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SubjectRe: [PATCH v3] certs: Add EFI_CERT_X509_GUID support for dbx entries
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

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