This is a note to let you know that I've just added the patch titled
X.509: fix BUG_ON() when hash algorithm is unsupported
to the 4.15-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-bug_on-when-hash-algorithm-is-unsupported.patch and it can be found in the queue-4.15 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 437499eea4291ae9621e8763a41df027c110a1ef Mon Sep 17 00:00:00 2001
From: Eric Biggers ebiggers@google.com Date: Thu, 22 Feb 2018 14:38:33 +0000 Subject: X.509: fix BUG_ON() when hash algorithm is unsupported
From: Eric Biggers ebiggers@google.com
commit 437499eea4291ae9621e8763a41df027c110a1ef upstream.
The X.509 parser mishandles the case where the certificate's signature's hash algorithm is not available in the crypto API. In this case, x509_get_sig_params() doesn't allocate the cert->sig->digest buffer; this part seems to be intentional. However, public_key_verify_signature() is still called via x509_check_for_self_signed(), which triggers the 'BUG_ON(!sig->digest)'.
Fix this by making public_key_verify_signature() return -ENOPKG if the hash buffer has not been allocated.
Reproducer when all the CONFIG_CRYPTO_SHA512* options are disabled:
openssl req -new -sha512 -x509 -batch -nodes -outform der \ | keyctl padd asymmetric desc @s
Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier") Reported-by: Paolo Valente paolo.valente@linaro.org Cc: Paolo Valente paolo.valente@linaro.org 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/public_key.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -79,9 +79,11 @@ int public_key_verify_signature(const st
BUG_ON(!pkey); BUG_ON(!sig); - BUG_ON(!sig->digest); BUG_ON(!sig->s);
+ if (!sig->digest) + return -ENOPKG; + alg_name = sig->pkey_algo; if (strcmp(sig->pkey_algo, "rsa") == 0) { /* The data wangled by the RSA algorithm is typically padded
Patches currently in stable-queue which might be from ebiggers@google.com are
queue-4.15/pkcs-7-fix-certificate-blacklisting.patch queue-4.15/x.509-fix-null-dereference-when-restricting-key-with-unsupported_sig.patch queue-4.15/x.509-fix-bug_on-when-hash-algorithm-is-unsupported.patch queue-4.15/pkcs-7-fix-certificate-chain-verification.patch