This is a note to let you know that I've just added the patch titled ima: force signature verification when CONFIG_KEXEC_SIG is configured to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ima-force-signature-verification-when-config_kexec_s.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 88c69fd7a6542d6df8d34b7252ff15ac3721f869 Author: Coiby Xu <coxu@xxxxxxxxxx> Date: Wed Jul 13 15:21:11 2022 +0800 ima: force signature verification when CONFIG_KEXEC_SIG is configured [ Upstream commit af16df54b89dee72df253abc5e7b5e8a6d16c11c ] Currently, an unsigned kernel could be kexec'ed when IMA arch specific policy is configured unless lockdown is enabled. Enforce kernel signature verification check in the kexec_file_load syscall when IMA arch specific policy is configured. Fixes: 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE") Reported-and-suggested-by: Mimi Zohar <zohar@xxxxxxxxxxxxx> Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx> Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/include/linux/kexec.h b/include/linux/kexec.h index fcd5035209f1..8d573baaab29 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -452,6 +452,12 @@ static inline int kexec_crash_loaded(void) { return 0; } #define kexec_in_progress false #endif /* CONFIG_KEXEC_CORE */ +#ifdef CONFIG_KEXEC_SIG +void set_kexec_sig_enforced(void); +#else +static inline void set_kexec_sig_enforced(void) {} +#endif + #endif /* !defined(__ASSEBMLY__) */ #endif /* LINUX_KEXEC_H */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index c108a2a88754..bb0fb63f563c 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -29,6 +29,15 @@ #include <linux/vmalloc.h> #include "kexec_internal.h" +#ifdef CONFIG_KEXEC_SIG +static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE); + +void set_kexec_sig_enforced(void) +{ + sig_enforce = true; +} +#endif + static int kexec_calculate_store_digests(struct kimage *image); /* @@ -159,7 +168,7 @@ kimage_validate_signature(struct kimage *image) image->kernel_buf_len); if (ret) { - if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) { + if (sig_enforce) { pr_notice("Enforced kernel signature verification failed (%d).\n", ret); return ret; } diff --git a/security/integrity/ima/ima_efi.c b/security/integrity/ima/ima_efi.c index 71786d01946f..9db66fe310d4 100644 --- a/security/integrity/ima/ima_efi.c +++ b/security/integrity/ima/ima_efi.c @@ -67,6 +67,8 @@ const char * const *arch_get_ima_policy(void) if (IS_ENABLED(CONFIG_IMA_ARCH_POLICY) && arch_ima_get_secureboot()) { if (IS_ENABLED(CONFIG_MODULE_SIG)) set_module_sig_enforced(); + if (IS_ENABLED(CONFIG_KEXEC_SIG)) + set_kexec_sig_enforced(); return sb_arch_rules; } return NULL;