| Message ID | 20210907160110.2699645-2-eric.snowberg@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Enroll kernel keys thru MOK | expand |
On Tue, 2021-09-07 at 12:00 -0400, Eric Snowberg wrote: > Many UEFI Linux distributions boot using shim. The UEFI shim provides > what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure > Boot DB and MOK keys to validate the next step in the boot chain. The > MOK facility can be used to import user generated keys. These keys can > be used to sign an end-users development kernel build. When Linux > boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux > .platform keyring. > > Add a new Linux keyring called machine. This keyring shall contain just > MOK CA keys and not the remaining keys in the platform keyring. This new > machine keyring will be used in follow on patches. Unlike keys in the > platform keyring, keys contained in the machine keyring will be trusted > within the kernel if the end-user has chosen to do so. > > Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> I guess this is somewhat sealed so Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> /Jarkko
On Tue, 2021-09-07 at 12:00 -0400, Eric Snowberg wrote: > Many UEFI Linux distributions boot using shim. The UEFI shim provides > what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure > Boot DB and MOK keys to validate the next step in the boot chain. The > MOK facility can be used to import user generated keys. These keys can > be used to sign an end-users development kernel build. When Linux > boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux > .platform keyring. > > Add a new Linux keyring called machine. This keyring shall contain just ^Define > MOK CA keys and not the remaining keys in the platform keyring. This new > machine keyring will be used in follow on patches. Unlike keys in the > platform keyring, keys contained in the machine keyring will be trusted > within the kernel if the end-user has chosen to do so. > > Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> > --- > v1: Initial version > v2: Removed destory keyring code > v3: Unmodified from v2 > v4: Add Kconfig, merged in "integrity: add add_to_mok_keyring" > v5: Rename to machine keyring > --- > security/integrity/Kconfig | 11 +++++ > security/integrity/Makefile | 1 + > security/integrity/digsig.c | 1 + > security/integrity/integrity.h | 12 +++++- > .../platform_certs/machine_keyring.c | 42 +++++++++++++++++++ > 5 files changed, 66 insertions(+), 1 deletion(-) > create mode 100644 security/integrity/platform_certs/machine_keyring.c > > diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig > index 71f0177e8716..52193b86768a 100644 > --- a/security/integrity/Kconfig > +++ b/security/integrity/Kconfig > @@ -62,6 +62,17 @@ config INTEGRITY_PLATFORM_KEYRING > provided by the platform for verifying the kexec'ed kerned image > and, possibly, the initramfs signature. > > +config INTEGRITY_MACHINE_KEYRING > + bool "Provide a keyring to which CA Machine Owner Keys may be added" > + depends on SECONDARY_TRUSTED_KEYRING > + depends on INTEGRITY_ASYMMETRIC_KEYS > + depends on SYSTEM_BLACKLIST_KEYRING > + help > + If set, provide a keyring to which CA Machine Owner Keys (MOK) may > + be added. This keyring shall contain just CA MOK keys. Unlike keys > + in the platform keyring, keys contained in the .machine keyring will > + be trusted within the kernel. No sense in creating the ".machine" keyring, unless it is possible to safely load CA certificates on it. At least for the time being, this should also be dependent on EFI. <snip> > +++ b/security/integrity/platform_certs/machine_keyring.c > @@ -0,0 +1,42 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Machine keyring routines. > + * > + * Copyright (c) 2021, Oracle and/or its affiliates. > + */ > + > +#include "../integrity.h" > + > +static __init int machine_keyring_init(void) > +{ > + int rc; > + > + rc = integrity_init_keyring(INTEGRITY_KEYRING_MACHINE); > + if (rc) > + return rc; > + > + pr_notice("Machine keyring initialized\n"); > + return 0; > +} > +device_initcall(machine_keyring_init); > + > +void __init add_to_machine_keyring(const char *source, const void *data, size_t len) > +{ > + key_perm_t perm; > + int rc; > + > + perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW; > + rc = integrity_load_cert(INTEGRITY_KEYRING_MACHINE, source, data, len, perm); > + > + /* > + * Some MOKList keys may not pass the machine keyring restrictions. > + * If the restriction check does not pass and the platform keyring > + * is configured, try to add it into that keyring instead. > + */ > + if (rc) In addition to the comment, also test to see if the ".platform" keyring is configured. thanks, Mimi > + rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source, > + data, len, perm); > + > + if (rc) > + pr_info("Error adding keys to machine keyring %s\n", source); > +}
> On Sep 9, 2021, at 9:19 AM, Mimi Zohar <zohar@linux.ibm.com> wrote: > > On Tue, 2021-09-07 at 12:00 -0400, Eric Snowberg wrote: >> Many UEFI Linux distributions boot using shim. The UEFI shim provides >> what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure >> Boot DB and MOK keys to validate the next step in the boot chain. The >> MOK facility can be used to import user generated keys. These keys can >> be used to sign an end-users development kernel build. When Linux >> boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux >> .platform keyring. >> >> Add a new Linux keyring called machine. This keyring shall contain just > > ^Define I’ll change this in the next round. > >> MOK CA keys and not the remaining keys in the platform keyring. This new >> machine keyring will be used in follow on patches. Unlike keys in the >> platform keyring, keys contained in the machine keyring will be trusted >> within the kernel if the end-user has chosen to do so. >> >> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> >> --- >> v1: Initial version >> v2: Removed destory keyring code >> v3: Unmodified from v2 >> v4: Add Kconfig, merged in "integrity: add add_to_mok_keyring" >> v5: Rename to machine keyring >> --- >> security/integrity/Kconfig | 11 +++++ >> security/integrity/Makefile | 1 + >> security/integrity/digsig.c | 1 + >> security/integrity/integrity.h | 12 +++++- >> .../platform_certs/machine_keyring.c | 42 +++++++++++++++++++ >> 5 files changed, 66 insertions(+), 1 deletion(-) >> create mode 100644 security/integrity/platform_certs/machine_keyring.c >> >> diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig >> index 71f0177e8716..52193b86768a 100644 >> --- a/security/integrity/Kconfig >> +++ b/security/integrity/Kconfig >> @@ -62,6 +62,17 @@ config INTEGRITY_PLATFORM_KEYRING >> provided by the platform for verifying the kexec'ed kerned image >> and, possibly, the initramfs signature. >> >> +config INTEGRITY_MACHINE_KEYRING >> + bool "Provide a keyring to which CA Machine Owner Keys may be added" >> + depends on SECONDARY_TRUSTED_KEYRING >> + depends on INTEGRITY_ASYMMETRIC_KEYS >> + depends on SYSTEM_BLACKLIST_KEYRING >> + help >> + If set, provide a keyring to which CA Machine Owner Keys (MOK) may >> + be added. This keyring shall contain just CA MOK keys. Unlike keys >> + in the platform keyring, keys contained in the .machine keyring will >> + be trusted within the kernel. > > No sense in creating the ".machine" keyring, unless it is possible to > safely load CA certificates on it. At least for the time being, this > should also be dependent on EFI. > Will also add a depends for EFI >> +++ b/security/integrity/platform_certs/machine_keyring.c >> @@ -0,0 +1,42 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Machine keyring routines. >> + * >> + * Copyright (c) 2021, Oracle and/or its affiliates. >> + */ >> + >> +#include "../integrity.h" >> + >> +static __init int machine_keyring_init(void) >> +{ >> + int rc; >> + >> + rc = integrity_init_keyring(INTEGRITY_KEYRING_MACHINE); >> + if (rc) >> + return rc; >> + >> + pr_notice("Machine keyring initialized\n"); >> + return 0; >> +} >> +device_initcall(machine_keyring_init); >> + >> +void __init add_to_machine_keyring(const char *source, const void *data, size_t len) >> +{ >> + key_perm_t perm; >> + int rc; >> + >> + perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW; >> + rc = integrity_load_cert(INTEGRITY_KEYRING_MACHINE, source, data, len, perm); >> + >> + /* >> + * Some MOKList keys may not pass the machine keyring restrictions. >> + * If the restriction check does not pass and the platform keyring >> + * is configured, try to add it into that keyring instead. >> + */ >> + if (rc) > > In addition to the comment, also test to see if the ".platform" keyring > is configured. and will add this too. Thanks.
diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig index 71f0177e8716..52193b86768a 100644 --- a/security/integrity/Kconfig +++ b/security/integrity/Kconfig @@ -62,6 +62,17 @@ config INTEGRITY_PLATFORM_KEYRING provided by the platform for verifying the kexec'ed kerned image and, possibly, the initramfs signature. +config INTEGRITY_MACHINE_KEYRING + bool "Provide a keyring to which CA Machine Owner Keys may be added" + depends on SECONDARY_TRUSTED_KEYRING + depends on INTEGRITY_ASYMMETRIC_KEYS + depends on SYSTEM_BLACKLIST_KEYRING + help + If set, provide a keyring to which CA Machine Owner Keys (MOK) may + be added. This keyring shall contain just CA MOK keys. Unlike keys + in the platform keyring, keys contained in the .machine keyring will + be trusted within the kernel. + config LOAD_UEFI_KEYS depends on INTEGRITY_PLATFORM_KEYRING depends on EFI diff --git a/security/integrity/Makefile b/security/integrity/Makefile index 7ee39d66cf16..d0ffe37dc1d6 100644 --- a/security/integrity/Makefile +++ b/security/integrity/Makefile @@ -10,6 +10,7 @@ integrity-$(CONFIG_INTEGRITY_AUDIT) += integrity_audit.o integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o +integrity-$(CONFIG_INTEGRITY_MACHINE_KEYRING) += platform_certs/machine_keyring.o integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \ platform_certs/load_uefi.o \ platform_certs/keyring_handler.o diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index 3b06a01bd0fd..8c315be8ad99 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -30,6 +30,7 @@ static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = { ".ima", #endif ".platform", + ".machine", }; #ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 547425c20e11..730771eececd 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -151,7 +151,8 @@ int integrity_kernel_read(struct file *file, loff_t offset, #define INTEGRITY_KEYRING_EVM 0 #define INTEGRITY_KEYRING_IMA 1 #define INTEGRITY_KEYRING_PLATFORM 2 -#define INTEGRITY_KEYRING_MAX 3 +#define INTEGRITY_KEYRING_MACHINE 3 +#define INTEGRITY_KEYRING_MAX 4 extern struct dentry *integrity_dir; @@ -283,3 +284,12 @@ static inline void __init add_to_platform_keyring(const char *source, { } #endif + +#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING +void __init add_to_machine_keyring(const char *source, const void *data, size_t len); +#else +static inline void __init add_to_machine_keyring(const char *source, + const void *data, size_t len) +{ +} +#endif diff --git a/security/integrity/platform_certs/machine_keyring.c b/security/integrity/platform_certs/machine_keyring.c new file mode 100644 index 000000000000..948ec6c738c8 --- /dev/null +++ b/security/integrity/platform_certs/machine_keyring.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Machine keyring routines. + * + * Copyright (c) 2021, Oracle and/or its affiliates. + */ + +#include "../integrity.h" + +static __init int machine_keyring_init(void) +{ + int rc; + + rc = integrity_init_keyring(INTEGRITY_KEYRING_MACHINE); + if (rc) + return rc; + + pr_notice("Machine keyring initialized\n"); + return 0; +} +device_initcall(machine_keyring_init); + +void __init add_to_machine_keyring(const char *source, const void *data, size_t len) +{ + key_perm_t perm; + int rc; + + perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW; + rc = integrity_load_cert(INTEGRITY_KEYRING_MACHINE, source, data, len, perm); + + /* + * Some MOKList keys may not pass the machine keyring restrictions. + * If the restriction check does not pass and the platform keyring + * is configured, try to add it into that keyring instead. + */ + if (rc) + rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source, + data, len, perm); + + if (rc) + pr_info("Error adding keys to machine keyring %s\n", source); +}
Many UEFI Linux distributions boot using shim. The UEFI shim provides what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure Boot DB and MOK keys to validate the next step in the boot chain. The MOK facility can be used to import user generated keys. These keys can be used to sign an end-users development kernel build. When Linux boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux .platform keyring. Add a new Linux keyring called machine. This keyring shall contain just MOK CA keys and not the remaining keys in the platform keyring. This new machine keyring will be used in follow on patches. Unlike keys in the platform keyring, keys contained in the machine keyring will be trusted within the kernel if the end-user has chosen to do so. Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> --- v1: Initial version v2: Removed destory keyring code v3: Unmodified from v2 v4: Add Kconfig, merged in "integrity: add add_to_mok_keyring" v5: Rename to machine keyring --- security/integrity/Kconfig | 11 +++++ security/integrity/Makefile | 1 + security/integrity/digsig.c | 1 + security/integrity/integrity.h | 12 +++++- .../platform_certs/machine_keyring.c | 42 +++++++++++++++++++ 5 files changed, 66 insertions(+), 1 deletion(-) create mode 100644 security/integrity/platform_certs/machine_keyring.c