Commit d25282d1 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module signing support from Rusty Russell:
 "module signing is the highlight, but it's an all-over David Howells frenzy..."

Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG.

* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits)
  X.509: Fix indefinite length element skip error handling
  X.509: Convert some printk calls to pr_devel
  asymmetric keys: fix printk format warning
  MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
  MODSIGN: Make mrproper should remove generated files.
  MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs
  MODSIGN: Use the same digest for the autogen key sig as for the module sig
  MODSIGN: Sign modules during the build process
  MODSIGN: Provide a script for generating a key ID from an X.509 cert
  MODSIGN: Implement module signature checking
  MODSIGN: Provide module signing public keys to the kernel
  MODSIGN: Automatically generate module signing keys if missing
  MODSIGN: Provide Kconfig options
  MODSIGN: Provide gitignore and make clean rules for extra files
  MODSIGN: Add FIPS policy
  module: signature checking hook
  X.509: Add a crypto key parser for binary (DER) X.509 certificates
  MPILIB: Provide a function to read raw data into an MPI
  X.509: Add an ASN.1 decoder
  X.509: Add simple ASN.1 grammar compiler
  ...
parents b6eea87f dbadc176
......@@ -14,6 +14,10 @@
*.o.*
*.a
*.s
*.ko.unsigned
*.ko.stripped
*.ko.stripped.dig
*.ko.stripped.sig
*.ko
*.so
*.so.dbg
......@@ -84,3 +88,13 @@ GTAGS
*.orig
*~
\#*#
#
# Leavings from module signing
#
extra_certificates
signing_key.priv
signing_key.x509
signing_key.x509.keyid
signing_key.x509.signer
x509.genkey
=============================================
ASYMMETRIC / PUBLIC-KEY CRYPTOGRAPHY KEY TYPE
=============================================
Contents:
- Overview.
- Key identification.
- Accessing asymmetric keys.
- Signature verification.
- Asymmetric key subtypes.
- Instantiation data parsers.
========
OVERVIEW
========
The "asymmetric" key type is designed to be a container for the keys used in
public-key cryptography, without imposing any particular restrictions on the
form or mechanism of the cryptography or form of the key.
The asymmetric key is given a subtype that defines what sort of data is
associated with the key and provides operations to describe and destroy it.
However, no requirement is made that the key data actually be stored in the
key.
A completely in-kernel key retention and operation subtype can be defined, but
it would also be possible to provide access to cryptographic hardware (such as
a TPM) that might be used to both retain the relevant key and perform
operations using that key. In such a case, the asymmetric key would then
merely be an interface to the TPM driver.
Also provided is the concept of a data parser. Data parsers are responsible
for extracting information from the blobs of data passed to the instantiation
function. The first data parser that recognises the blob gets to set the
subtype of the key and define the operations that can be done on that key.
A data parser may interpret the data blob as containing the bits representing a
key, or it may interpret it as a reference to a key held somewhere else in the
system (for example, a TPM).
==================
KEY IDENTIFICATION
==================
If a key is added with an empty name, the instantiation data parsers are given
the opportunity to pre-parse a key and to determine the description the key
should be given from the content of the key.
This can then be used to refer to the key, either by complete match or by
partial match. The key type may also use other criteria to refer to a key.
The asymmetric key type's match function can then perform a wider range of
comparisons than just the straightforward comparison of the description with
the criterion string:
(1) If the criterion string is of the form "id:<hexdigits>" then the match
function will examine a key's fingerprint to see if the hex digits given
after the "id:" match the tail. For instance:
keyctl search @s asymmetric id:5acc2142
will match a key with fingerprint:
1A00 2040 7601 7889 DE11 882C 3823 04AD 5ACC 2142
(2) If the criterion string is of the form "<subtype>:<hexdigits>" then the
match will match the ID as in (1), but with the added restriction that
only keys of the specified subtype (e.g. tpm) will be matched. For
instance:
keyctl search @s asymmetric tpm:5acc2142
Looking in /proc/keys, the last 8 hex digits of the key fingerprint are
displayed, along with the subtype:
1a39e171 I----- 1 perm 3f010000 0 0 asymmetri modsign.0: DSA 5acc2142 []
=========================
ACCESSING ASYMMETRIC KEYS
=========================
For general access to asymmetric keys from within the kernel, the following
inclusion is required:
#include <crypto/public_key.h>
This gives access to functions for dealing with asymmetric / public keys.
Three enums are defined there for representing public-key cryptography
algorithms:
enum pkey_algo
digest algorithms used by those:
enum pkey_hash_algo
and key identifier representations:
enum pkey_id_type
Note that the key type representation types are required because key
identifiers from different standards aren't necessarily compatible. For
instance, PGP generates key identifiers by hashing the key data plus some
PGP-specific metadata, whereas X.509 has arbitrary certificate identifiers.
The operations defined upon a key are:
(1) Signature verification.
Other operations are possible (such as encryption) with the same key data
required for verification, but not currently supported, and others
(eg. decryption and signature generation) require extra key data.
SIGNATURE VERIFICATION
----------------------
An operation is provided to perform cryptographic signature verification, using
an asymmetric key to provide or to provide access to the public key.
int verify_signature(const struct key *key,
const struct public_key_signature *sig);
The caller must have already obtained the key from some source and can then use
it to check the signature. The caller must have parsed the signature and
transferred the relevant bits to the structure pointed to by sig.
struct public_key_signature {
u8 *digest;
u8 digest_size;
enum pkey_hash_algo pkey_hash_algo : 8;
u8 nr_mpi;
union {
MPI mpi[2];
...
};
};
The algorithm used must be noted in sig->pkey_hash_algo, and all the MPIs that
make up the actual signature must be stored in sig->mpi[] and the count of MPIs
placed in sig->nr_mpi.
In addition, the data must have been digested by the caller and the resulting
hash must be pointed to by sig->digest and the size of the hash be placed in
sig->digest_size.
The function will return 0 upon success or -EKEYREJECTED if the signature
doesn't match.
The function may also return -ENOTSUPP if an unsupported public-key algorithm
or public-key/hash algorithm combination is specified or the key doesn't
support the operation; -EBADMSG or -ERANGE if some of the parameters have weird
data; or -ENOMEM if an allocation can't be performed. -EINVAL can be returned
if the key argument is the wrong type or is incompletely set up.
=======================
ASYMMETRIC KEY SUBTYPES
=======================
Asymmetric keys have a subtype that defines the set of operations that can be
performed on that key and that determines what data is attached as the key
payload. The payload format is entirely at the whim of the subtype.
The subtype is selected by the key data parser and the parser must initialise
the data required for it. The asymmetric key retains a reference on the
subtype module.
The subtype definition structure can be found in:
#include <keys/asymmetric-subtype.h>
and looks like the following:
struct asymmetric_key_subtype {
struct module *owner;
const char *name;
void (*describe)(const struct key *key, struct seq_file *m);
void (*destroy)(void *payload);
int (*verify_signature)(const struct key *key,
const struct public_key_signature *sig);
};
Asymmetric keys point to this with their type_data[0] member.
The owner and name fields should be set to the owning module and the name of
the subtype. Currently, the name is only used for print statements.
There are a number of operations defined by the subtype:
(1) describe().
Mandatory. This allows the subtype to display something in /proc/keys
against the key. For instance the name of the public key algorithm type
could be displayed. The key type will display the tail of the key
identity string after this.
(2) destroy().
Mandatory. This should free the memory associated with the key. The
asymmetric key will look after freeing the fingerprint and releasing the
reference on the subtype module.
(3) verify_signature().
Optional. These are the entry points for the key usage operations.
Currently there is only the one defined. If not set, the caller will be
given -ENOTSUPP. The subtype may do anything it likes to implement an
operation, including offloading to hardware.
==========================
INSTANTIATION DATA PARSERS
==========================
The asymmetric key type doesn't generally want to store or to deal with a raw
blob of data that holds the key data. It would have to parse it and error
check it each time it wanted to use it. Further, the contents of the blob may
have various checks that can be performed on it (eg. self-signatures, validity
dates) and may contain useful data about the key (identifiers, capabilities).
Also, the blob may represent a pointer to some hardware containing the key
rather than the key itself.
Examples of blob formats for which parsers could be implemented include:
- OpenPGP packet stream [RFC 4880].
- X.509 ASN.1 stream.
- Pointer to TPM key.
- Pointer to UEFI key.
During key instantiation each parser in the list is tried until one doesn't
return -EBADMSG.
The parser definition structure can be found in:
#include <keys/asymmetric-parser.h>
and looks like the following:
struct asymmetric_key_parser {
struct module *owner;
const char *name;
int (*parse)(struct key_preparsed_payload *prep);
};
The owner and name fields should be set to the owning module and the name of
the parser.
There is currently only a single operation defined by the parser, and it is
mandatory:
(1) parse().
This is called to preparse the key from the key creation and update paths.
In particular, it is called during the key creation _before_ a key is
allocated, and as such, is permitted to provide the key's description in
the case that the caller declines to do so.
The caller passes a pointer to the following struct with all of the fields
cleared, except for data, datalen and quotalen [see
Documentation/security/keys.txt].
struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};
The instantiation data is in a blob pointed to by data and is datalen in
size. The parse() function is not permitted to change these two values at
all, and shouldn't change any of the other values _unless_ they are
recognise the blob format and will not return -EBADMSG to indicate it is
not theirs.
If the parser is happy with the blob, it should propose a description for
the key and attach it to ->description, ->type_data[0] should be set to
point to the subtype to be used, ->payload should be set to point to the
initialised data for that subtype, ->type_data[1] should point to a hex
fingerprint and quotalen should be updated to indicate how much quota this
key should account for.
When clearing up, the data attached to ->type_data[1] and ->description
will be kfree()'d and the data attached to ->payload will be passed to the
subtype's ->destroy() method to be disposed of. A module reference for
the subtype pointed to by ->type_data[0] will be put.
If the data format is not recognised, -EBADMSG should be returned. If it
is recognised, but the key cannot for some reason be set up, some other
negative error code should be returned. On success, 0 should be returned.
The key's fingerprint string may be partially matched upon. For a
public-key algorithm such as RSA and DSA this will likely be a printable
hex version of the key's fingerprint.
Functions are provided to register and unregister parsers:
int register_asymmetric_key_parser(struct asymmetric_key_parser *parser);
void unregister_asymmetric_key_parser(struct asymmetric_key_parser *subtype);
Parsers may not have the same name. The names are otherwise only used for
displaying in debugging messages.
......@@ -1593,6 +1593,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
log everything. Information is printed at KERN_DEBUG
so loglevel=8 may also need to be specified.
module.sig_enforce
[KNL] When CONFIG_MODULE_SIG is set, this means that
modules without (valid) signatures will fail to load.
Note that if CONFIG_MODULE_SIG_ENFORCE is set, that
is always true, so this option does nothing.
mousedev.tap_time=
[MOUSE] Maximum time between finger touching and
leaving touchpad surface for touch to be considered
......
......@@ -412,6 +412,10 @@ The main syscalls are:
to the keyring. In this case, an error will be generated if the process
does not have permission to write to the keyring.
If the key type supports it, if the description is NULL or an empty
string, the key type will try and generate a description from the content
of the payload.
The payload is optional, and the pointer can be NULL if not required by
the type. The payload is plen in size, and plen can be zero for an empty
payload.
......@@ -1114,12 +1118,53 @@ The structure has a number of fields, some of which are mandatory:
it should return 0.
(*) int (*instantiate)(struct key *key, const void *data, size_t datalen);
(*) int (*preparse)(struct key_preparsed_payload *prep);
This optional method permits the key type to attempt to parse payload
before a key is created (add key) or the key semaphore is taken (update or
instantiate key). The structure pointed to by prep looks like:
struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};
Before calling the method, the caller will fill in data and datalen with
the payload blob parameters; quotalen will be filled in with the default
quota size from the key type and the rest will be cleared.
If a description can be proposed from the payload contents, that should be
attached as a string to the description field. This will be used for the
key description if the caller of add_key() passes NULL or "".
The method can attach anything it likes to type_data[] and payload. These
are merely passed along to the instantiate() or update() operations.
The method should return 0 if success ful or a negative error code
otherwise.
(*) void (*free_preparse)(struct key_preparsed_payload *prep);
This method is only required if the preparse() method is provided,
otherwise it is unused. It cleans up anything attached to the
description, type_data and payload fields of the key_preparsed_payload
struct as filled in by the preparse() method.
(*) int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
This method is called to attach a payload to a key during construction.
The payload attached need not bear any relation to the data passed to this
function.
The prep->data and prep->datalen fields will define the original payload
blob. If preparse() was supplied then other fields may be filled in also.
If the amount of data attached to the key differs from the size in
keytype->def_datalen, then key_payload_reserve() should be called.
......@@ -1135,6 +1180,9 @@ The structure has a number of fields, some of which are mandatory:
If this type of key can be updated, then this method should be provided.
It is called to update a key's payload from the blob of data provided.
The prep->data and prep->datalen fields will define the original payload
blob. If preparse() was supplied then other fields may be filled in also.
key_payload_reserve() should be called if the data length might change
before any changes are actually made. Note that if this succeeds, the type
is committed to changing the key because it's already been altered, so all
......
......@@ -997,7 +997,10 @@ CLEAN_DIRS += $(MODVERDIR)
MRPROPER_DIRS += include/config usr/include include/generated \
arch/*/include/generated
MRPROPER_FILES += .config .config.old .version .old_version $(version_h) \
Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \
signing_key.priv signing_key.x509 x509.genkey \
extra_certificates signing_key.x509.keyid \
signing_key.x509.signer
# clean - Delete most, but leave enough to build external modules
#
......@@ -1241,6 +1244,7 @@ clean: $(clean-dirs)
$(call cmd,rmfiles)
@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
-o -name '*.ko.*' \
-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-o -name '*.symtypes' -o -name 'modules.order' \
-o -name modules.builtin -o -name '.tmp_*.o.*' \
......
......@@ -322,4 +322,23 @@ config HAVE_IRQ_TIME_ACCOUNTING
config HAVE_ARCH_TRANSPARENT_HUGEPAGE
bool
config HAVE_MOD_ARCH_SPECIFIC
bool
help
The arch uses struct mod_arch_specific to store data. Many arches
just need a simple module loader without arch specific data - those
should not enable this.
config MODULES_USE_ELF_RELA
bool
help
Modules only use ELF RELA relocations. Modules with ELF REL
relocations will give an error.
config MODULES_USE_ELF_REL
bool
help
Modules only use ELF REL relocations. Modules with ELF RELA
relocations will give an error.
source "kernel/gcov/Kconfig"
......@@ -22,6 +22,8 @@ config ALPHA
select GENERIC_STRNLEN_USER
select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
select HAVE_MOD_ARCH_SPECIFIC
select MODULES_USE_ELF_RELA
help
The Alpha is a 64-bit general-purpose processor designed and
marketed by the Digital Equipment Corporation of blessed memory,
......
#ifndef _ALPHA_MODULE_H
#define _ALPHA_MODULE_H
#include <asm-generic/module.h>
struct mod_arch_specific
{
unsigned int gotsecindex;
};
#define Elf_Sym Elf64_Sym
#define Elf_Shdr Elf64_Shdr
#define Elf_Ehdr Elf64_Ehdr
#define Elf_Phdr Elf64_Phdr
#define Elf_Dyn Elf64_Dyn
#define Elf_Rel Elf64_Rel
#define Elf_Rela Elf64_Rela
#define ARCH_SHF_SMALL SHF_ALPHA_GPREL
#ifdef MODULE
......
......@@ -53,6 +53,8 @@ config ARM
select PERF_USE_VMALLOC
select RTC_LIB
select SYS_SUPPORTS_APM_EMULATION
select HAVE_MOD_ARCH_SPECIFIC if ARM_UNWIND
select MODULES_USE_ELF_REL
help
The ARM series is a line of low-power-consumption RISC chip designs
licensed by ARM Ltd and targeted at embedded applications and
......
#ifndef _ASM_ARM_MODULE_H
#define _ASM_ARM_MODULE_H
#define Elf_Shdr Elf32_Shdr
#define Elf_Sym Elf32_Sym
#define Elf_Ehdr Elf32_Ehdr
#include <asm-generic/module.h>
struct unwind_table;
......@@ -16,13 +14,11 @@ enum {
ARM_SEC_DEVEXIT,
ARM_SEC_MAX,
};
#endif
struct mod_arch_specific {
#ifdef CONFIG_ARM_UNWIND
struct unwind_table *unwind[ARM_SEC_MAX];
#endif
};
#endif
/*
* Add the ARM architecture version to the version magic string
......
......@@ -15,6 +15,8 @@ config AVR32
select ARCH_WANT_IPC_PARSE_VERSION
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_CLOCKEVENTS
select HAVE_MOD_ARCH_SPECIFIC
select MODULES_USE_ELF_RELA
help
AVR32 is a high-performance 32-bit RISC microprocessor core,
designed for cost-sensitive embedded applications, with particular
......
#ifndef __ASM_AVR32_MODULE_H
#define __ASM_AVR32_MODULE_H
#include <asm-generic/module.h>
struct mod_arch_syminfo {
unsigned long got_offset;
int got_initialized;
......@@ -17,10 +19,6 @@ struct mod_arch_specific {
struct mod_arch_syminfo *syminfo;
};
#define Elf_Shdr Elf32_Shdr
#define Elf_Sym Elf32_Sym
#define Elf_Ehdr Elf32_Ehdr
#define MODULE_PROC_FAMILY "AVR32v1"
#define MODULE_ARCH_VERMAGIC MODULE_PROC_FAMILY
......
......@@ -43,6 +43,8 @@ config BLACKFIN
select HAVE_NMI_WATCHDOG if NMI_WATCHDOG
select GENERIC_SMP_IDLE_THREAD
select ARCH_USES_GETTIMEOFFSET if !GENERIC_CLOCKEVENTS
select HAVE_MOD_ARCH_SPECIFIC
select MODULES_USE_ELF_RELA
config GENERIC_CSUM
def_bool y
......
......@@ -7,9 +7,7 @@
#ifndef _ASM_BFIN_MODULE_H
#define _ASM_BFIN_MODULE_H
#define Elf_Shdr Elf32_Shdr
#define Elf_Sym Elf32_Sym
#define Elf_Ehdr Elf32_Ehdr
#include <asm-generic/module.h>
struct mod_arch_specific {
Elf_Shdr *text_l1;
......
......@@ -18,6 +18,7 @@ config C6X
select OF_EARLY_FLATTREE
select GENERIC_CLOCKEVENTS
select GENERIC_KERNEL_THREAD
select MODULES_USE_ELF_RELA
config MMU
def_bool n
......
......@@ -13,17 +13,7 @@
#ifndef _ASM_C6X_MODULE_H
#define _ASM_C6X_MODULE_H
#define Elf_Shdr Elf32_Shdr
#define Elf_Sym Elf32_Sym
#define Elf_Ehdr Elf32_Ehdr
#define Elf_Addr Elf32_Addr
#define Elf_Word Elf32_Word
/*
* This file contains the C6x architecture specific module code.
*/
struct mod_arch_specific {
};
#include <asm-generic/module.h>
struct loaded_sections {
unsigned int new_vaddr;
......
......@@ -48,6 +48,7 @@ config CRIS
select GENERIC_IOMAP
select GENERIC_SMP_IDLE_THREAD if ETRAX_ARCH_V32
select GENERIC_CMOS_UPDATE
select MODULES_USE_ELF_RELA
config HZ
int
......
......@@ -10,3 +10,4 @@ header-y += sync_serial.h
generic-y += clkdev.h
generic-y += exec.h
generic-y += module.h
#ifndef _ASM_CRIS_MODULE_H
#define _ASM_CRIS_MODULE_H
/* cris is simple */
struct mod_arch_specific { };