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2016-04-11certs: Add a secondary system keyring that can be added to dynamicallyDavid Howells
Add a secondary system keyring that can be added to by root whilst the system is running - provided the key being added is vouched for by a key built into the kernel or already added to the secondary keyring. Rename .system_keyring to .builtin_trusted_keys to distinguish it more obviously from the new keyring (called .secondary_trusted_keys). The new keyring needs to be enabled with CONFIG_SECONDARY_TRUSTED_KEYRING. If the secondary keyring is enabled, a link is created from that to .builtin_trusted_keys so that the the latter will automatically be searched too if the secondary keyring is searched. Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-11KEYS: Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTEDDavid Howells
Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer meaningful. Also we can drop the trusted flag from the preparse structure. Given this, we no longer need to pass the key flags through to restrict_link(). Further, we can now get rid of keyring_restrict_trusted_only() also. Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-11KEYS: Move the point of trust determination to __key_link()David Howells
Move the point at which a key is determined to be trustworthy to __key_link() so that we use the contents of the keyring being linked in to to determine whether the key being linked in is trusted or not. What is 'trusted' then becomes a matter of what's in the keyring. Currently, the test is done when the key is parsed, but given that at that point we can only sensibly refer to the contents of the system trusted keyring, we can only use that as the basis for working out the trustworthiness of a new key. With this change, a trusted keyring is a set of keys that once the trusted-only flag is set cannot be added to except by verification through one of the contained keys. Further, adding a key into a trusted keyring, whilst it might grant trustworthiness in the context of that keyring, does not automatically grant trustworthiness in the context of a second keyring to which it could be secondarily linked. To accomplish this, the authentication data associated with the key source must now be retained. For an X.509 cert, this means the contents of the AuthorityKeyIdentifier and the signature data. If system keyrings are disabled then restrict_link_by_builtin_trusted() resolves to restrict_link_reject(). The integrity digital signature code still works correctly with this as it was previously using KEY_FLAG_TRUSTED_ONLY, which doesn't permit anything to be added if there is no system keyring against which trust can be determined. Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-11KEYS: Make the system trusted keyring depend on the asymmetric key typeDavid Howells
Make the system trusted keyring depend on the asymmetric key type as there's not a lot of point having it if you can't then load asymmetric keys onto it. This requires the ASYMMETRIC_KEY_TYPE to be made a bool, not a tristate, as the Kconfig language doesn't then correctly force ASYMMETRIC_KEY_TYPE to 'y' rather than 'm' if SYSTEM_TRUSTED_KEYRING is 'y'. Making SYSTEM_TRUSTED_KEYRING *select* ASYMMETRIC_KEY_TYPE instead doesn't work as the Kconfig interpreter then wrongly complains about dependency loops. Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-11KEYS: Add a facility to restrict new links into a keyringDavid Howells
Add a facility whereby proposed new links to be added to a keyring can be vetted, permitting them to be rejected if necessary. This can be used to block public keys from which the signature cannot be verified or for which the signature verification fails. It could also be used to provide blacklisting. This affects operations like add_key(), KEYCTL_LINK and KEYCTL_INSTANTIATE. To this end: (1) A function pointer is added to the key struct that, if set, points to the vetting function. This is called as: int (*restrict_link)(struct key *keyring, const struct key_type *key_type, unsigned long key_flags, const union key_payload *key_payload), where 'keyring' will be the keyring being added to, key_type and key_payload will describe the key being added and key_flags[*] can be AND'ed with KEY_FLAG_TRUSTED. [*] This parameter will be removed in a later patch when KEY_FLAG_TRUSTED is removed. The function should return 0 to allow the link to take place or an error (typically -ENOKEY, -ENOPKG or -EKEYREJECTED) to reject the link. The pointer should not be set directly, but rather should be set through keyring_alloc(). Note that if called during add_key(), preparse is called before this method, but a key isn't actually allocated until after this function is called. (2) KEY_ALLOC_BYPASS_RESTRICTION is added. This can be passed to key_create_or_update() or key_instantiate_and_link() to bypass the restriction check. (3) KEY_FLAG_TRUSTED_ONLY is removed. The entire contents of a keyring with this restriction emplaced can be considered 'trustworthy' by virtue of being in the keyring when that keyring is consulted. (4) key_alloc() and keyring_alloc() take an extra argument that will be used to set restrict_link in the new key. This ensures that the pointer is set before the key is published, thus preventing a window of unrestrictedness. Normally this argument will be NULL. (5) As a temporary affair, keyring_restrict_trusted_only() is added. It should be passed to keyring_alloc() as the extra argument instead of setting KEY_FLAG_TRUSTED_ONLY on a keyring. This will be replaced in a later patch with functions that look in the appropriate places for authoritative keys. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2016-04-06PKCS#7: Make trust determination dependent on contents of trust keyringDavid Howells
Make the determination of the trustworthiness of a key dependent on whether a key that can verify it is present in the supplied ring of trusted keys rather than whether or not the verifying key has KEY_FLAG_TRUSTED set. verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust chain cannot be verified. Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-06KEYS: Generalise system_verify_data() to provide access to internal contentDavid Howells
Generalise system_verify_data() to provide access to internal content through a callback. This allows all the PKCS#7 stuff to be hidden inside this function and removed from the PE file parser and the PKCS#7 test key. If external content is not required, NULL should be passed as data to the function. If the callback is not required, that can be set to NULL. The function is now called verify_pkcs7_signature() to contrast with verify_pefile_signature() and the definitions of both have been moved into linux/verification.h along with the key_being_used_for enum. Signed-off-by: David Howells <dhowells@redhat.com>
2016-02-29certs: Fix misaligned data in extra certificate listDavid Howells
Fix the following warning found by kbuild: certs/system_certificates.S:24: Error: misaligned data because: KEYS: Reserve an extra certificate symbol for inserting without recompiling doesn't correctly align system_extra_cert_used. Signed-off-by: David Howells <dhowells@redhat.com> cc: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>
2016-02-26KEYS: Reserve an extra certificate symbol for inserting without recompilingMehmet Kayaalp
Place a system_extra_cert buffer of configurable size, right after the system_certificate_list, so that inserted keys can be readily processed by the existing mechanism. Added script takes a key file and a kernel image and inserts its contents to the reserved area. The system_certificate_list_size is also adjusted accordingly. Call the script as: scripts/insert-sys-cert -b <vmlinux> -c <certfile> If vmlinux has no symbol table, supply System.map file with -s flag. Subsequent runs replace the previously inserted key, instead of appending the new one. Signed-off-by: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2016-02-26modsign: hide openssl output in silent buildsArnd Bergmann
When a user calls 'make -s', we can assume they don't want to see any output except for warnings and errors, but instead they see this for a warning free build: ### ### Now generating an X.509 key pair to be used for signing modules. ### ### If this takes a long time, you might wish to run rngd in the ### background to keep the supply of entropy topped up. It ### needs to be run as root, and uses a hardware random ### number generator if one is available. ### Generating a 4096 bit RSA private key .................................................................................................................................................................................................................................++ ..............................................................................................................................++ writing new private key to 'certs/signing_key.pem' ----- ### ### Key pair generated. ### The output can confuse simple build testing scripts that just check for an empty build log. This patch silences all the output: - "echo" is changed to "@$(kecho)", which is dropped when "-s" gets passed - the openssl command itself is only printed with V=1, using the $(Q) macro - The output of openssl gets redirected to /dev/null on "-s" builds. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David Howells <dhowells@redhat.com>
2016-02-09KEYS: Add an alloc flag to convey the builtinness of a keyDavid Howells
Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN set rather than setting it after the fact. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-10-21certs: add .gitignore to stop git nagging about x509_certificate_listPaul Gortmaker
Currently we see this in "git status" if we build in the source dir: Untracked files: (use "git add <file>..." to include in what will be committed) certs/x509_certificate_list It looks like it used to live in kernel/ so we squash that .gitignore entry at the same time. I didn't bother to dig through git history to see when it moved, since it is just a minor annoyance at most. Cc: David Woodhouse <dwmw2@infradead.org> Cc: keyrings@linux-nfs.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David Howells <dhowells@redhat.com>
2015-08-14modsign: Handle signing key in source treeDavid Woodhouse
Since commit 1329e8cc69 ("modsign: Extract signing cert from CONFIG_MODULE_SIG_KEY if needed"), the build system has carefully coped with the signing key being specified as a relative path in either the source or or the build trees. However, the actual signing of modules has not worked if the filename is relative to the source tree. Fix that by moving the config_filename helper into scripts/Kbuild.include so that it can be used from elsewhere, and then using it in the top-level Makefile to find the signing key file. Kill the intermediate $(MODPUBKEY) and $(MODSECKEY) variables too, while we're at it. There's no need for them. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: David Howells <dhowells@redhat.com>
2015-08-14modsign: Use if_changed rule for extracting cert from module signing keyDavid Woodhouse
We couldn't use if_changed for this before, because it didn't live in the kernel/ directory so we couldn't add it to $(targets). It was easier just to leave it as it was. Now it's in the certs/ directory we can use if_changed, the same as we do for the trusted certificate list. Aside from making things consistent, this means we don't need to depend explicitly on the include/config/module/sig/key.h file. And we also get to automatically do the right thing and re-extract the cert if the user does odd things like using a relative filename and then playing silly buggers with adding/removing that file in both the source and object trees. We always favour the one in the object tree if it exists, and now we'll correctly re-extract the cert when it changes. Previously we'd *only* re-extract the cert if the config option changed, even if the actual file we're using did change. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: David Howells <dhowells@redhat.com>
2015-08-14Move certificate handling to its own directoryDavid Howells
Move certificate handling out of the kernel/ directory and into a certs/ directory to get all the weird stuff in one place and move the generated signing keys into this directory. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: David Woodhouse <David.Woodhouse@intel.com>