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authorVivek Goyal <vgoyal@redhat.com>2014-08-08 14:26:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-08 15:57:33 -0700
commit8e7d838103feac320baf9e68d73f954840ac1eea (patch)
treec9426b2a0b83962a08d0cf48001594e4b8e59541 /arch/x86/kernel/kexec-bzimage64.c
parent6a2c20e7d8900ed273dc34a9af9bf02fc478e427 (diff)
kexec: verify the signature of signed PE bzImage
This is the final piece of the puzzle of verifying kernel image signature during kexec_file_load() syscall. 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 introduced. 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+ Patch details: 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> Cc: Borislav Petkov <bp@suse.de> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Greg Kroah-Hartman <greg@kroah.com> Cc: Dave Young <dyoung@redhat.com> Cc: WANG Chao <chaowang@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Matt Fleming <matt@console-pimps.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/kernel/kexec-bzimage64.c')
-rw-r--r--arch/x86/kernel/kexec-bzimage64.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 623e6c58081f..9642b9b33655 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
};