From: Nayna Jain nayna@linux.ibm.com
commit fa4f3f56ccd28ac031ab275e673ed4098855fed4 upstream.
To prevent verifying the kernel module appended signature twice (finit_module), once by the module_sig_check() and again by IMA, powerpc secure boot rules define an IMA architecture specific policy rule only if CONFIG_MODULE_SIG_FORCE is not enabled. This, unfortunately, does not take into account the ability of enabling "sig_enforce" on the boot command line (module.sig_enforce=1).
Including the IMA module appraise rule results in failing the finit_module syscall, unless the module signing public key is loaded onto the IMA keyring.
This patch fixes secure boot policy rules to be based on CONFIG_MODULE_SIG instead.
Fixes: 4238fad366a6 ("powerpc/ima: Add support to initialize ima policy rules") Signed-off-by: Nayna Jain nayna@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Mimi Zohar zohar@linux.ibm.com Link: https://lore.kernel.org/r/1588342612-14532-1-git-send-email-nayna@linux.ibm.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/kernel/ima_arch.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/powerpc/kernel/ima_arch.c +++ b/arch/powerpc/kernel/ima_arch.c @@ -19,12 +19,12 @@ bool arch_ima_get_secureboot(void) * to be stored as an xattr or as an appended signature. * * To avoid duplicate signature verification as much as possible, the IMA - * policy rule for module appraisal is added only if CONFIG_MODULE_SIG_FORCE + * policy rule for module appraisal is added only if CONFIG_MODULE_SIG * is not enabled. */ static const char *const secure_rules[] = { "appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", -#ifndef CONFIG_MODULE_SIG_FORCE +#ifndef CONFIG_MODULE_SIG "appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", #endif NULL @@ -50,7 +50,7 @@ static const char *const secure_and_trus "measure func=KEXEC_KERNEL_CHECK template=ima-modsig", "measure func=MODULE_CHECK template=ima-modsig", "appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", -#ifndef CONFIG_MODULE_SIG_FORCE +#ifndef CONFIG_MODULE_SIG "appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", #endif NULL