| Message ID | 1569594360-7141-6-git-send-email-nayna@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | powerpc: Enabling IMA arch specific secure boot policies | expand |
On Fri, 2019-09-27 at 10:25 -0400, Nayna Jain wrote: > This patch adds the measurement rules to the arch specific policies for the > systems with trusted boot. > on trusted boot enabled systems. > Signed-off-by: Nayna Jain <nayna@linux.ibm.com> Minor comment correction below. Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> > --- > arch/powerpc/kernel/ima_arch.c | 44 +++++++++++++++++++++++++++++++--- > 1 file changed, 41 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c > index 39401b67f19e..77c61b142042 100644 > --- a/arch/powerpc/kernel/ima_arch.c > +++ b/arch/powerpc/kernel/ima_arch.c > @@ -12,8 +12,18 @@ bool arch_ima_get_secureboot(void) > return is_powerpc_os_secureboot_enabled(); > } > > -/* Defines IMA appraise rules for secureboot */ > +/* > + * The "arch_rules" contains both the securebot and trustedboot rules for adding > + * the kexec kernel image and kernel modules file hashes to the IMA measurement > + * list and verifying the file signatures against known good values. > + * > + * The "appraise_type=imasig|modsig" option allows the good signature to be > + * stored as an xattr or as an appended signature. The "template=ima-modsig" > + * option includes the appended signature in the IMA measurement list. includes the appended signature, when available, in the IMA measurement list. > + */ > static const char *const arch_rules[] = { > + "measure func=KEXEC_KERNEL_CHECK template=ima-modsig", > + "measure func=MODULE_CHECK template=ima-modsig", > "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig", > #if !IS_ENABLED(CONFIG_MODULE_SIG) > "appraise func=MODULE_CHECK appraise_type=imasig|modsig", > @@ -22,12 +32,40 @@ static const char *const arch_rules[] = { > }; > > /* > - * Returns the relevant IMA arch policies based on the system secureboot state. > + * The "measure_rules" are enabled only on "trustedboot" enabled systems. > + * These rules add the kexec kernel image and kernel modules file hashes to > + * the IMA measurement list. > + */ > +static const char *const measure_rules[] = { > + "measure func=KEXEC_KERNEL_CHECK", > + "measure func=MODULE_CHECK", > + NULL > +}; > + > +/* > + * Returns the relevant IMA arch policies based on the system secureboot > + * and trustedboot state. > */ > const char *const *arch_get_ima_policy(void) > { > - if (is_powerpc_os_secureboot_enabled()) > + const char *const *rules; > + int offset = 0; > + > + for (rules = arch_rules; *rules != NULL; rules++) { > + if (strncmp(*rules, "appraise", 8) == 0) > + break; > + offset++; > + } > + > + if (is_powerpc_os_secureboot_enabled() > + && is_powerpc_trustedboot_enabled()) > return arch_rules; > > + if (is_powerpc_os_secureboot_enabled()) > + return arch_rules + offset; > + > + if (is_powerpc_trustedboot_enabled()) > + return measure_rules; > + > return NULL; > }
diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c index 39401b67f19e..77c61b142042 100644 --- a/arch/powerpc/kernel/ima_arch.c +++ b/arch/powerpc/kernel/ima_arch.c @@ -12,8 +12,18 @@ bool arch_ima_get_secureboot(void) return is_powerpc_os_secureboot_enabled(); } -/* Defines IMA appraise rules for secureboot */ +/* + * The "arch_rules" contains both the securebot and trustedboot rules for adding + * the kexec kernel image and kernel modules file hashes to the IMA measurement + * list and verifying the file signatures against known good values. + * + * The "appraise_type=imasig|modsig" option allows the good signature to be + * stored as an xattr or as an appended signature. The "template=ima-modsig" + * option includes the appended signature in the IMA measurement list. + */ static const char *const arch_rules[] = { + "measure func=KEXEC_KERNEL_CHECK template=ima-modsig", + "measure func=MODULE_CHECK template=ima-modsig", "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig", #if !IS_ENABLED(CONFIG_MODULE_SIG) "appraise func=MODULE_CHECK appraise_type=imasig|modsig", @@ -22,12 +32,40 @@ static const char *const arch_rules[] = { }; /* - * Returns the relevant IMA arch policies based on the system secureboot state. + * The "measure_rules" are enabled only on "trustedboot" enabled systems. + * These rules add the kexec kernel image and kernel modules file hashes to + * the IMA measurement list. + */ +static const char *const measure_rules[] = { + "measure func=KEXEC_KERNEL_CHECK", + "measure func=MODULE_CHECK", + NULL +}; + +/* + * Returns the relevant IMA arch policies based on the system secureboot + * and trustedboot state. */ const char *const *arch_get_ima_policy(void) { - if (is_powerpc_os_secureboot_enabled()) + const char *const *rules; + int offset = 0; + + for (rules = arch_rules; *rules != NULL; rules++) { + if (strncmp(*rules, "appraise", 8) == 0) + break; + offset++; + } + + if (is_powerpc_os_secureboot_enabled() + && is_powerpc_trustedboot_enabled()) return arch_rules; + if (is_powerpc_os_secureboot_enabled()) + return arch_rules + offset; + + if (is_powerpc_trustedboot_enabled()) + return measure_rules; + return NULL; }
This patch adds the measurement rules to the arch specific policies for the systems with trusted boot. Signed-off-by: Nayna Jain <nayna@linux.ibm.com> --- arch/powerpc/kernel/ima_arch.c | 44 +++++++++++++++++++++++++++++++--- 1 file changed, 41 insertions(+), 3 deletions(-)