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authorEric Biggers <ebiggers@google.com>2018-02-22 14:38:33 +0000
committerDavid Howells <dhowells@redhat.com>2018-02-22 14:38:33 +0000
commit6459ae386699a5fe0dc52cf30255f75274fa43a4 (patch)
tree92ebf88fb34ed78abaddb1a69f1940868096546d
parent29f4a67c17e19314b7d74b8569be935e6c7edf50 (diff)
downloadlinux-6459ae386699a5fe0dc52cf30255f75274fa43a4.tar.bz2
PKCS#7: fix direct verification of SignerInfo signature
If none of the certificates in a SignerInfo's certificate chain match a trusted key, nor is the last certificate signed by a trusted key, then pkcs7_validate_trust_one() tries to check whether the SignerInfo's signature was made directly by a trusted key. But, it actually fails to set the 'sig' variable correctly, so it actually verifies the last signature seen. That will only be the SignerInfo's signature if the certificate chain is empty; otherwise it will actually be the last certificate's signature. This is not by itself a security problem, since verifying any of the certificates in the chain should be sufficient to verify the SignerInfo. Still, it's not working as intended so it should be fixed. Fix it by setting 'sig' correctly for the direct verification case. Fixes: 757932e6da6d ("PKCS#7: Handle PKCS#7 messages that contain no X.509 certs") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
-rw-r--r--crypto/asymmetric_keys/pkcs7_trust.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index 1f4e25f10049..598906b1e28d 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -106,6 +106,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
pr_devel("sinfo %u: Direct signer is key %x\n",
sinfo->index, key_serial(key));
x509 = NULL;
+ sig = sinfo->sig;
goto matched;
}
if (PTR_ERR(key) != -ENOKEY)