struct swap_map_handle *handle,
> >  	if (!m)
> >  		m = 1;
> >  	nr_pages = 0;
> > +	crypto_page_idx = 0;
> > +	if (handle->crypto) {
> > +		crypt_buf = (void *)get_zeroed_page(GFP_KERNEL);
> > +		if (!crypt_buf)
> > +			return -ENOMEM;
> > +	}
> >  	start = ktime_get();
> >  	for ( ; ; ) {
> >  		ret = snapshot_write_next(snapshot);
> >  		if (ret <= 0)
> >  			break;
> > -		ret = swap_read_page(handle, data_of(*snapshot), &hb);
> > +		if (handle->crypto)
> > +			ret = swap_read_page(handle, crypt_buf, &hb);
> > +		else
> > +			ret = swap_read_page(handle, data_of(*snapshot), &hb);
> >  		if (ret)
> >  			break;
> >  		if (snapshot->sync_read)
> >  			ret = hib_wait_io(&hb);
> >  		if (ret)
> >  			break;
> > +		if (handle->crypto) {
> > +			/*
> > +			 * Need a decryption for the
> > +			 * data read from the block
> > +			 * device.
> > +			 */
> > +			ret = crypto_data(crypt_buf, PAGE_SIZE,
> > +					  data_of(*snapshot),
> > +					  PAGE_SIZE,
> > +					  false,
> > +					  crypto_page_idx);
> > +			if (ret)
> > +				break;
> > +			crypto_page_idx++;
> > +		}
> >  		if (!(nr_pages % m))
> >  			pr_info("Image loading progress: %3d%%\n",
> >  				nr_pages / m * 10);
> > @@ -1097,6 +1223,8 @@ static int load_image(struct swap_map_handle *handle,
> >  			ret = -ENODATA;
> >  	}
> >  	swsusp_show_speed(start, stop, nr_to_read, "Read");
> > +	if (crypt_buf)
> > +		free_page((unsigned long)crypt_buf);
> >  	return ret;
> >  }
> >  
> > @@ -1164,7 +1292,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  	struct hib_bio_batch hb;
> >  	ktime_t start;
> >  	ktime_t stop;
> > -	unsigned nr_pages;
> > +	unsigned nr_pages, crypto_page_idx;
> >  	size_t off;
> >  	unsigned i, thr, run_threads, nr_threads;
> >  	unsigned ring = 0, pg = 0, ring_size = 0,
> > @@ -1173,6 +1301,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  	unsigned char **page = NULL;
> >  	struct dec_data *data = NULL;
> >  	struct crc_data *crc = NULL;
> > +	void *first_page = NULL;
> >  
> >  	hib_init_batch(&hb);
> >  
> > @@ -1278,6 +1407,18 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  	}
> >  	want = ring_size = i;
> >  
> > +	/*
> > +	 * The first page of data[thr] contains the length of
> > +	 * compressed data, this page should not mess up the
> > +	 * read buffer, so we allocate a separate page for it.
> > +	 */
> > +	if (handle->crypto) {
> > +		first_page = (void *)get_zeroed_page(GFP_KERNEL);
> > +		if (!first_page) {
> > +			ret = -ENOMEM;
> > +			goto out_clean;
> > +		}
> > +	}
> >  	pr_info("Using %u thread(s) for decompression\n", nr_threads);
> >  	pr_info("Loading and decompressing image data (%u pages)...\n",
> >  		nr_to_read);
> > @@ -1285,6 +1426,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  	if (!m)
> >  		m = 1;
> >  	nr_pages = 0;
> > +	crypto_page_idx = 0;
> >  	start = ktime_get();
> >  
> >  	ret = snapshot_write_next(snapshot);
> > @@ -1336,7 +1478,24 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  		}
> >  
> >  		for (thr = 0; have && thr < nr_threads; thr++) {
> > -			data[thr].cmp_len = *(size_t *)page[pg];
> > +			if (handle->crypto) {
> > +				/*
> > +				 * Need to decrypt the first page
> > +				 * of each data[thr], which contains
> > +				 * the compressed data length.
> > +				 */
> > +				ret = crypto_data(page[pg],
> > +						  PAGE_SIZE,
> > +						  first_page,
> > +						  PAGE_SIZE,
> > +						  false,
> > +						  crypto_page_idx);
> > +				if (ret)
> > +					goto out_finish;
> > +				data[thr].cmp_len = *(size_t *)first_page;
> > +			} else {
> > +				data[thr].cmp_len = *(size_t *)page[pg];
> > +			}
> >  			if (unlikely(!data[thr].cmp_len ||
> >  			             data[thr].cmp_len >
> >  			             lzo1x_worst_compress(LZO_UNC_SIZE))) {
> > @@ -1358,8 +1517,26 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  			for (off = 0;
> >  			     off < LZO_HEADER + data[thr].cmp_len;
> >  			     off += PAGE_SIZE) {
> > -				memcpy(data[thr].cmp + off,
> > -				       page[pg], PAGE_SIZE);
> > +				if (handle->crypto) {
> > +					/*
> > +					 * Decrypt the compressed data
> > +					 * and leverage the decompression
> > +					 * threads to get it done.
> > +					 */
> > +					ret = crypto_data(page[pg],
> > +							  PAGE_SIZE,
> > +							  data[thr].cmp + off,
> > +							  PAGE_SIZE,
> > +							  false,
> > +							  crypto_page_idx);
> > +					if (ret)
> > +						goto out_finish;
> > +					crypto_page_idx++;
> > +				} else {
> > +					memcpy(data[thr].cmp + off,
> > +						page[pg], PAGE_SIZE);
> > +
> > +				}
> >  				have--;
> >  				want++;
> >  				if (++pg >= ring_size)
> > @@ -1452,6 +1629,8 @@ static int load_image_lzo(struct swap_map_handle *handle,
> >  out_clean:
> >  	for (i = 0; i < ring_size; i++)
> >  		free_page((unsigned long)page[i]);
> > +	if (first_page)
> > +		free_page((unsigned long)first_page);
> >  	if (crc) {
> >  		if (crc->thr)
> >  			kthread_stop(crc->thr);
> > @@ -1482,6 +1661,7 @@ int swsusp_read(unsigned int *flags_p)
> >  	struct swsusp_info *header;
> >  
> >  	memset(&snapshot, 0, sizeof(struct snapshot_handle));
> > +	memset(&handle, 0, sizeof(struct swap_map_handle));
> >  	error = snapshot_write_next(&snapshot);
> >  	if (error < PAGE_SIZE)
> >  		return error < 0 ? error : -EFAULT;
> > @@ -1489,6 +1669,16 @@ int swsusp_read(unsigned int *flags_p)
> >  	error = get_swap_reader(&handle, flags_p);
> >  	if (error)
> >  		goto end;
> > +	if (*flags_p & SF_ENCRYPT_MODE) {
> > +		error = crypto_init(false);
> > +		if (!error) {
> > +			/* The image has been encrypted. */
> > +			handle.crypto = true;
> > +		} else {
> > +			pr_err("Failed to init cipher during resume.\n");
> > +			goto end;
> > +		}
> > +	}
> >  	if (!error)
> >  		error = swap_read_page(&handle, header, NULL);
> >  	if (!error) {
> > @@ -1526,6 +1716,9 @@ int swsusp_check(void)
> >  
> >  		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
> >  			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
> > +			/* Read salt passed from previous kernel. */
> > +			if (swsusp_header->flags & SF_ENCRYPT_MODE)
> > +				crypto_restore((void *)&swsusp_header->salt);
> >  			/* Reset swap signature now */
> >  			error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
> >  						swsusp_resume_block,
> > -- 
> > 2.7.4
> > 

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