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-rw-r--r--src/lib/crypto/enc_provider/ChangeLog8
-rw-r--r--src/lib/crypto/enc_provider/Makefile.in8
-rw-r--r--src/lib/crypto/enc_provider/arcfour.c193
-rw-r--r--src/lib/crypto/enc_provider/enc_provider.h3
4 files changed, 208 insertions, 4 deletions
diff --git a/src/lib/crypto/enc_provider/ChangeLog b/src/lib/crypto/enc_provider/ChangeLog
index 6a63ec8..035d41b 100644
--- a/src/lib/crypto/enc_provider/ChangeLog
+++ b/src/lib/crypto/enc_provider/ChangeLog
@@ -1,3 +1,11 @@
+2001-10-23 Sam Hartman <hartmans@mit.edu>
+
+ * enc_provider.h: New encryption provider: rc4
+
+2001-10-19 Sam Hartman <hartmans@mit.edu>
+
+ * arcfour.c: Move prototype for static functions here rather than in a header file.
+
2001-05-31 Ezra Peisach <epeisach@mit.edu>
* des.c (k5_des_docrypt): Do not use a variable named "encrypt"
diff --git a/src/lib/crypto/enc_provider/Makefile.in b/src/lib/crypto/enc_provider/Makefile.in
index 64922d4..64e7ac5 100644
--- a/src/lib/crypto/enc_provider/Makefile.in
+++ b/src/lib/crypto/enc_provider/Makefile.in
@@ -2,7 +2,7 @@ thisconfigdir=./..
myfulldir=lib/crypto/enc_provider
mydir=enc_provider
BUILDTOP=$(REL)$(U)$(S)$(U)$(S)$(U)
-LOCALINCLUDES = -I$(srcdir)/../des
+LOCALINCLUDES = -I$(srcdir)/../des -I$(srcdir)/../arcfour
##DOS##BUILDTOP = ..\..\..
##DOS##PREFIXDIR=enc_provider
@@ -14,11 +14,11 @@ PROG_RPATH=$(KRB5_LIBDIR)
RUN_SETUP = @KRB5_RUN_ENV@ KRB5_CONFIG=$(SRCTOP)/config-files/krb5.conf
-STLIBOBJS= des.o des3.o
+STLIBOBJS= des.o des3.o arcfour.o
-OBJS= $(OUTPRE)des.$(OBJEXT) $(OUTPRE)des3.$(OBJEXT)
+OBJS= $(OUTPRE)des.$(OBJEXT) $(OUTPRE)des3.$(OBJEXT) $(OUTPRE)arcfour.$(OBJEXT)
-SRCS= $(srcdir)/des.c $(srcdir)/des3.c
+SRCS= $(srcdir)/des.c $(srcdir)/des3.c $(srcdir)/arcfour.c
##DOS##LIBOBJS = $(OBJS)
diff --git a/src/lib/crypto/enc_provider/arcfour.c b/src/lib/crypto/enc_provider/arcfour.c
new file mode 100644
index 0000000..956b75e
--- /dev/null
+++ b/src/lib/crypto/enc_provider/arcfour.c
@@ -0,0 +1,193 @@
+/* arcfour.c
+ *
+ * Copyright (c) 2000 by Computer Science Laboratory,
+ * Rensselaer Polytechnic Institute
+ *
+ * #include STD_DISCLAIMER
+ */
+
+#include "k5-int.h"
+#include "arcfour-int.h"
+#include "enc_provider.h"
+/* gets the next byte from the PRNG */
+static inline unsigned int k5_arcfour_byte(ArcfourContext *);
+
+/* Initializes the context and sets the key. */
+static krb5_error_code k5_arcfour_init(ArcfourContext *ctx, const unsigned char *key,
+ unsigned int keylen);
+
+/* Encrypts/decrypts data. */
+static void k5_arcfour_crypt(ArcfourContext *ctx, unsigned char *dest,
+ const unsigned char *src, unsigned int len);
+
+/* Interface layer to kerb5 crypto layer */
+static krb5_error_code
+k5_arcfour_docrypt(krb5_const krb5_keyblock *, krb5_const krb5_data *,
+ krb5_const krb5_data *, krb5_data *);
+
+
+/* The blocksize for the enctype */
+static void k5_arcfour_blocksize(size_t *);
+
+/* keysize for the enctype (number of bytes, and length of key (parity/etc) */
+static void k5_arcfour_keysize(size_t *, size_t *);
+
+/* from a random bitstrem, construct a key */
+static krb5_error_code
+k5_arcfour_make_key(krb5_const krb5_data *, krb5_keyblock *);
+
+static char arcfour_weakkey1[] = {0x00, 0x00, 0xfd};
+static char arcfour_weakkey2[] = {0x03, 0xfd, 0xfc};
+static krb5_data arcfour_weakkeys[] = { {KV5M_DATA, sizeof (arcfour_weakkey1),
+ arcfour_weakkey1},
+ {KV5M_DATA, sizeof (arcfour_weakkey2),
+ arcfour_weakkey2},
+ {KV5M_DATA, 0, 0}
+};
+
+static inline unsigned int k5_arcfour_byte(ArcfourContext *ctx)
+{
+ unsigned int x;
+ unsigned int y;
+ unsigned int sx, sy;
+ unsigned char *state;
+
+ state = ctx->state;
+ x = (ctx->x + 1) & 0xff;
+ sx = state[x];
+ y = (sx + ctx->y) & 0xff;
+ sy = state[y];
+ ctx->x = x;
+ ctx->y = y;
+ state[y] = sx;
+ state[x] = sy;
+ return state[(sx + sy) & 0xff];
+}
+
+static void k5_arcfour_crypt(ArcfourContext *ctx, unsigned char *dest,
+ const unsigned char *src, unsigned int len)
+{
+ unsigned int i;
+ for (i = 0; i < len; i++)
+ dest[i] = src[i] ^ k5_arcfour_byte(ctx);
+}
+
+
+static krb5_error_code
+k5_arcfour_init(ArcfourContext *ctx, const unsigned char *key,
+ unsigned int key_len)
+{
+ unsigned int t, u;
+ unsigned int keyindex;
+ unsigned int stateindex;
+ unsigned char* state;
+ unsigned int counter;
+
+ if (key_len != 16)
+ return KRB5_BAD_MSIZE; /*this is probably not the correct error code
+ to return */
+ for(counter=0;arcfour_weakkeys[counter].length >0; counter++)
+ if (memcmp(key, arcfour_weakkeys[counter].data,
+ arcfour_weakkeys[counter].length) == 0)
+ return KRB5DES_WEAK_KEY; /* most certainly not the correct error */
+
+ state = &ctx->state[0];
+ ctx->x = 0;
+ ctx->y = 0;
+ for (counter = 0; counter < 256; counter++)
+ state[counter] = counter;
+ keyindex = 0;
+ stateindex = 0;
+ for (counter = 0; counter < 256; counter++)
+ {
+ t = state[counter];
+ stateindex = (stateindex + key[keyindex] + t) & 0xff;
+ u = state[stateindex];
+ state[stateindex] = t;
+ state[counter] = u;
+ if (++keyindex >= key_len)
+ keyindex = 0;
+ }
+ return 0;
+}
+
+/* This seems to work... although I am not sure what the implications are
+ in other places in the kerberos library */
+static void
+k5_arcfour_blocksize(size_t *blocksize)
+{
+ *blocksize = 1;
+}
+
+/* Keysize is arbitrary in arcfour, but the constraints of the system, and
+ to attempt to work with the MSFT system forces us to 16byte/128bit.
+ Since there is no parity in the key, the byte and length are the same.
+*/
+static void
+k5_arcfour_keysize(size_t *keybytes, size_t *keylength)
+{
+ *keybytes = 16;
+ *keylength = 16;
+}
+
+/* The workhorse of the arcfour system, this impliments the cipher */
+static krb5_error_code
+k5_arcfour_docrypt(krb5_const krb5_keyblock *key, krb5_const krb5_data *state,
+ krb5_const krb5_data *input, krb5_data *output)
+{
+ ArcfourContext *arcfour_ctx;
+ int ret;
+
+ if (key->length != 16)
+ return(KRB5_BAD_KEYSIZE);
+ if (state && (state->length != sizeof (ArcfourContext)))
+ return(KRB5_BAD_MSIZE);
+ if (input->length != output->length)
+ return(KRB5_BAD_MSIZE);
+
+ if (state) {
+ arcfour_ctx=(ArcfourContext *)state->data;
+ k5_arcfour_crypt(arcfour_ctx, output->data, input->data, input->length);
+ }
+ else {
+ arcfour_ctx=malloc(sizeof (ArcfourContext));
+ if (arcfour_ctx == NULL)
+ return ENOMEM;
+ if ((ret=k5_arcfour_init(arcfour_ctx, key->contents, key->length))) {
+ free(arcfour_ctx);
+ return (ret);
+ }
+ k5_arcfour_crypt(arcfour_ctx, output->data, input->data, input->length);
+ memset(arcfour_ctx, 0, sizeof (ArcfourContext));
+ free(arcfour_ctx);
+ }
+
+ return 0;
+}
+
+static krb5_error_code
+k5_arcfour_make_key(krb5_const krb5_data *randombits, krb5_keyblock *key)
+{
+ if (key->length != 16)
+ return(KRB5_BAD_KEYSIZE);
+ if (randombits->length != 16)
+ return(KRB5_CRYPTO_INTERNAL);
+
+ key->magic = KV5M_KEYBLOCK;
+ key->length = 16;
+
+ memcpy(key->contents, randombits->data, randombits->length);
+
+ return(0);
+}
+
+/* Since the arcfour cipher is identical going forwards and backwards,
+ we just call "docrypt" directly
+*/
+const struct krb5_enc_provider krb5int_enc_arcfour = {
+ k5_arcfour_blocksize,
+ k5_arcfour_keysize,
+ k5_arcfour_docrypt,
+ k5_arcfour_docrypt,
+ k5_arcfour_make_key
+};
diff --git a/src/lib/crypto/enc_provider/enc_provider.h b/src/lib/crypto/enc_provider/enc_provider.h
index ac95b58..9a3dafb 100644
--- a/src/lib/crypto/enc_provider/enc_provider.h
+++ b/src/lib/crypto/enc_provider/enc_provider.h
@@ -28,3 +28,6 @@
extern const struct krb5_enc_provider krb5int_enc_des;
extern const struct krb5_enc_provider krb5int_enc_des3;
+extern const struct krb5_enc_provider krb5int_enc_arcfour;
+
+
generated by cgit v1.1 at 2024-07-09 03:20:43 +0000