/src/libsrtp/crypto/replay/rdb.c

Source (jump to first uncovered line)
/*
 * rdb.c
 *
 * Implements a replay database for packet security
 *
 * David A. McGrew
 * Cisco Systems, Inc.
 */

/*
 *
 * Copyright (c) 2001-2017, 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.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "rdb.h"

#define rdb_bits_in_bitmask (8 * sizeof(v128_t))

/*
 * 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
 *
 */

/* srtp_rdb_init initalizes rdb */
srtp_err_status_t srtp_rdb_init(srtp_rdb_t *rdb)
{
    v128_set_to_zero(&rdb->bitmask);
    rdb->window_start = 0;
    return srtp_err_status_ok;
}

/*
 * srtp_rdb_check checks to see if index appears in rdb
 */
srtp_err_status_t srtp_rdb_check(const srtp_rdb_t *rdb, uint32_t p_index)
{
    /* if the index appears after (or at very end of) the window, its good */
    if (p_index >= rdb->window_start + rdb_bits_in_bitmask) {
        return srtp_err_status_ok;
    }

    /* if the index appears before the window, its bad */
    if (p_index < rdb->window_start) {
        return srtp_err_status_replay_old;
    }

    /* otherwise, the index appears within the window, so check the bitmask */
    if (v128_get_bit(&rdb->bitmask, (p_index - rdb->window_start)) == 1) {
        return srtp_err_status_replay_fail;
    }

    /* otherwise, the index is okay */
    return srtp_err_status_ok;
}

/*
 * srtp_rdb_add_index adds index to srtp_rdb_t (and does *not* check if
 * index appears in db)
 *
 * this function should be called only after srtp_rdb_check has
 * indicated that the index does not appear in the rdb, e.g., a mutex
 * should protect the rdb between these calls
 */
srtp_err_status_t srtp_rdb_add_index(srtp_rdb_t *rdb, uint32_t p_index)
{
    uint32_t delta;

    if (p_index < rdb->window_start) {
        return srtp_err_status_replay_fail;
    }

    delta = (p_index - rdb->window_start);
    if (delta < rdb_bits_in_bitmask) {
        /* if the p_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 - 1);
        rdb->window_start += delta;
    }

    return srtp_err_status_ok;
}

srtp_err_status_t srtp_rdb_increment(srtp_rdb_t *rdb)
{
    if (rdb->window_start >= 0x7fffffff) {
        return srtp_err_status_key_expired;
    }
    ++rdb->window_start;
    return srtp_err_status_ok;
}

uint32_t srtp_rdb_get_value(const srtp_rdb_t *rdb)
{
    return rdb->window_start;
}

Line	Count	Source (jump to first uncovered line)
1		/*
2		* rdb.c
3		*
4		* Implements a replay database for packet security
5		*
6		* David A. McGrew
7		* Cisco Systems, Inc.
8		*/
9
10		/*
11		*
12		* Copyright (c) 2001-2017, Cisco Systems, Inc.
13		* All rights reserved.
14		*
15		* Redistribution and use in source and binary forms, with or without
16		* modification, are permitted provided that the following conditions
17		* are met:
18		*
19		* Redistributions of source code must retain the above copyright
20		* notice, this list of conditions and the following disclaimer.
21		*
22		* Redistributions in binary form must reproduce the above
23		* copyright notice, this list of conditions and the following
24		* disclaimer in the documentation and/or other materials provided
25		* with the distribution.
26		*
27		* Neither the name of the Cisco Systems, Inc. nor the names of its
28		* contributors may be used to endorse or promote products derived
29		* from this software without specific prior written permission.
30		*
31		* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32		* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33		* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
34		* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
35		* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
36		* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
37		* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
38		* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39		* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40		* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41		* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
42		* OF THE POSSIBILITY OF SUCH DAMAGE.
43		*
44		*/
45
46		#ifdef HAVE_CONFIG_H
47		#include <config.h>
48		#endif
49
50		#include "rdb.h"
51
52	6.18k	#define rdb_bits_in_bitmask (8 * sizeof(v128_t))
53
54		/*
55		* this implementation of a replay database works as follows:
56		*
57		* window_start is the index of the first packet in the window
58		* bitmask a bit-buffer, containing the most recently entered
59		* index as the leftmost bit
60		*
61		*/
62
63		/* srtp_rdb_init initalizes rdb */
64		srtp_err_status_t srtp_rdb_init(srtp_rdb_t *rdb)
65	379k	{
66	379k	v128_set_to_zero(&rdb->bitmask);
67	379k	rdb->window_start = 0;
68	379k	return srtp_err_status_ok;
69	379k	}
70
71		/*
72		* srtp_rdb_check checks to see if index appears in rdb
73		*/
74		srtp_err_status_t srtp_rdb_check(const srtp_rdb_t *rdb, uint32_t p_index)
75	2.63k	{
76		/* if the index appears after (or at very end of) the window, its good */
77	2.63k	if (p_index >= rdb->window_start + rdb_bits_in_bitmask) {
78	997	return srtp_err_status_ok;
79	997	}
80
81		/* if the index appears before the window, its bad */
82	1.64k	if (p_index < rdb->window_start) {
83	57	return srtp_err_status_replay_old;
84	57	}
85
86		/* otherwise, the index appears within the window, so check the bitmask */
87	1.58k	if (v128_get_bit(&rdb->bitmask, (p_index - rdb->window_start)) == 1) {
88	2	return srtp_err_status_replay_fail;
89	2	}
90
91		/* otherwise, the index is okay */
92	1.58k	return srtp_err_status_ok;
93	1.58k	}
94
95		/*
96		* srtp_rdb_add_index adds index to srtp_rdb_t (and does not check if
97		* index appears in db)
98		*
99		* this function should be called only after srtp_rdb_check has
100		* indicated that the index does not appear in the rdb, e.g., a mutex
101		* should protect the rdb between these calls
102		*/
103		srtp_err_status_t srtp_rdb_add_index(srtp_rdb_t *rdb, uint32_t p_index)
104	2.56k	{
105	2.56k	uint32_t delta;
106
107	2.56k	if (p_index < rdb->window_start) {
108	0	return srtp_err_status_replay_fail;
109	0	}
110
111	2.56k	delta = (p_index - rdb->window_start);
112	2.56k	if (delta < rdb_bits_in_bitmask) {
113		/* if the p_index is within the window, set the appropriate bit */
114	1.58k	v128_set_bit(&rdb->bitmask, delta);
115
116	1.58k	} else {
117	981	delta -= rdb_bits_in_bitmask - 1;
118
119		/* shift the window forward by delta bits*/
120	981	v128_left_shift(&rdb->bitmask, delta);
121	981	v128_set_bit(&rdb->bitmask, rdb_bits_in_bitmask - 1);
122	981	rdb->window_start += delta;
123	981	}
124
125	2.56k	return srtp_err_status_ok;
126	2.56k	}
127
128		srtp_err_status_t srtp_rdb_increment(srtp_rdb_t *rdb)
129	306k	{
130	306k	if (rdb->window_start >= 0x7fffffff) {
131	2	return srtp_err_status_key_expired;
132	2	}
133	306k	++rdb->window_start;
134	306k	return srtp_err_status_ok;
135	306k	}
136
137		uint32_t srtp_rdb_get_value(const srtp_rdb_t *rdb)
138	306k	{
139	306k	return rdb->window_start;
140	306k	}

Coverage Report

Created: 2024-07-27 06:25