From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pg1-x543.google.com ([2607:f8b0:4864:20::543]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gWalY-0000Hb-7b for kexec@lists.infradead.org; Tue, 11 Dec 2018 05:39:37 +0000 Received: by mail-pg1-x543.google.com with SMTP id w6so6111801pgl.6 for ; Mon, 10 Dec 2018 21:39:21 -0800 (PST) Date: Tue, 11 Dec 2018 14:42:33 +0900 From: AKASHI Takahiro Subject: Re: [PATCH v16 15/16] arm64: kexec_file: add kernel signature verification support Message-ID: <20181211054231.GD21466@linaro.org> References: <20181115055254.2812-1-takahiro.akashi@linaro.org> <20181115055254.2812-16-takahiro.akashi@linaro.org> <20181130132113.GE9000@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20181130132113.GE9000@arm.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Will Deacon Cc: prudo@linux.ibm.com, herbert@gondor.apana.org.au, bhe@redhat.com, ard.biesheuvel@linaro.org, catalin.marinas@arm.com, bhsharma@redhat.com, heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, dhowells@redhat.com, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, kexec@lists.infradead.org, schwidefsky@de.ibm.com, james.morse@arm.com, dyoung@redhat.com, davem@davemloft.net, vgoyal@redhat.com On Fri, Nov 30, 2018 at 01:21:14PM +0000, Will Deacon wrote: > On Thu, Nov 15, 2018 at 02:52:54PM +0900, AKASHI Takahiro wrote: > > With this patch, kernel verification can be done without IMA security > > subsystem enabled. Turn on CONFIG_KEXEC_VERIFY_SIG instead. > > > > On x86, a signature is embedded into a PE file (Microsoft's format) header > > of binary. Since arm64's "Image" can also be seen as a PE file as far as > > CONFIG_EFI is enabled, we adopt this format for kernel signing. > > > > You can create a signed kernel image with: > > $ sbsign --key ${KEY} --cert ${CERT} Image > > > > Signed-off-by: AKASHI Takahiro > > Cc: Catalin Marinas > > Cc: Will Deacon > > Reviewed-by: James Morse > > --- > > arch/arm64/Kconfig | 24 ++++++++++++++++++++++++ > > arch/arm64/kernel/kexec_image.c | 17 +++++++++++++++++ > > 2 files changed, 41 insertions(+) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index 93dc4d36d6db..11f3e1a00588 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -867,6 +867,30 @@ config KEXEC_FILE > > for kernel and initramfs as opposed to list of segments as > > accepted by previous system call. > > > > +config KEXEC_VERIFY_SIG > > + bool "Verify kernel signature during kexec_file_load() syscall" > > + depends on KEXEC_FILE > > + help > > + Select this option to verify a signature with loaded kernel > > + image. If configured, any attempt of loading a image without > > + valid signature will fail. > > + > > + 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 KEXEC_IMAGE_VERIFY_SIG > > + bool "Enable Image signature verification support" > > + default y > > + depends on KEXEC_VERIFY_SIG > > + depends on EFI && SIGNED_PE_FILE_VERIFICATION > > + help > > + Enable Image signature verification support. > > + > > +comment "Support for PE file signature verification disabled" > > + depends on KEXEC_VERIFY_SIG > > + depends on !EFI || !SIGNED_PE_FILE_VERIFICATION > > + > > config CRASH_DUMP > > bool "Build kdump crash kernel" > > help > > diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c > > index 9f0d8b5d62d3..d1c6c54c22e3 100644 > > --- a/arch/arm64/kernel/kexec_image.c > > +++ b/arch/arm64/kernel/kexec_image.c > > @@ -12,7 +12,9 @@ > > #include > > #include > > #include > > +#include > > #include > > +#include > > #include > > #include > > #include > > @@ -29,6 +31,10 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len) > > sizeof(h->magic))) > > return -EINVAL; > > > > + pr_debug("PE format: %s\n", > > + memcmp(&((struct mz_hdr *)h)->magic, "MZ", 2) ? > > + "no" : "yes"); > > > > Is this hunk really necessary? I'd prefer not to commit pr_debug() > invocations. This line comes from kexec-tools' code, but I don't mind removing it. (as lots of lines diverge now from kexec-tools.) -Takahiro Akashi > Will _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec