diff options
| -rw-r--r-- | arch/x86/Kconfig | 22 | ||||
| -rw-r--r-- | arch/x86/kernel/kexec-bzimage64.c | 21 | ||||
| -rw-r--r-- | arch/x86/kernel/machine_kexec_64.c | 11 | ||||
| -rw-r--r-- | include/linux/kexec.h | 3 | ||||
| -rw-r--r-- | kernel/kexec.c | 15 |
5 files changed, 72 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9558b9fcafb..4aafd322e21 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1599,6 +1599,28 @@ 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 623e6c58081..9642b9b3365 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 9330434da77..8b04018e5d1 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 9481703b0e7..4b2a0e11cc5 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 f18c780f971..0b49a0a5810 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -416,6 +416,12 @@ 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, @@ -494,6 +500,15 @@ 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, |