1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/webrtc/signaling/src/sipcc/plat/unix-common/random.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,76 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#include <sys/types.h>
1.9 +#include <unistd.h>
1.10 +#include <fcntl.h>
1.11 +#include <syslog.h>
1.12 +#include <inttypes.h>
1.13 +
1.14 +/**
1.15 + * platGenerateCryptoRand
1.16 + * @brief Generates a Random Number
1.17 + *
1.18 + * Generate crypto graphically random number for a desired length.
1.19 + * The function uses "secd" 's provided API. The random bytes are
1.20 + * generated by "secd" which runs as another process. The function
1.21 + * will be much slower than the cpr_rand(). This function should be
1.22 + * used when good random number is needed such as random number that
1.23 + * to be used for SRTP key for an example.
1.24 + *
1.25 + * @param[in] buf - pointer to the buffer to store the result of random
1.26 + * bytes requested.
1.27 + * @param[in] len - pointer to the length of the desired random bytes.
1.28 + * When calling the function, the integer's value
1.29 + * should be set to the desired number of random
1.30 + * bytes ('buf' should be of at least this size).
1.31 + * upon success, its value will be set to the
1.32 + * actual number of random bytes being returned.
1.33 + * (realistically, there is a maximum number of
1.34 + * random bytes that can be returned at a time.
1.35 + * if the caller request more than that, the
1.36 + * 'len' will indicate how many bytes are actually being
1.37 + * returned) on failure, its value will be set to 0.
1.38 + *
1.39 + * @return
1.40 + * 1 - success.
1.41 + * 0 - fail.
1.42 + *
1.43 + * @note This function MUST BE REWRITTEN BY THE VENDORS
1.44 + * @note The intent of this function is to generate a cryptographically strong
1.45 + * random number. Vendors can map this to HandyIron or OpenSSL random number
1.46 + * generation functions.
1.47 + */
1.48 +int
1.49 +platGenerateCryptoRand(uint8_t *buf, int *len)
1.50 +{
1.51 + int fd;
1.52 + int rc = 0;
1.53 + ssize_t s;
1.54 +
1.55 + if ((fd = open("/dev/urandom", O_RDONLY)) == -1) {
1.56 + syslog(LOG_ERR, "Failed to open prng driver");
1.57 + return 0;
1.58 + }
1.59 +
1.60 + /*
1.61 + * Try to read the given amount of bytes from the PRNG device. We do not
1.62 + * handle short reads but just return the number of bytes read from the
1.63 + * device. The caller has to manage this.
1.64 + * E.g. gsmsdp_generate_key() in core/gsm/gsm_sdp_crypto.c
1.65 + */
1.66 + s = read(fd, buf, (size_t) *len);
1.67 +
1.68 + if (s > 0) {
1.69 + *len = s;
1.70 + rc = 1; /* Success */
1.71 + } else {
1.72 + *len = 0;
1.73 + rc = 0; /* Failure */
1.74 + }
1.75 +
1.76 + (void) close(fd);
1.77 + return rc;
1.78 +}
1.79 +
