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authorKevin Coffman <kwc@citi.umich.edu>2010-03-17 20:02:53 +0300
committerTrond Myklebust <Trond.Myklebust@netapp.com>2010-05-14 23:09:16 +0400
commit4891f2d008e4343eedea39ba1fe74864f1d32be0 (patch)
tree6fb4048a44cd1c91f818ddc372d5410e59108bdb /net/sunrpc/auth_gss/gss_krb5_keys.c
parente1f6c07b1160ef28e8754d12e6c03288dd9d5ca8 (diff)
downloadlinux-4891f2d008e4343eedea39ba1fe74864f1d32be0.tar.xz
gss_krb5: import functionality to derive keys into the kernel
Import the code to derive Kerberos keys from a base key into the kernel. This will allow us to change the format of the context information sent down from gssd to include only a single key. Signed-off-by: Kevin Coffman <kwc@citi.umich.edu> Signed-off-by: Steve Dickson <steved@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc/auth_gss/gss_krb5_keys.c')
-rw-r--r--net/sunrpc/auth_gss/gss_krb5_keys.c252
1 files changed, 252 insertions, 0 deletions
diff --git a/net/sunrpc/auth_gss/gss_krb5_keys.c b/net/sunrpc/auth_gss/gss_krb5_keys.c
new file mode 100644
index 000000000000..832ce901bf68
--- /dev/null
+++ b/net/sunrpc/auth_gss/gss_krb5_keys.c
@@ -0,0 +1,252 @@
+/*
+ * COPYRIGHT (c) 2008
+ * The Regents of the University of Michigan
+ * ALL RIGHTS RESERVED
+ *
+ * Permission is granted to use, copy, create derivative works
+ * and redistribute this software and such derivative works
+ * for any purpose, so long as the name of The University of
+ * Michigan is not used in any advertising or publicity
+ * pertaining to the use of distribution of this software
+ * without specific, written prior authorization. If the
+ * above copyright notice or any other identification of the
+ * University of Michigan is included in any copy of any
+ * portion of this software, then the disclaimer below must
+ * also be included.
+ *
+ * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
+ * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
+ * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
+ * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
+ * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
+ * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
+ * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
+ * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
+ * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGES.
+ */
+
+/*
+ * Copyright (C) 1998 by the FundsXpress, INC.
+ *
+ * All rights reserved.
+ *
+ * Export of this software from the United States of America may require
+ * a specific license from the United States Government. It is the
+ * responsibility of any person or organization contemplating export to
+ * obtain such a license before exporting.
+ *
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of FundsXpress. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission. FundsXpress makes no representations about the suitability of
+ * this software for any purpose. It is provided "as is" without express
+ * or implied warranty.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include <linux/sunrpc/gss_krb5.h>
+#include <linux/sunrpc/xdr.h>
+
+#ifdef RPC_DEBUG
+# define RPCDBG_FACILITY RPCDBG_AUTH
+#endif
+
+/*
+ * This is the n-fold function as described in rfc3961, sec 5.1
+ * Taken from MIT Kerberos and modified.
+ */
+
+static void krb5_nfold(u32 inbits, const u8 *in,
+ u32 outbits, u8 *out)
+{
+ int a, b, c, lcm;
+ int byte, i, msbit;
+
+ /* the code below is more readable if I make these bytes
+ instead of bits */
+
+ inbits >>= 3;
+ outbits >>= 3;
+
+ /* first compute lcm(n,k) */
+
+ a = outbits;
+ b = inbits;
+
+ while (b != 0) {
+ c = b;
+ b = a%b;
+ a = c;
+ }
+
+ lcm = outbits*inbits/a;
+
+ /* now do the real work */
+
+ memset(out, 0, outbits);
+ byte = 0;
+
+ /* this will end up cycling through k lcm(k,n)/k times, which
+ is correct */
+ for (i = lcm-1; i >= 0; i--) {
+ /* compute the msbit in k which gets added into this byte */
+ msbit = (
+ /* first, start with the msbit in the first,
+ * unrotated byte */
+ ((inbits << 3) - 1)
+ /* then, for each byte, shift to the right
+ * for each repetition */
+ + (((inbits << 3) + 13) * (i/inbits))
+ /* last, pick out the correct byte within
+ * that shifted repetition */
+ + ((inbits - (i % inbits)) << 3)
+ ) % (inbits << 3);
+
+ /* pull out the byte value itself */
+ byte += (((in[((inbits - 1) - (msbit >> 3)) % inbits] << 8)|
+ (in[((inbits) - (msbit >> 3)) % inbits]))
+ >> ((msbit & 7) + 1)) & 0xff;
+
+ /* do the addition */
+ byte += out[i % outbits];
+ out[i % outbits] = byte & 0xff;
+
+ /* keep around the carry bit, if any */
+ byte >>= 8;
+
+ }
+
+ /* if there's a carry bit left over, add it back in */
+ if (byte) {
+ for (i = outbits - 1; i >= 0; i--) {
+ /* do the addition */
+ byte += out[i];
+ out[i] = byte & 0xff;
+
+ /* keep around the carry bit, if any */
+ byte >>= 8;
+ }
+ }
+}
+
+/*
+ * This is the DK (derive_key) function as described in rfc3961, sec 5.1
+ * Taken from MIT Kerberos and modified.
+ */
+
+u32 krb5_derive_key(struct gss_krb5_enctype *gk5e,
+ const struct xdr_netobj *inkey,
+ struct xdr_netobj *outkey,
+ const struct xdr_netobj *in_constant)
+{
+ size_t blocksize, keybytes, keylength, n;
+ unsigned char *inblockdata, *outblockdata, *rawkey;
+ struct xdr_netobj inblock, outblock;
+ struct crypto_blkcipher *cipher;
+ u32 ret = EINVAL;
+
+ blocksize = gk5e->blocksize;
+ keybytes = gk5e->keybytes;
+ keylength = gk5e->keylength;
+
+ if ((inkey->len != keylength) || (outkey->len != keylength))
+ goto err_return;
+
+ cipher = crypto_alloc_blkcipher(gk5e->encrypt_name, 0,
+ CRYPTO_ALG_ASYNC);
+ if (IS_ERR(cipher))
+ goto err_return;
+ if (crypto_blkcipher_setkey(cipher, inkey->data, inkey->len))
+ goto err_return;
+
+ /* allocate and set up buffers */
+
+ ret = ENOMEM;
+ inblockdata = kmalloc(blocksize, GFP_KERNEL);
+ if (inblockdata == NULL)
+ goto err_free_cipher;
+
+ outblockdata = kmalloc(blocksize, GFP_KERNEL);
+ if (outblockdata == NULL)
+ goto err_free_in;
+
+ rawkey = kmalloc(keybytes, GFP_KERNEL);
+ if (rawkey == NULL)
+ goto err_free_out;
+
+ inblock.data = (char *) inblockdata;
+ inblock.len = blocksize;
+
+ outblock.data = (char *) outblockdata;
+ outblock.len = blocksize;
+
+ /* initialize the input block */
+
+ if (in_constant->len == inblock.len) {
+ memcpy(inblock.data, in_constant->data, inblock.len);
+ } else {
+ krb5_nfold(in_constant->len * 8, in_constant->data,
+ inblock.len * 8, inblock.data);
+ }
+
+ /* loop encrypting the blocks until enough key bytes are generated */
+
+ n = 0;
+ while (n < keybytes) {
+ (*(gk5e->encrypt))(cipher, NULL, inblock.data,
+ outblock.data, inblock.len);
+
+ if ((keybytes - n) <= outblock.len) {
+ memcpy(rawkey + n, outblock.data, (keybytes - n));
+ break;
+ }
+
+ memcpy(rawkey + n, outblock.data, outblock.len);
+ memcpy(inblock.data, outblock.data, outblock.len);
+ n += outblock.len;
+ }
+
+ /* postprocess the key */
+
+ inblock.data = (char *) rawkey;
+ inblock.len = keybytes;
+
+ BUG_ON(gk5e->mk_key == NULL);
+ ret = (*(gk5e->mk_key))(gk5e, &inblock, outkey);
+ if (ret) {
+ dprintk("%s: got %d from mk_key function for '%s'\n",
+ __func__, ret, gk5e->encrypt_name);
+ goto err_free_raw;
+ }
+
+ /* clean memory, free resources and exit */
+
+ ret = 0;
+
+err_free_raw:
+ memset(rawkey, 0, keybytes);
+ kfree(rawkey);
+err_free_out:
+ memset(outblockdata, 0, blocksize);
+ kfree(outblockdata);
+err_free_in:
+ memset(inblockdata, 0, blocksize);
+ kfree(inblockdata);
+err_free_cipher:
+ crypto_free_blkcipher(cipher);
+err_return:
+ return ret;
+}