diff options
Diffstat (limited to 'srtp/crypto/replay')
| -rw-r--r-- | srtp/crypto/replay/CVS/Entries | 4 | ||||
| -rw-r--r-- | srtp/crypto/replay/CVS/Repository | 1 | ||||
| -rw-r--r-- | srtp/crypto/replay/CVS/Root | 1 | ||||
| -rw-r--r-- | srtp/crypto/replay/rdb.c | 137 | ||||
| -rw-r--r-- | srtp/crypto/replay/rdbx.c | 289 | ||||
| -rw-r--r-- | srtp/crypto/replay/ut_sim.c | 105 |
6 files changed, 537 insertions, 0 deletions
diff --git a/srtp/crypto/replay/CVS/Entries b/srtp/crypto/replay/CVS/Entries new file mode 100644 index 0000000..5201253 --- /dev/null +++ b/srtp/crypto/replay/CVS/Entries @@ -0,0 +1,4 @@ +/rdb.c/1.4/Thu Jun 8 17:00:28 2006// +/rdbx.c/1.4/Thu Jun 8 17:00:28 2006// +/ut_sim.c/1.3/Thu Jun 8 17:00:28 2006// +D diff --git a/srtp/crypto/replay/CVS/Repository b/srtp/crypto/replay/CVS/Repository new file mode 100644 index 0000000..f4ad54d --- /dev/null +++ b/srtp/crypto/replay/CVS/Repository @@ -0,0 +1 @@ +srtp/crypto/replay diff --git a/srtp/crypto/replay/CVS/Root b/srtp/crypto/replay/CVS/Root new file mode 100644 index 0000000..05e15d8 --- /dev/null +++ b/srtp/crypto/replay/CVS/Root @@ -0,0 +1 @@ +srtp.cvs.sourceforge.net:/cvsroot/srtp diff --git a/srtp/crypto/replay/rdb.c b/srtp/crypto/replay/rdb.c new file mode 100644 index 0000000..9f2ea87 --- /dev/null +++ b/srtp/crypto/replay/rdb.c @@ -0,0 +1,137 @@ +/* + * rdb.c + * + * Implements a replay database for packet security + * + * David A. McGrew + * Cisco Systems, Inc. + */ + +/* + * + * Copyright (c) 2001-2006, Cisco Systems, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials provided + * with the distribution. + * + * Neither the name of the Cisco Systems, Inc. nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + + +#include "rdb.h" + + +/* + * this implementation of a replay database works as follows: + * + * window_start is the index of the first packet in the window + * bitmask a bit-buffer, containing the most recently entered + * index as the leftmost bit + * + */ + +/* rdb_init initalizes rdb */ + +err_status_t +rdb_init(rdb_t *rdb) { + v128_set_to_zero(&rdb->bitmask); + rdb->window_start = 0; + return err_status_ok; +} + +/* + * rdb_check checks to see if index appears in rdb + */ + +err_status_t +rdb_check(const rdb_t *rdb, uint32_t index) { + + /* if the index appears after (or at very end of) the window, its good */ + if (index >= rdb->window_start + rdb_bits_in_bitmask) + return err_status_ok; + + /* if the index appears before the window, its bad */ + if (index < rdb->window_start) + return err_status_replay_old; + + /* otherwise, the index appears within the window, so check the bitmask */ + if (v128_get_bit(&rdb->bitmask, (index - rdb->window_start)) == 1) + return err_status_replay_fail; + + /* otherwise, the index is okay */ + return err_status_ok; +} + +/* + * rdb_add_index adds index to rdb_t (and does *not* check if + * index appears in db) + * + * this function should be called only after rdb_check has + * indicated that the index does not appear in the rdb, e.g., a mutex + * should protect the rdb between these calls + */ + +err_status_t +rdb_add_index(rdb_t *rdb, uint32_t index) { + int delta; + + /* here we *assume* that index > rdb->window_start */ + + delta = (index - rdb->window_start); + if (delta < rdb_bits_in_bitmask) { + + /* if the index is within the window, set the appropriate bit */ + v128_set_bit(&rdb->bitmask, delta); + + } else { + + delta -= rdb_bits_in_bitmask - 1; + + /* shift the window forward by delta bits*/ + v128_left_shift(&rdb->bitmask, delta); + v128_set_bit(&rdb->bitmask, rdb_bits_in_bitmask-delta); + rdb->window_start += delta; + + } + + return err_status_ok; +} + +err_status_t +rdb_increment(rdb_t *rdb) { + + if (rdb->window_start++ > 0x7fffffff) + return err_status_key_expired; + return err_status_ok; +} + +uint32_t +rdb_get_value(const rdb_t *rdb) { + return rdb->window_start; +} diff --git a/srtp/crypto/replay/rdbx.c b/srtp/crypto/replay/rdbx.c new file mode 100644 index 0000000..12e4e8f --- /dev/null +++ b/srtp/crypto/replay/rdbx.c @@ -0,0 +1,289 @@ +/* + * rdbx.c + * + * a replay database with extended range, using a rollover counter + * + * David A. McGrew + * Cisco Systems, Inc. + */ + +/* + * + * Copyright (c) 2001-2006, Cisco Systems, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials provided + * with the distribution. + * + * Neither the name of the Cisco Systems, Inc. nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +#include "rdbx.h" + +#define rdbx_high_bit_in_bitmask 127 + +/* + * from draft-ietf-avt-srtp-00.txt: + * + * A receiver reconstructs the index i of a packet with sequence + * number s using the estimate + * + * i = 65,536 * t + s, + * + * where t is chosen from the set { r-1, r, r+1 } such that i is + * closest to the value 65,536 * r + s_l. If the value r+1 is used, + * then the rollover counter r in the cryptographic context is + * incremented by one (if the packet containing s is authentic). + */ + + + +/* + * rdbx implementation notes + * + * A xtd_seq_num_t is essentially a sequence number for which some of + * the data on the wire are implicit. It logically consists of a + * rollover counter and a sequence number; the sequence number is the + * explicit part, and the rollover counter is the implicit part. + * + * Upon receiving a sequence_number (e.g. in a newly received SRTP + * packet), the complete xtd_seq_num_t can be estimated by using a + * local xtd_seq_num_t as a basis. This is done using the function + * index_guess(&local, &guess, seq_from_packet). This function + * returns the difference of the guess and the local value. The local + * xtd_seq_num_t can be moved forward to the guess using the function + * index_advance(&guess, delta), where delta is the difference. + * + * + * A rdbx_t consists of a xtd_seq_num_t and a bitmask. The index is highest + * sequence number that has been received, and the bitmask indicates + * which of the recent indicies have been received as well. The + * highest bit in the bitmask corresponds to the index in the bitmask. + */ + + +void +index_init(xtd_seq_num_t *pi) { +#ifdef NO_64BIT_MATH + *pi = make64(0,0); +#else + *pi = 0; +#endif +} + +void +index_advance(xtd_seq_num_t *pi, sequence_number_t s) { +#ifdef NO_64BIT_MATH + /* a > ~b means a+b will generate a carry */ + /* s is uint16 here */ + *pi = make64(high32(*pi) + (s > ~low32(*pi) ? 1 : 0),low32(*pi) + s); +#else + *pi += s; +#endif +} + + +/* + * index_guess(local, guess, s) + * + * given a xtd_seq_num_t local (which represents the last + * known-to-be-good received xtd_seq_num_t) and a sequence number s + * (from a newly arrived packet), sets the contents of *guess to + * contain the best guess of the packet index to which s corresponds, + * and returns the difference between *guess and *local + * + * nota bene - the output is a signed integer, DON'T cast it to a + * unsigned integer! + */ + +int +index_guess(const xtd_seq_num_t *local, + xtd_seq_num_t *guess, + sequence_number_t s) { +#ifdef NO_64BIT_MATH + uint32_t local_roc = ((high32(*local) << 16) | + (low32(*local) >> 16)); + uint16_t local_seq = (uint16_t) (low32(*local)); +#else + uint32_t local_roc = (uint32_t)(*local >> 16); + uint16_t local_seq = (uint16_t) *local; +#endif +#ifdef NO_64BIT_MATH + uint32_t guess_roc = ((high32(*guess) << 16) | + (low32(*guess) >> 16)); + uint16_t guess_seq = (uint16_t) (low32(*guess)); +#else + uint32_t guess_roc = (uint32_t)(*guess >> 16); + uint16_t guess_seq = (uint16_t) *guess; +#endif + int difference; + + if (local_seq < seq_num_median) { + if (s - local_seq > seq_num_median) { + guess_roc = local_roc - 1; + difference = seq_num_max - s + local_seq; + } else { + guess_roc = local_roc; + difference = s - local_seq; + } + } else { + if (local_seq - seq_num_median > s) { + guess_roc = local_roc+1; + difference = seq_num_max - local_seq + s; + } else { + difference = s - local_seq; + guess_roc = local_roc; + } + } + guess_seq = s; + + /* Note: guess_roc is 32 bits, so this generates a 48-bit result! */ +#ifdef NO_64BIT_MATH + *guess = make64(guess_roc >> 16, + (guess_roc << 16) | guess_seq); +#else + *guess = (((uint64_t) guess_roc) << 16) | guess_seq; +#endif + + return difference; +} + +/* + * rdbx + * + */ + + +/* + * rdbx_init(&r) initalizes the rdbx_t pointed to by r + */ + +err_status_t +rdbx_init(rdbx_t *rdbx) { + v128_set_to_zero(&rdbx->bitmask); + index_init(&rdbx->index); + + return err_status_ok; +} + + +/* + * rdbx_check(&r, delta) checks to see if the xtd_seq_num_t + * which is at rdbx->index + delta is in the rdb + */ + +err_status_t +rdbx_check(const rdbx_t *rdbx, int delta) { + + if (delta > 0) { /* if delta is positive, it's good */ + return err_status_ok; + } else if (rdbx_high_bit_in_bitmask + delta < 0) { + /* if delta is lower than the bitmask, it's bad */ + return err_status_replay_old; + } else if (v128_get_bit(&rdbx->bitmask, + rdbx_high_bit_in_bitmask + delta) == 1) { + /* delta is within the window, so check the bitmask */ + return err_status_replay_fail; + } + /* otherwise, the index is okay */ + + return err_status_ok; +} + +/* + * rdbx_add_index adds the xtd_seq_num_t at rdbx->window_start + d to + * replay_db (and does *not* check if that xtd_seq_num_t appears in db) + * + * this function should be called only after replay_check has + * indicated that the index does not appear in the rdbx, e.g., a mutex + * should protect the rdbx between these calls if need be + */ + +err_status_t +rdbx_add_index(rdbx_t *rdbx, int delta) { + + if (delta > 0) { + /* shift forward by delta */ + index_advance(&rdbx->index, delta); + v128_left_shift(&rdbx->bitmask, delta); + v128_set_bit(&rdbx->bitmask, 127); + } else { + /* delta is in window, so flip bit in bitmask */ + v128_set_bit(&rdbx->bitmask, -delta); + } + + /* note that we need not consider the case that delta == 0 */ + + return err_status_ok; +} + + + +/* + * rdbx_estimate_index(rdbx, guess, s) + * + * given an rdbx and a sequence number s (from a newly arrived packet), + * sets the contents of *guess to contain the best guess of the packet + * index to which s corresponds, and returns the difference between + * *guess and the locally stored synch info + */ + +int +rdbx_estimate_index(const rdbx_t *rdbx, + xtd_seq_num_t *guess, + sequence_number_t s) { + + /* + * if the sequence number and rollover counter in the rdbx are + * non-zero, then use the index_guess(...) function, otherwise, just + * set the rollover counter to zero (since the index_guess(...) + * function might incorrectly guess that the rollover counter is + * 0xffffffff) + */ + +#ifdef NO_64BIT_MATH + /* seq_num_median = 0x8000 */ + if (high32(rdbx->index) > 0 || + low32(rdbx->index) > seq_num_median) +#else + if (rdbx->index > seq_num_median) +#endif + return index_guess(&rdbx->index, guess, s); + +#ifdef NO_64BIT_MATH + *guess = make64(0,(uint32_t) s); +#else + *guess = s; +#endif + +#ifdef NO_64BIT_MATH + return s - (uint16_t) low32(rdbx->index); +#else + return s - (uint16_t) rdbx->index; +#endif +} diff --git a/srtp/crypto/replay/ut_sim.c b/srtp/crypto/replay/ut_sim.c new file mode 100644 index 0000000..43c411e --- /dev/null +++ b/srtp/crypto/replay/ut_sim.c @@ -0,0 +1,105 @@ +/* + * ut_sim.c + * + * an unreliable transport simulator + * (for testing replay databases and suchlike) + * + * David A. McGrew + * Cisco Systems, Inc. + */ + +/* + * + * Copyright (c) 2001-2006, Cisco Systems, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials provided + * with the distribution. + * + * Neither the name of the Cisco Systems, Inc. nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + + +#include "ut_sim.h" + + +int +ut_compar(const void *a, const void *b) { + return rand() > (RAND_MAX/2) ? -1 : 1; +} + +void +ut_init(ut_connection *utc) { + int i; + utc->index = 0; + + for (i=0; i < UT_BUF; i++) + utc->buffer[i] = i; + + qsort(utc->buffer, UT_BUF, sizeof(uint32_t), ut_compar); + + utc->index = UT_BUF - 1; +} + +uint32_t +ut_next_index(ut_connection *utc) { + uint32_t tmp; + + tmp = utc->buffer[0]; + utc->index++; + utc->buffer[0] = utc->index; + + qsort(utc->buffer, UT_BUF, sizeof(uint32_t), ut_compar); + + return tmp; +} + + + +#ifdef UT_TEST + +#include <stdio.h> + +int +main() { + uint32_t i, irecvd, idiff; + ut_connection utc; + + ut_init(&utc); + + for (i=0; i < 1000; i++) { + irecvd = ut_next_index(&utc); + idiff = i - irecvd; + printf("%lu\t%lu\t%d\n", i, irecvd, idiff); + } + + return 0; +} + + +#endif |