4.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers ebiggers@google.com
commit 29f4a67c17e19314b7d74b8569be935e6c7edf50 upstream.
If there is a blacklisted certificate in a SignerInfo's certificate chain, then pkcs7_verify_sig_chain() sets sinfo->blacklisted and returns 0. But, pkcs7_verify() fails to handle this case appropriately, as it actually continues on to the line 'actual_ret = 0;', indicating that the SignerInfo has passed verification. Consequently, PKCS#7 signature verification ignores the certificate blacklist.
Fix this by not considering blacklisted SignerInfos to have passed verification.
Also fix the function comment with regards to when 0 is returned.
Fixes: 03bb79315ddc ("PKCS#7: Handle blacklisted certificates") Cc: stable@vger.kernel.org # v4.12+ 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/pkcs7_verify.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -366,8 +366,7 @@ static int pkcs7_verify_one(struct pkcs7 * * (*) -EBADMSG if some part of the message was invalid, or: * - * (*) 0 if no signature chains were found to be blacklisted or to contain - * unsupported crypto, or: + * (*) 0 if a signature chain passed verification, or: * * (*) -EKEYREJECTED if a blacklisted key was encountered, or: * @@ -423,8 +422,11 @@ int pkcs7_verify(struct pkcs7_message *p
for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { ret = pkcs7_verify_one(pkcs7, sinfo); - if (sinfo->blacklisted && actual_ret == -ENOPKG) - actual_ret = -EKEYREJECTED; + if (sinfo->blacklisted) { + if (actual_ret == -ENOPKG) + actual_ret = -EKEYREJECTED; + continue; + } if (ret < 0) { if (ret == -ENOPKG) { sinfo->unsupported_crypto = true;