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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-21 19:46:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-21 19:46:00 -0800
commit78dc53c422172a317adb0776dfb687057ffa28b7 (patch)
tree7c5d15da75d769d01f6a992c24c3490b3867d5b2 /kernel
parent3eaded86ac3e7f00fb3eeb8162d89e9a34e42fb0 (diff)
parent62fe318256befbd1b4a6765e71d9c997f768fe79 (diff)
Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris: "In this patchset, we finally get an SELinux update, with Paul Moore taking over as maintainer of that code. Also a significant update for the Keys subsystem, as well as maintenance updates to Smack, IMA, TPM, and Apparmor" and since I wanted to know more about the updates to key handling, here's the explanation from David Howells on that: "Okay. There are a number of separate bits. I'll go over the big bits and the odd important other bit, most of the smaller bits are just fixes and cleanups. If you want the small bits accounting for, I can do that too. (1) Keyring capacity expansion. KEYS: Consolidate the concept of an 'index key' for key access KEYS: Introduce a search context structure KEYS: Search for auth-key by name rather than target key ID Add a generic associative array implementation. KEYS: Expand the capacity of a keyring Several of the patches are providing an expansion of the capacity of a keyring. Currently, the maximum size of a keyring payload is one page. Subtract a small header and then divide up into pointers, that only gives you ~500 pointers on an x86_64 box. However, since the NFS idmapper uses a keyring to store ID mapping data, that has proven to be insufficient to the cause. Whatever data structure I use to handle the keyring payload, it can only store pointers to keys, not the keys themselves because several keyrings may point to a single key. This precludes inserting, say, and rb_node struct into the key struct for this purpose. I could make an rbtree of records such that each record has an rb_node and a key pointer, but that would use four words of space per key stored in the keyring. It would, however, be able to use much existing code. I selected instead a non-rebalancing radix-tree type approach as that could have a better space-used/key-pointer ratio. I could have used the radix tree implementation that we already have and insert keys into it by their serial numbers, but that means any sort of search must iterate over the whole radix tree. Further, its nodes are a bit on the capacious side for what I want - especially given that key serial numbers are randomly allocated, thus leaving a lot of empty space in the tree. So what I have is an associative array that internally is a radix-tree with 16 pointers per node where the index key is constructed from the key type pointer and the key description. This means that an exact lookup by type+description is very fast as this tells us how to navigate directly to the target key. I made the data structure general in lib/assoc_array.c as far as it is concerned, its index key is just a sequence of bits that leads to a pointer. It's possible that someone else will be able to make use of it also. FS-Cache might, for example. (2) Mark keys as 'trusted' and keyrings as 'trusted only'. KEYS: verify a certificate is signed by a 'trusted' key KEYS: Make the system 'trusted' keyring viewable by userspace KEYS: Add a 'trusted' flag and a 'trusted only' flag KEYS: Separate the kernel signature checking keyring from module signing These patches allow keys carrying asymmetric public keys to be marked as being 'trusted' and allow keyrings to be marked as only permitting the addition or linkage of trusted keys. Keys loaded from hardware during kernel boot or compiled into the kernel during build are marked as being trusted automatically. New keys can be loaded at runtime with add_key(). They are checked against the system keyring contents and if their signatures can be validated with keys that are already marked trusted, then they are marked trusted also and can thus be added into the master keyring. Patches from Mimi Zohar make this usable with the IMA keyrings also. (3) Remove the date checks on the key used to validate a module signature. X.509: Remove certificate date checks It's not reasonable to reject a signature just because the key that it was generated with is no longer valid datewise - especially if the kernel hasn't yet managed to set the system clock when the first module is loaded - so just remove those checks. (4) Make it simpler to deal with additional X.509 being loaded into the kernel. KEYS: Load *.x509 files into kernel keyring KEYS: Have make canonicalise the paths of the X.509 certs better to deduplicate The builder of the kernel now just places files with the extension ".x509" into the kernel source or build trees and they're concatenated by the kernel build and stuffed into the appropriate section. (5) Add support for userspace kerberos to use keyrings. KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches KEYS: Implement a big key type that can save to tmpfs Fedora went to, by default, storing kerberos tickets and tokens in tmpfs. We looked at storing it in keyrings instead as that confers certain advantages such as tickets being automatically deleted after a certain amount of time and the ability for the kernel to get at these tokens more easily. To make this work, two things were needed: (a) A way for the tickets to persist beyond the lifetime of all a user's sessions so that cron-driven processes can still use them. The problem is that a user's session keyrings are deleted when the session that spawned them logs out and the user's user keyring is deleted when the UID is deleted (typically when the last log out happens), so neither of these places is suitable. I've added a system keyring into which a 'persistent' keyring is created for each UID on request. Each time a user requests their persistent keyring, the expiry time on it is set anew. If the user doesn't ask for it for, say, three days, the keyring is automatically expired and garbage collected using the existing gc. All the kerberos tokens it held are then also gc'd. (b) A key type that can hold really big tickets (up to 1MB in size). The problem is that Active Directory can return huge tickets with lots of auxiliary data attached. We don't, however, want to eat up huge tracts of unswappable kernel space for this, so if the ticket is greater than a certain size, we create a swappable shmem file and dump the contents in there and just live with the fact we then have an inode and a dentry overhead. If the ticket is smaller than that, we slap it in a kmalloc()'d buffer" * 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (121 commits) KEYS: Fix keyring content gc scanner KEYS: Fix error handling in big_key instantiation KEYS: Fix UID check in keyctl_get_persistent() KEYS: The RSA public key algorithm needs to select MPILIB ima: define '_ima' as a builtin 'trusted' keyring ima: extend the measurement list to include the file signature kernel/system_certificate.S: use real contents instead of macro GLOBAL() KEYS: fix error return code in big_key_instantiate() KEYS: Fix keyring quota misaccounting on key replacement and unlink KEYS: Fix a race between negating a key and reading the error set KEYS: Make BIG_KEYS boolean apparmor: remove the "task" arg from may_change_ptraced_domain() apparmor: remove parent task info from audit logging apparmor: remove tsk field from the apparmor_audit_struct apparmor: fix capability to not use the current task, during reporting Smack: Ptrace access check mode ima: provide hash algo info in the xattr ima: enable support for larger default filedata hash algorithms ima: define kernel parameter 'ima_template=' to change configured default ima: add Kconfig default measurement list template ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Makefile50
-rw-r--r--kernel/modsign_certificate.S12
-rw-r--r--kernel/modsign_pubkey.c104
-rw-r--r--kernel/module-internal.h2
-rw-r--r--kernel/module_signing.c11
-rw-r--r--kernel/system_certificates.S10
-rw-r--r--kernel/system_keyring.c105
-rw-r--r--kernel/user.c4
-rw-r--r--kernel/user_namespace.c6
9 files changed, 173 insertions, 131 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index 09a9c94f42b..bbaf7d59c1b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -41,8 +41,9 @@ ifneq ($(CONFIG_SMP),y)
obj-y += up.o
endif
obj-$(CONFIG_UID16) += uid16.o
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
obj-$(CONFIG_MODULES) += module.o
-obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o modsign_certificate.o
+obj-$(CONFIG_MODULE_SIG) += module_signing.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
@@ -122,19 +123,52 @@ targets += timeconst.h
$(obj)/timeconst.h: $(obj)/hz.bc $(src)/timeconst.bc FORCE
$(call if_changed,bc)
-ifeq ($(CONFIG_MODULE_SIG),y)
+###############################################################################
+#
+# Roll all the X.509 certificates that we can find together and pull them into
+# the kernel so that they get loaded into the system trusted keyring during
+# boot.
#
-# Pull the signing certificate and any extra certificates into the kernel
+# We look in the source root and the build root for all files whose name ends
+# in ".x509". Unfortunately, this will generate duplicate filenames, so we
+# have make canonicalise the pathnames and then sort them to discard the
+# duplicates.
#
+###############################################################################
+ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
+X509_CERTIFICATES-y := $(wildcard *.x509) $(wildcard $(srctree)/*.x509)
+X509_CERTIFICATES-$(CONFIG_MODULE_SIG) += signing_key.x509
+X509_CERTIFICATES := $(sort $(foreach CERT,$(X509_CERTIFICATES-y), \
+ $(or $(realpath $(CERT)),$(CERT))))
+
+ifeq ($(X509_CERTIFICATES),)
+$(warning *** No X.509 certificates found ***)
+endif
+
+ifneq ($(wildcard $(obj)/.x509.list),)
+ifneq ($(shell cat $(obj)/.x509.list),$(X509_CERTIFICATES))
+$(info X.509 certificate list changed)
+$(shell rm $(obj)/.x509.list)
+endif
+endif
+
+kernel/system_certificates.o: $(obj)/x509_certificate_list
-quiet_cmd_touch = TOUCH $@
- cmd_touch = touch $@
+quiet_cmd_x509certs = CERTS $@
+ cmd_x509certs = cat $(X509_CERTIFICATES) /dev/null >$@ $(foreach X509,$(X509_CERTIFICATES),; echo " - Including cert $(X509)")
-extra_certificates:
- $(call cmd,touch)
+targets += $(obj)/x509_certificate_list
+$(obj)/x509_certificate_list: $(X509_CERTIFICATES) $(obj)/.x509.list
+ $(call if_changed,x509certs)
-kernel/modsign_certificate.o: signing_key.x509 extra_certificates
+targets += $(obj)/.x509.list
+$(obj)/.x509.list:
+ @echo $(X509_CERTIFICATES) >$@
+clean-files := x509_certificate_list .x509.list
+endif
+
+ifeq ($(CONFIG_MODULE_SIG),y)
###############################################################################
#
# If module signing is requested, say by allyesconfig, but a key has not been
diff --git a/kernel/modsign_certificate.S b/kernel/modsign_certificate.S
deleted file mode 100644
index 4a9a86d12c8..00000000000
--- a/kernel/modsign_certificate.S
+++ /dev/null
@@ -1,12 +0,0 @@
-#include <linux/export.h>
-
-#define GLOBAL(name) \
- .globl VMLINUX_SYMBOL(name); \
- VMLINUX_SYMBOL(name):
-
- .section ".init.data","aw"
-
-GLOBAL(modsign_certificate_list)
- .incbin "signing_key.x509"
- .incbin "extra_certificates"
-GLOBAL(modsign_certificate_list_end)
diff --git a/kernel/modsign_pubkey.c b/kernel/modsign_pubkey.c
deleted file mode 100644
index 7cbd4507a7e..00000000000
--- a/kernel/modsign_pubkey.c
+++ /dev/null
@@ -1,104 +0,0 @@
-/* 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 __initconst const u8 modsign_certificate_list[];
-extern __initconst const u8 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 __initconst 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 = keyring_alloc(".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, NULL);
- if (IS_ERR(modsign_keyring))
- panic("Can't allocate 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
index 24f9247b7d0..915e123a430 100644
--- a/kernel/module-internal.h
+++ b/kernel/module-internal.h
@@ -9,6 +9,4 @@
* 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);
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index f2970bddc5e..be5b8fac4bd 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -14,6 +14,7 @@
#include <crypto/public_key.h>
#include <crypto/hash.h>
#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
#include "module-internal.h"
/*
@@ -28,7 +29,7 @@
*/
struct module_signature {
u8 algo; /* Public-key crypto algorithm [enum pkey_algo] */
- u8 hash; /* Digest algorithm [enum pkey_hash_algo] */
+ u8 hash; /* Digest algorithm [enum hash_algo] */
u8 id_type; /* Key identifier type [enum pkey_id_type] */
u8 signer_len; /* Length of signer's name */
u8 key_id_len; /* Length of key identifier */
@@ -39,7 +40,7 @@ struct module_signature {
/*
* Digest the module contents.
*/
-static struct public_key_signature *mod_make_digest(enum pkey_hash_algo hash,
+static struct public_key_signature *mod_make_digest(enum hash_algo hash,
const void *mod,
unsigned long modlen)
{
@@ -54,7 +55,7 @@ static struct public_key_signature *mod_make_digest(enum pkey_hash_algo hash,
/* 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);
+ tfm = crypto_alloc_shash(hash_algo_name[hash], 0, 0);
if (IS_ERR(tfm))
return (PTR_ERR(tfm) == -ENOENT) ? ERR_PTR(-ENOPKG) : ERR_CAST(tfm);
@@ -157,7 +158,7 @@ static struct key *request_asymmetric_key(const char *signer, size_t signer_len,
pr_debug("Look up: \"%s\"\n", id);
- key = keyring_search(make_key_ref(modsign_keyring, 1),
+ key = keyring_search(make_key_ref(system_trusted_keyring, 1),
&key_type_asymmetric, id);
if (IS_ERR(key))
pr_warn("Request for unknown module key '%s' err %ld\n",
@@ -217,7 +218,7 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
return -ENOPKG;
if (ms.hash >= PKEY_HASH__LAST ||
- !pkey_hash_algo[ms.hash])
+ !hash_algo_name[ms.hash])
return -ENOPKG;
key = request_asymmetric_key(sig, ms.signer_len,
diff --git a/kernel/system_certificates.S b/kernel/system_certificates.S
new file mode 100644
index 00000000000..4aef390671c
--- /dev/null
+++ b/kernel/system_certificates.S
@@ -0,0 +1,10 @@
+#include <linux/export.h>
+#include <linux/init.h>
+
+ __INITRODATA
+
+ .globl VMLINUX_SYMBOL(system_certificate_list)
+VMLINUX_SYMBOL(system_certificate_list):
+ .incbin "kernel/x509_certificate_list"
+ .globl VMLINUX_SYMBOL(system_certificate_list_end)
+VMLINUX_SYMBOL(system_certificate_list_end):
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
new file mode 100644
index 00000000000..564dd93430a
--- /dev/null
+++ b/kernel/system_keyring.c
@@ -0,0 +1,105 @@
+/* System trusted keyring for trusted public keys
+ *
+ * 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/export.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "module-internal.h"
+
+struct key *system_trusted_keyring;
+EXPORT_SYMBOL_GPL(system_trusted_keyring);
+
+extern __initconst const u8 system_certificate_list[];
+extern __initconst const u8 system_certificate_list_end[];
+
+/*
+ * Load the compiled-in keys
+ */
+static __init int system_trusted_keyring_init(void)
+{
+ pr_notice("Initialise system trusted keyring\n");
+
+ system_trusted_keyring =
+ keyring_alloc(".system_keyring",
+ KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
+ KEY_ALLOC_NOT_IN_QUOTA, NULL);
+ if (IS_ERR(system_trusted_keyring))
+ panic("Can't allocate system trusted keyring\n");
+
+ set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
+ return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(system_trusted_keyring_init);
+
+/*
+ * Load the compiled-in list of X.509 certificates.
+ */
+static __init int load_system_certificate_list(void)
+{
+ key_ref_t key;
+ const u8 *p, *end;
+ size_t plen;
+
+ pr_notice("Loading compiled-in X.509 certificates\n");
+
+ end = system_certificate_list_end;
+ p = system_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(system_trusted_keyring, 1),
+ "asymmetric",
+ NULL,
+ p,
+ plen,
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ),
+ KEY_ALLOC_NOT_IN_QUOTA |
+ KEY_ALLOC_TRUSTED);
+ if (IS_ERR(key)) {
+ pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
+ PTR_ERR(key));
+ } else {
+ pr_notice("Loaded X.509 cert '%s'\n",
+ key_ref_to_ptr(key)->description);
+ key_ref_put(key);
+ }
+ p += plen;
+ }
+
+ return 0;
+
+dodgy_cert:
+ pr_err("Problem parsing in-kernel X.509 certificate list\n");
+ return 0;
+}
+late_initcall(load_system_certificate_list);
diff --git a/kernel/user.c b/kernel/user.c
index 5bbb91988e6..a3a0dbfda32 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -51,6 +51,10 @@ struct user_namespace init_user_ns = {
.owner = GLOBAL_ROOT_UID,
.group = GLOBAL_ROOT_GID,
.proc_inum = PROC_USER_INIT_INO,
+#ifdef CONFIG_KEYS_KERBEROS_CACHE
+ .krb_cache_register_sem =
+ __RWSEM_INITIALIZER(init_user_ns.krb_cache_register_sem),
+#endif
};
EXPORT_SYMBOL_GPL(init_user_ns);
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 13fb1134ba5..240fb62cf39 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -101,6 +101,9 @@ int create_user_ns(struct cred *new)
set_cred_user_ns(new, ns);
+#ifdef CONFIG_PERSISTENT_KEYRINGS
+ init_rwsem(&ns->persistent_keyring_register_sem);
+#endif
return 0;
}
@@ -130,6 +133,9 @@ void free_user_ns(struct user_namespace *ns)
do {
parent = ns->parent;
+#ifdef CONFIG_PERSISTENT_KEYRINGS
+ key_put(ns->persistent_keyring_register);
+#endif
proc_free_inum(ns->proc_inum);
kmem_cache_free(user_ns_cachep, ns);
ns = parent;