| Message ID | 20200909172736.73003-1-eric.snowberg@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] certs: Add EFI_CERT_X509_GUID support for dbx entries | expand |
On 9/9/20 10:27 AM, Eric Snowberg wrote: > diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h > index 38ec7f5f9041..d8f2e0fdfbf4 100644 > --- a/include/crypto/pkcs7.h > +++ b/include/crypto/pkcs7.h > @@ -26,11 +26,19 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, > const void **_data, size_t *_datalen, > size_t *_headerlen); > > +#ifdef CONFIG_PKCS7_MESSAGE_PARSER > /* > * pkcs7_trust.c > */ > extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, > struct key *trust_keyring); > +#else > +static inline int pkcs7_validate_trust(struct pkcs7_message *pkcs7, > + struct key *trust_keyring) > +{ > + return -ENOKEY; > +} > +#endif Just to be clear, you want to do the #else block when CONFIG_PKCS7_MESSAGE_PARSER=m. Is that correct? If so, it might be clearer to use #if IS_BUILTIN(CONFIG_PKCS7_MESSAGE_PARSER)
> On Sep 9, 2020, at 11:40 AM, Randy Dunlap <rdunlap@infradead.org> wrote: > > On 9/9/20 10:27 AM, Eric Snowberg wrote: >> diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h >> index 38ec7f5f9041..d8f2e0fdfbf4 100644 >> --- a/include/crypto/pkcs7.h >> +++ b/include/crypto/pkcs7.h >> @@ -26,11 +26,19 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, >> const void **_data, size_t *_datalen, >> size_t *_headerlen); >> >> +#ifdef CONFIG_PKCS7_MESSAGE_PARSER >> /* >> * pkcs7_trust.c >> */ >> extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, >> struct key *trust_keyring); >> +#else >> +static inline int pkcs7_validate_trust(struct pkcs7_message *pkcs7, >> + struct key *trust_keyring) >> +{ >> + return -ENOKEY; >> +} >> +#endif > > Just to be clear, you want to do the #else block when > CONFIG_PKCS7_MESSAGE_PARSER=m. Is that correct? > > If so, it might be clearer to use > > #if IS_BUILTIN(CONFIG_PKCS7_MESSAGE_PARSER) > I just added this part to fix a build error when none of the asymmetrical keys are defined within a config. I failed to notice CONFIG_PKCS7_MESSAGE_PARSER could be configured to build as a module too. The code I added that uses pkcs7_validate_trust is always builtin. Taking this into account, please disregard this patch. I will need to solve this a different way. Thanks for pointing this out.
On Mon, Sep 14, 2020 at 09:01:34PM +0300, Jarkko Sakkinen wrote: > On Wed, Sep 09, 2020 at 01:27:36PM -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> > > --- > > > > v2: > > Fixed build issue reported by kernel test robot <lkp@intel.com> > > Commit message update (suggested by Jarkko Sakkinen) > > > > --- > > certs/blacklist.c | 36 +++++++++++++++++++ > > certs/system_keyring.c | 6 ++++ > > include/crypto/pkcs7.h | 8 +++++ > > include/keys/system_keyring.h | 11 ++++++ > > .../platform_certs/keyring_handler.c | 11 ++++++ > > 5 files changed, 72 insertions(+) > > > > diff --git a/certs/blacklist.c b/certs/blacklist.c > > index 6514f9ebc943..17ebf50cf0ae 100644 > > --- a/certs/blacklist.c > > +++ b/certs/blacklist.c > > @@ -15,6 +15,7 @@ > > #include <linux/err.h> > > #include <linux/seq_file.h> > > #include <keys/system_keyring.h> > > +#include <crypto/pkcs7.h> > > #include "blacklist.h" > > > > static struct key *blacklist_keyring; > > @@ -100,6 +101,41 @@ 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 = pkcs7_validate_trust(pkcs7, blacklist_keyring); > > + > > + if (ret == 0) > > + return -EKEYREJECTED; > > + > > + return -ENOKEY; > > +} > > +EXPORT_SYMBOL_GPL(is_key_revocationlisted); > > What required this callable from a module? Right, nees to be exported for pkcs7. /Jarkko
diff --git a/certs/blacklist.c b/certs/blacklist.c index 6514f9ebc943..17ebf50cf0ae 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -15,6 +15,7 @@ #include <linux/err.h> #include <linux/seq_file.h> #include <keys/system_keyring.h> +#include <crypto/pkcs7.h> #include "blacklist.h" static struct key *blacklist_keyring; @@ -100,6 +101,41 @@ 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 = pkcs7_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/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/crypto/pkcs7.h b/include/crypto/pkcs7.h index 38ec7f5f9041..d8f2e0fdfbf4 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -26,11 +26,19 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, const void **_data, size_t *_datalen, size_t *_headerlen); +#ifdef CONFIG_PKCS7_MESSAGE_PARSER /* * pkcs7_trust.c */ extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, struct key *trust_keyring); +#else +static inline int pkcs7_validate_trust(struct pkcs7_message *pkcs7, + struct key *trust_keyring) +{ + return -ENOKEY; +} +#endif /* * pkcs7_verify.c 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> --- v2: Fixed build issue reported by kernel test robot <lkp@intel.com> Commit message update (suggested by Jarkko Sakkinen) --- certs/blacklist.c | 36 +++++++++++++++++++ certs/system_keyring.c | 6 ++++ include/crypto/pkcs7.h | 8 +++++ include/keys/system_keyring.h | 11 ++++++ .../platform_certs/keyring_handler.c | 11 ++++++ 5 files changed, 72 insertions(+)