This is a note to let you know that I've just added the patch titled
X.509: fix NULL dereference when restricting key with unsupported_sig
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x.509-fix-null-dereference-when-restricting-key-with-unsupported_sig.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From ebiggers3@gmail.com Mon Feb 26 20:46:24 2018
From: Eric Biggers ebiggers3@gmail.com Date: Mon, 26 Feb 2018 10:17:15 -0800 Subject: X.509: fix NULL dereference when restricting key with unsupported_sig To: stable@vger.kernel.org, Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: keyrings@vger.kernel.org, Eric Biggers ebiggers@google.com, David Howells dhowells@redhat.com Message-ID: 20180226181715.194965-1-ebiggers3@gmail.com
From: Eric Biggers ebiggers@google.com
commit 4b34968e77ad09628cfb3c4a7daf2adc2cefc6e8 upstream.
The asymmetric key type allows an X.509 certificate to be added even if its signature's hash algorithm is not available in the crypto API. In that case 'payload.data[asym_auth]' will be NULL. But the key restriction code failed to check for this case before trying to use the signature, resulting in a NULL pointer dereference in key_or_keyring_common() or in restrict_link_by_signature().
Fix this by returning -ENOPKG when the signature is unsupported.
Reproducer when all the CONFIG_CRYPTO_SHA512* options are disabled and keyctl has support for the 'restrict_keyring' command:
keyctl new_session keyctl restrict_keyring @s asymmetric builtin_trusted openssl req -new -sha512 -x509 -batch -nodes -outform der \ | keyctl padd asymmetric desc @s
Fixes: a511e1af8b12 ("KEYS: Move the point of trust determination to __key_link()") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- crypto/asymmetric_keys/restrict.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/crypto/asymmetric_keys/restrict.c +++ b/crypto/asymmetric_keys/restrict.c @@ -66,8 +66,9 @@ __setup("ca_keys=", ca_keys_setup); * * Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a * matching parent certificate in the trusted list, -EKEYREJECTED if the - * signature check fails or the key is blacklisted and some other error if - * there is a matching certificate but the signature check cannot be performed. + * signature check fails or the key is blacklisted, -ENOPKG if the signature + * uses unsupported crypto, or some other error if there is a matching + * certificate but the signature check cannot be performed. */ int restrict_link_by_signature(struct key *trust_keyring, const struct key_type *type, @@ -86,6 +87,8 @@ int restrict_link_by_signature(struct ke return -EOPNOTSUPP;
sig = payload->data[asym_auth]; + if (!sig) + return -ENOPKG; if (!sig->auth_ids[0] && !sig->auth_ids[1]) return -ENOKEY;
Patches currently in stable-queue which might be from ebiggers3@gmail.com are
queue-4.9/x.509-fix-null-dereference-when-restricting-key-with-unsupported_sig.patch queue-4.9/binder-add-missing-binder_unlock.patch