Revision 706a1ea65e6faaf853427a0e931f59d604dd45e3 authored by Linus Torvalds on 23 August 2018, 21:55:01 UTC, committed by Linus Torvalds on 23 August 2018, 21:55:01 UTC
Merge fixes for missing TLB shootdowns. This fixes a couple of cases that involved us possibly freeing page table structures before the required TLB shootdown had been done. There are a few cleanup patches to make the code easier to follow, and to avoid some of the more problematic cases entirely when not necessary. To make this easier for backports, it undoes the recent lazy TLB patches, because the cleanups and fixes are more important, and Rik is ok with re-doing them later when things have calmed down. The missing TLB flush was only delayed, and the wrong ordering only happened under memory pressure (and in theory under a couple of other fairly theoretical situations), so this may have been all very unlikely to have hit people in practice. But getting the TLB shootdown wrong is _so_ hard to debug and see that I consider this a crticial fix. Many thanks to Jann Horn for having debugged this. * tlb-fixes: x86/mm: Only use tlb_remove_table() for paravirt mm: mmu_notifier fix for tlb_end_vma mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE mm/tlb: Remove tlb_remove_table() non-concurrent condition mm: move tlb_table_flush to tlb_flush_mmu_free x86/mm/tlb: Revert the recent lazy TLB patches
system_keyring.c
/* 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 <linux/slab.h>
#include <linux/verification.h>
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include <crypto/pkcs7.h>
static struct key *builtin_trusted_keys;
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
static struct key *secondary_trusted_keys;
#endif
extern __initconst const u8 system_certificate_list[];
extern __initconst const unsigned long system_certificate_list_size;
/**
* restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
*
* Restrict the addition of keys into a keyring based on the key-to-be-added
* being vouched for by a key in the built in system keyring.
*/
int restrict_link_by_builtin_trusted(struct key *dest_keyring,
const struct key_type *type,
const union key_payload *payload,
struct key *restriction_key)
{
return restrict_link_by_signature(dest_keyring, type, payload,
builtin_trusted_keys);
}
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
/**
* restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
* addition by both builtin and secondary keyrings
*
* Restrict the addition of keys into a keyring based on the key-to-be-added
* being vouched for by a key in either the built-in or the secondary system
* keyrings.
*/
int restrict_link_by_builtin_and_secondary_trusted(
struct key *dest_keyring,
const struct key_type *type,
const union key_payload *payload,
struct key *restrict_key)
{
/* If we have a secondary trusted keyring, then that contains a link
* through to the builtin keyring and the search will follow that link.
*/
if (type == &key_type_keyring &&
dest_keyring == secondary_trusted_keys &&
payload == &builtin_trusted_keys->payload)
/* Allow the builtin keyring to be added to the secondary */
return 0;
return restrict_link_by_signature(dest_keyring, type, payload,
secondary_trusted_keys);
}
/**
* Allocate a struct key_restriction for the "builtin and secondary trust"
* keyring. Only for use in system_trusted_keyring_init().
*/
static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
{
struct key_restriction *restriction;
restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
if (!restriction)
panic("Can't allocate secondary trusted keyring restriction\n");
restriction->check = restrict_link_by_builtin_and_secondary_trusted;
return restriction;
}
#endif
/*
* Create the trusted keyrings
*/
static __init int system_trusted_keyring_init(void)
{
pr_notice("Initialise system trusted keyrings\n");
builtin_trusted_keys =
keyring_alloc(".builtin_trusted_keys",
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, NULL);
if (IS_ERR(builtin_trusted_keys))
panic("Can't allocate builtin trusted keyring\n");
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
secondary_trusted_keys =
keyring_alloc(".secondary_trusted_keys",
KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
KEY_USR_WRITE),
KEY_ALLOC_NOT_IN_QUOTA,
get_builtin_and_secondary_restriction(),
NULL);
if (IS_ERR(secondary_trusted_keys))
panic("Can't allocate secondary trusted keyring\n");
if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
panic("Can't link trusted keyrings\n");
#endif
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");
p = system_certificate_list;
end = p + system_certificate_list_size;
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(builtin_trusted_keys, 1),
"asymmetric",
NULL,
p,
plen,
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ),
KEY_ALLOC_NOT_IN_QUOTA |
KEY_ALLOC_BUILT_IN |
KEY_ALLOC_BYPASS_RESTRICTION);
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);
#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
/**
* verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
* @data: The data to be verified (NULL if expecting internal data).
* @len: Size of @data.
* @raw_pkcs7: The PKCS#7 message that is the signature.
* @pkcs7_len: The size of @raw_pkcs7.
* @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
* (void *)1UL for all trusted keys).
* @usage: The use to which the key is being put.
* @view_content: Callback to gain access to content.
* @ctx: Context for callback.
*/
int verify_pkcs7_signature(const void *data, size_t len,
const void *raw_pkcs7, size_t pkcs7_len,
struct key *trusted_keys,
enum key_being_used_for usage,
int (*view_content)(void *ctx,
const void *data, size_t len,
size_t asn1hdrlen),
void *ctx)
{
struct pkcs7_message *pkcs7;
int ret;
pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
if (IS_ERR(pkcs7))
return PTR_ERR(pkcs7);
/* The data should be detached - so we need to supply it. */
if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
pr_err("PKCS#7 signature with non-detached data\n");
ret = -EBADMSG;
goto error;
}
ret = pkcs7_verify(pkcs7, usage);
if (ret < 0)
goto error;
if (!trusted_keys) {
trusted_keys = builtin_trusted_keys;
} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
trusted_keys = secondary_trusted_keys;
#else
trusted_keys = builtin_trusted_keys;
#endif
}
ret = pkcs7_validate_trust(pkcs7, trusted_keys);
if (ret < 0) {
if (ret == -ENOKEY)
pr_err("PKCS#7 signature not signed with a trusted key\n");
goto error;
}
if (view_content) {
size_t asn1hdrlen;
ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
if (ret < 0) {
if (ret == -ENODATA)
pr_devel("PKCS#7 message does not contain data\n");
goto error;
}
ret = view_content(ctx, data, len, asn1hdrlen);
}
error:
pkcs7_free_message(pkcs7);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
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