[RFC v2 2/6] kernel: generalize module signing as system data signing
From: Luis R. Rodriguez
Date: Wed May 13 2015 - 14:30:35 EST
From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>
This generalizes the module signing code as helpers, we do
this as we'll later re-use this same code for firmware and
other system data signing.
Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx> (module parts)
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Cc: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
Cc: Kyle McMartin <kyle@xxxxxxxxxx>
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
---
init/Kconfig | 24 ++++++----
kernel/Makefile | 2 +-
kernel/module.c | 4 +-
kernel/{module-internal.h => sysdata-internal.h} | 4 +-
kernel/{module_signing.c => sysdata_signing.c} | 58 ++++++++++++------------
kernel/system_keyring.c | 2 +-
6 files changed, 49 insertions(+), 45 deletions(-)
rename kernel/{module-internal.h => sysdata-internal.h} (79%)
rename kernel/{module_signing.c => sysdata_signing.c} (64%)
diff --git a/init/Kconfig b/init/Kconfig
index fb98cba..a75c587 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1793,6 +1793,19 @@ config BASE_SMALL
default 0 if BASE_FULL
default 1 if !BASE_FULL
+config SYSDATA_SIG
+ def_bool n
+ select SYSTEM_TRUSTED_KEYRING
+ select KEYS
+ select CRYPTO
+ select ASYMMETRIC_KEY_TYPE
+ select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+ select PUBLIC_KEY_ALGO_RSA
+ select ASN1
+ select OID_REGISTRY
+ select X509_CERTIFICATE_PARSER
+ select PKCS7_MESSAGE_PARSER
+
menuconfig MODULES
bool "Enable loadable module support"
option modules
@@ -1866,16 +1879,7 @@ config MODULE_SRCVERSION_ALL
config MODULE_SIG
bool "Module signature verification"
depends on MODULES
- select SYSTEM_TRUSTED_KEYRING
- select KEYS
- select CRYPTO
- select ASYMMETRIC_KEY_TYPE
- select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
- select PUBLIC_KEY_ALGO_RSA
- select ASN1
- select OID_REGISTRY
- select X509_CERTIFICATE_PARSER
- select PKCS7_MESSAGE_PARSER
+ select SYSDATA_SIG
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 60c302c..ed6a32b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -47,7 +47,7 @@ endif
obj-$(CONFIG_UID16) += uid16.o
obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
obj-$(CONFIG_MODULES) += module.o
-obj-$(CONFIG_MODULE_SIG) += module_signing.o
+obj-$(CONFIG_SYSDATA_SIG) += sysdata_signing.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
diff --git a/kernel/module.c b/kernel/module.c
index 9e51b37..6a3f629 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -60,7 +60,7 @@
#include <linux/pfn.h>
#include <linux/bsearch.h>
#include <uapi/linux/module.h>
-#include "module-internal.h"
+#include "sysdata-internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/module.h>
@@ -2404,7 +2404,7 @@ static int module_sig_check(struct load_info *info)
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->len);
+ err = sysdata_verify_sig(mod, &info->len);
}
if (!err) {
diff --git a/kernel/module-internal.h b/kernel/sysdata-internal.h
similarity index 79%
rename from kernel/module-internal.h
rename to kernel/sysdata-internal.h
index 915e123..0aa573e 100644
--- a/kernel/module-internal.h
+++ b/kernel/sysdata-internal.h
@@ -1,4 +1,4 @@
-/* Module internals
+/* System Data internals
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@xxxxxxxxxx)
@@ -9,4 +9,4 @@
* 2 of the Licence, or (at your option) any later version.
*/
-extern int mod_verify_sig(const void *mod, unsigned long *_modlen);
+extern int sysdata_verify_sig(const void *data, unsigned long *_len);
diff --git a/kernel/module_signing.c b/kernel/sysdata_signing.c
similarity index 64%
rename from kernel/module_signing.c
rename to kernel/sysdata_signing.c
index 8eb20cc..adc44d4 100644
--- a/kernel/module_signing.c
+++ b/kernel/sysdata_signing.c
@@ -1,4 +1,4 @@
-/* Module signature checker
+/* System Data signature checker
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@xxxxxxxxxx)
@@ -14,10 +14,10 @@
#include <keys/system_keyring.h>
#include <crypto/public_key.h>
#include <crypto/pkcs7.h>
-#include "module-internal.h"
+#include "sysdata-internal.h"
/*
- * Module signature information block.
+ * System Data signature information block.
*
* The constituents of the signature section are, in order:
*
@@ -26,7 +26,7 @@
* - Signature data
* - Information block
*/
-struct module_signature {
+struct sysdata_signature {
u8 algo; /* Public-key crypto algorithm [0] */
u8 hash; /* Digest algorithm [0] */
u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */
@@ -37,10 +37,10 @@ struct module_signature {
};
/*
- * Verify a PKCS#7-based signature on a module.
+ * Verify a PKCS#7-based signature on system data.
*/
-static int mod_verify_pkcs7(const void *mod, unsigned long modlen,
- const void *raw_pkcs7, size_t pkcs7_len)
+static int data_verify_pkcs7(const void *data, unsigned long len,
+ const void *raw_pkcs7, size_t pkcs7_len)
{
struct pkcs7_message *pkcs7;
bool trusted;
@@ -51,7 +51,7 @@ static int mod_verify_pkcs7(const void *mod, unsigned long modlen,
return PTR_ERR(pkcs7);
/* The data should be detached - so we need to supply it. */
- if (pkcs7_supply_detached_data(pkcs7, mod, modlen) < 0) {
+ if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
pr_err("PKCS#7 signature with non-detached data\n");
ret = -EBADMSG;
goto error;
@@ -77,42 +77,42 @@ error:
}
/*
- * Verify the signature on a module.
+ * Verify the signature on system data.
*/
-int mod_verify_sig(const void *mod, unsigned long *_modlen)
+int sysdata_verify_sig(const void *data, unsigned long *_len)
{
- struct module_signature ms;
- size_t modlen = *_modlen, sig_len;
+ struct sysdata_signature ds;
+ size_t len = *_len, sig_len;
- pr_devel("==>%s(,%zu)\n", __func__, modlen);
+ pr_devel("==>%s(,%zu)\n", __func__, len);
- if (modlen <= sizeof(ms))
+ if (len <= sizeof(ds))
return -EBADMSG;
- memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
- modlen -= sizeof(ms);
+ memcpy(&ds, data + (len - sizeof(ds)), sizeof(ds));
+ len -= sizeof(ds);
- sig_len = be32_to_cpu(ms.sig_len);
- if (sig_len >= modlen)
+ sig_len = be32_to_cpu(ds.sig_len);
+ if (sig_len >= len)
return -EBADMSG;
- modlen -= sig_len;
- *_modlen = modlen;
+ len -= sig_len;
+ *_len = len;
- if (ms.id_type != PKEY_ID_PKCS7) {
+ if (ds.id_type != PKEY_ID_PKCS7) {
pr_err("Module is not signed with expected PKCS#7 message\n");
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) {
+ if (ds.algo != 0 ||
+ ds.hash != 0 ||
+ ds.signer_len != 0 ||
+ ds.key_id_len != 0 ||
+ ds.__pad[0] != 0 ||
+ ds.__pad[1] != 0 ||
+ ds.__pad[2] != 0) {
pr_err("PKCS#7 signature info has unexpected non-zero params\n");
return -EBADMSG;
}
- return mod_verify_pkcs7(mod, modlen, mod + modlen, sig_len);
+ return data_verify_pkcs7(data, len, data + len, sig_len);
}
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
index 875f64e..1eb0c86 100644
--- a/kernel/system_keyring.c
+++ b/kernel/system_keyring.c
@@ -16,7 +16,7 @@
#include <linux/err.h>
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
-#include "module-internal.h"
+#include "sysdata-internal.h"
struct key *system_trusted_keyring;
EXPORT_SYMBOL_GPL(system_trusted_keyring);
--
2.3.2.209.gd67f9d5.dirty
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/