631cc66eb9
Include a PGP keyring containing the public keys required to perform module verification in the kernel image during build and create a special keyring during boot which is then populated with keys of crypto type holding the public keys found in the PGP keyring. These can be seen by root: [root@andromeda ~]# cat /proc/keys 07ad4ee0 I----- 1 perm 3f010000 0 0 crypto modsign.0: RSA 87b9b3bd [] 15c7f8c3 I----- 1 perm 1f030000 0 0 keyring .module_sign: 1/4 ... It is probably worth permitting root to invalidate these keys, resulting in their removal and preventing further modules from being loaded with that key. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/* Public keys for module signature verification
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*
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* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/cred.h>
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#include <linux/err.h>
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#include <keys/asymmetric-type.h>
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#include "module-internal.h"
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struct key *modsign_keyring;
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extern __initdata const u8 modsign_certificate_list[];
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extern __initdata const u8 modsign_certificate_list_end[];
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asm(".section .init.data,\"aw\"\n"
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"modsign_certificate_list:\n"
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".incbin \"signing_key.x509\"\n"
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".incbin \"extra_certificates\"\n"
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"modsign_certificate_list_end:"
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);
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/*
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* We need to make sure ccache doesn't cache the .o file as it doesn't notice
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* if modsign.pub changes.
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*/
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static __initdata const char annoy_ccache[] = __TIME__ "foo";
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/*
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* Load the compiled-in keys
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*/
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static __init int module_verify_init(void)
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{
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pr_notice("Initialise module verification\n");
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modsign_keyring = key_alloc(&key_type_keyring, ".module_sign",
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KUIDT_INIT(0), KGIDT_INIT(0),
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current_cred(),
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(KEY_POS_ALL & ~KEY_POS_SETATTR) |
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KEY_USR_VIEW | KEY_USR_READ,
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KEY_ALLOC_NOT_IN_QUOTA);
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if (IS_ERR(modsign_keyring))
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panic("Can't allocate module signing keyring\n");
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if (key_instantiate_and_link(modsign_keyring, NULL, 0, NULL, NULL) < 0)
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panic("Can't instantiate module signing keyring\n");
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return 0;
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}
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/*
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* Must be initialised before we try and load the keys into the keyring.
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*/
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device_initcall(module_verify_init);
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/*
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* Load the compiled-in keys
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*/
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static __init int load_module_signing_keys(void)
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{
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key_ref_t key;
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const u8 *p, *end;
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size_t plen;
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pr_notice("Loading module verification certificates\n");
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end = modsign_certificate_list_end;
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p = modsign_certificate_list;
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while (p < end) {
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/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
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* than 256 bytes in size.
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*/
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if (end - p < 4)
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goto dodgy_cert;
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if (p[0] != 0x30 &&
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p[1] != 0x82)
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goto dodgy_cert;
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plen = (p[2] << 8) | p[3];
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plen += 4;
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if (plen > end - p)
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goto dodgy_cert;
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key = key_create_or_update(make_key_ref(modsign_keyring, 1),
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"asymmetric",
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NULL,
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p,
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plen,
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(KEY_POS_ALL & ~KEY_POS_SETATTR) |
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KEY_USR_VIEW,
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KEY_ALLOC_NOT_IN_QUOTA);
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if (IS_ERR(key))
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pr_err("MODSIGN: Problem loading in-kernel X.509 certificate (%ld)\n",
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PTR_ERR(key));
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else
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pr_notice("MODSIGN: Loaded cert '%s'\n",
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key_ref_to_ptr(key)->description);
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p += plen;
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}
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return 0;
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dodgy_cert:
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pr_err("MODSIGN: Problem parsing in-kernel X.509 certificate list\n");
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return 0;
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}
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late_initcall(load_module_signing_keys);
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