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Message-Id: <ba7ffddf9e15288baeae6c2099e573509321738c.1635948742.git.msuchanek@suse.de>
Date: Wed, 3 Nov 2021 15:27:08 +0100
From: Michal Suchanek <msuchanek@...e.de>
To: keyrings@...r.kernel.org
Cc: Michal Suchanek <msuchanek@...e.de>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
David Howells <dhowells@...hat.com>,
Luis Chamberlain <mcgrof@...nel.org>,
Jessica Yu <jeyu@...nel.org>, Rob Herring <robh@...nel.org>,
Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
Hari Bathini <hbathini@...ux.ibm.com>,
Frank van der Linden <fllinden@...zon.com>,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
linux-s390@...r.kernel.org
Subject: [PATCH 3/3] powerpc/kexec_file: Add KEXEC_SIG support.
Use the module verifier for the kernel image verification.
Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
arch/powerpc/Kconfig | 11 +++++++++++
arch/powerpc/kexec/elf_64.c | 14 ++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 743c9783c64f..27bffafa9e79 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -558,6 +558,17 @@ config KEXEC_FILE
config ARCH_HAS_KEXEC_PURGATORY
def_bool KEXEC_FILE
+config KEXEC_SIG
+ bool "Verify kernel signature during kexec_file_load() syscall"
+ depends on KEXEC_FILE && MODULE_SIG_FORMAT
+ help
+ This option makes kernel signature verification mandatory for
+ the kexec_file_load() syscall.
+
+ In addition to that option, you need to enable signature
+ verification for the corresponding kernel image type being
+ loaded in order for this to work.
+
config PPC64_BUILD_ELF_V2_ABI
bool
diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index eeb258002d1e..e8dff6b23ac5 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -23,6 +23,7 @@
#include <linux/of_fdt.h>
#include <linux/slab.h>
#include <linux/types.h>
+#include <linux/verification.h>
static void *elf64_load(struct kimage *image, char *kernel_buf,
unsigned long kernel_len, char *initrd,
@@ -151,7 +152,20 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
return ret ? ERR_PTR(ret) : NULL;
}
+#ifdef CONFIG_KEXEC_SIG
+int elf64_verify_sig(const char *kernel, unsigned long length)
+{
+ size_t kernel_len = length;
+
+ return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING,
+ "kexec_file");
+}
+#endif /* CONFIG_KEXEC_SIG */
+
const struct kexec_file_ops kexec_elf64_ops = {
.probe = kexec_elf_probe,
.load = elf64_load,
+#ifdef CONFIG_KEXEC_SIG
+ .verify_sig = elf64_verify_sig,
+#endif
};
--
2.31.1
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