This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / crypto / signature / ksign.c

diff --git a/crypto/signature/ksign.c b/crypto/signature/ksign.c
new file mode 100644 (file)
index 0000000..32b0b63
--- /dev/null
+++ b/crypto/signature/ksign.c
@@ -0,0 +1,179 @@
+/* ksign.c: signature checker
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <asm/errno.h>
+#include "local.h"
+
+#if 0
+#define _debug(FMT, ...) printk(KERN_DEBUG FMT, ##__VA_ARGS__)
+#else
+#define _debug(FMT, ...) do { ; } while (0)
+#endif
+
+/*****************************************************************************/
+/*
+ * check the signature which is contained in SIG.
+ */
+static int ksign_signature_check(const struct ksign_signature *sig,
+                                struct crypto_tfm *sha1_tfm)
+{
+       struct ksign_public_key *pk;
+       uint8_t sha1[SHA1_DIGEST_SIZE];
+       MPI result = NULL;
+       int rc = 0, i;
+
+       pk = ksign_get_public_key(sig->keyid);
+       if (!pk) {
+               printk("ksign: module signed with unknown public key\n");
+               printk("- signature keyid: %08x%08x ver=%u\n",
+                      sig->keyid[0], sig->keyid[1], sig->version);
+               return -EPERM;
+       }
+
+       if (pk->timestamp > sig->timestamp)
+               printk("ksign:"
+                      " public key is %lu seconds newer than the signature\n",
+                      pk->timestamp - sig->timestamp);
+
+       /* complete the digest */
+       if (sig->version >= 4)
+               SHA1_putc(sha1_tfm, sig->version);
+       SHA1_putc(sha1_tfm, sig->sig_class);
+
+       if (sig->version < 4) {
+               u32 a = sig->timestamp;
+               SHA1_putc(sha1_tfm, (a >> 24) & 0xff);
+               SHA1_putc(sha1_tfm, (a >> 16) & 0xff);
+               SHA1_putc(sha1_tfm, (a >>  8) & 0xff);
+               SHA1_putc(sha1_tfm, (a >>  0) & 0xff);
+       }
+       else {
+               uint8_t buf[6];
+               size_t n;
+               SHA1_putc(sha1_tfm, PUBKEY_ALGO_DSA);
+               SHA1_putc(sha1_tfm, DIGEST_ALGO_SHA1);
+               if (sig->hashed_data) {
+                       n = (sig->hashed_data[0] << 8) | sig->hashed_data[1];
+                       SHA1_write(sha1_tfm, sig->hashed_data, n + 2);
+                       n += 6;
+               }
+               else {
+                       n = 6;
+               }
+
+               /* add some magic */
+               buf[0] = sig->version;
+               buf[1] = 0xff;
+               buf[2] = n >> 24;
+               buf[3] = n >> 16;
+               buf[4] = n >>  8;
+               buf[5] = n;
+               SHA1_write(sha1_tfm, buf, 6);
+       }
+
+       crypto_digest_final(sha1_tfm, sha1);
+       crypto_free_tfm(sha1_tfm);
+
+
+
+
+
+
+       rc = -ENOMEM;
+       result = mpi_alloc((SHA1_DIGEST_SIZE + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB);
+       if (!result)
+               goto cleanup;
+
+       rc = mpi_set_buffer(result, sha1, SHA1_DIGEST_SIZE, 0);
+       if (rc < 0)
+               goto cleanup;
+
+       rc = DSA_verify(result, sig->data, pk->pkey);
+
+ cleanup:
+       mpi_free(result);
+       ksign_put_public_key(pk);
+
+       return rc;
+} /* end ksign_signature_check() */
+
+/*****************************************************************************/
+/*
+ * examine the signatures that are parsed out of the signature data - we keep
+ * the first one that's appropriate and ignore the rest
+ * - return 0 if signature of interest (sig not freed by caller)
+ * - return 1 if no interest (caller frees)
+ */
+static int ksign_grab_signature(struct ksign_signature *sig, void *fnxdata)
+{
+       struct ksign_signature **_sig = fnxdata;
+
+       if (sig->sig_class != 0x00) {
+               _debug("ksign: standalone signature of class 0x%02x\n",
+                      sig->sig_class);
+               return 1;
+       }
+
+       if (*_sig)
+               return 1;
+
+       *_sig = sig;
+       return 0;
+} /* end ksign_grab_signature() */
+
+/*****************************************************************************/
+/*
+ * verify the signature of some data with one of the kernel's known public keys
+ * - the SHA1 context should be currently open with the signed data digested
+ *   into it so that more data can be appended
+ * - the SHA1 context is finalised and freed before returning
+ */
+int ksign_verify_signature(const char *sigdata, unsigned sig_size,
+                          struct crypto_tfm *sha1)
+{
+       struct ksign_signature *sig = NULL;
+       int retval;
+
+       /* parse the signature data to get the actual signature */
+       retval = ksign_parse_packets(sigdata, sig_size,
+                                    &ksign_grab_signature, NULL, NULL,
+                                    &sig);
+       if (retval < 0)
+               goto cleanup;
+
+       if (!sig) {
+               printk("Couldn't find valid DSA signature in module\n");
+               return -ENOENT;
+       }
+
+       _debug("signature keyid: %08x%08x ver=%u\n",
+              sig->keyid[0], sig->keyid[1], sig->version);
+
+       /* check the data SHA1 transformation against the public key */
+       retval = ksign_signature_check(sig, sha1);
+       if (retval == 0) {
+               _debug("ksign: Signature check succeeded\n");
+       }
+       else if (retval != -ENOMEM) {
+               _debug("ksign: Signature check failed\n");
+               retval = -EPERM;
+       }
+       else {
+               _debug("ksign: Signature check ENOMEM\n");
+       }
+
+ cleanup:
+       if (sig)
+               ksign_free_signature(sig);
+
+       return retval;
+} /* end ksign_verify_signature() */