diff options
| -rw-r--r-- | arch/s390/Kconfig | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/machine_kexec_file.c | 24 | ||||
| -rw-r--r-- | include/linux/module.h | 3 | ||||
| -rw-r--r-- | include/linux/module_signature.h | 44 | ||||
| -rw-r--r-- | init/Kconfig | 6 | ||||
| -rw-r--r-- | kernel/Makefile | 1 | ||||
| -rw-r--r-- | kernel/module.c | 1 | ||||
| -rw-r--r-- | kernel/module_signature.c | 46 | ||||
| -rw-r--r-- | kernel/module_signing.c | 56 | ||||
| -rw-r--r-- | scripts/Makefile | 2 |
10 files changed, 108 insertions, 77 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index a4ad2733eedf..e0ae0d51f985 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -538,7 +538,7 @@ config ARCH_HAS_KEXEC_PURGATORY config KEXEC_VERIFY_SIG bool "Verify kernel signature during kexec_file_load() syscall" - depends on KEXEC_FILE && SYSTEM_DATA_VERIFICATION + depends on KEXEC_FILE && MODULE_SIG_FORMAT 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 fbdd3ea73667..1ac9fbc6e01e 100644 --- a/arch/s390/kernel/machine_kexec_file.c +++ b/arch/s390/kernel/machine_kexec_file.c @@ -10,7 +10,7 @@ #include <linux/elf.h> #include <linux/errno.h> #include <linux/kexec.h> -#include <linux/module.h> +#include <linux/module_signature.h> #include <linux/verification.h> #include <asm/boot_data.h> #include <asm/ipl.h> @@ -23,28 +23,6 @@ const struct kexec_file_ops * const kexec_file_loaders[] = { }; #ifdef CONFIG_KEXEC_VERIFY_SIG -/* - * Module signature information block. - * - * The constituents of the signature section are, in order: - * - * - Signer's name - * - Key identifier - * - Signature data - * - Information block - */ -struct module_signature { - u8 algo; /* Public-key crypto algorithm [0] */ - u8 hash; /* Digest algorithm [0] */ - u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */ - u8 signer_len; /* Length of signer's name [0] */ - u8 key_id_len; /* Length of key identifier [0] */ - u8 __pad[3]; - __be32 sig_len; /* Length of signature data */ -}; - -#define PKEY_ID_PKCS7 2 - int s390_verify_sig(const char *kernel, unsigned long kernel_len) { const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; diff --git a/include/linux/module.h b/include/linux/module.h index 1455812dd325..f6fc1dae74f4 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -26,9 +26,6 @@ #include <linux/percpu.h> #include <asm/module.h> -/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */ -#define MODULE_SIG_STRING "~Module signature appended~\n" - /* Not Yet Implemented */ #define MODULE_SUPPORTED_DEVICE(name) diff --git a/include/linux/module_signature.h b/include/linux/module_signature.h new file mode 100644 index 000000000000..523617fc5b6a --- /dev/null +++ b/include/linux/module_signature.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Module signature handling. + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#ifndef _LINUX_MODULE_SIGNATURE_H +#define _LINUX_MODULE_SIGNATURE_H + +/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */ +#define MODULE_SIG_STRING "~Module signature appended~\n" + +enum pkey_id_type { + PKEY_ID_PGP, /* OpenPGP generated key ID */ + PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */ + PKEY_ID_PKCS7, /* Signature in PKCS#7 message */ +}; + +/* + * Module signature information block. + * + * The constituents of the signature section are, in order: + * + * - Signer's name + * - Key identifier + * - Signature data + * - Information block + */ +struct module_signature { + u8 algo; /* Public-key crypto algorithm [0] */ + u8 hash; /* Digest algorithm [0] */ + u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */ + u8 signer_len; /* Length of signer's name [0] */ + u8 key_id_len; /* Length of key identifier [0] */ + u8 __pad[3]; + __be32 sig_len; /* Length of signature data */ +}; + +int mod_check_sig(const struct module_signature *ms, size_t file_len, + const char *name); + +#endif /* _LINUX_MODULE_SIGNATURE_H */ diff --git a/init/Kconfig b/init/Kconfig index bd7d650d4a99..2dca877c9ed7 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1930,6 +1930,10 @@ config BASE_SMALL default 0 if BASE_FULL default 1 if !BASE_FULL +config MODULE_SIG_FORMAT + def_bool n + select SYSTEM_DATA_VERIFICATION + menuconfig MODULES bool "Enable loadable module support" option modules @@ -2007,7 +2011,7 @@ config MODULE_SRCVERSION_ALL config MODULE_SIG bool "Module signature verification" depends on MODULES - select SYSTEM_DATA_VERIFICATION + select MODULE_SIG_FORMAT help Check modules for valid signatures upon load: the signature is simply appended to the module. For more information see diff --git a/kernel/Makefile b/kernel/Makefile index a8d923b5481b..179b44ab8b46 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -58,6 +58,7 @@ endif obj-$(CONFIG_UID16) += uid16.o obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_MODULE_SIG) += module_signing.o +obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o obj-$(CONFIG_KALLSYMS) += kallsyms.o obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o obj-$(CONFIG_CRASH_CORE) += crash_core.o diff --git a/kernel/module.c b/kernel/module.c index 5933395af9a0..5ac22efc3685 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -7,6 +7,7 @@ #include <linux/export.h> #include <linux/extable.h> #include <linux/moduleloader.h> +#include <linux/module_signature.h> #include <linux/trace_events.h> #include <linux/init.h> #include <linux/kallsyms.h> diff --git a/kernel/module_signature.c b/kernel/module_signature.c new file mode 100644 index 000000000000..4224a1086b7d --- /dev/null +++ b/kernel/module_signature.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Module signature checker + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/errno.h> +#include <linux/printk.h> +#include <linux/module_signature.h> +#include <asm/byteorder.h> + +/** + * mod_check_sig - check that the given signature is sane + * + * @ms: Signature to check. + * @file_len: Size of the file to which @ms is appended. + * @name: What is being checked. Used for error messages. + */ +int mod_check_sig(const struct module_signature *ms, size_t file_len, + const char *name) +{ + if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms)) + return -EBADMSG; + + if (ms->id_type != PKEY_ID_PKCS7) { + pr_err("%s: Module is not signed with expected PKCS#7 message\n", + name); + return -ENOPKG; + } + + if (ms->algo != 0 || + ms->hash != 0 || + ms->signer_len != 0 || + ms->key_id_len != 0 || + ms->__pad[0] != 0 || + ms->__pad[1] != 0 || + ms->__pad[2] != 0) { + pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n", + name); + return -EBADMSG; + } + + return 0; +} diff --git a/kernel/module_signing.c b/kernel/module_signing.c index b10fb1986ca9..9d9fc678c91d 100644 --- a/kernel/module_signing.c +++ b/kernel/module_signing.c @@ -7,37 +7,13 @@ #include <linux/kernel.h> #include <linux/errno.h> +#include <linux/module.h> +#include <linux/module_signature.h> #include <linux/string.h> #include <linux/verification.h> #include <crypto/public_key.h> #include "module-internal.h" -enum pkey_id_type { - PKEY_ID_PGP, /* OpenPGP generated key ID */ - PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */ - PKEY_ID_PKCS7, /* Signature in PKCS#7 message */ -}; - -/* - * Module signature information block. - * - * The constituents of the signature section are, in order: - * - * - Signer's name - * - Key identifier - * - Signature data - * - Information block - */ -struct module_signature { - u8 algo; /* Public-key crypto algorithm [0] */ - u8 hash; /* Digest algorithm [0] */ - u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */ - u8 signer_len; /* Length of signer's name [0] */ - u8 key_id_len; /* Length of key identifier [0] */ - u8 __pad[3]; - __be32 sig_len; /* Length of signature data */ -}; - /* * Verify the signature on a module. */ @@ -45,6 +21,7 @@ int mod_verify_sig(const void *mod, struct load_info *info) { struct module_signature ms; size_t sig_len, modlen = info->len; + int ret; pr_devel("==>%s(,%zu)\n", __func__, modlen); @@ -52,32 +29,15 @@ int mod_verify_sig(const void *mod, struct load_info *info) return -EBADMSG; memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms)); - modlen -= sizeof(ms); + + ret = mod_check_sig(&ms, modlen, info->name); + if (ret) + return ret; sig_len = be32_to_cpu(ms.sig_len); - if (sig_len >= modlen) - return -EBADMSG; - modlen -= sig_len; + modlen -= sig_len + sizeof(ms); info->len = modlen; - if (ms.id_type != PKEY_ID_PKCS7) { - pr_err("%s: Module is not signed with expected PKCS#7 message\n", - info->name); - return -ENOPKG; - } - - if (ms.algo != 0 || - ms.hash != 0 || - ms.signer_len != 0 || - ms.key_id_len != 0 || - ms.__pad[0] != 0 || - ms.__pad[1] != 0 || - ms.__pad[2] != 0) { - pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n", - info->name); - return -EBADMSG; - } - return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len, VERIFY_USE_SECONDARY_KEYRING, VERIFYING_MODULE_SIGNATURE, diff --git a/scripts/Makefile b/scripts/Makefile index 16bcb8087899..532f7e0915c3 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -17,7 +17,7 @@ hostprogs-$(CONFIG_VT) += conmakehash hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount hostprogs-$(CONFIG_BUILDTIME_EXTABLE_SORT) += sortextable hostprogs-$(CONFIG_ASN1) += asn1_compiler -hostprogs-$(CONFIG_MODULE_SIG) += sign-file +hostprogs-$(CONFIG_MODULE_SIG_FORMAT) += sign-file hostprogs-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert hostprogs-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert |