1 files changed, 53 insertions, 0 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_keys.c b/net/sunrpc/auth_gss/gss_krb5_keys.c
index 253b4149584a..d54668790f0c 100644
--- a/net/sunrpc/auth_gss/gss_krb5_keys.c
+++ b/net/sunrpc/auth_gss/gss_krb5_keys.c
@@ -250,3 +250,56 @@ err_free_cipher:
 err_return:
         return ret;
 }
+
+#define smask(step) ((1<<step)-1)
+#define pstep(x, step) (((x)&smask(step))^(((x)>>step)&smask(step)))
+#define parity_char(x) pstep(pstep(pstep((x), 4), 2), 1)
+
+static void mit_des_fixup_key_parity(u8 key[8])
+{
+        int i;
+        for (i = 0; i < 8; i++) {
+                key[i] &= 0xfe;
+                key[i] |= 1^parity_char(key[i]);
+        }
+}
+
+/*
+ * This is the des3 key derivation postprocess function
+ */
+u32 gss_krb5_des3_make_key(const struct gss_krb5_enctype *gk5e,
+                           struct xdr_netobj *randombits,
+                           struct xdr_netobj *key)
+{
+        int i;
+        u32 ret = EINVAL;
+
+        if (key->len != 24) {
+                dprintk("%s: key->len is %d\n", __func__, key->len);
+                goto err_out;
+        }
+        if (randombits->len != 21) {
+                dprintk("%s: randombits->len is %d\n",
+                        __func__, randombits->len);
+                goto err_out;
+        }
+
+        /* take the seven bytes, move them around into the top 7 bits of the
+           8 key bytes, then compute the parity bits.  Do this three times. */
+
+        for (i = 0; i < 3; i++) {
+                memcpy(key->data + i*8, randombits->data + i*7, 7);
+                key->data[i*8+7] = (((key->data[i*8]&1)<<1) |
+                                    ((key->data[i*8+1]&1)<<2) |
+                                    ((key->data[i*8+2]&1)<<3) |
+                                    ((key->data[i*8+3]&1)<<4) |
+                                    ((key->data[i*8+4]&1)<<5) |
+                                    ((key->data[i*8+5]&1)<<6) |
+                                    ((key->data[i*8+6]&1)<<7));
+
+                mit_des_fixup_key_parity(key->data + i*8);
+        }
+        ret = 0;
+err_out:
+        return ret;
+}