* [PATCH 0/1] kexec: verify bzImage signature
@ 2014-07-09 18:24 Vivek Goyal
2014-07-09 18:24 ` [PATCH 1/1] kexec: Verify the signature of signed PE bzImage Vivek Goyal
0 siblings, 1 reply; 4+ messages in thread
From: Vivek Goyal @ 2014-07-09 18:24 UTC (permalink / raw)
To: linux-kernel, kexec; +Cc: ebiederm, hpa, mjg59, bp, akpm, dhowells, Vivek Goyal
Hi,
This is the final piece of the puzzle of verifying kernel image signature
during kexec_file_load() syscall.
It relies on following two patch series.
- kexec_file_load() syscall patches
https://lkml.org/lkml/2014/6/26/497
This patch series is now available in -mm tree.
- PE File parsing and signature verification
http://thread.gmane.org/gmane.linux.kernel/1742967
This patch series is also available here.
http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-modsign.git/log/?h=pefile
This patch calls into PE file routines to verify signature of bzImage. If
signature are valid, kexec_file_load() succeeds otherwise it fails.
Two new config options have been intorduced. First one is
CONFIG_KEXEC_VERIFY_SIG. This option enforces that kernel has to be
validly signed otherwise kernel load will fail. If this option is not
set, no signature verification will be done. Only exception will be
when secureboot is enabled. In that case signature verification should
be automatically enforced when secureboot is enabled. But that will
happen when secureboot patches are merged.
Second config option is CONFIG_KEXEC_BZIMAGE_VERIFY_SIG. This option
enables signature verification support on bzImage. If this option is
not set and previous one is set, kernel image loading will fail because
kernel does not have support to verify signature of bzImage.
I tested these patches with both "pesign" and "sbsign" signed bzImages.
I used signing_key.priv key and signing_key.x509 cert for signing as
generated during kernel build process (if module signing is enabled).
Used following method to sign bzImage.
pesign
======
- Convert DER format cert to PEM format cert
openssl x509 -in signing_key.x509 -inform DER -out signing_key.x509.PEM -outform
PEM
- Generate a .p12 file from existing cert and private key file
openssl pkcs12 -export -out kernel-key.p12 -inkey signing_key.priv -in
signing_key.x509.PEM
- Import .p12 file into pesign db
pk12util -i /tmp/kernel-key.p12 -d /etc/pki/pesign
- Sign bzImage
pesign -i /boot/vmlinuz-3.16.0-rc3+ -o /boot/vmlinuz-3.16.0-rc3+.signed.pesign
-c "Glacier signing key - Magrathea" -s
sbsign
======
sbsign --key signing_key.priv --cert signing_key.x509.PEM --output
/boot/vmlinuz-3.16.0-rc3+.signed.sbsign /boot/vmlinuz-3.16.0-rc3+
Thanks
Vivek
Vivek Goyal (1):
kexec: Verify the signature of signed PE bzImage
arch/x86/Kconfig | 22 ++++++++++++++++++++++
arch/x86/kernel/kexec-bzimage64.c | 21 +++++++++++++++++++++
arch/x86/kernel/machine_kexec_64.c | 11 +++++++++++
include/linux/kexec.h | 3 +++
kernel/kexec.c | 15 +++++++++++++++
5 files changed, 72 insertions(+)
--
1.9.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 1/1] kexec: Verify the signature of signed PE bzImage
2014-07-09 18:24 [PATCH 0/1] kexec: verify bzImage signature Vivek Goyal
@ 2014-07-09 18:24 ` Vivek Goyal
2014-07-24 14:16 ` Vivek Goyal
0 siblings, 1 reply; 4+ messages in thread
From: Vivek Goyal @ 2014-07-09 18:24 UTC (permalink / raw)
To: linux-kernel, kexec; +Cc: ebiederm, hpa, mjg59, bp, akpm, dhowells, Vivek Goyal
Well all the hard work is done in previous patches. Now bzImage loader
has just call into that code and verify whether bzImage signature are
valid or not.
Also create two config options. First one is CONFIG_KEXEC_VERIFY_SIG.
This option enforces that kernel has to be validly signed otherwise
kernel load will fail. If this option is not set, no signature verification
will be done. Only exception will be when secureboot is enabled. In that
case signature verification should be automatically enforced when secureboot
is enabled. But that will happen when secureboot patches are merged.
Second config option is CONFIG_KEXEC_BZIMAGE_VERIFY_SIG. This option
enables signature verification support on bzImage. If this option is
not set and previous one is set, kernel image loading will fail because
kernel does not have support to verify signature of bzImage.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
arch/x86/Kconfig | 22 ++++++++++++++++++++++
arch/x86/kernel/kexec-bzimage64.c | 21 +++++++++++++++++++++
arch/x86/kernel/machine_kexec_64.c | 11 +++++++++++
include/linux/kexec.h | 3 +++
kernel/kexec.c | 15 +++++++++++++++
5 files changed, 72 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2cee2a6..1c1d3a9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1593,6 +1593,28 @@ config KEXEC
interface is strongly in flux, so no good recommendation can be
made.
+config KEXEC_VERIFY_SIG
+ bool "Verify kernel signature during kexec_file_load() syscall"
+ depends on KEXEC
+ ---help---
+ This option makes kernel signature verification mandatory for
+ kexec_file_load() syscall. If kernel is signature can not be
+ verified, kexec_file_load() will fail.
+
+ This option enforces signature verification at generic level.
+ One needs to enable signature verification for type of kernel
+ image being loaded to make sure it works. For example, enable
+ bzImage signature verification option to be able to load and
+ verify signatures of bzImage. Otherwise kernel loading will fail.
+
+config KEXEC_BZIMAGE_VERIFY_SIG
+ bool "Enable bzImage signature verification support"
+ depends on KEXEC_VERIFY_SIG
+ depends on SIGNED_PE_FILE_VERIFICATION
+ select SYSTEM_TRUSTED_KEYRING
+ ---help---
+ Enable bzImage signature verification support.
+
config CRASH_DUMP
bool "kernel crash dumps"
depends on X86_64 || (X86_32 && HIGHMEM)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 623e6c5..9642b9b 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -19,6 +19,8 @@
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/efi.h>
+#include <linux/verify_pefile.h>
+#include <keys/system_keyring.h>
#include <asm/bootparam.h>
#include <asm/setup.h>
@@ -525,8 +527,27 @@ int bzImage64_cleanup(void *loader_data)
return 0;
}
+#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
+int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
+{
+ bool trusted;
+ int ret;
+
+ ret = verify_pefile_signature(kernel, kernel_len,
+ system_trusted_keyring, &trusted);
+ if (ret < 0)
+ return ret;
+ if (!trusted)
+ return -EKEYREJECTED;
+ return 0;
+}
+#endif
+
struct kexec_file_ops kexec_bzImage64_ops = {
.probe = bzImage64_probe,
.load = bzImage64_load,
.cleanup = bzImage64_cleanup,
+#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
+ .verify_sig = bzImage64_verify_sig,
+#endif
};
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 9330434..8b04018 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -372,6 +372,17 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
return image->fops->cleanup(image->image_loader_data);
}
+int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
+ unsigned long kernel_len)
+{
+ if (!image->fops || !image->fops->verify_sig) {
+ pr_debug("kernel loader does not support signature verification.");
+ return -EKEYREJECTED;
+ }
+
+ return image->fops->verify_sig(kernel, kernel_len);
+}
+
/*
* Apply purgatory relocations.
*
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9481703..4b2a0e1 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -191,11 +191,14 @@ typedef void *(kexec_load_t)(struct kimage *image, char *kernel_buf,
unsigned long initrd_len, char *cmdline,
unsigned long cmdline_len);
typedef int (kexec_cleanup_t)(void *loader_data);
+typedef int (kexec_verify_sig_t)(const char *kernel_buf,
+ unsigned long kernel_len);
struct kexec_file_ops {
kexec_probe_t *probe;
kexec_load_t *load;
kexec_cleanup_t *cleanup;
+ kexec_verify_sig_t *verify_sig;
};
/* kexec interface functions */
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 3cd56af..564432a 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -415,6 +415,12 @@ void __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
{
}
+int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
+ unsigned long buf_len)
+{
+ return -EKEYREJECTED;
+}
+
/* Apply relocations of type RELA */
int __weak
arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
@@ -493,6 +499,15 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
if (ret)
goto out;
+#ifdef CONFIG_KEXEC_VERIFY_SIG
+ ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
+ image->kernel_buf_len);
+ if (ret) {
+ pr_debug("kernel signature verification failed.\n");
+ goto out;
+ }
+ pr_debug("kernel signature verification successful.\n");
+#endif
/* It is possible that there no initramfs is being loaded */
if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
--
1.9.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] kexec: Verify the signature of signed PE bzImage
2014-07-09 18:24 ` [PATCH 1/1] kexec: Verify the signature of signed PE bzImage Vivek Goyal
@ 2014-07-24 14:16 ` Vivek Goyal
2014-07-24 22:07 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: Vivek Goyal @ 2014-07-24 14:16 UTC (permalink / raw)
To: akpm; +Cc: ebiederm, hpa, mjg59, bp, dhowells, linux-kernel, kexec
On Wed, Jul 09, 2014 at 02:24:07PM -0400, Vivek Goyal wrote:
> Well all the hard work is done in previous patches. Now bzImage loader
> has just call into that code and verify whether bzImage signature are
> valid or not.
>
> Also create two config options. First one is CONFIG_KEXEC_VERIFY_SIG.
> This option enforces that kernel has to be validly signed otherwise
> kernel load will fail. If this option is not set, no signature verification
> will be done. Only exception will be when secureboot is enabled. In that
> case signature verification should be automatically enforced when secureboot
> is enabled. But that will happen when secureboot patches are merged.
>
> Second config option is CONFIG_KEXEC_BZIMAGE_VERIFY_SIG. This option
> enables signature verification support on bzImage. If this option is
> not set and previous one is set, kernel image loading will fail because
> kernel does not have support to verify signature of bzImage.
>
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Hi Andrew,
I am wondering how this final kexec patch should be routed. Issue here is that
this patch depends on David Howells's PKCS7 and PEFILE patches. Which are now
sitting in security tree. (security/next).
http://git.kernel.org/cgit/linux/kernel/git/jmorris/linux-security.git/log/?h=next
Not sure how to handle this dependency issue.
Thanks
Vivek
> ---
> arch/x86/Kconfig | 22 ++++++++++++++++++++++
> arch/x86/kernel/kexec-bzimage64.c | 21 +++++++++++++++++++++
> arch/x86/kernel/machine_kexec_64.c | 11 +++++++++++
> include/linux/kexec.h | 3 +++
> kernel/kexec.c | 15 +++++++++++++++
> 5 files changed, 72 insertions(+)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 2cee2a6..1c1d3a9 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1593,6 +1593,28 @@ config KEXEC
> interface is strongly in flux, so no good recommendation can be
> made.
>
> +config KEXEC_VERIFY_SIG
> + bool "Verify kernel signature during kexec_file_load() syscall"
> + depends on KEXEC
> + ---help---
> + This option makes kernel signature verification mandatory for
> + kexec_file_load() syscall. If kernel is signature can not be
> + verified, kexec_file_load() will fail.
> +
> + This option enforces signature verification at generic level.
> + One needs to enable signature verification for type of kernel
> + image being loaded to make sure it works. For example, enable
> + bzImage signature verification option to be able to load and
> + verify signatures of bzImage. Otherwise kernel loading will fail.
> +
> +config KEXEC_BZIMAGE_VERIFY_SIG
> + bool "Enable bzImage signature verification support"
> + depends on KEXEC_VERIFY_SIG
> + depends on SIGNED_PE_FILE_VERIFICATION
> + select SYSTEM_TRUSTED_KEYRING
> + ---help---
> + Enable bzImage signature verification support.
> +
> config CRASH_DUMP
> bool "kernel crash dumps"
> depends on X86_64 || (X86_32 && HIGHMEM)
> diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
> index 623e6c5..9642b9b 100644
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -19,6 +19,8 @@
> #include <linux/kernel.h>
> #include <linux/mm.h>
> #include <linux/efi.h>
> +#include <linux/verify_pefile.h>
> +#include <keys/system_keyring.h>
>
> #include <asm/bootparam.h>
> #include <asm/setup.h>
> @@ -525,8 +527,27 @@ int bzImage64_cleanup(void *loader_data)
> return 0;
> }
>
> +#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
> +int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
> +{
> + bool trusted;
> + int ret;
> +
> + ret = verify_pefile_signature(kernel, kernel_len,
> + system_trusted_keyring, &trusted);
> + if (ret < 0)
> + return ret;
> + if (!trusted)
> + return -EKEYREJECTED;
> + return 0;
> +}
> +#endif
> +
> struct kexec_file_ops kexec_bzImage64_ops = {
> .probe = bzImage64_probe,
> .load = bzImage64_load,
> .cleanup = bzImage64_cleanup,
> +#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
> + .verify_sig = bzImage64_verify_sig,
> +#endif
> };
> diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> index 9330434..8b04018 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -372,6 +372,17 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
> return image->fops->cleanup(image->image_loader_data);
> }
>
> +int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
> + unsigned long kernel_len)
> +{
> + if (!image->fops || !image->fops->verify_sig) {
> + pr_debug("kernel loader does not support signature verification.");
> + return -EKEYREJECTED;
> + }
> +
> + return image->fops->verify_sig(kernel, kernel_len);
> +}
> +
> /*
> * Apply purgatory relocations.
> *
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 9481703..4b2a0e1 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -191,11 +191,14 @@ typedef void *(kexec_load_t)(struct kimage *image, char *kernel_buf,
> unsigned long initrd_len, char *cmdline,
> unsigned long cmdline_len);
> typedef int (kexec_cleanup_t)(void *loader_data);
> +typedef int (kexec_verify_sig_t)(const char *kernel_buf,
> + unsigned long kernel_len);
>
> struct kexec_file_ops {
> kexec_probe_t *probe;
> kexec_load_t *load;
> kexec_cleanup_t *cleanup;
> + kexec_verify_sig_t *verify_sig;
> };
>
> /* kexec interface functions */
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 3cd56af..564432a 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -415,6 +415,12 @@ void __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
> {
> }
>
> +int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
> + unsigned long buf_len)
> +{
> + return -EKEYREJECTED;
> +}
> +
> /* Apply relocations of type RELA */
> int __weak
> arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
> @@ -493,6 +499,15 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
> if (ret)
> goto out;
>
> +#ifdef CONFIG_KEXEC_VERIFY_SIG
> + ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
> + image->kernel_buf_len);
> + if (ret) {
> + pr_debug("kernel signature verification failed.\n");
> + goto out;
> + }
> + pr_debug("kernel signature verification successful.\n");
> +#endif
> /* It is possible that there no initramfs is being loaded */
> if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
> ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
> --
> 1.9.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] kexec: Verify the signature of signed PE bzImage
2014-07-24 14:16 ` Vivek Goyal
@ 2014-07-24 22:07 ` Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2014-07-24 22:07 UTC (permalink / raw)
To: Vivek Goyal; +Cc: ebiederm, hpa, mjg59, bp, dhowells, linux-kernel, kexec
On Thu, 24 Jul 2014 10:16:42 -0400 Vivek Goyal <vgoyal@redhat.com> wrote:
> I am wondering how this final kexec patch should be routed. Issue here is that
> this patch depends on David Howells's PKCS7 and PEFILE patches. Which are now
> sitting in security tree. (security/next).
>
> http://git.kernel.org/cgit/linux/kernel/git/jmorris/linux-security.git/log/?h=next
>
> Not sure how to handle this dependency issue.
I have all these patches staged after linux-next so it fitted
straight in.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-07-24 22:07 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-07-09 18:24 [PATCH 0/1] kexec: verify bzImage signature Vivek Goyal
2014-07-09 18:24 ` [PATCH 1/1] kexec: Verify the signature of signed PE bzImage Vivek Goyal
2014-07-24 14:16 ` Vivek Goyal
2014-07-24 22:07 ` Andrew Morton
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox