cregit-Linux how code gets into the kernel

Release 4.12 certs/system_keyring.c

Directory: certs
/* System trusted keyring for trusted public keys
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (
 * 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 <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include <crypto/pkcs7.h>

static struct key *builtin_trusted_keys;

static struct key *secondary_trusted_keys;

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); }


David Howells3076.92%266.67%
Mat Martineau923.08%133.33%

#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); }


David Howells5283.87%266.67%
Mat Martineau1016.13%133.33%

/** * 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; }


David Howells14296.60%571.43%
Mat Martineau32.04%114.29%
Mimi Zohar21.36%114.29%

/* * 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; }


David Howells19395.07%675.00%
Hendrik Brueckner62.96%112.50%
Mimi Zohar41.97%112.50%

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 == (void *)1UL) { #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; }


David Howells286100.00%5100.00%

EXPORT_SYMBOL_GPL(verify_pkcs7_signature); #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */

Overall Contributors

David Howells78689.73%1270.59%
Mat Martineau738.33%211.76%
Hendrik Brueckner91.03%15.88%
Mimi Zohar60.68%15.88%
Andi Kleen20.23%15.88%
Directory: certs
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