| Message ID | 20200911182230.62266-1-eric.snowberg@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] certs: Add EFI_CERT_X509_GUID support for dbx entries | expand |
> On Sep 14, 2020, at 12:12 PM, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> wrote: > > On Fri, Sep 11, 2020 at 02:22:30PM -0400, Eric Snowberg wrote: >> The Secure Boot Forbidden Signature Database, dbx, contains a list of now >> revoked signatures and keys previously approved to boot with UEFI Secure >> Boot enabled. The dbx is capable of containing any number of >> EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID >> entries. >> >> Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are >> skipped. >> >> Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID >> is found, it is added as an asymmetrical key to the .blacklist keyring. >> Anytime the .platform keyring is used, the keys in the .blacklist keyring >> are referenced, if a matching key is found, the key will be rejected. >> >> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> >> --- >> v3: >> Fixed an issue when CONFIG_PKCS7_MESSAGE_PARSER is not builtin and defined >> as a module instead, pointed out by Randy Dunlap >> >> v2: >> Fixed build issue reported by kernel test robot <lkp@intel.com> >> Commit message update (suggested by Jarkko Sakkinen) >> --- >> certs/blacklist.c | 33 +++++++++++++++++++ >> certs/blacklist.h | 12 +++++++ >> certs/system_keyring.c | 6 ++++ >> include/keys/system_keyring.h | 11 +++++++ >> .../platform_certs/keyring_handler.c | 11 +++++++ >> 5 files changed, 73 insertions(+) >> >> diff --git a/certs/blacklist.c b/certs/blacklist.c >> index 6514f9ebc943..3d1514ba5d47 100644 >> --- a/certs/blacklist.c >> +++ b/certs/blacklist.c >> @@ -100,6 +100,39 @@ int mark_hash_blacklisted(const char *hash) >> return 0; >> } >> >> +int mark_key_revocationlisted(const char *data, size_t size) >> +{ >> + key_ref_t key; >> + >> + key = key_create_or_update(make_key_ref(blacklist_keyring, true), >> + "asymmetric", >> + NULL, >> + data, >> + size, >> + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW), >> + KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); >> + >> + if (IS_ERR(key)) { >> + pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key)); >> + return PTR_ERR(key); >> + } >> + >> + return 0; >> +} >> + >> +int is_key_revocationlisted(struct pkcs7_message *pkcs7) >> +{ >> + int ret; >> + >> + ret = validate_trust(pkcs7, blacklist_keyring); >> + >> + if (ret == 0) >> + return -EKEYREJECTED; >> + >> + return -ENOKEY; >> +} >> +EXPORT_SYMBOL_GPL(is_key_revocationlisted); > > Hmm... ignore my previous comment about this. Export symbol is called > only by system keyring code. > > Would be best if the commit message would explicitly reason new exports. I don’t see a good reason to keep the export now, I’ll remove it from the next version. Thanks.
On Tue, Sep 15, 2020 at 09:42:27AM -0600, Eric Snowberg wrote: > > > On Sep 14, 2020, at 12:12 PM, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> wrote: > > > > On Fri, Sep 11, 2020 at 02:22:30PM -0400, Eric Snowberg wrote: > >> The Secure Boot Forbidden Signature Database, dbx, contains a list of now > >> revoked signatures and keys previously approved to boot with UEFI Secure > >> Boot enabled. The dbx is capable of containing any number of > >> EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID > >> entries. > >> > >> Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are > >> skipped. > >> > >> Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID > >> is found, it is added as an asymmetrical key to the .blacklist keyring. > >> Anytime the .platform keyring is used, the keys in the .blacklist keyring > >> are referenced, if a matching key is found, the key will be rejected. > >> > >> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> > >> --- > >> v3: > >> Fixed an issue when CONFIG_PKCS7_MESSAGE_PARSER is not builtin and defined > >> as a module instead, pointed out by Randy Dunlap > >> > >> v2: > >> Fixed build issue reported by kernel test robot <lkp@intel.com> > >> Commit message update (suggested by Jarkko Sakkinen) > >> --- > >> certs/blacklist.c | 33 +++++++++++++++++++ > >> certs/blacklist.h | 12 +++++++ > >> certs/system_keyring.c | 6 ++++ > >> include/keys/system_keyring.h | 11 +++++++ > >> .../platform_certs/keyring_handler.c | 11 +++++++ > >> 5 files changed, 73 insertions(+) > >> > >> diff --git a/certs/blacklist.c b/certs/blacklist.c > >> index 6514f9ebc943..3d1514ba5d47 100644 > >> --- a/certs/blacklist.c > >> +++ b/certs/blacklist.c > >> @@ -100,6 +100,39 @@ int mark_hash_blacklisted(const char *hash) > >> return 0; > >> } > >> > >> +int mark_key_revocationlisted(const char *data, size_t size) > >> +{ > >> + key_ref_t key; > >> + > >> + key = key_create_or_update(make_key_ref(blacklist_keyring, true), > >> + "asymmetric", > >> + NULL, > >> + data, > >> + size, > >> + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW), > >> + KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); > >> + > >> + if (IS_ERR(key)) { > >> + pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key)); > >> + return PTR_ERR(key); > >> + } > >> + > >> + return 0; > >> +} > >> + > >> +int is_key_revocationlisted(struct pkcs7_message *pkcs7) > >> +{ > >> + int ret; > >> + > >> + ret = validate_trust(pkcs7, blacklist_keyring); > >> + > >> + if (ret == 0) > >> + return -EKEYREJECTED; > >> + > >> + return -ENOKEY; > >> +} > >> +EXPORT_SYMBOL_GPL(is_key_revocationlisted); > > > > Hmm... ignore my previous comment about this. Export symbol is called > > only by system keyring code. > > > > Would be best if the commit message would explicitly reason new exports. > > I don’t see a good reason to keep the export now, I’ll remove it from the > next version. Thanks. OK, great, thanks. Was somewhat puzzled with this for a while :-) /Jarkko
diff --git a/certs/blacklist.c b/certs/blacklist.c index 6514f9ebc943..3d1514ba5d47 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -100,6 +100,39 @@ int mark_hash_blacklisted(const char *hash) return 0; } +int mark_key_revocationlisted(const char *data, size_t size) +{ + key_ref_t key; + + key = key_create_or_update(make_key_ref(blacklist_keyring, true), + "asymmetric", + NULL, + data, + size, + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW), + KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); + + if (IS_ERR(key)) { + pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key)); + return PTR_ERR(key); + } + + return 0; +} + +int is_key_revocationlisted(struct pkcs7_message *pkcs7) +{ + int ret; + + ret = validate_trust(pkcs7, blacklist_keyring); + + if (ret == 0) + return -EKEYREJECTED; + + return -ENOKEY; +} +EXPORT_SYMBOL_GPL(is_key_revocationlisted); + /** * is_hash_blacklisted - Determine if a hash is blacklisted * @hash: The hash to be checked as a binary blob diff --git a/certs/blacklist.h b/certs/blacklist.h index 1efd6fa0dc60..420bb7c86e07 100644 --- a/certs/blacklist.h +++ b/certs/blacklist.h @@ -1,3 +1,15 @@ #include <linux/kernel.h> +#include <linux/errno.h> +#include <crypto/pkcs7.h> extern const char __initconst *const blacklist_hashes[]; + +#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING +#define validate_trust pkcs7_validate_trust +#else +static inline int validate_trust(struct pkcs7_message *pkcs7, + struct key *trust_keyring) +{ + return -ENOKEY; +} +#endif diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 798291177186..f8ea96219155 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -241,6 +241,12 @@ int verify_pkcs7_message_sig(const void *data, size_t len, pr_devel("PKCS#7 platform keyring is not available\n"); goto error; } + + ret = is_key_revocationlisted(pkcs7); + if (ret != -ENOKEY) { + pr_devel("PKCS#7 platform key revocationlisted\n"); + goto error; + } } ret = pkcs7_validate_trust(pkcs7, trusted_keys); if (ret < 0) { diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h index fb8b07daa9d1..b6991cfe1b6d 100644 --- a/include/keys/system_keyring.h +++ b/include/keys/system_keyring.h @@ -31,11 +31,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted( #define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted #endif +extern struct pkcs7_message *pkcs7; #ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING extern int mark_hash_blacklisted(const char *hash); +extern int mark_key_revocationlisted(const char *data, size_t size); extern int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type); extern int is_binary_blacklisted(const u8 *hash, size_t hash_len); +extern int is_key_revocationlisted(struct pkcs7_message *pkcs7); #else static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type) @@ -47,6 +50,14 @@ static inline int is_binary_blacklisted(const u8 *hash, size_t hash_len) { return 0; } +static inline int mark_key_revocationlisted(const char *data, size_t size) +{ + return 0; +} +static inline int is_key_revocationlisted(struct pkcs7_message *pkcs7) +{ + return -ENOKEY; +} #endif #ifdef CONFIG_IMA_BLACKLIST_KEYRING diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c index c5ba695c10e3..cc5a43804bc4 100644 --- a/security/integrity/platform_certs/keyring_handler.c +++ b/security/integrity/platform_certs/keyring_handler.c @@ -55,6 +55,15 @@ static __init void uefi_blacklist_binary(const char *source, uefi_blacklist_hash(source, data, len, "bin:", 4); } +/* + * Revocationlist the X509 cert + */ +static __init void uefi_revocationlist_x509(const char *source, + const void *data, size_t len) +{ + mark_key_revocationlisted(data, len); +} + /* * Return the appropriate handler for particular signature list types found in * the UEFI db and MokListRT tables. @@ -76,5 +85,7 @@ __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type) return uefi_blacklist_x509_tbs; if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0) return uefi_blacklist_binary; + if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) + return uefi_revocationlist_x509; return 0; }
The Secure Boot Forbidden Signature Database, dbx, contains a list of now revoked signatures and keys previously approved to boot with UEFI Secure Boot enabled. The dbx is capable of containing any number of EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID entries. Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are skipped. Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID is found, it is added as an asymmetrical key to the .blacklist keyring. Anytime the .platform keyring is used, the keys in the .blacklist keyring are referenced, if a matching key is found, the key will be rejected. Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> --- v3: Fixed an issue when CONFIG_PKCS7_MESSAGE_PARSER is not builtin and defined as a module instead, pointed out by Randy Dunlap v2: Fixed build issue reported by kernel test robot <lkp@intel.com> Commit message update (suggested by Jarkko Sakkinen) --- certs/blacklist.c | 33 +++++++++++++++++++ certs/blacklist.h | 12 +++++++ certs/system_keyring.c | 6 ++++ include/keys/system_keyring.h | 11 +++++++ .../platform_certs/keyring_handler.c | 11 +++++++ 5 files changed, 73 insertions(+)