From: mdw Date: Tue, 19 Jun 2001 22:10:57 +0000 (+0000) Subject: Some more constants for the algorithms. Document the packet format X-Git-Tag: 1.0.0pre3~29 X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/commitdiff_plain/aeeb56115b65dd5cc32ad396876522c2e861a661 Some more constants for the algorithms. Document the packet format change for non-malleability. Moved @buf@ definitions to separate header file. --- diff --git a/tripe.h b/tripe.h index f3816b40..9a180328 100644 --- a/tripe.h +++ b/tripe.h @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: tripe.h,v 1.7 2001/03/03 12:07:08 mdw Exp $ + * $Id: tripe.h,v 1.8 2001/06/19 22:10:57 mdw Exp $ * * Main header file for TrIPE * @@ -29,6 +29,11 @@ /*----- Revision history --------------------------------------------------* * * $Log: tripe.h,v $ + * Revision 1.8 2001/06/19 22:10:57 mdw + * Some more constants for the algorithms. Document the packet format + * change for non-malleability. Moved @buf@ definitions to separate header + * file. + * * Revision 1.7 2001/03/03 12:07:08 mdw * Rename word get and put functions now that there's 16-bit support. * @@ -121,6 +126,7 @@ #include #include +#include "buf.h" #include "util.h" #undef sun @@ -197,16 +203,17 @@ /* --- Symmetric encryption and keysets --- * * - * Packets consist of a 64-bit MAC, a 32-bit sequence number, and the + * Packets consist of an 80-bit MAC, a 32-bit sequence number, and the * encrypted payload. * - * The MAC is computed using the HMAC construction with RIPEMD160 over the - * sequence number and the original packet plaintext; the first 64 bits of - * the output are used. - * * The plaintext is encrypted using Blowfish in CBC mode with ciphertext * stealing (as described in [Schneier]. The initialization vector is - * precisely the 64-bit MAC computed previously. + * selected randomly, and prepended to the actual ciphertext. + * + * The MAC is computed using the HMAC construction with RIPEMD160 over the + * sequence number and the ciphertext (with iV); the first 80 bits of the + * output are used. (This is the minimum allowed by the draft FIPS for HMAC, + * and the recommended truncation.) * * A keyset consists of * @@ -247,20 +254,11 @@ #define HASH_DONE rmd160_done #define HASHSZ RMD160_HASHSZ -/*----- Data structures ---------------------------------------------------*/ +#define SEQSZ 4 +#define IVSZ BLOWFISH_BLKSZ +#define MACSZ 10 -/* --- Buffers --- * - * - * Buffers provide a simple stream-like interface for building and parsing - * packets. - */ - -typedef struct buf { - octet *base, *p, *limit; /* Pointers to the buffer */ - unsigned f; /* Various flags */ -} buf; - -#define BF_BROKEN 1u /* Buffer is broken */ +/*----- Data structures ---------------------------------------------------*/ /* --- Socket addresses --- * * @@ -988,191 +986,6 @@ extern void tun_inject(tunnel */*t*/, buf */*b*/); extern void tun_destroy(tunnel */*t*/); -/*----- Buffer handling ---------------------------------------------------*/ - -/* --- Useful macros --- */ - -#define BBASE(b) ((b)->base) -#define BLIM(b) ((b)->limit) -#define BCUR(b) ((b)->p) -#define BSZ(b) ((b)->limit - (b)->base) -#define BLEN(b) ((b)->p - (b)->base) -#define BLEFT(b) ((b)->limit - (b)->p) -#define BSTEP(b, sz) ((b)->p += (sz)) -#define BBAD(b) ((b)->f & BF_BROKEN) -#define BOK(b) (!BBAD(b)) - -#define BENSURE(b, sz) \ - (BBAD(b) ? -1 : (sz) > BLEFT(b) ? (b)->f |= BF_BROKEN, -1 : 0) - -/* --- @buf_init@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @void *p@ = pointer to a buffer - * @size_t sz@ = size of the buffer - * - * Returns: --- - * - * Use: Initializes the buffer block appropriately. - */ - -extern void buf_init(buf */*b*/, void */*p*/, size_t /*sz*/); - -/* --- @buf_break@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * - * Returns: Some negative value. - * - * Use: Marks a buffer as broken. - */ - -extern int buf_break(buf */*b*/); - -/* --- @buf_flip@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * - * Returns: --- - * - * Use: Flips a buffer so that if you've just been writing to it, - * you can now read from the bit you've written. - */ - -extern void buf_flip(buf */*b*/); - -/* --- @buf_ensure@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @size_t sz@ = size of data wanted - * - * Returns: Zero if it worked, nonzero if there wasn't enough space. - * - * Use: Ensures that there are @sz@ bytes still in the buffer. - */ - -extern int buf_ensure(buf */*b*/, size_t /*sz*/); - -/* --- @buf_get@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @size_t sz@ = size of the buffer - * - * Returns: Pointer to the place in the buffer. - * - * Use: Reserves a space in the buffer of the requested size, and - * returns its start address. - */ - -extern void *buf_get(buf */*b*/, size_t /*sz*/); - -/* --- @buf_put@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @const void *p@ = pointer to a buffer - * @size_t sz@ = size of the buffer - * - * Returns: Zero if it worked, nonzero if there wasn't enough space. - * - * Use: Fetches data from some place and puts it in the buffer - */ - -extern int buf_put(buf */*b*/, const void */*p*/, size_t /*sz*/); - -/* --- @buf_getbyte@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * - * Returns: A byte, or less than zero if there wasn't a byte there. - * - * Use: Gets a single byte from a buffer. - */ - -extern int buf_getbyte(buf */*b*/); - -/* --- @buf_putbyte@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @int ch@ = byte to write - * - * Returns: Zero if OK, nonzero if there wasn't enough space. - * - * Use: Puts a single byte in a buffer. - */ - -extern int buf_putbyte(buf */*b*/, int /*ch*/); - -/* --- @buf_getu16@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @uint16 *w@ = where to put the word - * - * Returns: Zero if OK, or nonzero if there wasn't a word there. - * - * Use: Gets a 16-bit word from a buffer. - */ - -extern int buf_getu16(buf */*b*/, uint16 */*w*/); - -/* --- @buf_putu16@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @uint16 w@ = word to write - * - * Returns: Zero if OK, nonzero if there wasn't enough space. - * - * Use: Puts a 16-but word in a buffer. - */ - -extern int buf_putu16(buf */*b*/, uint16 /*w*/); - -/* --- @buf_getu32@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @uint32 *w@ = where to put the word - * - * Returns: Zero if OK, or nonzero if there wasn't a word there. - * - * Use: Gets a 32-bit word from a buffer. - */ - -extern int buf_getu32(buf */*b*/, uint32 */*w*/); - -/* --- @buf_putu32@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @uint32 w@ = word to write - * - * Returns: Zero if OK, nonzero if there wasn't enough space. - * - * Use: Puts a 32-but word in a buffer. - */ - -extern int buf_putu32(buf */*b*/, uint32 /*w*/); - -/* --- @buf_getmp@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * - * Returns: A multiprecision integer, or null if there wasn't one there. - * - * Use: Gets a multiprecision integer from a buffer. - */ - -extern mp *buf_getmp(buf */*b*/); - -/* --- @buf_putmp@ --- * - * - * Arguments: @buf *b@ = pointer to a buffer block - * @mp *m@ = a multiprecision integer - * - * Returns: Zero if it worked, nonzero if there wasn't enough space. - * - * Use: Puts a multiprecision integer to a buffer. - */ - -extern int buf_putmp(buf */*b*/, mp */*m*/); - /*----- Other handy utilities ---------------------------------------------*/ /* --- @mpstr@ --- *