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Date: Tue, 12 Oct 2021 11:53:24 +0800 From: Coiby Xu <coxu@...hat.com> To: "Eric W. Biederman" <ebiederm@...ssion.com> Cc: kexec@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, Dave Young <dyoung@...hat.com>, Will Deacon <will@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>, "H. Peter Anvin" <hpa@...or.com>, "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v2 1/2] kexec, KEYS: make the code in bzImage64_verify_sig generic On Mon, Oct 11, 2021 at 08:58:36AM -0500, Eric W. Biederman wrote: >Coiby Xu <coxu@...hat.com> writes: > >> The code in bzImage64_verify_sig could make use of system keyrings including >> .buitin_trusted_keys, .secondary_trusted_keys and .platform keyring to verify >> signed kernel image as PE file. Make it generic so both x86_64 and arm64 can >> use it. > >The naming is problematic. > >At a minimum please name the new function kexec_kernel_verify_pe_sig. >AKA what you named it without the "arch_" prefix. A function named with >an "arch_" prefix implies that it has an architecture specific >implementation. Thanks for bringing up this issue and providing the fix and the explanation. > >It looks like arch_kexec_kernel_verify_sig should be killed as well >as it only has one implementation in the generic code. And the code >should always call kexec_image_verify_sig_default. Not that you should >do that but I am pointing it out as it seems that is the bad example you >are copying. Yes, you are right about it. This is a leftover issue of commit 9ec4ecef0af7790551109283ca039a7c52de343c ("kexec_file,x86,powerpc: factor out kexec_file_ops functions"), As arch_kexec_kernel_image_{probe,load}(), arch_kimage_file_post_load_cleanup() and arch_kexec_kernel_verify_sig() are almost duplicated among architectures, they can be commonalized with an architecture-defined kexec_file_ops array. So let's factor them out. That commit moves the architecture specific implementation of arch_kexec_kernel_verify_sig to kexec_file_ops->verify_sig. So actually arch_kexec_kernel_verify_sig should be removed. Then we rename kexec_image_verify_sig_default to kimage_validate_signature and call it in kimage_validate_signature directly. I'll include a new patch to do the clean-up work in v3. > >Eric > >> Signed-off-by: Coiby Xu <coxu@...hat.com> >> --- >> arch/x86/kernel/kexec-bzimage64.c | 13 +------------ >> include/linux/kexec.h | 3 +++ >> kernel/kexec_file.c | 17 +++++++++++++++++ >> 3 files changed, 21 insertions(+), 12 deletions(-) >> >> diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c >> index 170d0fd68b1f..4136dd3be5a9 100644 >> --- a/arch/x86/kernel/kexec-bzimage64.c >> +++ b/arch/x86/kernel/kexec-bzimage64.c >> @@ -17,7 +17,6 @@ >> #include <linux/kernel.h> >> #include <linux/mm.h> >> #include <linux/efi.h> >> -#include <linux/verification.h> >> >> #include <asm/bootparam.h> >> #include <asm/setup.h> >> @@ -531,17 +530,7 @@ static int bzImage64_cleanup(void *loader_data) >> #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG >> static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len) >> { >> - int ret; >> - >> - ret = verify_pefile_signature(kernel, kernel_len, >> - VERIFY_USE_SECONDARY_KEYRING, >> - VERIFYING_KEXEC_PE_SIGNATURE); >> - if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) { >> - ret = verify_pefile_signature(kernel, kernel_len, >> - VERIFY_USE_PLATFORM_KEYRING, >> - VERIFYING_KEXEC_PE_SIGNATURE); >> - } >> - return ret; >> + return arch_kexec_kernel_verify_pe_sig(kernel, kernel_len); >> } >> #endif >> >> diff --git a/include/linux/kexec.h b/include/linux/kexec.h >> index 0c994ae37729..d45f32336dbe 100644 >> --- a/include/linux/kexec.h >> +++ b/include/linux/kexec.h >> @@ -19,6 +19,7 @@ >> #include <asm/io.h> >> >> #include <uapi/linux/kexec.h> >> +#include <linux/verification.h> >> >> #ifdef CONFIG_KEXEC_CORE >> #include <linux/list.h> >> @@ -199,6 +200,8 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image); >> #ifdef CONFIG_KEXEC_SIG >> int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, >> unsigned long buf_len); >> +int arch_kexec_kernel_verify_pe_sig(const char *kernel, >> + unsigned long kernel_len); >> #endif >> int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf); >> >> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c >> index 33400ff051a8..0530275b7aa3 100644 >> --- a/kernel/kexec_file.c >> +++ b/kernel/kexec_file.c >> @@ -106,6 +106,23 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, >> { >> return kexec_image_verify_sig_default(image, buf, buf_len); >> } >> + >> +#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION >> +int arch_kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len) >> +{ >> + int ret; >> + >> + ret = verify_pefile_signature(kernel, kernel_len, >> + VERIFY_USE_SECONDARY_KEYRING, >> + VERIFYING_KEXEC_PE_SIGNATURE); >> + if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) { >> + ret = verify_pefile_signature(kernel, kernel_len, >> + VERIFY_USE_PLATFORM_KEYRING, >> + VERIFYING_KEXEC_PE_SIGNATURE); >> + } >> + return ret; >> +} >> +#endif >> #endif >> >> /* > -- Best regards, Coiby
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