@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/oid_registry.h>
+#include <linux/ctype.h>
#include "public_key.h"
#include "pkcs7_parser.h"
#include "pkcs7-asn1.h"
@@ -29,6 +30,13 @@ struct pkcs7_parse_context {
enum OID last_oid; /* Last OID encountered */
unsigned x509_index;
unsigned sinfo_index;
+ unsigned firmware_name_len;
+ enum {
+ maybe_firmware_sig,
+ is_firmware_sig,
+ isnt_firmware_sig
+ } firmware_sig_state : 8;
+ bool signer_has_firmware_name;
const void *raw_serial;
unsigned raw_serial_size;
unsigned raw_issuer_size;
@@ -73,6 +81,7 @@ void pkcs7_free_message(struct pkcs7_message *pkcs7)
pkcs7->signed_infos = sinfo->next;
pkcs7_free_signed_info(sinfo);
}
+ kfree(pkcs7->firmware_name);
kfree(pkcs7);
}
}
@@ -310,6 +319,8 @@ int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
+ char *p;
+ int i;
pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
@@ -320,6 +331,45 @@ int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
ctx->sinfo->msgdigest = value;
ctx->sinfo->msgdigest_len = vlen;
return 0;
+
+ case OID_firmwareName:
+ if (tag != ASN1_UTF8STR || vlen == 0)
+ return -EBADMSG;
+
+ /* If there's more than one signature, they must have the same
+ * firmware name.
+ */
+ switch (ctx->firmware_sig_state) {
+ case maybe_firmware_sig:
+ for (i = 0; i < vlen; i++)
+ if (!isprint(((const char *)value)[i]))
+ return -EBADMSG;
+ p = kmalloc(vlen + 1, GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ memcpy(p, value, vlen);
+ p[vlen] = 0;
+ ctx->msg->firmware_name = p;
+ ctx->firmware_name_len = vlen;
+ ctx->firmware_sig_state = is_firmware_sig;
+ pr_debug("Found firmware name '%s'\n", p);
+ ctx->signer_has_firmware_name = true;
+ return 0;
+
+ case is_firmware_sig:
+ if (ctx->firmware_name_len != vlen ||
+ memcmp(ctx->msg->firmware_name, value, vlen) != 0) {
+ pr_warn("Mismatched firmware names\n");
+ return -EBADMSG;
+ }
+ ctx->signer_has_firmware_name = true;
+ return 0;
+
+ case isnt_firmware_sig:
+ pr_warn("Mismatched presence of firmware name\n");
+ return -EBADMSG;
+ }
+
default:
return 0;
}
@@ -334,12 +384,39 @@ int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
{
struct pkcs7_parse_context *ctx = context;
+ /* Make sure we either have all or no firmware names */
+ switch (ctx->firmware_sig_state) {
+ case maybe_firmware_sig:
+ ctx->firmware_sig_state = isnt_firmware_sig;
+ case isnt_firmware_sig:
+ break;
+ case is_firmware_sig:
+ if (!ctx->signer_has_firmware_name) {
+ pr_warn("Mismatched presence of firmware name\n");
+ return -EBADMSG;
+ }
+ ctx->signer_has_firmware_name = false;
+ break;
+ }
+
/* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
ctx->sinfo->authattrs = value - (hdrlen - 1);
ctx->sinfo->authattrs_len = vlen + (hdrlen - 1);
return 0;
}
+/**
+ * pkcs7_get_firmware_name - Get firmware name extension value
+ * @pkcs7: The preparsed PKCS#7 message to access
+ *
+ * Get the value of the firmware name extension if there was one or NULL
+ * otherwise.
+ */
+const char *pkcs7_get_firmware_name(const struct pkcs7_message *pkcs7)
+{
+ return pkcs7->firmware_name;
+}
+
/*
* Note the issuing certificate serial number
*/
@@ -50,6 +50,7 @@ struct pkcs7_message {
struct x509_certificate *certs; /* Certificate list */
struct x509_certificate *crl; /* Revocation list */
struct pkcs7_signed_info *signed_infos;
+ char *firmware_name; /* Firmware name if present */
/* Content Data (or NULL) */
enum OID data_type; /* Type of Data */
@@ -22,6 +22,7 @@ extern void pkcs7_free_message(struct pkcs7_message *pkcs7);
extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
const void **_data, size_t *_datalen,
bool want_wrapper);
+extern const char *pkcs7_get_firmware_name(const struct pkcs7_message *pkcs7);
/*
* pkcs7_trust.c
@@ -30,7 +30,8 @@ static inline struct key *get_system_trusted_keyring(void)
#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
extern int system_verify_data(const void *data, unsigned long len,
- const void *raw_pkcs7, size_t pkcs7_len);
+ const void *raw_pkcs7, size_t pkcs7_len,
+ const char *firmware_name);
#endif
#endif /* _KEYS_SYSTEM_KEYRING_H */
@@ -88,6 +88,10 @@ enum OID {
OID_authorityKeyIdentifier, /* 2.5.29.35 */
OID_extKeyUsage, /* 2.5.29.37 */
+ /* Signing */
+ OID_firmwareName, /* 1.3.6.1.4.1.2312.99.1 */
+ OID_firmwareOnlyKey, /* 1.3.6.1.4.1.2312.99.2 */
+
OID__NR
};
@@ -72,5 +72,5 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
return -EBADMSG;
}
- return system_verify_data(mod, modlen, mod + modlen, sig_len);
+ return system_verify_data(mod, modlen, mod + modlen, sig_len, NULL);
}
@@ -113,11 +113,14 @@ late_initcall(load_system_certificate_list);
* @len: Size of @data.
* @raw_pkcs7: The PKCS#7 message that is the signature.
* @pkcs7_len: The size of @raw_pkcs7.
+ * @firmware_name: The required firmware name or NULL.
*/
int system_verify_data(const void *data, unsigned long len,
- const void *raw_pkcs7, size_t pkcs7_len)
+ const void *raw_pkcs7, size_t pkcs7_len,
+ const char *firmware_name)
{
struct pkcs7_message *pkcs7;
+ const char *p7_firmware_name;
bool trusted;
int ret;
@@ -125,6 +128,27 @@ int system_verify_data(const void *data, unsigned long len,
if (IS_ERR(pkcs7))
return PTR_ERR(pkcs7);
+ ret = -EINVAL;
+ p7_firmware_name = pkcs7_get_firmware_name(pkcs7);
+ if (firmware_name) {
+ if (!p7_firmware_name) {
+ pr_err("Expected name '%s' in firmware signature but not present\n",
+ firmware_name);
+ goto error;
+ }
+ if (strcmp(p7_firmware_name, firmware_name) != 0) {
+ pr_err("Expected name '%s' in firmware signature but got '%s'\n",
+ firmware_name, p7_firmware_name);
+ goto error;
+ }
+ } else {
+ if (p7_firmware_name) {
+ pr_err("Unexpected firmware name in signature '%s'\n",
+ p7_firmware_name);
+ goto error;
+ }
+ }
+
/* The data should be detached - so we need to supply it. */
if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
pr_err("PKCS#7 signature with non-detached data\n");
@@ -43,6 +43,8 @@ void format(void)
{
fprintf(stderr,
"Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
+ fprintf(stderr,
+ " scripts/sign-file [-dp] -F <firmware name> <hash algo> <key> <x509> <firmware> [<dest>]\n");
exit(2);
}
@@ -105,12 +107,14 @@ static int pem_pw_cb(char *buf, int len, int w, void *v)
int main(int argc, char **argv)
{
struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
+ const char *firmware_name = NULL;
char *hash_algo = NULL;
char *private_key_name, *x509_name, *module_name, *dest_name;
bool save_pkcs7 = false, replace_orig;
bool sign_only = false;
unsigned char buf[4096];
unsigned long module_size, pkcs7_size;
+ PKCS7_SIGNER_INFO *signer;
const EVP_MD *digest_algo;
EVP_PKEY *private_key;
PKCS7 *pkcs7;
@@ -125,10 +129,11 @@ int main(int argc, char **argv)
key_pass = getenv("KBUILD_SIGN_PIN");
do {
- opt = getopt(argc, argv, "dp");
+ opt = getopt(argc, argv, "dpF:");
switch (opt) {
case 'p': save_pkcs7 = true; break;
case 'd': sign_only = true; save_pkcs7 = true; break;
+ case 'F': firmware_name = optarg; break;
case -1: break;
default: format();
}
@@ -213,8 +218,28 @@ int main(int argc, char **argv)
PKCS7_NOCERTS | PKCS7_PARTIAL | PKCS7_BINARY | PKCS7_DETACHED | PKCS7_STREAM);
ERR(!pkcs7, "PKCS7_sign");
- ERR(!PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY),
- "PKCS7_sign_add_signer");
+ signer = PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY);
+ ERR(!signer, "PKCS7_sign_add_signer");
+
+ if (firmware_name) {
+ /* Add an entry into the authenticated attributes to note the
+ * firmware name if this is a firmware signature.
+ */
+ ASN1_UTF8STRING *str;
+ int nid;
+
+ // As an example, use an OID of redhat.99.1 - which is not assigned
+ nid = OBJ_create("1.3.6.1.4.1.2312.99.1", NULL, NULL);
+ ERR(!nid, "OBJ_create");
+
+ str = M_ASN1_UTF8STRING_new();
+ ERR(!str, "M_ASN1_UTF8STRING_new");
+ ERR(!ASN1_STRING_set(str, firmware_name, strlen(firmware_name)),
+ "ASN1_STRING_set");
+ ERR(!PKCS7_add_signed_attribute(signer, nid, V_ASN1_UTF8STRING, str),
+ "PKCS7_add_signed_attribute");
+ }
+
ERR(PKCS7_final(pkcs7, bm, PKCS7_NOCERTS | PKCS7_BINARY) < 0,
"PKCS7_final");
Assuming we want to tag firmware signatures with the name of the firmware blob as passed to request_firmware(), the attached patch would provide the PKCS#7 side of the support you need. David --- commit ef479eb8e645a95ef172918e4df215ecdc823e42 Author: David Howells <dhowells@redhat.com> Date: Fri May 22 10:13:37 2015 +0100 PKCS#7: Add an optional authenticated attribute to hold firmware name Modify the sign-file program to take a "-F <firmware name>" parameter. The name is a utf8 string that, if given, is inserted in a PKCS#7 authenticated attribute from where it can be extracted by the kernel. Authenticated attributes are added to the signature digest. If the attribute is present, the signature would be assumed to be for firmware and would not be permitted with module signing or kexec. The name associated with the attribute would be compared to the name passed to request_firmware() and the load request would be denied if they didn't match. If not present, the signature would be rejected if used for firmware. One oddity is that the attribute is per-signature, so if a second signature was added (which PKCS#7 supports), it would have to have the attribute added separately to that signature also. Note that the OID I have selected is an unregistered element of the Red Hat OID space to serve as an example. An OID would need to be allocated for this purpose. The kernel then parses this out, saves the string and makes sure the same string (or lack thereof) is present from all signers. Then when system_verify_data() is called, it is passed a NULL if the attribute is expected not to be present and the name from request_firmware() if it is expected to be present. Verification is rejected if there's a mismatch. This should probably be combined with tagging the X.509 certificate to indicate what it can be used for. Not-yet-signed-off-by: David Howells <dhowells@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html