Re: [PATCH v10 01/12] MODSIGN: Export module signature definitions
Mimi Zohar writes: > On Thu, 2019-04-18 at 00:51 -0300, Thiago Jung Bauermann wrote: >> IMA will use the module_signature format for append signatures, so export >> the relevant definitions and factor out the code which verifies that the >> appended signature trailer is valid. >> >> Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it >> and be able to use mod_check_sig() without having to depend on either >> CONFIG_MODULE_SIG or CONFIG_MODULES. >> >> Signed-off-by: Thiago Jung Bauermann >> Cc: Jessica Yu > > Just a couple minor questions/comments below. > > Reviewed-by: Mimi Zohar Thanks for your review and your comments! >> diff --git a/init/Kconfig b/init/Kconfig >> index 4592bf7997c0..a71019553ee1 100644 >> --- a/init/Kconfig >> +++ b/init/Kconfig >> @@ -1906,7 +1906,7 @@ 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 >> @@ -2036,6 +2036,10 @@ config TRIM_UNUSED_KSYMS >> >> endif # MODULES >> >> +config MODULE_SIG_FORMAT >> +def_bool n >> +select SYSTEM_DATA_VERIFICATION > > Normally Kconfigs, in the same file, are defined before they are used. > I'm not sure if that is required or just a convention. I think it's a convention, because it seemed to work in the current way. For the next version I moved the config MODULE_SIG_FORMAT definition to just before "menuconfig MODULES" >> diff --git a/kernel/module_signature.c b/kernel/module_signature.c >> new file mode 100644 >> index ..6d5e59f27f55 >> --- /dev/null >> +++ b/kernel/module_signature.c >> @@ -0,0 +1,45 @@ >> +// SPDX-License-Identifier: GPL-2.0+ >> +/* >> + * Module signature checker >> + * >> + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. >> + * Written by David Howells (dhowe...@redhat.com) >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> + >> +/** >> + * 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" is missing. Fixed. -- Thiago Jung Bauermann IBM Linux Technology Center
Re: [PATCH v10 01/12] MODSIGN: Export module signature definitions
On Thu, 2019-04-18 at 00:51 -0300, Thiago Jung Bauermann wrote: > IMA will use the module_signature format for append signatures, so export > the relevant definitions and factor out the code which verifies that the > appended signature trailer is valid. > > Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it > and be able to use mod_check_sig() without having to depend on either > CONFIG_MODULE_SIG or CONFIG_MODULES. > > Signed-off-by: Thiago Jung Bauermann > Cc: Jessica Yu Just a couple minor questions/comments below. Reviewed-by: Mimi Zohar > --- < snip > > diff --git a/init/Kconfig b/init/Kconfig > index 4592bf7997c0..a71019553ee1 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1906,7 +1906,7 @@ 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 > @@ -2036,6 +2036,10 @@ config TRIM_UNUSED_KSYMS > > endif # MODULES > > +config MODULE_SIG_FORMAT > + def_bool n > + select SYSTEM_DATA_VERIFICATION Normally Kconfigs, in the same file, are defined before they are used. I'm not sure if that is required or just a convention. > config MODULES_TREE_LOOKUP > def_bool y > depends on PERF_EVENTS || TRACING > diff --git a/kernel/Makefile b/kernel/Makefile > index 6c57e78817da..d2f2488f80ab 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -57,6 +57,7 @@ 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 985caa467aef..326ddeb364dd 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -19,6 +19,7 @@ > #include > #include > #include > +#include > #include > #include > #include > diff --git a/kernel/module_signature.c b/kernel/module_signature.c > new file mode 100644 > index ..6d5e59f27f55 > --- /dev/null > +++ b/kernel/module_signature.c > @@ -0,0 +1,45 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Module signature checker > + * > + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. > + * Written by David Howells (dhowe...@redhat.com) > + */ > + > +#include > +#include > +#include > +#include > + > +/** > + * 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" is missing. Mimi > + */
[PATCH v10 01/12] MODSIGN: Export module signature definitions
IMA will use the module_signature format for append signatures, so export
the relevant definitions and factor out the code which verifies that the
appended signature trailer is valid.
Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it
and be able to use mod_check_sig() without having to depend on either
CONFIG_MODULE_SIG or CONFIG_MODULES.
Signed-off-by: Thiago Jung Bauermann
Cc: Jessica Yu
---
include/linux/module.h | 3 --
include/linux/module_signature.h | 44 +
init/Kconfig | 6 +++-
kernel/Makefile | 1 +
kernel/module.c | 1 +
kernel/module_signature.c| 45 +
kernel/module_signing.c | 56 +---
scripts/Makefile | 2 +-
8 files changed, 105 insertions(+), 53 deletions(-)
diff --git a/include/linux/module.h b/include/linux/module.h
index 73ee2b10e816..cd919ec972d6 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -25,9 +25,6 @@
#include
#include
-/* 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 ..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 (dhowe...@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 4592bf7997c0..a71019553ee1 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1906,7 +1906,7 @@ 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
@@ -2036,6 +2036,10 @@ config TRIM_UNUSED_KSYMS
endif # MODULES
+config MODULE_SIG_FORMAT
+ def_bool n
+ select SYSTEM_DATA_VERIFICATION
+
config MODULES_TREE_LOOKUP
def_bool y
depends on PERF_EVENTS || TRACING
diff --git a/kernel/Makefile b/kernel/Makefile
index 6c57e78817da..d2f2488f80ab 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -57,6 +57,7 @@ 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 985caa467aef..326ddeb364dd 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -19,6 +19,7 @@
#include
#include
#include
+#include
#include
#include
#include
diff --git a/kernel/module_signature.c b/kernel/module_signature.c
new file mode 100644
index ..6d5e59f27f55
--- /dev/null
+++ b/kernel/module_signature.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Module signature checker
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowe...@redhat.com)
+ */
+
+#include
+#include
+#include
+#include
+
+/**
+ * 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.
+ */
+int mod_check_sig(const struct module_signature
