From: Nayna Jain <nayna@linux.ibm.com>
To: linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org, Mimi Zohar <zohar@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nayna Jain <nayna@linux.ibm.com>
Subject: [PATCH v2] powerpc/ima: fix secure boot rules in ima arch policy
Date: Fri, 1 May 2020 10:16:52 -0400 [thread overview]
Message-ID: <1588342612-14532-1-git-send-email-nayna@linux.ibm.com> (raw)
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>
---
v2:
* Fixes the patch description to specify the problem more clearly as asked
by Michael Ellerman.
arch/powerpc/kernel/ima_arch.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
index e34116255ced..957abd592075 100644
--- 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_trusted_rules[] = {
"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
--
2.18.1
next reply other threads:[~2020-05-01 14:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 14:16 Nayna Jain [this message]
2020-05-07 2:05 ` [PATCH v2] powerpc/ima: fix secure boot rules in ima arch policy Mimi Zohar
2020-05-13 12:43 ` Michael Ellerman
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