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PKCS#7: Handle blacklisted certificates

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PKCS#7: Handle certificates that are blacklisted when verifying the chain
of trust on the signatures on a PKCS#7 message.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2017-04-03 16:07:25 +01:00
parent 436529562d
commit 03bb79315d
2 changed files with 25 additions and 8 deletions
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1
crypto/asymmetric_keys/pkcs7_parser.h
View file

@ -23,6 +23,7 @@ struct pkcs7_signed_info {
struct x509_certificate *signer; /* Signing certificate (in msg->certs) */
unsigned index;
bool unsupported_crypto; /* T if not usable due to missing crypto */
bool blacklisted;
/* Message digest - the digest of the Content Data (or NULL) */
const void *msgdigest;

32
crypto/asymmetric_keys/pkcs7_verify.c
View file

@ -190,6 +190,18 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
x509->subject,
x509->raw_serial_size, x509->raw_serial);
x509->seen = true;
if (x509->blacklisted) {
/* If this cert is blacklisted, then mark everything
* that depends on this as blacklisted too.
*/
sinfo->blacklisted = true;
for (p = sinfo->signer; p != x509; p = p->signer)
p->blacklisted = true;
pr_debug("- blacklisted\n");
return 0;
}
if (x509->unsupported_key)
goto unsupported_crypto_in_x509;
@ -357,17 +369,19 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
*
* (*) -EBADMSG if some part of the message was invalid, or:
*
* (*) -ENOPKG if none of the signature chains are verifiable because suitable
* crypto modules couldn't be found, or:
* (*) 0 if no signature chains were found to be blacklisted or to contain
* unsupported crypto, or:
*
* (*) 0 if all the signature chains that don't incur -ENOPKG can be verified
* (note that a signature chain may be of zero length), or:
* (*) -EKEYREJECTED if a blacklisted key was encountered, or:
*
* (*) -ENOPKG if none of the signature chains are verifiable because suitable
* crypto modules couldn't be found.
*/
int pkcs7_verify(struct pkcs7_message *pkcs7,
enum key_being_used_for usage)
{
struct pkcs7_signed_info *sinfo;
int enopkg = -ENOPKG;
int actual_ret = -ENOPKG;
int ret;
kenter("");
@ -412,6 +426,8 @@ int pkcs7_verify(struct pkcs7_message *pkcs7,
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 (ret < 0) {
if (ret == -ENOPKG) {
sinfo->unsupported_crypto = true;
@ -420,11 +436,11 @@ int pkcs7_verify(struct pkcs7_message *pkcs7,
kleave(" = %d", ret);
return ret;
}
enopkg = 0;
actual_ret = 0;
}
kleave(" = %d", enopkg);
return enopkg;
kleave(" = %d", actual_ret);
return actual_ret;
}
EXPORT_SYMBOL_GPL(pkcs7_verify);