LinuxLists.cc - [PATCH 11/18] Hibernate: introduced RSA key-pair to verify signature of snapshot

2013-08-22 11:01:50

Subject: [PATCH 11/18] Hibernate: introduced RSA key-pair to verify signature of snapshot

Introduced a hibernate_key.c file to query the key pair from EFI variables
and maintain key pair for check signature of S4 snapshot image. We
loaded the private key when snapshot image stored success.

This patch introduced 2 EFI variables for store the key to sign S4 image and
verify signature when S4 wake up. The names and GUID are:
S4SignKey-fe141863-c070-478e-b8a3-878a5dc9ef21
S4WakeKey-fe141863-c070-478e-b8a3-878a5dc9ef21

S4SignKey is used by EFI bootloader to pass the RSA private key that packaged
by PKCS#8 format, kernel will read and parser it when system boot and reload
it when S4 resume. EFI bootloader need gnerate a new private key when every
time system boot.

S4WakeKey is used to pass the RSA public key that packaged by X.509
certificate, kernel will read and parser it for check the signature of
S4 snapshot image when S4 resume.

The follow-up patch will remove S4SignKey and S4WakeKey after load them
to kernel for avoid anyone can access it through efivarfs.

v3:
- Load S4 sign key before ExitBootServices.
Load private key before ExitBootServices() then bootloader doesn't need
generate key-pair for each booting:
+ Add setup_s4_keys() to eboot.c to load S4 sign key before ExitBootServices.
+ Reserve the memory block of sign key data blob in efi.c
- In Makefile, moved hibernate_keys.o before hibernate.o for load S4 sign
key before check hibernate image. It makes sure the new sign key will be
transfer to resume target kernel.
- Set "depends on EFI_STUB" in Kconfig

v2:
Add CONFIG_SNAPSHOT_VERIFICATION for build of hibernate_keys.c depend on
Kconfig.

Cc: Matthew Garrett <[email protected]>
Cc: Takashi Iwai <[email protected]>
Reviewed-by: Jiri Kosina <[email protected]>
Signed-off-by: Lee, Chun-Yi <jlee-IBi9RG/[email protected]>
---
arch/x86/boot/compressed/eboot.c | 89 ++++++++++
arch/x86/include/asm/efi.h | 9 +
arch/x86/include/uapi/asm/bootparam.h | 1 +
arch/x86/platform/efi/efi.c | 68 ++++++++
include/linux/efi.h | 17 ++
kernel/power/Kconfig | 16 ++-
kernel/power/Makefile | 1 +
kernel/power/hibernate.c | 3 +
kernel/power/hibernate_keys.c | 290 +++++++++++++++++++++++++++++++++
kernel/power/power.h | 27 +++
10 files changed, 519 insertions(+), 2 deletions(-)
create mode 100644 kernel/power/hibernate_keys.c

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 9baee3e..855bda4 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -368,6 +368,91 @@ free_handle:
return status;
}

+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+static efi_status_t setup_s4_keys(struct boot_params *params)
+{
+ struct setup_data *data;
+ unsigned long datasize;
+ u32 attr;
+ struct efi_s4_key *s4key;
+ efi_status_t status;
+
+ data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
+
+ while (data && data->next)
+ data = (struct setup_data *)(unsigned long)data->next;
+
+ status = efi_call_phys3(sys_table->boottime->allocate_pool,
+ EFI_LOADER_DATA, sizeof(*s4key), &s4key);
+ if (status != EFI_SUCCESS) {
+ efi_printk("Failed to alloc memory for efi_s4_key\n");
+ goto error_setup;
+ }
+
+ s4key->data.type = SETUP_S4_KEY;
+ s4key->data.len = sizeof(struct efi_s4_key) -
+ sizeof(struct setup_data);
+ s4key->data.next = 0;
+ s4key->skey_dsize = 0;
+ s4key->err_status = 0;
+
+ if (data)
+ data->next = (unsigned long)s4key;
+ else
+ params->hdr.setup_data = (unsigned long)s4key;
+
+ /* obtain the size of key data */
+ datasize = 0;
+ status = efi_call_phys5(sys_table->runtime->get_variable,
+ EFI_S4_SIGN_KEY_NAME, &EFI_HIBERNATE_GUID,
+ NULL, &datasize, NULL);
+ if (status != EFI_BUFFER_TOO_SMALL) {
+ efi_printk("Couldn't get S4 key data size\n");
+ goto error_size;
+ }
+ if (datasize > PAGE_SIZE - sizeof(datasize)) {
+ efi_printk("The size of S4 sign key is too large\n");
+ status = EFI_UNSUPPORTED;
+ goto error_size;
+ }
+
+ s4key->skey_dsize = datasize;
+ status = efi_call_phys3(sys_table->boottime->allocate_pool,
+ EFI_LOADER_DATA, s4key->skey_dsize,
+ &s4key->skey_data_addr);
+ if (status != EFI_SUCCESS) {
+ efi_printk("Failed to alloc page for S4 key data\n");
+ goto error_s4key;
+ }
+
+ attr = 0;
+ memset((void *)s4key->skey_data_addr, 0, s4key->skey_dsize);
+ status = efi_call_phys5(sys_table->runtime->get_variable,
+ EFI_S4_SIGN_KEY_NAME, &EFI_HIBERNATE_GUID, &attr,
+ &(s4key->skey_dsize), s4key->skey_data_addr);
+ if (status) {
+ efi_printk("Couldn't get S4 key data\n");
+ goto error_gets4key;
+ }
+ if (attr & EFI_VARIABLE_RUNTIME_ACCESS) {
+ efi_printk("S4 sign key can not be a runtime variable\n");
+ memset((void *)s4key->skey_data_addr, 0, s4key->skey_dsize);
+ status = EFI_UNSUPPORTED;
+ goto error_gets4key;
+ }
+
+ return 0;
+
+error_gets4key:
+ efi_call_phys1(sys_table->boottime->free_pool, s4key->skey_data_addr);
+error_s4key:
+error_size:
+ s4key->err_status = status;
+error_setup:
+ return status;
+}
+#endif /* CONFIG_SNAPSHOT_VERIFICATION */
+
/*
* See if we have Graphics Output Protocol
*/
@@ -1205,6 +1290,10 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,

setup_efi_pci(boot_params);

+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+ setup_s4_keys(boot_params);
+#endif
+
status = efi_call_phys3(sys_table->boottime->allocate_pool,
EFI_LOADER_DATA, sizeof(*gdt),
(void **)&gdt);
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 0062a01..56ececa 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -102,6 +102,15 @@ extern void efi_call_phys_epilog(void);
extern void efi_unmap_memmap(void);
extern void efi_memory_uc(u64 addr, unsigned long size);

+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+struct efi_s4_key {
+ struct setup_data data;
+ unsigned long err_status;
+ unsigned long skey_dsize;
+ void *skey_data_addr;
+};
+#endif
+
#ifdef CONFIG_EFI

static inline bool efi_is_native(void)
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 85d7685..79398ff 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -6,6 +6,7 @@
#define SETUP_E820_EXT 1
#define SETUP_DTB 2
#define SETUP_PCI 3
+#define SETUP_S4_KEY 4

/* ram_size flags */
#define RAMDISK_IMAGE_START_MASK 0x07FF
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 90f6ed1..c8a4fca 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -704,6 +704,69 @@ static int __init efi_memmap_init(void)
return 0;
}

+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+static unsigned long skey_dsize;
+static u64 skey_data_addr;
+static unsigned long skey_err_status;
+
+bool efi_s4_key_available(void)
+{
+ return skey_dsize && skey_data_addr && !skey_err_status;
+}
+
+unsigned long __init efi_copy_skey_data(void *page_addr)
+{
+ void *key_addr;
+
+ if (efi_s4_key_available()) {
+ key_addr = early_ioremap(skey_data_addr, skey_dsize);
+ memcpy(page_addr, key_addr, skey_dsize);
+ early_iounmap(key_addr, skey_dsize);
+ }
+
+ return skey_dsize;
+}
+
+void __init efi_erase_s4_skey_data(void)
+{
+ void *key_addr;
+
+ key_addr = early_ioremap(skey_data_addr, skey_dsize);
+ memset(key_addr, 0, skey_dsize);
+ early_iounmap(key_addr, skey_dsize);
+ memblock_free(skey_data_addr, skey_dsize);
+ skey_data_addr = 0;
+ skey_dsize = 0;
+}
+
+static void __init efi_reserve_s4_skey_data(void)
+{
+ u64 pa_data;
+ struct setup_data *data;
+ struct efi_s4_key *s4key;
+
+ skey_err_status = 0;
+ pa_data = boot_params.hdr.setup_data;
+ while (pa_data) {
+ data = early_ioremap(pa_data, sizeof(*s4key));
+ if (data->type == SETUP_S4_KEY) {
+ s4key = (struct efi_s4_key *)data;
+ if (!s4key->err_status) {
+ skey_dsize = s4key->skey_dsize;
+ skey_data_addr = (u64) s4key->skey_data_addr;
+ memblock_reserve(skey_data_addr, skey_dsize);
+ } else {
+ skey_err_status = s4key->err_status;
+ pr_err("Get S4 sign key from EFI fail: 0x%lx\n",
+ skey_err_status);
+ }
+ }
+ pa_data = data->next;
+ early_iounmap(data, sizeof(*s4key));
+ }
+}
+#endif /* CONFIG_SNAPSHOT_VERIFICATION */
+
void __init efi_init(void)
{
efi_char16_t *c16;
@@ -729,6 +792,11 @@ void __init efi_init(void)

set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);

+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+ /* keep s4 key from setup_data */
+ efi_reserve_s4_skey_data();
+#endif
+
/*
* Show what we know for posterity
*/
diff --git a/include/linux/efi.h b/include/linux/efi.h
index febce85..55f80be 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -389,6 +389,18 @@ typedef efi_status_t efi_query_variable_store_t(u32 attributes, unsigned long si
#define EFI_FILE_SYSTEM_GUID \
EFI_GUID( 0x964e5b22, 0x6459, 0x11d2, 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b )

+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+#define EFI_HIBERNATE_GUID \
+ EFI_GUID(0xfe141863, 0xc070, 0x478e, 0xb8, 0xa3, 0x87, 0x8a, 0x5d, 0xc9, 0xef, 0x21)
+/*
+ * The UEFI variable names of the key-pair to verify S4 snapshot image:
+ * S4SignKey-EFI_HIBERNATE_GUID: The private key is used to sign snapshot
+ * S4WakeKey-EFI_HIBERNATE_GUID: The public key is used to verify snapshot
+ */
+#define EFI_S4_SIGN_KEY_NAME ((efi_char16_t [10]) { 'S', '4', 'S', 'i', 'g', 'n', 'K', 'e', 'y', 0 })
+#define EFI_S4_WAKE_KEY_NAME ((efi_char16_t [10]) { 'S', '4', 'W', 'a', 'k', 'e', 'K', 'e', 'y', 0 })
+#endif /* CONFIG_SNAPSHOT_VERIFICATION */
+
typedef struct {
efi_guid_t guid;
u64 table;
@@ -577,6 +589,11 @@ extern void efi_enter_virtual_mode (void); /* switch EFI to virtual mode, if pos
extern void efi_late_init(void);
extern void efi_free_boot_services(void);
extern efi_status_t efi_query_variable_store(u32 attributes, unsigned long size);
+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+extern bool efi_s4_key_available(void);
+extern unsigned long efi_copy_skey_data(void *page_addr);
+extern void efi_erase_s4_skey_data(void);
+#endif /* CONFIG_SNAPSHOT_VERIFICATION */
#else
static inline void efi_late_init(void) {}
static inline void efi_free_boot_services(void) {}
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index d444c4e..b592d88 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -66,8 +66,17 @@ config HIBERNATION

For more information take a look at <file:Documentation/power/swsusp.txt>.

-config ARCH_SAVE_PAGE_KEYS
- bool
+config SNAPSHOT_VERIFICATION
+ bool "Hibernate snapshot verification"
+ depends on HIBERNATION
+ depends on EFI_STUB
+ depends on X86
+ select PKCS8_PRIVATE_KEY_INFO_PARSER
+ help
+ This option provides support for generate anad verify the signautre by
+ RSA key-pair against hibernate snapshot image. Current mechanism
+ dependent on UEFI environment. EFI bootloader should generate the
+ key-pair.

config PM_STD_PARTITION
string "Default resume partition"
@@ -91,6 +100,9 @@ config PM_STD_PARTITION
suspended image to. It will simply pick the first available swap
device.

+config ARCH_SAVE_PAGE_KEYS
+ bool
+
config PM_SLEEP
def_bool y
depends on SUSPEND || HIBERNATE_CALLBACKS
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 29472bf..46b6422 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_VT_CONSOLE_SLEEP) += console.o
obj-$(CONFIG_FREEZER) += process.o
obj-$(CONFIG_SUSPEND) += suspend.o
obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o
+obj-$(CONFIG_SNAPSHOT_VERIFICATION) += hibernate_keys.o
obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o user.o \
block_io.o
obj-$(CONFIG_PM_AUTOSLEEP) += autosleep.o
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index b26f5f1..c545b15 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -28,6 +28,7 @@
#include <linux/syscore_ops.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
+#include <linux/key.h>

#include "power.h"

@@ -631,6 +632,7 @@ static void power_down(void)
int hibernate(void)
{
int error;
+ int skey_error;

lock_system_sleep();
/* The snapshot device should not be opened while we're running */
@@ -680,6 +682,7 @@ int hibernate(void)
pm_restore_gfp_mask();
} else {
pr_debug("PM: Image restored successfully.\n");
+ restore_sign_key_data();
}

Thaw:
diff --git a/kernel/power/hibernate_keys.c b/kernel/power/hibernate_keys.c
new file mode 100644
index 0000000..1bc5976
--- /dev/null
+++ b/kernel/power/hibernate_keys.c
@@ -0,0 +1,290 @@
+#include <linux/sched.h>
+#include <linux/efi.h>
+#include <linux/mpi.h>
+#include <linux/asn1.h>
+#include <crypto/public_key.h>
+#include <keys/asymmetric-type.h>
+
+#include "power.h"
+
+static void *skey_data;
+static void *skey_data_buf;
+static unsigned long skey_dsize;
+
+static int efi_status_to_err(efi_status_t status)
+{
+ int err;
+
+ switch (status) {
+ 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 = -ENODATA;
+ break;
+ default:
+ err = -EINVAL;
+ }
+
+ return err;
+}
+
+bool swsusp_page_is_sign_key(struct page *page)
+{
+ unsigned long skey_data_pfn;
+ bool ret;
+
+ if (!skey_data || IS_ERR(skey_data))
+ return false;
+
+ skey_data_pfn = page_to_pfn(virt_to_page(skey_data));
+ ret = (page_to_pfn(page) == skey_data_pfn) ? true : false;
+ if (ret)
+ pr_info("PM: Avoid snapshot the page of S4 sign key.\n");
+
+ return ret;
+}
+
+unsigned long get_skey_data_buf_pfn(void)
+{
+ if (!skey_data_buf || IS_ERR(skey_data_buf))
+ return 0;
+
+ return page_to_pfn(virt_to_page(skey_data_buf));
+}
+
+void clone_skey_data(void *page)
+{
+ if (!page)
+ return;
+
+ if (skey_data && !IS_ERR(skey_data)) {
+ memcpy(page, &skey_dsize, sizeof(skey_dsize));
+ memcpy(page + sizeof(skey_dsize), skey_data, PAGE_SIZE - sizeof(skey_dsize));
+ }
+}
+
+void restore_sign_key_data(void)
+{
+ memset(skey_data, 0, PAGE_SIZE);
+ if (skey_data_buf && !IS_ERR(skey_data_buf)) {
+ /* restore sign key size and data from buffer */
+ memcpy(&skey_dsize, skey_data_buf, sizeof(skey_dsize));
+ memcpy(skey_data, skey_data_buf + sizeof(skey_dsize),
+ PAGE_SIZE - sizeof(skey_dsize));
+ /* reset skey page buffer */
+ memset(skey_data_buf, 0, PAGE_SIZE);
+ pr_info("PM: Restore S4 sign key from buffer\n");
+ } else
+ pr_err("PM: Restore S4 sign key fail\n");
+}
+
+bool skey_data_available(void)
+{
+ static unsigned char const_seq = (ASN1_SEQ | (ASN1_CONS << 5));
+ bool ret = false;
+
+ /* Sign key is PKCS#8 format that must be a Constructed SEQUENCE */
+ ret = skey_data && !IS_ERR(skey_data) &&
+ (skey_dsize != 0) &&
+ ((unsigned char *)skey_data)[0] == const_seq;
+
+ return ret;
+}
+
+struct key *get_sign_key(void)
+{
+ const struct cred *cred = current_cred();
+ struct key *skey;
+ int err;
+
+ if (!skey_data || IS_ERR(skey_data))
+ return ERR_PTR(-EBADMSG);
+
+ skey = key_alloc(&key_type_asymmetric, "s4_sign_key",
+ GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
+ cred, 0, KEY_ALLOC_NOT_IN_QUOTA);
+ if (IS_ERR(skey)) {
+ pr_err("PM: Allocate s4 sign key error: %ld\n", PTR_ERR(skey));
+ goto error_keyalloc;
+ }
+
+ err = key_instantiate_and_link(skey, skey_data, skey_dsize, NULL, NULL);
+ if (err < 0) {
+ pr_err("PM: S4 sign key instantiate error: %d\n", err);
+ if (skey)
+ key_put(skey);
+ skey = ERR_PTR(err);
+ goto error_keyinit;
+ }
+
+ return skey;
+
+error_keyinit:
+error_keyalloc:
+ return skey;
+}
+
+void erase_skey_data(void)
+{
+ if (!skey_data || IS_ERR(skey_data))
+ return;
+
+ memset(skey_data, 0, PAGE_SIZE);
+}
+
+void destroy_sign_key(struct key *skey)
+{
+ erase_skey_data();
+ if (skey)
+ key_put(skey);
+}
+
+static void *load_wake_key_data(unsigned long *datasize)
+{
+ u32 attr;
+ void *wkey_data;
+ efi_status_t status;
+
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return ERR_PTR(-EPERM);
+
+ /* obtain the size */
+ *datasize = 0;
+ status = efi.get_variable(EFI_S4_WAKE_KEY_NAME, &EFI_HIBERNATE_GUID,
+ NULL, datasize, NULL);
+ if (status != EFI_BUFFER_TOO_SMALL) {
+ wkey_data = ERR_PTR(efi_status_to_err(status));
+ pr_err("PM: Couldn't get wake key data size: 0x%lx\n", status);
+ goto error;
+ }
+
+ /* check attributes */
+ wkey_data = kzalloc(*datasize, GFP_KERNEL);
+ if (!wkey_data) {
+ wkey_data = ERR_PTR(-ENOMEM);
+ goto error;
+ }
+
+ status = efi.get_variable(EFI_S4_WAKE_KEY_NAME, &EFI_HIBERNATE_GUID,
+ &attr, datasize, wkey_data);
+ if (status) {
+ kfree(wkey_data);
+ *datasize = 0;
+ wkey_data = ERR_PTR(efi_status_to_err(status));
+ pr_err("PM: Get wake key data error: 0x%lx\n", status);
+ goto error;
+ }
+ if (attr & EFI_VARIABLE_NON_VOLATILE) {
+ memset(wkey_data, 0, *datasize);
+ kfree(wkey_data);
+ *datasize = 0;
+ wkey_data = ERR_PTR(-EBADMSG);
+ pr_err("PM: Wake key has wrong attributes: 0x%x\n", attr);
+ goto error;
+ }
+
+error:
+ return wkey_data;
+}
+
+bool wkey_data_available(void)
+{
+ static int ret = 1;
+ unsigned long datasize;
+ void *wkey_data;
+
+ if (ret > 0) {
+ wkey_data = load_wake_key_data(&datasize);
+ if (wkey_data && IS_ERR(wkey_data)) {
+ ret = PTR_ERR(wkey_data);
+ goto error;
+ } else {
+ if (wkey_data) {
+ memset(wkey_data, 0, datasize);
+ kfree(wkey_data);
+ }
+ ret = 0;
+ }
+ }
+
+error:
+ return !ret;
+}
+
+struct key *get_wake_key(void)
+{
+ const struct cred *cred = current_cred();
+ void *wkey_data;
+ unsigned long datasize = 0;
+ struct key *wkey;
+ int err;
+
+ wkey_data = load_wake_key_data(&datasize);
+ if (IS_ERR(wkey_data)) {
+ wkey = (struct key *)wkey_data;
+ goto error_data;
+ }
+
+ wkey = key_alloc(&key_type_asymmetric, "s4_wake_key",
+ GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
+ cred, 0, KEY_ALLOC_NOT_IN_QUOTA);
+ if (IS_ERR(wkey)) {
+ pr_err("PM: Allocate s4 wake key error: %ld\n", PTR_ERR(wkey));
+ goto error_keyalloc;
+ }
+ err = key_instantiate_and_link(wkey, wkey_data, datasize, NULL, NULL);
+ if (err < 0) {
+ pr_err("PM: S4 wake key instantiate error: %d\n", err);
+ if (wkey)
+ key_put(wkey);
+ wkey = ERR_PTR(err);
+ }
+
+error_keyalloc:
+ if (wkey_data && !IS_ERR(wkey_data))
+ kfree(wkey_data);
+error_data:
+ return wkey;
+}
+
+size_t get_key_length(const struct key *key)
+{
+ const struct public_key *pk = key->payload.data;
+ size_t len;
+
+ /* TODO: better check the RSA type */
+
+ len = mpi_get_nbits(pk->rsa.n);
+ len = (len + 7) / 8;
+
+ return len;
+}
+
+static int __init init_sign_key_data(void)
+{
+ skey_data = (void *)get_zeroed_page(GFP_KERNEL);
+ skey_data_buf = (void *)get_zeroed_page(GFP_KERNEL);
+
+ if (skey_data && efi_s4_key_available()) {
+ skey_dsize = efi_copy_skey_data(skey_data);
+ efi_erase_s4_skey_data();
+ pr_info("PM: Load s4 sign key from EFI\n");
+ }
+
+ return 0;
+}
+
+late_initcall(init_sign_key_data);
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 7d4b7ff..69a81d8 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -160,6 +160,33 @@ extern void swsusp_close(fmode_t);
extern int swsusp_unmark(void);
#endif

+/* kernel/power/hibernate_key.c */
+extern bool skey_data_available(void);
+extern struct key *get_sign_key(void);
+extern void erase_skey_data(void);
+extern void snapshot_fill_s4_skey(void);
+extern void destroy_sign_key(struct key *key);
+extern bool wkey_data_available(void);
+extern struct key *get_wake_key(void);
+extern size_t get_key_length(const struct key *key);
+
+#ifdef CONFIG_SNAPSHOT_VERIFICATION
+extern void restore_sign_key_data(void);
+extern bool swsusp_page_is_sign_key(struct page *page);
+extern unsigned long get_skey_data_buf_pfn(void);
+extern void clone_skey_data(void *page_addr);
+#else /* !CONFIG_SUSPEND */
+static inline void restore_sign_key_data(void) {}
+static inline bool swsusp_page_is_sign_key(struct page *page)
+{
+ return false;
+}
+static inline unsigned long get_skey_data_buf_pfn(void)
+{
+ return 0;
+}
+#endif /* !CONFIG_SNAPSHOT_VERIFICATION */
+
/* kernel/power/block_io.c */
extern struct block_device *hib_resume_bdev;

--
1.6.4.2

2013-08-25 16:25:54

by Pavel Machek

[permalink] [raw]

Subject: Re: [PATCH 11/18] Hibernate: introduced RSA key-pair to verify signature of snapshot

On Thu 2013-08-22 19:01:50, Lee, Chun-Yi wrote:
> Introduced a hibernate_key.c file to query the key pair from EFI variables
> and maintain key pair for check signature of S4 snapshot image. We
> loaded the private key when snapshot image stored success.
>
> This patch introduced 2 EFI variables for store the key to sign S4 image and
> verify signature when S4 wake up. The names and GUID are:
> S4SignKey-fe141863-c070-478e-b8a3-878a5dc9ef21
> S4WakeKey-fe141863-c070-478e-b8a3-878a5dc9ef21
>
> S4SignKey is used by EFI bootloader to pass the RSA private key that packaged
> by PKCS#8 format, kernel will read and parser it when system boot and reload
> it when S4 resume. EFI bootloader need gnerate a new private key when every
> time system boot.
>
> S4WakeKey is used to pass the RSA public key that packaged by X.509
> certificate, kernel will read and parser it for check the signature of
> S4 snapshot image when S4 resume.
>
> The follow-up patch will remove S4SignKey and S4WakeKey after load them
> to kernel for avoid anyone can access it through efivarfs.
>
> v3:
> - Load S4 sign key before ExitBootServices.
> Load private key before ExitBootServices() then bootloader doesn't need
> generate key-pair for each booting:
> + Add setup_s4_keys() to eboot.c to load S4 sign key before ExitBootServices.
> + Reserve the memory block of sign key data blob in efi.c
> - In Makefile, moved hibernate_keys.o before hibernate.o for load S4 sign
> key before check hibernate image. It makes sure the new sign key will be
> transfer to resume target kernel.
> - Set "depends on EFI_STUB" in Kconfig
>
> v2:
> Add CONFIG_SNAPSHOT_VERIFICATION for build of hibernate_keys.c depend on
> Kconfig.
>
> Cc: Matthew Garrett <[email protected]>
> Cc: Takashi Iwai <[email protected]>
> Reviewed-by: Jiri Kosina <[email protected]>
> Signed-off-by: Lee, Chun-Yi <[email protected]>

> --- a/arch/x86/boot/compressed/eboot.c
> +++ b/arch/x86/boot/compressed/eboot.c
> @@ -368,6 +368,91 @@ free_handle:
> return status;
> }
>
> +#ifdef CONFIG_SNAPSHOT_VERIFICATION
> +static efi_status_t setup_s4_keys(struct boot_params *params)
> +{
> + struct setup_data *data;
> + unsigned long datasize;
> + u32 attr;
> + struct efi_s4_key *s4key;
> + efi_status_t status;
> +
> + data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

A bit too many casts.

> @@ -1205,6 +1290,10 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,
>
> setup_efi_pci(boot_params);
>
> +#ifdef CONFIG_SNAPSHOT_VERIFICATION
> + setup_s4_keys(boot_params);
> +#endif
> +

Move ifdef inside the function?

> @@ -729,6 +792,11 @@ void __init efi_init(void)
>
> set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
>
> +#ifdef CONFIG_SNAPSHOT_VERIFICATION
> + /* keep s4 key from setup_data */
> + efi_reserve_s4_skey_data();
> +#endif
> +

Here too.

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

2013-08-27 09:04:43