From patchwork Tue Jan 11 11:37:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Suchanek X-Patchwork-Id: 12709759 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B4FEC4332F for ; Tue, 11 Jan 2022 11:38:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349595AbiAKLiC (ORCPT ); Tue, 11 Jan 2022 06:38:02 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:33626 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349546AbiAKLh7 (ORCPT ); Tue, 11 Jan 2022 06:37:59 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 9ACCA1F3BE; Tue, 11 Jan 2022 11:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1641901077; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E5S+PDIMt0cv778Ug4dTHgOhwSV6I7mLY7fYsPSMbc8=; b=cNTa4UdEI8NMT2ulyV45F/C/V13CVcxnHg2/esmZQ9mIhQ4wW8tFjineNtW9R8OYNjpyzQ /zlZ9M4CizPX6Da//4DbLf1GFhpmIzRgQqK8WzvxT/I3jGEGk7/mfQepNvv2M1J7zCxtl2 fc3gS9gTAYfCRnrha03OmoNgg3j/HZY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1641901077; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E5S+PDIMt0cv778Ug4dTHgOhwSV6I7mLY7fYsPSMbc8=; b=Gx/naHnidUOgdbPPRqig0Wgs+UDBOAiZnhMMzrD37EGj9I3JOKbn2QGeVXTk7DLgO/rsjU BxTzShMlokMLUABA== Received: from kitsune.suse.cz (kitsune.suse.cz [10.100.12.127]) by relay2.suse.de (Postfix) with ESMTP id 5459AA3B8F; Tue, 11 Jan 2022 11:37:57 +0000 (UTC) From: Michal Suchanek To: keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org Cc: Michal Suchanek , kexec@lists.infradead.org, Philipp Rudo , Mimi Zohar , Nayna , Rob Herring , linux-s390@vger.kernel.org, Vasily Gorbik , Lakshmi Ramasubramanian , Heiko Carstens , Jessica Yu , linux-kernel@vger.kernel.org, David Howells , Christian Borntraeger , Luis Chamberlain , Paul Mackerras , Hari Bathini , Alexander Gordeev , linuxppc-dev@lists.ozlabs.org, Frank van der Linden , Thiago Jung Bauermann , Daniel Axtens , buendgen@de.ibm.com, Michael Ellerman , Benjamin Herrenschmidt , Christian Borntraeger , Herbert Xu , "David S. Miller" , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , Sven Schnelle , Baoquan He , linux-security-module@vger.kernel.org Subject: [PATCH v5 3/6] kexec_file: Don't opencode appended signature verification. Date: Tue, 11 Jan 2022 12:37:45 +0100 Message-Id: <7834eb187ef67cd88fc67f10e831130e3717d776.1641900831.git.msuchanek@suse.de> X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Module verification already implements appeded signature verification. Reuse it for kexec_file. Signed-off-by: Michal Suchanek Reviewed-by: Luis Chamberlain --- v3: - Philipp Rudo : Update the dependency on MODULE_SIG_FORMAT to MODULE_SIG - Include linux/verification.h - previously added in earlier patch v4: - kernel test robot : Use unsigned long rather than size_t for data length - Update the code in kernel/module_signing.c to use pointer rather than memcpy as the kexec and IMA code does --- arch/powerpc/Kconfig | 2 +- arch/powerpc/kexec/elf_64.c | 19 +++------------ arch/s390/Kconfig | 2 +- arch/s390/kernel/machine_kexec_file.c | 18 ++------------ include/linux/verification.h | 3 +++ kernel/module-internal.h | 2 -- kernel/module.c | 4 +++- kernel/module_signing.c | 34 ++++++++++++++++----------- 8 files changed, 33 insertions(+), 51 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 1cde9b6c5987..4092187474ff 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -562,7 +562,7 @@ config ARCH_HAS_KEXEC_PURGATORY config KEXEC_SIG bool "Verify kernel signature during kexec_file_load() syscall" - depends on KEXEC_FILE && MODULE_SIG_FORMAT + depends on KEXEC_FILE && MODULE_SIG help This option makes kernel signature verification mandatory for the kexec_file_load() syscall. diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c index 98d1cb5135b4..64cd314cce0d 100644 --- a/arch/powerpc/kexec/elf_64.c +++ b/arch/powerpc/kexec/elf_64.c @@ -23,6 +23,7 @@ #include #include #include +#include #include static void *elf64_load(struct kimage *image, char *kernel_buf, @@ -156,9 +157,6 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, int elf64_verify_sig(const char *kernel, unsigned long kernel_len) { const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; - struct module_signature *ms; - unsigned long sig_len; - int ret; if (marker_len > kernel_len) return -EKEYREJECTED; @@ -168,19 +166,8 @@ int elf64_verify_sig(const char *kernel, unsigned long kernel_len) return -EKEYREJECTED; kernel_len -= marker_len; - ms = (void *)kernel + kernel_len - sizeof(*ms); - ret = mod_check_sig(ms, kernel_len, "kexec"); - if (ret) - return ret; - - sig_len = be32_to_cpu(ms->sig_len); - kernel_len -= sizeof(*ms) + sig_len; - - return verify_pkcs7_signature(kernel, kernel_len, - kernel + kernel_len, sig_len, - VERIFY_USE_PLATFORM_KEYRING, - VERIFYING_MODULE_SIGNATURE, - NULL, NULL); + return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING, + "kexec_file"); } #endif /* CONFIG_KEXEC_SIG */ diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 2a5bb4f29cfe..cece7152ea35 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -544,7 +544,7 @@ config ARCH_HAS_KEXEC_PURGATORY config KEXEC_SIG bool "Verify kernel signature during kexec_file_load() syscall" - depends on KEXEC_FILE && MODULE_SIG_FORMAT + depends on KEXEC_FILE && MODULE_SIG help This option makes kernel signature verification mandatory for the kexec_file_load() syscall. diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c index c944d71316c7..345f2eab6e04 100644 --- a/arch/s390/kernel/machine_kexec_file.c +++ b/arch/s390/kernel/machine_kexec_file.c @@ -29,9 +29,6 @@ const struct kexec_file_ops * const kexec_file_loaders[] = { int s390_verify_sig(const char *kernel, unsigned long kernel_len) { const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; - struct module_signature *ms; - unsigned long sig_len; - int ret; /* Skip signature verification when not secure IPLed. */ if (!ipl_secure_flag) @@ -45,19 +42,8 @@ int s390_verify_sig(const char *kernel, unsigned long kernel_len) return -EKEYREJECTED; kernel_len -= marker_len; - ms = (void *)kernel + kernel_len - sizeof(*ms); - ret = mod_check_sig(ms, kernel_len, "kexec"); - if (ret) - return ret; - - sig_len = be32_to_cpu(ms->sig_len); - kernel_len -= sizeof(*ms) + sig_len; - - return verify_pkcs7_signature(kernel, kernel_len, - kernel + kernel_len, sig_len, - VERIFY_USE_PLATFORM_KEYRING, - VERIFYING_MODULE_SIGNATURE, - NULL, NULL); + return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING, + "kexec_file"); } #endif /* CONFIG_KEXEC_SIG */ diff --git a/include/linux/verification.h b/include/linux/verification.h index a655923335ae..32db9287a7b0 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -60,5 +60,8 @@ extern int verify_pefile_signature(const void *pebuf, unsigned pelen, enum key_being_used_for usage); #endif +int verify_appended_signature(const void *data, unsigned long *len, + struct key *trusted_keys, const char *what); + #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ #endif /* _LINUX_VERIFY_PEFILE_H */ diff --git a/kernel/module-internal.h b/kernel/module-internal.h index 33783abc377b..80461e14bf29 100644 --- a/kernel/module-internal.h +++ b/kernel/module-internal.h @@ -27,5 +27,3 @@ struct load_info { unsigned int sym, str, mod, vers, info, pcpu; } index; }; - -extern int mod_verify_sig(const void *mod, struct load_info *info); diff --git a/kernel/module.c b/kernel/module.c index 84a9141a5e15..8481933dfa92 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -57,6 +57,7 @@ #include #include #include +#include #include #include "module-internal.h" @@ -2894,7 +2895,8 @@ static int module_sig_check(struct load_info *info, int flags) memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { /* We truncate the module to discard the signature */ info->len -= markerlen; - err = mod_verify_sig(mod, info); + err = verify_appended_signature(mod, &info->len, + VERIFY_USE_SECONDARY_KEYRING, "module"); if (!err) { info->sig_ok = true; return 0; diff --git a/kernel/module_signing.c b/kernel/module_signing.c index 8723ae70ea1f..30149969f21f 100644 --- a/kernel/module_signing.c +++ b/kernel/module_signing.c @@ -14,32 +14,38 @@ #include #include "module-internal.h" -/* - * Verify the signature on a module. +/** + * verify_appended_signature - Verify the signature on a module with the + * signature marker stripped. + * @data: The data to be verified + * @len: Size of @data. + * @trusted_keys: Keyring to use for verification + * @what: Informational string for log messages */ -int mod_verify_sig(const void *mod, struct load_info *info) +int verify_appended_signature(const void *data, unsigned long *len, + struct key *trusted_keys, const char *what) { - struct module_signature ms; - size_t sig_len, modlen = info->len; + struct module_signature *ms; + unsigned long sig_len, modlen = *len; int ret; - pr_devel("==>%s(,%zu)\n", __func__, modlen); + pr_devel("==>%s(,%lu)\n", __func__, modlen); - if (modlen <= sizeof(ms)) + if (modlen <= sizeof(*ms)) return -EBADMSG; - memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms)); + ms = data + modlen - sizeof(*ms); - ret = mod_check_sig(&ms, modlen, "module"); + ret = mod_check_sig(ms, modlen, what); if (ret) return ret; - sig_len = be32_to_cpu(ms.sig_len); - modlen -= sig_len + sizeof(ms); - info->len = modlen; + sig_len = be32_to_cpu(ms->sig_len); + modlen -= sig_len + sizeof(*ms); + *len = modlen; - return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len, - VERIFY_USE_SECONDARY_KEYRING, + return verify_pkcs7_signature(data, modlen, data + modlen, sig_len, + trusted_keys, VERIFYING_MODULE_SIGNATURE, NULL, NULL); }