Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1185901 > unrolled thread

[RFC PATCH 00/16] Signature verification of hibernate snapshot

Back to article view | Back to linux.kernel

Contents

  [RFC PATCH 00/16] Signature verification of hibernate snapshot "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:30 +0200
    [RFC PATCH 12/16] PM / hibernate: Forward signature verifying result and key to image kernel "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:30 +0200
    [RFC PATCH 15/16] PM / hibernate: Bypass verification logic on legacy BIOS "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:30 +0200
    [RFC PATCH 16/16] PM / hibernate: Document signature verification of hibernate snapshot "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:30 +0200
    [RFC PATCH 13/16] PM / hibernate: Add configuration to enforce signature verification "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:30 +0200
    [RFC PATCH 08/16] x86/efi: Carrying swsusp key by setup data "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:30 +0200
    [RFC PATCH 07/16] efi: Public the function of transferring EFI status to kernel error "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:40 +0200
    [RFC PATCH 03/16] x86/boot: Public getting random boot function "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:40 +0200
    [RFC PATCH 05/16] x86/efi: Get entropy through EFI random number generator protocol "Lee, Chun-Yi" <joeyli.kernel@gmail.com> - 2015-07-16 16:40 +0200

#1185901 — [RFC PATCH 00/16] Signature verification of hibernate snapshot

Hi experts,

This patchset is the implementation of signature verification of hibernate
snapshot image. The origin idea is from Jiri Kosina: Let EFI bootloader
generate key-pair in UEFI secure boot environment, then forward it to kernel
for sign/verify hibernate image.

The first patchset for this function was sent in Sep. 2013, the implementation
is base on PKI. This new patchset is base on HMAC-SHA1. 

The hibernate function provided by kernel was used to snapshot memory
to be a image for keeping in storage, then restored in appropriate time.
There have potential threat from hacking the memory snapshot image.
Cracker may triggers hibernating process through ioctl to grab snapshot
image, then restoring modified image back to memory. Another situation
is booting to other hacked OS to modify the snapshot image in swap
partition or file, then user may runs malware after image restored to
memory. In addition, the above weakness cause kernel is not fully trusted
in EFI secure boot environment.

So, kernel hibernate function needs a mechanism to verify integrity of
hibernate snapshot image.

For signing hibernate image, kernel need a key for generating signature of
image. The origin idea is using PKI, the EFI bootloader, shim generates key
pair and forward to boot kernel for signing/verifying image. In Linux Plumbers
Conference 2013, we got response from community experts for just using
symmetric key algorithm to generate signature, that's simpler and no EFI
bootloader's involving.

Current solution is using HMAC-SHA1 algorithm, it generating HMAC key in EFI
stub, the HMAC key stored in efi boot service variable, When hibernate
recovering, kernel will verify the image signature before switch whole system
to image kernel and image memory space. When verifying failed, kernel is
tainted or stop recovering and discarding image.

Set HIBERNATE_VERIFICATION compile option to true for enabling hibernate
verification. The default behavior of verifying failed is accept restoring
image but tainting kernel with H taint flag. Using HIBERNATE_VERIFICATION_FORCE
kernel compile option or "sigenforce" kernel parameter to force hibernate
recovery process stop when verification failed. It allows user to trigger the
key re-generating process in EFI stub through SNAPSHOT_REGENERATE_KEY ioctl.


Lee, Chun-Yi (16):
  PM / hibernate: define HMAC algorithm and digest size of swsusp
  x86/efi: Add get and set variable to EFI services pointer table
  x86/boot: Public getting random boot function
  x86/efi: Generating random number in EFI stub
  x86/efi: Get entropy through EFI random number generator protocol
  x86/efi: Generating random HMAC key for siging hibernate image
  efi: Public the function of transferring EFI status to kernel error
  x86/efi: Carrying swsusp key by setup data
  PM / hibernate: Reserve swsusp key and earse footprints
  PM / hibernate: Generate and verify signature of hibernate snapshot
  PM / hibernate: Avoid including swsusp key to hibernate image
  PM / hibernate: Forward signature verifying result and key to image
    kernel
  PM / hibernate: Add configuration to enforce signature verification
  PM / hibernate: Allow user trigger swsusp key re-generating
  PM / hibernate: Bypass verification logic on legacy BIOS
  PM / hibernate: Document signature verification of hibernate snapshot

 Documentation/kernel-parameters.txt             |   5 +
 Documentation/power/swsusp-signature-verify.txt |  86 +++++++
 arch/x86/boot/compressed/Makefile               |   1 +
 arch/x86/boot/compressed/aslr.c                 |  55 +----
 arch/x86/boot/compressed/eboot.c                |  94 ++++++++
 arch/x86/boot/compressed/efi_random.c           | 281 +++++++++++++++++++++++
 arch/x86/boot/compressed/head_32.S              |   6 +-
 arch/x86/boot/compressed/head_64.S              |   8 +-
 arch/x86/boot/compressed/misc.c                 |  55 +++++
 arch/x86/boot/compressed/misc.h                 |   4 +
 arch/x86/include/asm/efi.h                      |   2 +
 arch/x86/include/asm/suspend.h                  |  13 ++
 arch/x86/include/uapi/asm/bootparam.h           |   1 +
 arch/x86/kernel/setup.c                         |  21 +-
 arch/x86/power/Makefile                         |   1 +
 arch/x86/power/hibernate_keys.c                 | 173 ++++++++++++++
 drivers/firmware/Makefile                       |   1 +
 drivers/firmware/efi/Kconfig                    |   4 +
 drivers/firmware/efi/Makefile                   |   1 +
 drivers/firmware/efi/efi-hibernate_keys.c       |  46 ++++
 drivers/firmware/efi/vars.c                     |  33 ---
 include/linux/efi.h                             |  79 +++++++
 include/linux/kernel.h                          |   1 +
 include/linux/suspend.h                         |  26 +++
 include/uapi/linux/suspend_ioctls.h             |   3 +-
 kernel/panic.c                                  |   2 +
 kernel/power/Kconfig                            |  23 ++
 kernel/power/hibernate.c                        |  10 +
 kernel/power/power.h                            |  20 ++
 kernel/power/snapshot.c                         | 293 ++++++++++++++++++++++--
 kernel/power/swap.c                             |   4 +
 kernel/power/user.c                             |  16 ++
 kernel/reboot.c                                 |   3 +
 33 files changed, 1260 insertions(+), 111 deletions(-)
 create mode 100644 Documentation/power/swsusp-signature-verify.txt
 create mode 100644 arch/x86/boot/compressed/efi_random.c
 create mode 100644 arch/x86/power/hibernate_keys.c
 create mode 100644 drivers/firmware/efi/efi-hibernate_keys.c

-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1185903 — [RFC PATCH 12/16] PM / hibernate: Forward signature verifying result and key to image kernel

Due to the memory space of boot kernel will be overwritten after restoring
snapshot image and switching to image kernel. There have some informations
should be forwarded from boot kernel to image kernel: the result of
signature verifying, flag of enforce verifying signature and swsusp key.
That because those informations did not include in hibernate image or
produced when restoring.

The significant reason is image kernel needs swsusp key to sign image for
next hibernate cycle, otherwise the signature generating will be failed in
next cycle. In additional, it's also useful to expose the verification
result in dmesg after recovery.

The codes in hibernate key handler allocates an empty page as the buffer
of forward information that will be included in snapshot iamge, then keeps
page frame number in image header. When restoring snapshot image to memory
space of boot kernel, snapshot codes will asking key handler to fill forward
informations to buffer page. Then restoring swsusp key data to key page,
and cleaning this page buffer for next cycle.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 arch/x86/power/hibernate_keys.c | 63 +++++++++++++++++++++++++++++++++++++++++
 kernel/power/hibernate.c        |  1 +
 kernel/power/power.h            |  6 ++++
 kernel/power/snapshot.c         | 27 +++++++++++++++++-
 kernel/power/user.c             |  1 +
 5 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/arch/x86/power/hibernate_keys.c b/arch/x86/power/hibernate_keys.c
index 775c6d8..9c3d2fe 100644
--- a/arch/x86/power/hibernate_keys.c
+++ b/arch/x86/power/hibernate_keys.c
@@ -20,6 +20,15 @@ static u64 keys_phys_addr;
 /* A page used to keep swsusp keys */
 static struct swsusp_keys *swsusp_keys;
 
+/* Forward information and keys from boot kernel to image kernel */
+struct forward_info {
+	bool            sig_enforce;
+	int             sig_verify_ret;
+	struct swsusp_keys swsusp_keys;
+};
+
+static struct forward_info *forward_buff;
+
 void __init parse_swsusp_keys(u64 phys_addr, u32 data_len)
 {
 	struct setup_data *swsusp_setup_data;
@@ -62,6 +71,55 @@ bool swsusp_page_is_keys(struct page *page)
 	return ret;
 }
 
+unsigned long get_forward_buff_pfn(void)
+{
+	if (!forward_buff)
+		return 0;
+
+	return page_to_pfn(virt_to_page(forward_buff));
+}
+
+void fill_forward_info(void *forward_buff_page, int verify_ret)
+{
+	struct forward_info *info;
+
+	if (!forward_buff_page)
+		return;
+
+	memset(forward_buff_page, 0, PAGE_SIZE);
+	info = (struct forward_info *)forward_buff_page;
+	info->sig_verify_ret = verify_ret;
+
+	if (swsusp_keys && !swsusp_keys->skey_status) {
+		info->swsusp_keys = *swsusp_keys;
+		memset(swsusp_keys, 0, PAGE_SIZE);
+	} else
+		pr_info("PM: Fill swsusp keys failed\n");
+
+	pr_info("PM: Filled sign information to forward buffer\n");
+}
+
+void restore_sig_forward_info(void)
+{
+	if (!forward_buff) {
+		pr_warn("PM: Did not allocate forward buffer\n");
+		return;
+	}
+
+	if (forward_buff->sig_verify_ret)
+		pr_warn("PM: Signature verifying failed: %d\n",
+			forward_buff->sig_verify_ret);
+
+	if (swsusp_keys) {
+		memset(swsusp_keys, 0, PAGE_SIZE);
+		*swsusp_keys = forward_buff->swsusp_keys;
+		pr_info("PM: Restored swsusp keys\n");
+	}
+
+	/* clean forward information buffer for next round */
+	memset(forward_buff, 0, PAGE_SIZE);
+}
+
 static int __init init_hibernate_keys(void)
 {
 	struct swsusp_keys *keys;
@@ -76,6 +134,11 @@ static int __init init_hibernate_keys(void)
 	swsusp_keys = (struct swsusp_keys *)get_zeroed_page(GFP_KERNEL);
 	if (swsusp_keys) {
 		*swsusp_keys = *keys;
+		forward_buff = (struct forward_info *)get_zeroed_page(GFP_KERNEL);
+		if (!forward_buff) {
+			pr_err("PM: Allocate forward buffer failed\n");
+			ret = -ENOMEM;
+		}
 	} else {
 		pr_err("PM: Allocate swsusp keys page failed\n");
 		ret = -ENOMEM;
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 690f78f..640ca8a 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -702,6 +702,7 @@ int hibernate(void)
 		pm_restore_gfp_mask();
 	} else {
 		pr_debug("PM: Image restored successfully.\n");
+		restore_sig_forward_info();
 	}
 
  Free_bitmaps:
diff --git a/kernel/power/power.h b/kernel/power/power.h
index a09b21d..5ee0074 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -12,6 +12,7 @@ struct swsusp_info {
 	unsigned long		image_pages;
 	unsigned long		pages;
 	unsigned long		size;
+	unsigned long           forward_buff_pfn;
 	u8                      signature[SWSUSP_DIGEST_SIZE];
 } __aligned(PAGE_SIZE);
 
@@ -20,8 +21,13 @@ struct swsusp_info {
 /* arch/x86/power/hibernate_keys.c */
 extern int get_swsusp_key(u8 **skey);
 extern bool swsusp_page_is_keys(struct page *page);
+extern unsigned long get_forward_buff_pfn(void);
+extern void fill_forward_info(void *forward_buff_page, int verify_ret);
+extern void restore_sig_forward_info(void);
 #else
 static inline bool swsusp_page_is_keys(struct page *page) { return false; }
+static inline unsigned long get_forward_buff_pfn(void) { return 0; }
+static inline void restore_sig_forward_info(void) {}
 #endif
 
 /* kernel/power/snapshot.c */
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index c2bce90..a19ac11 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1281,6 +1281,14 @@ static unsigned int nr_copy_pages;
  */
 static u8 signature[SWSUSP_DIGEST_SIZE];
 
+/*
+ * Keep the pfn of forwarding information buffer from resume target.
+ * Writing swsusp keys to this buffer in snapshot image before restoring.
+ */
+unsigned long forward_buff_pfn;
+
+void *forward_buff;
+
 /* Buffer point array for collecting address of page buffers */
 void **h_buf;
 
@@ -1383,13 +1391,24 @@ error_key:
 	return ret;
 }
 
+static void snapshot_fill_sig_forward_info(int verify_ret)
+{
+	if (!forward_buff_pfn || !forward_buff) {
+		pr_err("PM: Did not find forward buffer\n");
+		return;
+	}
+
+	/* Fill swsusp keys to snapshot in memory for next round */
+	fill_forward_info(forward_buff, verify_ret);
+}
+
 int snapshot_image_verify(void)
 {
 	struct crypto_shash *tfm;
 	struct shash_desc *desc;
 	u8 *key, *digest;
 	size_t digest_size, desc_size;
-	int ret, i;
+	int i, ret = 0;
 
 	if (!h_buf)
 		return 0;
@@ -1450,6 +1469,7 @@ error_digest:
 forward_ret:
 	if (ret)
 		pr_warn("PM: Signature verifying failed: %d\n", ret);
+	snapshot_fill_sig_forward_info(ret);
 	return ret;
 }
 
@@ -2126,6 +2146,7 @@ static int init_header(struct swsusp_info *info)
 	info->pages = snapshot_get_image_size();
 	info->size = info->pages;
 	info->size <<= PAGE_SHIFT;
+	info->forward_buff_pfn = get_forward_buff_pfn();
 	memcpy(info->signature, signature, SWSUSP_DIGEST_SIZE);
 	return init_header_complete(info);
 }
@@ -2289,6 +2310,7 @@ load_header(struct swsusp_info *info)
 	if (!error) {
 		nr_copy_pages = info->image_pages;
 		nr_meta_pages = info->pages - info->image_pages - 1;
+		forward_buff_pfn = info->forward_buff_pfn;
 		memset(signature, 0, SWSUSP_DIGEST_SIZE);
 		memcpy(signature, info->signature, SWSUSP_DIGEST_SIZE);
 	}
@@ -2757,6 +2779,9 @@ int snapshot_write_next(struct snapshot_handle *handle)
 			handle->sync_read = 0;
 		if (h_buf)
 			*(h_buf + (handle->cur - nr_meta_pages - 1)) = handle->buffer;
+		/* Keep the buffer of swsusp keys in snapshot */
+		if (forward_buff_pfn && pfn == forward_buff_pfn)
+			forward_buff = handle->buffer;
 	}
 	handle->cur++;
 	return PAGE_SIZE;
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 9b891d5..ffd327a 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -241,6 +241,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		if (!data->frozen || data->ready)
 			break;
 		pm_restore_gfp_mask();
+		restore_sig_forward_info();
 		free_basic_memory_bitmaps();
 		data->free_bitmaps = false;
 		thaw_processes();
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185904 — [RFC PATCH 15/16] PM / hibernate: Bypass verification logic on legacy BIOS

Current hibernate signature verification solution relies on EFI stub
and efi boot service variable on x86 architecture. So the verification
logic was bypassed on legacy BIOS through checking EFI_BOOT flag.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/firmware/efi/efi-hibernate_keys.c | 3 +++
 kernel/power/Kconfig                      | 3 ++-
 kernel/power/snapshot.c                   | 8 ++++++--
 kernel/power/user.c                       | 6 +++++-
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/efi/efi-hibernate_keys.c b/drivers/firmware/efi/efi-hibernate_keys.c
index 90ae912..f33bf70 100644
--- a/drivers/firmware/efi/efi-hibernate_keys.c
+++ b/drivers/firmware/efi/efi-hibernate_keys.c
@@ -21,6 +21,9 @@ void create_swsusp_key_regen_flag(void)
 	struct efivar_entry *entry = NULL;
 	int err = 0;
 
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		return;
+
 	if (!set_swsusp_key_regen_flag)
 		return;
 
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 7a64bda..5b04ab9 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -78,7 +78,8 @@ config HIBERNATE_VERIFICATION
 	  This option provides support for generating and verifying the
 	  signature of memory snapshot image by HMAC-SHA1. Current mechanism
 	  relies on UEFI secure boot environment, EFI stub generates HMAC
-	  key for hibernate verification.
+	  key for hibernate verification. So, the verification logic will be
+	  bypassed on legacy BIOS.
 
 config HIBERNATE_VERIFICATION_FORCE
 	bool "Require hibernate snapshot image to be validly signed"
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 3eda715..0d64c3a 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -29,6 +29,7 @@
 #include <linux/slab.h>
 #include <linux/compiler.h>
 #include <linux/ktime.h>
+#include <linux/efi.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -1469,8 +1470,11 @@ error_digest:
 forward_ret:
 	if (ret)
 		pr_warn("PM: Signature verifying failed: %d\n", ret);
-	/* forward check result when verifying pass or not enforce verifying */
-	if (!ret || !sigenforce) {
+	if (ret == -ENODEV && !efi_enabled(EFI_BOOT)) {
+		pr_warn("PM: Bypass verification on non-EFI machine\n");
+		ret = 0;
+	} else if (!ret || !sigenforce) {
+		/* forward check result when verifying pass or not enforce verifying */
 		snapshot_fill_sig_forward_info(ret);
 		ret = 0;
 	}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 8bcb051..d7407ef 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -24,6 +24,7 @@
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/freezer.h>
+#include <linux/efi.h>
 
 #include <asm/uaccess.h>
 
@@ -390,7 +391,10 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		break;
 
 	case SNAPSHOT_REGENERATE_KEY:
-		set_swsusp_key_regen_flag = !!arg;
+		if (!efi_enabled(EFI_BOOT))
+			error = -ENODEV;
+		else
+			set_swsusp_key_regen_flag = !!arg;
 		break;
 
 	default:
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185905 — [RFC PATCH 16/16] PM / hibernate: Document signature verification of hibernate snapshot

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 Documentation/power/swsusp-signature-verify.txt | 86 +++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 Documentation/power/swsusp-signature-verify.txt

diff --git a/Documentation/power/swsusp-signature-verify.txt b/Documentation/power/swsusp-signature-verify.txt
new file mode 100644
index 0000000..492e047
--- /dev/null
+++ b/Documentation/power/swsusp-signature-verify.txt
@@ -0,0 +1,86 @@
+Signature verification of hibernate snapshot
+============================================
+
+1) Introduction
+2) How to enable
+3) How does it work
+4) Trigger key re-generate
+
+1) Introduction
+---------------------
+
+The hibernate function provided by kernel was used to snapshot memory
+to be a image for keeping in storage, then restored in appropriate time.
+There have potential threat from hacking the memory snapshot image.
+Cracker may triggers hibernating process through ioctl to grab snapshot
+image, then restoring modified image back to memory. Another situation
+is booting to other hacked OS to modify the snapshot image in swap
+partition or file, then user may runs malware after image restored to
+memory. In addition, the above weakness cause kernel is not fully trusted
+in EFI secure boot environment.
+
+So, kernel hibernate function needs a mechanism to verify integrity of
+hibernate snapshot image.
+
+The origin idea is from Jiri Kosina: Let EFI bootloader generates key-pair
+in UEFI secure boot environment, then forwarding keys to boot kernel for
+signing/verifying snapshot image.
+
+
+2) How to enable
+-----------------
+
+If the HIBERNATE_VERIFICATION compile option is true, kernel hibernate code
+will generating and verifying the signature of memory snapshot image by
+HMAC-SHA1 algorithm. Current solution relies on EFI stub on x86 architecture,
+so the signature verification logic will be bypassed on legacy BIOS.
+
+When the snapshot image unsigned or signed with an unknown key, the signature
+verification will be failed. The default behavior of verifying failed is
+accept restoring image but tainting kernel with H taint flag.
+
+Like kernel module signature checking, there's both a config option and
+a boot parameter which control whether we accept or stop whole recovery
+process when verification failed. Using HIBERNATE_VERIFICATION_FORCE kernel
+compile option or "sigenforce" kernel parameter to force hibernate recovery
+process stop when verification failed.
+
+
+3) How does it work
+-------------------
+
+For signing hibernate image, kernel need a key for generating signature of
+image. The origin idea is using PKI, the EFI bootloader, shim generates key
+pair and forward to boot kernel for signing/verifying image. In Linux Plumbers
+Conference 2013, we got response from community experts for just using
+symmetric key algorithm to generate signature, that's simpler and no EFI
+bootloader's involving.
+
+Current solution is using HMAC-SHA1 algorithm, it generating HMAC key in EFI
+stub by using RDRAND, RDTSC and EFI RNG protocol to grab random number to be
+the entropy of key. Then the HMAC key stored in efi boot service variable,
+key's security relies on EFI secure boot: When EFI secure boot enabled, only
+trusted efi program allowed accessing boot service variables.
+
+In every EFI stub booting stage, it loads key from variable then forward key
+to boot kernel for waiting to sign snapshot image by user trigger hibernating.
+The HMAC-SHA1 algorithm generates signature then kernel put signature to the
+header with the memory snapshot image. The signature with image is delivered
+to userspace hibernating application or direct stored in swap partition.
+
+When hibernate recovering, kernel will verify the image signature before
+switch whole system to image kernel and image memory space. When verifying
+failed, kernel is tainted or stop recovering and discarding image.
+
+
+4) Trigger key re-generate
+--------------------------
+
+The hibernate signature verifying function allows user to trigger the key
+re-generating process in EFI stub through SNAPSHOT_REGENERATE_KEY ioctl.
+
+User can raise a key-regen flag in kernel through ioctl. When system runs
+normal shutdown or reboot, kernel writes a efi runtime variable as a flag
+then EFI stub will query the flag in next boot cycle. To avoid the swsusp
+key changes in hibernating cycle that causes hibernate restoring failed,
+the regen flag will be clear in a hibernate cycle.
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185910 — [RFC PATCH 13/16] PM / hibernate: Add configuration to enforce signature verification

Like kernel module signature checking, there's both a config option and
a boot parameter which control whether we accept or fail with unsigned
hibernate image and image that are signed with an unknown key.

If hibernate signing is enabled, the kernel will be tainted if a snapshot
image is restored that is unsigned or has a signature for which we don't
have the key. When the enforce flag is enabled, then the hibernate
restoring process will be failed and boot as normal.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 Documentation/kernel-parameters.txt |  5 +++++
 arch/x86/power/hibernate_keys.c     | 19 +++++++++++++++++--
 include/linux/kernel.h              |  1 +
 include/linux/suspend.h             |  3 +++
 kernel/panic.c                      |  2 ++
 kernel/power/Kconfig                |  8 ++++++++
 kernel/power/hibernate.c            |  7 +++++++
 kernel/power/snapshot.c             |  6 +++++-
 8 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1d6f045..86a6916 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3318,6 +3318,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 		noresume	Don't check if there's a hibernation image
 				present during boot.
 		nocompress	Don't compress/decompress hibernation images.
+		sigenforce	When CONFIG_HIBERNATE_VERIFICATION is set, this
+				menas that snapshot image without (valid)
+				signature will fail to restore. Note that if
+				HIBERNATE_VERIFICATION_FORCE is set, that is
+				always true, so this option does nothing.
 		no		Disable hibernation and resume.
 
 	retain_initrd	[RAM] Keep initrd memory after extraction
diff --git a/arch/x86/power/hibernate_keys.c b/arch/x86/power/hibernate_keys.c
index 9c3d2fe..9a0f3b3 100644
--- a/arch/x86/power/hibernate_keys.c
+++ b/arch/x86/power/hibernate_keys.c
@@ -89,6 +89,7 @@ void fill_forward_info(void *forward_buff_page, int verify_ret)
 	memset(forward_buff_page, 0, PAGE_SIZE);
 	info = (struct forward_info *)forward_buff_page;
 	info->sig_verify_ret = verify_ret;
+	info->sig_enforce = sigenforce;
 
 	if (swsusp_keys && !swsusp_keys->skey_status) {
 		info->swsusp_keys = *swsusp_keys;
@@ -106,10 +107,24 @@ void restore_sig_forward_info(void)
 		return;
 	}
 
-	if (forward_buff->sig_verify_ret)
-		pr_warn("PM: Signature verifying failed: %d\n",
+	sigenforce = forward_buff->sig_enforce;
+	if (sigenforce)
+		pr_info("PM: Enforce hibernate signature verifying\n");
+
+	if (forward_buff->sig_verify_ret) {
+		pr_warn("PM: Hibernate signature verifying failed: %d\n",
 			forward_buff->sig_verify_ret);
 
+		/* taint kernel */
+		if (!sigenforce) {
+			pr_warn("PM: System restored from unsafe snapshot - "
+				"tainting kernel\n");
+			add_taint(TAINT_UNSAFE_HIBERNATE, LOCKDEP_STILL_OK);
+			pr_info("%s\n", print_tainted());
+		}
+	} else
+		pr_info("PM: Signature verifying pass\n");
+
 	if (swsusp_keys) {
 		memset(swsusp_keys, 0, PAGE_SIZE);
 		*swsusp_keys = forward_buff->swsusp_keys;
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5f0be58..0add6e6 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -488,6 +488,7 @@ extern enum system_states {
 #define TAINT_UNSIGNED_MODULE		13
 #define TAINT_SOFTLOCKUP		14
 #define TAINT_LIVEPATCH			15
+#define TAINT_UNSAFE_HIBERNATE		16
 
 extern const char hex_asc[];
 #define hex_asc_lo(x)	hex_asc[((x) & 0x0f)]
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 1ec7d11..fc3dde0 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -335,6 +335,9 @@ struct platform_hibernation_ops {
 #define SWSUSP_HMAC		"hmac(sha1)"
 #define SWSUSP_DIGEST_SIZE	20
 
+/* kernel/power/hibernate.c */
+extern int sigenforce;
+
 /* kernel/power/snapshot.c */
 extern void __register_nosave_region(unsigned long b, unsigned long e, int km);
 static inline void __init register_nosave_region(unsigned long b, unsigned long e)
diff --git a/kernel/panic.c b/kernel/panic.c
index 04e91ff..a53da16 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -228,6 +228,7 @@ static const struct tnt tnts[] = {
 	{ TAINT_UNSIGNED_MODULE,	'E', ' ' },
 	{ TAINT_SOFTLOCKUP,		'L', ' ' },
 	{ TAINT_LIVEPATCH,		'K', ' ' },
+	{ TAINT_UNSAFE_HIBERNATE,	'H', ' ' },
 };
 
 /**
@@ -249,6 +250,7 @@ static const struct tnt tnts[] = {
  *  'E' - Unsigned module has been loaded.
  *  'L' - A soft lockup has previously occurred.
  *  'K' - Kernel has been live patched.
+ *  'H' - System restored from unsafe hibernate snapshot image.
  *
  *	The string is overwritten by the next call to print_tainted().
  */
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 8608b3b..f2a7e21 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -79,6 +79,14 @@ config HIBERNATE_VERIFICATION
 	  relies on UEFI secure boot environment, EFI stub generates HMAC
 	  key for hibernate verification.
 
+config HIBERNATE_VERIFICATION_FORCE
+	bool "Require hibernate snapshot image to be validly signed"
+	depends on HIBERNATE_VERIFICATION
+	help
+	  Reject hibernate resuming from unsigned snapshot image or signed
+	  snapshot image for which we don't have a key. Without this, such
+	  snapshot image will simply taint the kernel when resuming.
+
 config ARCH_SAVE_PAGE_KEYS
 	bool
 
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 640ca8a..2c2cc90 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -43,6 +43,11 @@ static char resume_file[256] = CONFIG_PM_STD_PARTITION;
 dev_t swsusp_resume_device;
 sector_t swsusp_resume_block;
 __visible int in_suspend __nosavedata;
+#ifdef CONFIG_HIBERNATE_VERIFICATION_FORCE
+int sigenforce = 1;
+#else
+int sigenforce;
+#endif
 
 enum {
 	HIBERNATION_INVALID,
@@ -1119,6 +1124,8 @@ static int __init hibernate_setup(char *str)
 		noresume = 1;
 	else if (!strncmp(str, "nocompress", 10))
 		nocompress = 1;
+	else if (!strncmp(str, "sigenforce", 10))
+		sigenforce = 1;
 	else if (!strncmp(str, "no", 2)) {
 		noresume = 1;
 		nohibernate = 1;
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index a19ac11..3eda715 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1469,7 +1469,11 @@ error_digest:
 forward_ret:
 	if (ret)
 		pr_warn("PM: Signature verifying failed: %d\n", ret);
-	snapshot_fill_sig_forward_info(ret);
+	/* forward check result when verifying pass or not enforce verifying */
+	if (!ret || !sigenforce) {
+		snapshot_fill_sig_forward_info(ret);
+		ret = 0;
+	}
 	return ret;
 }
 
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185911 — [RFC PATCH 08/16] x86/efi: Carrying swsusp key by setup data

For forwarding swsusp key from EFI stub to boot kernel, this patch
allocates setup data for carrying swsusp key, size and the status
of efi operating.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 arch/x86/boot/compressed/eboot.c      | 29 +++++++++++++++++++++++++----
 arch/x86/include/uapi/asm/bootparam.h |  1 +
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 97b356f..5e1476e 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -1392,19 +1392,23 @@ free_mem_map:
 
 static void setup_swsusp_keys(struct boot_params *params)
 {
-	unsigned long key_size, attributes;
+	struct setup_data *setup_data, *swsusp_setup_data;
 	struct swsusp_keys *swsusp_keys;
+	int size = 0;
+	unsigned long key_size, attributes;
 	efi_status_t status;
 
 	/* Allocate setup_data to carry keys */
+	size = sizeof(struct setup_data) + sizeof(struct swsusp_keys);
 	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
-				sizeof(struct swsusp_keys), &swsusp_keys);
+				size, &swsusp_setup_data);
 	if (status != EFI_SUCCESS) {
 		efi_printk(sys_table, "Failed to alloc mem for swsusp_keys\n");
 		return;
 	}
 
-	memset(swsusp_keys, 0, sizeof(struct swsusp_keys));
+	memset(swsusp_setup_data, 0, size);
+	swsusp_keys = (struct swsusp_keys *)swsusp_setup_data->data;
 
 	status = efi_call_early(get_variable, SWSUSP_KEY, &EFI_SWSUSP_GUID,
 				&attributes, &key_size, swsusp_keys->swsusp_key);
@@ -1413,7 +1417,9 @@ static void setup_swsusp_keys(struct boot_params *params)
 		memset(swsusp_keys->swsusp_key, 0, SWSUSP_DIGEST_SIZE);
 		status = efi_call_early(set_variable, SWSUSP_KEY,
 					&EFI_SWSUSP_GUID, attributes, 0, NULL);
-		if (status == EFI_SUCCESS) {
+		if (status)
+			goto clean_fail;
+		else {
 			efi_printk(sys_table, "Cleaned existing swsusp key\n");
 			status = EFI_NOT_FOUND;
 		}
@@ -1433,6 +1439,21 @@ static void setup_swsusp_keys(struct boot_params *params)
 		if (status != EFI_SUCCESS)
 			efi_printk(sys_table, "Failed to set swsusp key\n");
 	}
+
+clean_fail:
+	swsusp_setup_data->type = SETUP_SWSUSP_KEYS;
+	swsusp_setup_data->len = sizeof(struct swsusp_keys);
+	swsusp_setup_data->next = 0;
+	swsusp_keys->skey_status = efi_status_to_err(status);
+
+	setup_data = (struct setup_data *)params->hdr.setup_data;
+	while (setup_data && setup_data->next)
+		setup_data = (struct setup_data *)setup_data->next;
+
+	if (setup_data)
+		setup_data->next = (unsigned long)swsusp_setup_data;
+	else
+		params->hdr.setup_data = (unsigned long)swsusp_setup_data;
 }
 #else
 static void setup_swsusp_keys(struct boot_params *params) {}
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index ab456dc..12e0a203 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -7,6 +7,7 @@
 #define SETUP_DTB			2
 #define SETUP_PCI			3
 #define SETUP_EFI			4
+#define SETUP_SWSUSP_KEYS		5
 
 /* ram_size flags */
 #define RAMDISK_IMAGE_START_MASK	0x07FF
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185918 — [RFC PATCH 07/16] efi: Public the function of transferring EFI status to kernel error

Moved the function of transferring EFI status to kernel error for
later used by EFI stub.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/firmware/efi/vars.c | 33 ---------------------------------
 include/linux/efi.h         | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 33 deletions(-)

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 70a0fb1..f5ede94 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -237,39 +237,6 @@ check_var_size(u32 attributes, unsigned long size)
 	return fops->query_variable_store(attributes, size);
 }
 
-static int efi_status_to_err(efi_status_t status)
-{
-	int err;
-
-	switch (status) {
-	case EFI_SUCCESS:
-		err = 0;
-		break;
-	case EFI_INVALID_PARAMETER:
-		err = -EINVAL;
-		break;
-	case EFI_OUT_OF_RESOURCES:
-		err = -ENOSPC;
-		break;
-	case EFI_DEVICE_ERROR:
-		err = -EIO;
-		break;
-	case EFI_WRITE_PROTECTED:
-		err = -EROFS;
-		break;
-	case EFI_SECURITY_VIOLATION:
-		err = -EACCES;
-		break;
-	case EFI_NOT_FOUND:
-		err = -ENOENT;
-		break;
-	default:
-		err = -EINVAL;
-	}
-
-	return err;
-}
-
 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
 				struct list_head *head)
 {
diff --git a/include/linux/efi.h b/include/linux/efi.h
index a628f83..9239f32 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -907,6 +907,39 @@ static inline char *efi_status_to_str(efi_status_t status)
 	return str;
 }
 
+static inline int efi_status_to_err(efi_status_t status)
+{
+	int err;
+
+	switch (status) {
+	case EFI_SUCCESS:
+		err = 0;
+		break;
+	case EFI_INVALID_PARAMETER:
+		err = -EINVAL;
+		break;
+	case EFI_OUT_OF_RESOURCES:
+		err = -ENOSPC;
+		break;
+	case EFI_DEVICE_ERROR:
+		err = -EIO;
+		break;
+	case EFI_WRITE_PROTECTED:
+		err = -EROFS;
+		break;
+	case EFI_SECURITY_VIOLATION:
+		err = -EACCES;
+		break;
+	case EFI_NOT_FOUND:
+		err = -ENOENT;
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
 extern void efi_init (void);
 extern void *efi_get_pal_addr (void);
 extern void efi_map_pal_code (void);
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185921 — [RFC PATCH 03/16] x86/boot: Public getting random boot function

This patch moves the getting random boot function from aslr to misc
for later used by EFI stub to generate the first entropy of hmac key
for signing hibernate snapshot image.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 arch/x86/boot/compressed/aslr.c | 55 +----------------------------------------
 arch/x86/boot/compressed/misc.c | 55 +++++++++++++++++++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h |  4 +++
 3 files changed, 60 insertions(+), 54 deletions(-)

diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index d7b1f65..bd6550a 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -6,59 +6,6 @@
 
 #include <generated/compile.h>
 #include <linux/module.h>
-#include <linux/uts.h>
-#include <linux/utsname.h>
-#include <generated/utsrelease.h>
-
-/* Simplified build-specific string for starting entropy. */
-static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
-		LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
-
-#define I8254_PORT_CONTROL	0x43
-#define I8254_PORT_COUNTER0	0x40
-#define I8254_CMD_READBACK	0xC0
-#define I8254_SELECT_COUNTER0	0x02
-#define I8254_STATUS_NOTREADY	0x40
-static inline u16 i8254(void)
-{
-	u16 status, timer;
-
-	do {
-		outb(I8254_PORT_CONTROL,
-		     I8254_CMD_READBACK | I8254_SELECT_COUNTER0);
-		status = inb(I8254_PORT_COUNTER0);
-		timer  = inb(I8254_PORT_COUNTER0);
-		timer |= inb(I8254_PORT_COUNTER0) << 8;
-	} while (status & I8254_STATUS_NOTREADY);
-
-	return timer;
-}
-
-static unsigned long rotate_xor(unsigned long hash, const void *area,
-				size_t size)
-{
-	size_t i;
-	unsigned long *ptr = (unsigned long *)area;
-
-	for (i = 0; i < size / sizeof(hash); i++) {
-		/* Rotate by odd number of bits and XOR. */
-		hash = (hash << ((sizeof(hash) * 8) - 7)) | (hash >> 7);
-		hash ^= ptr[i];
-	}
-
-	return hash;
-}
-
-/* Attempt to create a simple but unpredictable starting entropy. */
-static unsigned long get_random_boot(void)
-{
-	unsigned long hash = 0;
-
-	hash = rotate_xor(hash, build_str, sizeof(build_str));
-	hash = rotate_xor(hash, real_mode, sizeof(*real_mode));
-
-	return hash;
-}
 
 static unsigned long get_random_long(void)
 {
@@ -67,7 +14,7 @@ static unsigned long get_random_long(void)
 #else
 	const unsigned long mix_const = 0x3f39e593UL;
 #endif
-	unsigned long raw, random = get_random_boot();
+	unsigned long raw, random = get_random_boot(real_mode);
 	bool use_i8254 = true;
 
 	debug_putstr("KASLR using");
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index a107b93..d929506 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -12,6 +12,9 @@
 #include "misc.h"
 #include "../string.h"
 
+#include <generated/compile.h>
+#include <generated/utsrelease.h>
+
 /* WARNING!!
  * This code is compiled with -fPIC and it is relocated dynamically
  * at run time, but no relocation processing is performed.
@@ -435,3 +438,55 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
 	debug_putstr("done.\nBooting the kernel.\n");
 	return output;
 }
+
+#if CONFIG_RANDOMIZE_BASE
+#define I8254_PORT_CONTROL	0x43
+#define I8254_PORT_COUNTER0	0x40
+#define I8254_CMD_READBACK	0xC0
+#define I8254_SELECT_COUNTER0	0x02
+#define I8254_STATUS_NOTREADY	0x40
+u16 i8254(void)
+{
+	u16 status, timer;
+
+	do {
+		outb(I8254_PORT_CONTROL,
+		     I8254_CMD_READBACK | I8254_SELECT_COUNTER0);
+		status = inb(I8254_PORT_COUNTER0);
+		timer  = inb(I8254_PORT_COUNTER0);
+		timer |= inb(I8254_PORT_COUNTER0) << 8;
+	} while (status & I8254_STATUS_NOTREADY);
+
+	return timer;
+}
+
+static unsigned long rotate_xor(unsigned long hash, const void *area,
+				size_t size)
+{
+	size_t i;
+	unsigned long *ptr = (unsigned long *)area;
+
+	for (i = 0; i < size / sizeof(hash); i++) {
+		/* Rotate by odd number of bits and XOR. */
+		hash = (hash << ((sizeof(hash) * 8) - 7)) | (hash >> 7);
+		hash ^= ptr[i];
+	}
+
+	return hash;
+}
+
+/* Simplified build-specific string for starting entropy. */
+static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
+		LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
+
+/* Attempt to create a simple but unpredictable starting entropy. */
+unsigned long get_random_boot(struct boot_params *boot_params)
+{
+	unsigned long hash = 0;
+
+	hash = rotate_xor(hash, build_str, sizeof(build_str));
+	hash = rotate_xor(hash, boot_params, sizeof(*boot_params));
+
+	return hash;
+}
+#endif /* CONFIG_RANDOMIZE_BASE */
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 805d25c..e10908c 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -53,6 +53,10 @@ int cmdline_find_option(const char *option, char *buffer, int bufsize);
 int cmdline_find_option_bool(const char *option);
 #endif
 
+#if CONFIG_RANDOMIZE_BASE
+extern u16 i8254(void);
+extern unsigned long get_random_boot(struct boot_params *boot_params);
+#endif
 
 #if CONFIG_RANDOMIZE_BASE
 /* aslr.c */
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1185924 — [RFC PATCH 05/16] x86/efi: Get entropy through EFI random number generator protocol

To grab random numbers through EFI protocol as one of the entropies
source of swsusp key, this patch adds the logic for accessing EFI RNG
(random number generator) protocol that's introduced since UEFI 2.4.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 arch/x86/boot/compressed/efi_random.c | 193 ++++++++++++++++++++++++++++++++++
 include/linux/efi.h                   |  46 ++++++++
 2 files changed, 239 insertions(+)

diff --git a/arch/x86/boot/compressed/efi_random.c b/arch/x86/boot/compressed/efi_random.c
index bdb2d46..1f5c63d 100644
--- a/arch/x86/boot/compressed/efi_random.c
+++ b/arch/x86/boot/compressed/efi_random.c
@@ -2,6 +2,191 @@
 
 #include <linux/efi.h>
 #include <asm/archrandom.h>
+#include <asm/efi.h>
+
+static efi_status_t efi_locate_rng(efi_system_table_t *sys_table,
+				   void ***rng_handle)
+{
+	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
+	unsigned long size = 0;
+	efi_status_t status;
+
+	status = efi_call_early(locate_handle,
+				EFI_LOCATE_BY_PROTOCOL,
+				&rng_proto, NULL, &size, *rng_handle);
+
+	if (status == EFI_BUFFER_TOO_SMALL) {
+		status = efi_call_early(allocate_pool,
+					EFI_LOADER_DATA,
+					size, (void **)rng_handle);
+
+		if (status != EFI_SUCCESS) {
+			efi_printk(sys_table, " Failed to alloc mem for rng_handle");
+			return status;
+		}
+
+		status = efi_call_early(locate_handle,
+					EFI_LOCATE_BY_PROTOCOL, &rng_proto,
+					NULL, &size, *rng_handle);
+	}
+
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table, " Failed to locate EFI_RNG_PROTOCOL");
+		goto free_handle;
+	}
+
+	return EFI_SUCCESS;
+
+free_handle:
+	efi_call_early(free_pool, *rng_handle);
+
+	return status;
+}
+
+static bool efi_rng_supported32(efi_system_table_t *sys_table, void **rng_handle)
+{
+	const struct efi_config *efi_early = __efi_early();
+	efi_rng_protocol_32 *rng = NULL;
+	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
+	u32 *handles = (u32 *)(unsigned long)rng_handle;
+	unsigned long size = 0;
+	void **algorithmlist = NULL;
+	efi_status_t status;
+
+	status = efi_call_early(handle_protocol, handles[0],
+				&rng_proto, (void **)&rng);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table, " Failed to get EFI_RNG_PROTOCOL handles");
+
+	if (status == EFI_SUCCESS && rng) {
+		status = efi_early->call((unsigned long)rng->get_info, rng,
+					&size, algorithmlist);
+		return (status == EFI_BUFFER_TOO_SMALL);
+	}
+
+	return false;
+}
+
+static bool efi_rng_supported64(efi_system_table_t *sys_table, void **rng_handle)
+{
+	const struct efi_config *efi_early = __efi_early();
+	efi_rng_protocol_64 *rng = NULL;
+	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
+	u64 *handles = (u64 *)(unsigned long)rng_handle;
+	unsigned long size = 0;
+	void **algorithmlist = NULL;
+	efi_status_t status;
+
+	status = efi_call_early(handle_protocol, handles[0],
+				&rng_proto, (void **)&rng);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table, " Failed to get EFI_RNG_PROTOCOL handles");
+
+	if (status == EFI_SUCCESS && rng) {
+		status = efi_early->call((unsigned long)rng->get_info, rng,
+					&size, algorithmlist);
+		return (status == EFI_BUFFER_TOO_SMALL);
+	}
+
+	return false;
+}
+
+static bool efi_rng_supported(efi_system_table_t *sys_table)
+{
+	const struct efi_config *efi_early = __efi_early();
+	u32 random = 0;
+	efi_status_t status;
+	void **rng_handle = NULL;
+
+	status = efi_locate_rng(sys_table, &rng_handle);
+	if (status != EFI_SUCCESS)
+		return false;
+
+	if (efi_early->is64)
+		random = efi_rng_supported64(sys_table, rng_handle);
+	else
+		random = efi_rng_supported32(sys_table, rng_handle);
+
+	efi_call_early(free_pool, rng_handle);
+
+	return random;
+
+}
+
+static unsigned long efi_get_rng32(efi_system_table_t *sys_table,
+				   void **rng_handle)
+{
+	const struct efi_config *efi_early = __efi_early();
+	efi_rng_protocol_32 *rng = NULL;
+	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
+	u32 *handles = (u32 *)(unsigned long)rng_handle;
+	efi_status_t status;
+	unsigned long rng_number = 0;
+
+	status = efi_call_early(handle_protocol, handles[0],
+				&rng_proto, (void **)&rng);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table, " Failed to get EFI_RNG_PROTOCOL handles");
+
+	if (status == EFI_SUCCESS && rng) {
+		status = efi_early->call((unsigned long)rng->get_rng, rng, NULL,
+					sizeof(rng_number), &rng_number);
+		if (status != EFI_SUCCESS) {
+			efi_printk(sys_table, " Failed to get RNG value ");
+			efi_printk(sys_table, efi_status_to_str(status));
+		}
+	}
+
+	return rng_number;
+}
+
+static unsigned long efi_get_rng64(efi_system_table_t *sys_table,
+				   void **rng_handle)
+{
+	const struct efi_config *efi_early = __efi_early();
+	efi_rng_protocol_64 *rng = NULL;
+	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
+	u64 *handles = (u64 *)(unsigned long)rng_handle;
+	efi_status_t status;
+	unsigned long rng_number;
+
+	status = efi_call_early(handle_protocol, handles[0],
+				&rng_proto, (void **)&rng);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table, " Failed to get EFI_RNG_PROTOCOL handles");
+
+	if (status == EFI_SUCCESS && rng) {
+		status = efi_early->call((unsigned long)rng->get_rng, rng, NULL,
+					sizeof(rng_number), &rng_number);
+		if (status != EFI_SUCCESS) {
+			efi_printk(sys_table, " Failed to get RNG value ");
+			efi_printk(sys_table, efi_status_to_str(status));
+		}
+	}
+
+	return rng_number;
+}
+
+static unsigned long efi_get_rng(efi_system_table_t *sys_table)
+{
+	const struct efi_config *efi_early = __efi_early();
+	unsigned long random = 0;
+	efi_status_t status;
+	void **rng_handle = NULL;
+
+	status = efi_locate_rng(sys_table, &rng_handle);
+	if (status != EFI_SUCCESS)
+		return 0;
+
+	if (efi_early->is64)
+		random = efi_get_rng64(sys_table, rng_handle);
+	else
+		random = efi_get_rng32(sys_table, rng_handle);
+
+	efi_call_early(free_pool, rng_handle);
+
+	return random;
+}
 
 #define X86_FEATURE_EDX_TSC	(1 << 4)
 #define X86_FEATURE_ECX_RDRAND	(1 << 30)
@@ -51,6 +236,14 @@ static unsigned long get_random_long(unsigned long entropy,
 		use_i8254 = false;
 	}
 
+	if (efi_rng_supported(sys_table)) {
+		efi_printk(sys_table, " EFI_RNG");
+		raw = efi_get_rng(sys_table);
+		if (raw)
+			random ^= raw;
+		use_i8254 = false;
+	}
+
 	if (use_i8254) {
 		efi_printk(sys_table, " i8254");
 		random ^= i8254();
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 85ef051..a628f83 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -427,6 +427,16 @@ typedef struct {
 #define EFI_PCI_IO_ATTRIBUTE_VGA_PALETTE_IO_16 0x20000
 #define EFI_PCI_IO_ATTRIBUTE_VGA_IO_16 0x40000
 
+typedef struct {
+	u32 get_info;
+	u32 get_rng;
+} efi_rng_protocol_32;
+
+typedef struct {
+	u64 get_info;
+	u64 get_rng;
+} efi_rng_protocol_64;
+
 /*
  * Types and defines for EFI ResetSystem
  */
@@ -595,6 +605,9 @@ void efi_native_runtime_setup(void);
 #define DEVICE_TREE_GUID \
     EFI_GUID(  0xb1b621d5, 0xf19c, 0x41a5, 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0 )
 
+#define EFI_RNG_PROTOCOL_GUID \
+    EFI_GUID(  0x3152bca5, 0xeade, 0x433d, 0x86, 0x2e, 0xc0, 0x1c, 0xdc, 0x29, 0x1f, 0x44 )
+
 typedef struct {
 	efi_guid_t guid;
 	u64 table;
@@ -861,6 +874,39 @@ efi_guid_to_str(efi_guid_t *guid, char *out)
         return out;
 }
 
+static inline char *efi_status_to_str(efi_status_t status)
+{
+	char *str;
+
+	switch (status) {
+	case EFI_SUCCESS:
+		str = "EFI_SUCCESS";
+		break;
+	case EFI_INVALID_PARAMETER:
+		str = "EFI_INVALID_PARAMETER";
+		break;
+	case EFI_OUT_OF_RESOURCES:
+		str = "EFI_OUT_OF_RESOURCES";
+		break;
+	case EFI_DEVICE_ERROR:
+		str = "EFI_DEVICE_ERROR";
+		break;
+	case EFI_WRITE_PROTECTED:
+		str = "EFI_WRITE_PROTECTED";
+		break;
+	case EFI_SECURITY_VIOLATION:
+		str = "EFI_SECURITY_VIOLATION";
+		break;
+	case EFI_NOT_FOUND:
+		str = "EFI_NOT_FOUND";
+		break;
+	default:
+		str = "";
+	}
+
+	return str;
+}
+
 extern void efi_init (void);
 extern void *efi_get_pal_addr (void);
 extern void efi_map_pal_code (void);
-- 
1.8.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web