@@ -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
@@ -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;
@@ -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)]
@@ -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)
@@ -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().
*/
@@ -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
@@ -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;
@@ -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;
}
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(-)