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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-14 13:39:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-14 13:39:34 -0700
commitd25282d1c9b9bc4cda7f9d3c0205108e99aa7a9d (patch)
treef414482d768b015a609924293b779b4ad0b8f764 /kernel
parentb6eea87fc6850d3531a64a27d2323a4498cd4e43 (diff)
parentdbadc17683e6c673a69b236c0f041b931cc55c42 (diff)
downloadvexpress-lsk-d25282d1c9b9bc4cda7f9d3c0205108e99aa7a9d.tar.gz
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 ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Makefile77
-rw-r--r--kernel/modsign_pubkey.c113
-rw-r--r--kernel/module-internal.h15
-rw-r--r--kernel/module.c157
-rw-r--r--kernel/module_signing.c243
5 files changed, 578 insertions, 27 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index 5404911eaee..0dfeca4324e 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
obj-$(CONFIG_UID16) += uid16.o
obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
@@ -130,3 +131,79 @@ quiet_cmd_timeconst = TIMEC $@
targets += timeconst.h
$(obj)/timeconst.h: $(src)/timeconst.pl FORCE
$(call if_changed,timeconst)
+
+ifeq ($(CONFIG_MODULE_SIG),y)
+#
+# Pull the signing certificate and any extra certificates into the kernel
+#
+extra_certificates:
+ touch $@
+
+kernel/modsign_pubkey.o: signing_key.x509 extra_certificates
+
+###############################################################################
+#
+# If module signing is requested, say by allyesconfig, but a key has not been
+# supplied, then one will need to be generated to make sure the build does not
+# fail and that the kernel may be used afterwards.
+#
+###############################################################################
+sign_key_with_hash :=
+ifeq ($(CONFIG_MODULE_SIG_SHA1),y)
+sign_key_with_hash := -sha1
+endif
+ifeq ($(CONFIG_MODULE_SIG_SHA224),y)
+sign_key_with_hash := -sha224
+endif
+ifeq ($(CONFIG_MODULE_SIG_SHA256),y)
+sign_key_with_hash := -sha256
+endif
+ifeq ($(CONFIG_MODULE_SIG_SHA384),y)
+sign_key_with_hash := -sha384
+endif
+ifeq ($(CONFIG_MODULE_SIG_SHA512),y)
+sign_key_with_hash := -sha512
+endif
+ifeq ($(sign_key_with_hash),)
+$(error Could not determine digest type to use from kernel config)
+endif
+
+signing_key.priv signing_key.x509: x509.genkey
+ @echo "###"
+ @echo "### Now generating an X.509 key pair to be used for signing modules."
+ @echo "###"
+ @echo "### If this takes a long time, you might wish to run rngd in the"
+ @echo "### background to keep the supply of entropy topped up. It"
+ @echo "### needs to be run as root, and should use a hardware random"
+ @echo "### number generator if one is available, eg:"
+ @echo "###"
+ @echo "### rngd -r /dev/hwrandom"
+ @echo "###"
+ openssl req -new -nodes -utf8 $(sign_key_with_hash) -days 36500 -batch \
+ -x509 -config x509.genkey \
+ -outform DER -out signing_key.x509 \
+ -keyout signing_key.priv
+ @echo "###"
+ @echo "### Key pair generated."
+ @echo "###"
+
+x509.genkey:
+ @echo Generating X.509 key generation config
+ @echo >x509.genkey "[ req ]"
+ @echo >>x509.genkey "default_bits = 4096"
+ @echo >>x509.genkey "distinguished_name = req_distinguished_name"
+ @echo >>x509.genkey "prompt = no"
+ @echo >>x509.genkey "string_mask = utf8only"
+ @echo >>x509.genkey "x509_extensions = myexts"
+ @echo >>x509.genkey
+ @echo >>x509.genkey "[ req_distinguished_name ]"
+ @echo >>x509.genkey "O = Magrathea"
+ @echo >>x509.genkey "CN = Glacier signing key"
+ @echo >>x509.genkey "emailAddress = slartibartfast@magrathea.h2g2"
+ @echo >>x509.genkey
+ @echo >>x509.genkey "[ myexts ]"
+ @echo >>x509.genkey "basicConstraints=critical,CA:FALSE"
+ @echo >>x509.genkey "keyUsage=digitalSignature"
+ @echo >>x509.genkey "subjectKeyIdentifier=hash"
+ @echo >>x509.genkey "authorityKeyIdentifier=keyid"
+endif
diff --git a/kernel/modsign_pubkey.c b/kernel/modsign_pubkey.c
new file mode 100644
index 00000000000..4646eb2c382
--- /dev/null
+++ b/kernel/modsign_pubkey.c
@@ -0,0 +1,113 @@
+/* Public keys for module signature verification
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <keys/asymmetric-type.h>
+#include "module-internal.h"
+
+struct key *modsign_keyring;
+
+extern __initdata const u8 modsign_certificate_list[];
+extern __initdata const u8 modsign_certificate_list_end[];
+asm(".section .init.data,\"aw\"\n"
+ "modsign_certificate_list:\n"
+ ".incbin \"signing_key.x509\"\n"
+ ".incbin \"extra_certificates\"\n"
+ "modsign_certificate_list_end:"
+ );
+
+/*
+ * We need to make sure ccache doesn't cache the .o file as it doesn't notice
+ * if modsign.pub changes.
+ */
+static __initdata const char annoy_ccache[] = __TIME__ "foo";
+
+/*
+ * Load the compiled-in keys
+ */
+static __init int module_verify_init(void)
+{
+ pr_notice("Initialise module verification\n");
+
+ modsign_keyring = key_alloc(&key_type_keyring, ".module_sign",
+ KUIDT_INIT(0), KGIDT_INIT(0),
+ current_cred(),
+ (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ,
+ KEY_ALLOC_NOT_IN_QUOTA);
+ if (IS_ERR(modsign_keyring))
+ panic("Can't allocate module signing keyring\n");
+
+ if (key_instantiate_and_link(modsign_keyring, NULL, 0, NULL, NULL) < 0)
+ panic("Can't instantiate module signing keyring\n");
+
+ return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(module_verify_init);
+
+/*
+ * Load the compiled-in keys
+ */
+static __init int load_module_signing_keys(void)
+{
+ key_ref_t key;
+ const u8 *p, *end;
+ size_t plen;
+
+ pr_notice("Loading module verification certificates\n");
+
+ end = modsign_certificate_list_end;
+ p = modsign_certificate_list;
+ while (p < end) {
+ /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
+ * than 256 bytes in size.
+ */
+ if (end - p < 4)
+ goto dodgy_cert;
+ if (p[0] != 0x30 &&
+ p[1] != 0x82)
+ goto dodgy_cert;
+ plen = (p[2] << 8) | p[3];
+ plen += 4;
+ if (plen > end - p)
+ goto dodgy_cert;
+
+ key = key_create_or_update(make_key_ref(modsign_keyring, 1),
+ "asymmetric",
+ NULL,
+ p,
+ plen,
+ (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW,
+ KEY_ALLOC_NOT_IN_QUOTA);
+ if (IS_ERR(key))
+ pr_err("MODSIGN: Problem loading in-kernel X.509 certificate (%ld)\n",
+ PTR_ERR(key));
+ else
+ pr_notice("MODSIGN: Loaded cert '%s'\n",
+ key_ref_to_ptr(key)->description);
+ p += plen;
+ }
+
+ return 0;
+
+dodgy_cert:
+ pr_err("MODSIGN: Problem parsing in-kernel X.509 certificate list\n");
+ return 0;
+}
+late_initcall(load_module_signing_keys);
diff --git a/kernel/module-internal.h b/kernel/module-internal.h
new file mode 100644
index 00000000000..6114a13419b
--- /dev/null
+++ b/kernel/module-internal.h
@@ -0,0 +1,15 @@
+/* Module internals
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+extern struct key *modsign_keyring;
+
+extern int mod_verify_sig(const void *mod, unsigned long modlen,
+ const void *sig, unsigned long siglen);
diff --git a/kernel/module.c b/kernel/module.c
index 4edbd9c11ac..0e2da8695f8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -58,6 +58,8 @@
#include <linux/jump_label.h>
#include <linux/pfn.h>
#include <linux/bsearch.h>
+#include <linux/fips.h>
+#include "module-internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/module.h>
@@ -102,6 +104,43 @@ static LIST_HEAD(modules);
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */
+#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_FORCE
+static bool sig_enforce = true;
+#else
+static bool sig_enforce = false;
+
+static int param_set_bool_enable_only(const char *val,
+ const struct kernel_param *kp)
+{
+ int err;
+ bool test;
+ struct kernel_param dummy_kp = *kp;
+
+ dummy_kp.arg = &test;
+
+ err = param_set_bool(val, &dummy_kp);
+ if (err)
+ return err;
+
+ /* Don't let them unset it once it's set! */
+ if (!test && sig_enforce)
+ return -EROFS;
+
+ if (test)
+ sig_enforce = true;
+ return 0;
+}
+
+static const struct kernel_param_ops param_ops_bool_enable_only = {
+ .set = param_set_bool_enable_only,
+ .get = param_get_bool,
+};
+#define param_check_bool_enable_only param_check_bool
+
+module_param(sig_enforce, bool_enable_only, 0644);
+#endif /* !CONFIG_MODULE_SIG_FORCE */
+#endif /* CONFIG_MODULE_SIG */
/* Block module loading/unloading? */
int modules_disabled = 0;
@@ -136,6 +175,7 @@ struct load_info {
unsigned long symoffs, stroffs;
struct _ddebug *debug;
unsigned int num_debug;
+ bool sig_ok;
struct {
unsigned int sym, str, mod, vers, info, pcpu;
} index;
@@ -1949,26 +1989,6 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
return ret;
}
-int __weak apply_relocate(Elf_Shdr *sechdrs,
- const char *strtab,
- unsigned int symindex,
- unsigned int relsec,
- struct module *me)
-{
- pr_err("module %s: REL relocation unsupported\n", me->name);
- return -ENOEXEC;
-}
-
-int __weak apply_relocate_add(Elf_Shdr *sechdrs,
- const char *strtab,
- unsigned int symindex,
- unsigned int relsec,
- struct module *me)
-{
- pr_err("module %s: RELA relocation unsupported\n", me->name);
- return -ENOEXEC;
-}
-
static int apply_relocations(struct module *mod, const struct load_info *info)
{
unsigned int i;
@@ -2399,7 +2419,52 @@ static inline void kmemleak_load_module(const struct module *mod,
}
#endif
-/* Sets info->hdr and info->len. */
+#ifdef CONFIG_MODULE_SIG
+static int module_sig_check(struct load_info *info,
+ const void *mod, unsigned long *len)
+{
+ int err = -ENOKEY;
+ const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
+ const void *p = mod, *end = mod + *len;
+
+ /* Poor man's memmem. */
+ while ((p = memchr(p, MODULE_SIG_STRING[0], end - p))) {
+ if (p + markerlen > end)
+ break;
+
+ if (memcmp(p, MODULE_SIG_STRING, markerlen) == 0) {
+ const void *sig = p + markerlen;
+ /* Truncate module up to signature. */
+ *len = p - mod;
+ err = mod_verify_sig(mod, *len, sig, end - sig);
+ break;
+ }
+ p++;
+ }
+
+ if (!err) {
+ info->sig_ok = true;
+ return 0;
+ }
+
+ /* Not having a signature is only an error if we're strict. */
+ if (err < 0 && fips_enabled)
+ panic("Module verification failed with error %d in FIPS mode\n",
+ err);
+ if (err == -ENOKEY && !sig_enforce)
+ err = 0;
+
+ return err;
+}
+#else /* !CONFIG_MODULE_SIG */
+static int module_sig_check(struct load_info *info,
+ void *mod, unsigned long *len)
+{
+ return 0;
+}
+#endif /* !CONFIG_MODULE_SIG */
+
+/* Sets info->hdr, info->len and info->sig_ok. */
static int copy_and_check(struct load_info *info,
const void __user *umod, unsigned long len,
const char __user *uargs)
@@ -2419,6 +2484,10 @@ static int copy_and_check(struct load_info *info,
goto free_hdr;
}
+ err = module_sig_check(info, hdr, &len);
+ if (err)
+ goto free_hdr;
+
/* Sanity checks against insmoding binaries or wrong arch,
weird elf version */
if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
@@ -2730,6 +2799,10 @@ static int check_module_license_and_versions(struct module *mod)
if (strcmp(mod->name, "driverloader") == 0)
add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+ /* lve claims to be GPL but upstream won't provide source */
+ if (strcmp(mod->name, "lve") == 0)
+ add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+
#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs)
|| (mod->num_gpl_syms && !mod->gpl_crcs)
@@ -2861,6 +2934,20 @@ static int post_relocation(struct module *mod, const struct load_info *info)
return module_finalize(info->hdr, info->sechdrs, mod);
}
+/* Is this module of this name done loading? No locks held. */
+static bool finished_loading(const char *name)
+{
+ struct module *mod;
+ bool ret;
+
+ mutex_lock(&module_mutex);
+ mod = find_module(name);
+ ret = !mod || mod->state != MODULE_STATE_COMING;
+ mutex_unlock(&module_mutex);
+
+ return ret;
+}
+
/* Allocate and load the module: note that size of section 0 is always
zero, and we rely on this for optional sections. */
static struct module *load_module(void __user *umod,
@@ -2868,7 +2955,7 @@ static struct module *load_module(void __user *umod,
const char __user *uargs)
{
struct load_info info = { NULL, };
- struct module *mod;
+ struct module *mod, *old;
long err;
pr_debug("load_module: umod=%p, len=%lu, uargs=%p\n",
@@ -2886,6 +2973,12 @@ static struct module *load_module(void __user *umod,
goto free_copy;
}
+#ifdef CONFIG_MODULE_SIG
+ mod->sig_ok = info.sig_ok;
+ if (!mod->sig_ok)
+ add_taint_module(mod, TAINT_FORCED_MODULE);
+#endif
+
/* Now module is in final location, initialize linked lists, etc. */
err = module_unload_init(mod);
if (err)
@@ -2934,8 +3027,18 @@ static struct module *load_module(void __user *umod,
* function to insert in a way safe to concurrent readers.
* The mutex protects against concurrent writers.
*/
+again:
mutex_lock(&module_mutex);
- if (find_module(mod->name)) {
+ if ((old = find_module(mod->name)) != NULL) {
+ if (old->state == MODULE_STATE_COMING) {
+ /* Wait in case it fails to load. */
+ mutex_unlock(&module_mutex);
+ err = wait_event_interruptible(module_wq,
+ finished_loading(mod->name));
+ if (err)
+ goto free_arch_cleanup;
+ goto again;
+ }
err = -EEXIST;
goto unlock;
}
@@ -2975,7 +3078,7 @@ static struct module *load_module(void __user *umod,
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
module_bug_cleanup(mod);
-
+ wake_up_all(&module_wq);
ddebug:
dynamic_debug_remove(info.debug);
unlock:
@@ -3050,7 +3153,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
free_module(mod);
- wake_up(&module_wq);
+ wake_up_all(&module_wq);
return ret;
}
if (ret > 0) {
@@ -3062,9 +3165,8 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
dump_stack();
}
- /* Now it's a first class citizen! Wake up anyone waiting for it. */
+ /* Now it's a first class citizen! */
mod->state = MODULE_STATE_LIVE;
- wake_up(&module_wq);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_LIVE, mod);
@@ -3087,6 +3189,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
mod->init_ro_size = 0;
mod->init_text_size = 0;
mutex_unlock(&module_mutex);
+ wake_up_all(&module_wq);
return 0;
}
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
new file mode 100644
index 00000000000..6b09f6983ac
--- /dev/null
+++ b/kernel/module_signing.c
@@ -0,0 +1,243 @@
+/* Module signature checker
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <crypto/public_key.h>
+#include <crypto/hash.h>
+#include <keys/asymmetric-type.h>
+#include "module-internal.h"
+
+/*
+ * 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 {
+ enum pkey_algo algo : 8; /* Public-key crypto algorithm */
+ enum pkey_hash_algo hash : 8; /* Digest algorithm */
+ enum pkey_id_type id_type : 8; /* Key identifier type */
+ u8 signer_len; /* Length of signer's name */
+ u8 key_id_len; /* Length of key identifier */
+ u8 __pad[3];
+ __be32 sig_len; /* Length of signature data */
+};
+
+/*
+ * Digest the module contents.
+ */
+static struct public_key_signature *mod_make_digest(enum pkey_hash_algo hash,
+ const void *mod,
+ unsigned long modlen)
+{
+ struct public_key_signature *pks;
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ size_t digest_size, desc_size;
+ int ret;
+
+ pr_devel("==>%s()\n", __func__);
+
+ /* Allocate the hashing algorithm we're going to need and find out how
+ * big the hash operational data will be.
+ */
+ tfm = crypto_alloc_shash(pkey_hash_algo[hash], 0, 0);
+ if (IS_ERR(tfm))
+ return (PTR_ERR(tfm) == -ENOENT) ? ERR_PTR(-ENOPKG) : ERR_CAST(tfm);
+
+ desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+ digest_size = crypto_shash_digestsize(tfm);
+
+ /* We allocate the hash operational data storage on the end of our
+ * context data and the digest output buffer on the end of that.
+ */
+ ret = -ENOMEM;
+ pks = kzalloc(digest_size + sizeof(*pks) + desc_size, GFP_KERNEL);
+ if (!pks)
+ goto error_no_pks;
+
+ pks->pkey_hash_algo = hash;
+ pks->digest = (u8 *)pks + sizeof(*pks) + desc_size;
+ pks->digest_size = digest_size;
+
+ desc = (void *)pks + sizeof(*pks);
+ desc->tfm = tfm;
+ desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ ret = crypto_shash_init(desc);
+ if (ret < 0)
+ goto error;
+
+ ret = crypto_shash_finup(desc, mod, modlen, pks->digest);
+ if (ret < 0)
+ goto error;
+
+ crypto_free_shash(tfm);
+ pr_devel("<==%s() = ok\n", __func__);
+ return pks;
+
+error:
+ kfree(pks);
+error_no_pks:
+ crypto_free_shash(tfm);
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ERR_PTR(ret);
+}
+
+/*
+ * Extract an MPI array from the signature data. This represents the actual
+ * signature. Each raw MPI is prefaced by a BE 2-byte value indicating the
+ * size of the MPI in bytes.
+ *
+ * RSA signatures only have one MPI, so currently we only read one.
+ */
+static int mod_extract_mpi_array(struct public_key_signature *pks,
+ const void *data, size_t len)
+{
+ size_t nbytes;
+ MPI mpi;
+
+ if (len < 3)
+ return -EBADMSG;
+ nbytes = ((const u8 *)data)[0] << 8 | ((const u8 *)data)[1];
+ data += 2;
+ len -= 2;
+ if (len != nbytes)
+ return -EBADMSG;
+
+ mpi = mpi_read_raw_data(data, nbytes);
+ if (!mpi)
+ return -ENOMEM;
+ pks->mpi[0] = mpi;
+ pks->nr_mpi = 1;
+ return 0;
+}
+
+/*
+ * Request an asymmetric key.
+ */
+static struct key *request_asymmetric_key(const char *signer, size_t signer_len,
+ const u8 *key_id, size_t key_id_len)
+{
+ key_ref_t key;
+ size_t i;
+ char *id, *q;
+
+ pr_devel("==>%s(,%zu,,%zu)\n", __func__, signer_len, key_id_len);
+
+ /* Construct an identifier. */
+ id = kmalloc(signer_len + 2 + key_id_len * 2 + 1, GFP_KERNEL);
+ if (!id)
+ return ERR_PTR(-ENOKEY);
+
+ memcpy(id, signer, signer_len);
+
+ q = id + signer_len;
+ *q++ = ':';
+ *q++ = ' ';
+ for (i = 0; i < key_id_len; i++) {
+ *q++ = hex_asc[*key_id >> 4];
+ *q++ = hex_asc[*key_id++ & 0x0f];
+ }
+
+ *q = 0;
+
+ pr_debug("Look up: \"%s\"\n", id);
+
+ key = keyring_search(make_key_ref(modsign_keyring, 1),
+ &key_type_asymmetric, id);
+ if (IS_ERR(key))
+ pr_warn("Request for unknown module key '%s' err %ld\n",
+ id, PTR_ERR(key));
+ kfree(id);
+
+ if (IS_ERR(key)) {
+ switch (PTR_ERR(key)) {
+ /* Hide some search errors */
+ case -EACCES:
+ case -ENOTDIR:
+ case -EAGAIN:
+ return ERR_PTR(-ENOKEY);
+ default:
+ return ERR_CAST(key);
+ }
+ }
+
+ pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key_ref_to_ptr(key)));
+ return key_ref_to_ptr(key);
+}
+
+/*
+ * Verify the signature on a module.
+ */
+int mod_verify_sig(const void *mod, unsigned long modlen,
+ const void *sig, unsigned long siglen)
+{
+ struct public_key_signature *pks;
+ struct module_signature ms;
+ struct key *key;
+ size_t sig_len;
+ int ret;
+
+ pr_devel("==>%s(,%lu,,%lu,)\n", __func__, modlen, siglen);
+
+ if (siglen <= sizeof(ms))
+ return -EBADMSG;
+
+ memcpy(&ms, sig + (siglen - sizeof(ms)), sizeof(ms));
+ siglen -= sizeof(ms);
+
+ sig_len = be32_to_cpu(ms.sig_len);
+ if (sig_len >= siglen ||
+ siglen - sig_len != (size_t)ms.signer_len + ms.key_id_len)
+ return -EBADMSG;
+
+ /* For the moment, only support RSA and X.509 identifiers */
+ if (ms.algo != PKEY_ALGO_RSA ||
+ ms.id_type != PKEY_ID_X509)
+ return -ENOPKG;
+
+ if (ms.hash >= PKEY_HASH__LAST ||
+ !pkey_hash_algo[ms.hash])
+ return -ENOPKG;
+
+ key = request_asymmetric_key(sig, ms.signer_len,
+ sig + ms.signer_len, ms.key_id_len);
+ if (IS_ERR(key))
+ return PTR_ERR(key);
+
+ pks = mod_make_digest(ms.hash, mod, modlen);
+ if (IS_ERR(pks)) {
+ ret = PTR_ERR(pks);
+ goto error_put_key;
+ }
+
+ ret = mod_extract_mpi_array(pks, sig + ms.signer_len + ms.key_id_len,
+ sig_len);
+ if (ret < 0)
+ goto error_free_pks;
+
+ ret = verify_signature(key, pks);
+ pr_devel("verify_signature() = %d\n", ret);
+
+error_free_pks:
+ mpi_free(pks->rsa.s);
+ kfree(pks);
+error_put_key:
+ key_put(key);
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+}