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TLS client: Add support for validating server certificate hash

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This commit adds support for "hash://server/sha256/cert_hash_in_hex"
scheme in ca_cert property for the internal TLS implementation.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
This commit is contained in:
Pali Rohár 2015-11-22 02:02:56 +01:00 committed by Jouni Malinen
parent 3665776e4e
commit fdc1614264
3 changed files with 56 additions and 4 deletions
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28
src/tls/tlsv1_client_read.c
View file

@ -364,9 +364,31 @@ static int tls_process_certificate(struct tlsv1_client *conn, u8 ct,
pos += cert_len;
}
if (conn->cred && conn->cred->ca_cert_verify &&
x509_certificate_chain_validate(conn->cred->trusted_certs, chain,
&reason, conn->disable_time_checks)
if (conn->cred && conn->cred->server_cert_only && chain) {
u8 hash[SHA256_MAC_LEN];
char buf[128];
wpa_printf(MSG_DEBUG,
"TLSv1: Validate server certificate hash");
x509_name_string(&chain->subject, buf, sizeof(buf));
wpa_printf(MSG_DEBUG, "TLSv1: 0: %s", buf);
if (sha256_vector(1, &chain->cert_start, &chain->cert_len,
hash) < 0 ||
os_memcmp(conn->cred->srv_cert_hash, hash,
SHA256_MAC_LEN) != 0) {
wpa_printf(MSG_DEBUG,
"TLSv1: Server certificate hash mismatch");
wpa_hexdump(MSG_MSGDUMP, "TLSv1: SHA256 hash",
hash, SHA256_MAC_LEN);
tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
TLS_ALERT_BAD_CERTIFICATE);
x509_certificate_chain_free(chain);
return -1;
}
} else if (conn->cred && conn->cred->ca_cert_verify &&
x509_certificate_chain_validate(conn->cred->trusted_certs,
chain, &reason,
conn->disable_time_checks)
< 0) {
int tls_reason;
wpa_printf(MSG_DEBUG, "TLSv1: Server certificate chain "

28
src/tls/tlsv1_cred.c
View file

@ -190,6 +190,34 @@ int tlsv1_set_ca_cert(struct tlsv1_credentials *cred, const char *cert,
const u8 *cert_blob, size_t cert_blob_len,
const char *path)
{
if (cert && os_strncmp(cert, "hash://", 7) == 0) {
const char *pos = cert + 7;
if (os_strncmp(pos, "server/sha256/", 14) != 0) {
wpa_printf(MSG_DEBUG,
"TLSv1: Unsupported ca_cert hash value '%s'",
cert);
return -1;
}
pos += 14;
if (os_strlen(pos) != 32 * 2) {
wpa_printf(MSG_DEBUG,
"TLSv1: Unexpected SHA256 hash length in ca_cert '%s'",
cert);
return -1;
}
if (hexstr2bin(pos, cred->srv_cert_hash, 32) < 0) {
wpa_printf(MSG_DEBUG,
"TLSv1: Invalid SHA256 hash value in ca_cert '%s'",
cert);
return -1;
}
cred->server_cert_only = 1;
cred->ca_cert_verify = 0;
wpa_printf(MSG_DEBUG,
"TLSv1: Checking only server certificate match");
return 0;
}
cred->ca_cert_verify = cert || cert_blob || path;
if (tlsv1_set_cert_chain(&cred->trusted_certs, cert,

2
src/tls/tlsv1_cred.h
View file

@ -15,6 +15,8 @@ struct tlsv1_credentials {
struct crypto_private_key *key;
unsigned int ca_cert_verify:1;
unsigned int server_cert_only:1;
u8 srv_cert_hash[32];
/* Diffie-Hellman parameters */
u8 *dh_p; /* prime */