Commit bda850cd authored by David Howells's avatar David Howells

PKCS#7: Make trust determination dependent on contents of trust keyring

Make the determination of the trustworthiness of a key dependent on whether
a key that can verify it is present in the supplied ring of trusted keys
rather than whether or not the verifying key has KEY_FLAG_TRUSTED set.

verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust
chain cannot be verified.
Signed-off-by: 's avatarDavid Howells <dhowells@redhat.com>
parent e68503bd
......@@ -121,7 +121,6 @@ late_initcall(load_system_certificate_list);
int verify_pkcs7_signature(const void *data, size_t len,
const void *raw_pkcs7, size_t pkcs7_len,
struct key *trusted_keys,
int untrusted_error,
enum key_being_used_for usage,
int (*view_content)(void *ctx,
const void *data, size_t len,
......@@ -129,7 +128,6 @@ int verify_pkcs7_signature(const void *data, size_t len,
void *ctx)
{
struct pkcs7_message *pkcs7;
bool trusted;
int ret;
pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
......@@ -149,13 +147,10 @@ int verify_pkcs7_signature(const void *data, size_t len,
if (!trusted_keys)
trusted_keys = system_trusted_keyring;
ret = pkcs7_validate_trust(pkcs7, trusted_keys, &trusted);
if (ret < 0)
goto error;
if (!trusted && untrusted_error) {
pr_err("PKCS#7 signature not signed with a trusted key\n");
ret = untrusted_error;
ret = pkcs7_validate_trust(pkcs7, trusted_keys);
if (ret < 0) {
if (ret == -ENOKEY)
pr_err("PKCS#7 signature not signed with a trusted key\n");
goto error;
}
......
......@@ -62,7 +62,7 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep)
return verify_pkcs7_signature(NULL, 0,
prep->data, prep->datalen,
NULL, -ENOKEY, usage,
NULL, usage,
pkcs7_view_content, prep);
}
......
......@@ -22,7 +22,6 @@ struct pkcs7_signed_info {
struct pkcs7_signed_info *next;
struct x509_certificate *signer; /* Signing certificate (in msg->certs) */
unsigned index;
bool trusted;
bool unsupported_crypto; /* T if not usable due to missing crypto */
/* Message digest - the digest of the Content Data (or NULL) */
......
......@@ -30,7 +30,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
struct public_key_signature *sig = sinfo->sig;
struct x509_certificate *x509, *last = NULL, *p;
struct key *key;
bool trusted;
int ret;
kenter(",%u,", sinfo->index);
......@@ -42,10 +41,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
for (x509 = sinfo->signer; x509; x509 = x509->signer) {
if (x509->seen) {
if (x509->verified) {
trusted = x509->trusted;
if (x509->verified)
goto verified;
}
kleave(" = -ENOKEY [cached]");
return -ENOKEY;
}
......@@ -122,7 +119,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
matched:
ret = verify_signature(key, sig);
trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags);
key_put(key);
if (ret < 0) {
if (ret == -ENOMEM)
......@@ -134,12 +130,9 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
verified:
if (x509) {
x509->verified = true;
for (p = sinfo->signer; p != x509; p = p->signer) {
for (p = sinfo->signer; p != x509; p = p->signer)
p->verified = true;
p->trusted = trusted;
}
}
sinfo->trusted = trusted;
kleave(" = 0");
return 0;
}
......@@ -148,7 +141,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
* pkcs7_validate_trust - Validate PKCS#7 trust chain
* @pkcs7: The PKCS#7 certificate to validate
* @trust_keyring: Signing certificates to use as starting points
* @_trusted: Set to true if trustworth, false otherwise
*
* Validate that the certificate chain inside the PKCS#7 message intersects
* keys we already know and trust.
......@@ -170,16 +162,13 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
* May also return -ENOMEM.
*/
int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
struct key *trust_keyring,
bool *_trusted)
struct key *trust_keyring)
{
struct pkcs7_signed_info *sinfo;
struct x509_certificate *p;
int cached_ret = -ENOKEY;
int ret;
*_trusted = false;
for (p = pkcs7->certs; p; p = p->next)
p->seen = false;
......@@ -193,7 +182,6 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
cached_ret = -ENOPKG;
continue;
case 0:
*_trusted |= sinfo->trusted;
cached_ret = 0;
continue;
default:
......
......@@ -436,7 +436,7 @@ int verify_pefile_signature(const void *pebuf, unsigned pelen,
ret = verify_pkcs7_signature(NULL, 0,
pebuf + ctx.sig_offset, ctx.sig_len,
trusted_keys, -EKEYREJECTED, usage,
trusted_keys, usage,
mscode_parse, &ctx);
if (ret < 0)
goto error;
......
......@@ -39,7 +39,6 @@ struct x509_certificate {
unsigned index;
bool seen; /* Infinite recursion prevention */
bool verified;
bool trusted;
bool self_signed; /* T if self-signed (check unsupported_sig too) */
bool unsupported_key; /* T if key uses unsupported crypto */
bool unsupported_sig; /* T if signature uses unsupported crypto */
......
......@@ -33,8 +33,7 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
* pkcs7_trust.c
*/
extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
struct key *trust_keyring,
bool *_trusted);
struct key *trust_keyring);
/*
* pkcs7_verify.c
......
......@@ -33,7 +33,6 @@ struct key;
extern int verify_pkcs7_signature(const void *data, size_t len,
const void *raw_pkcs7, size_t pkcs7_len,
struct key *trusted_keys,
int untrusted_error,
enum key_being_used_for usage,
int (*view_content)(void *ctx,
const void *data, size_t len,
......
......@@ -81,6 +81,6 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
}
return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
NULL, -ENOKEY, VERIFYING_MODULE_SIGNATURE,
NULL, VERIFYING_MODULE_SIGNATURE,
NULL, NULL);
}
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