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ff62d93b0e
Libottery itself is hosted here: https://github.com/nmathewson/libottery This import is a rough adoptation of libottery to use it for secure random numbers in rspamd when needed (and in DNS resolver specifically). This import makes the internal chacha20 code useless, hence it is removed now.
64 lines
1.8 KiB
C
64 lines
1.8 KiB
C
/* Libottery by Nick Mathewson.
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This software has been dedicated to the public domain under the CC0
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public domain dedication.
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To the extent possible under law, the person who associated CC0 with
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libottery has waived all copyright and related or neighboring rights
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to libottery.
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You should have received a copy of the CC0 legalcode along with this
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work in doc/cc0.txt. If not, see
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<http://creativecommons.org/publicdomain/zero/1.0/>.
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*/
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#if defined(i386) || \
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defined(__i386) || \
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defined(__x86_64) || \
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defined(__M_IX86) || \
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defined(_M_IX86) || \
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defined(__INTEL_COMPILER)
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/** Helper: invoke the RDRAND instruction to get 4 random bytes in the output
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* value. Return 0 on success, and an error on failure. */
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static int
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rdrand(uint32_t *therand) {
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unsigned char status;
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__asm volatile(".byte 0x0F, 0xC7, 0xF0 ; setc %1"
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: "=a" (*therand), "=qm" (status));
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return (status)==1 ? 0 : OTTERY_ERR_INIT_STRONG_RNG;
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}
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/** Generate bytes using the Intel RDRAND instruction. */
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static int
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ottery_get_entropy_rdrand(const struct ottery_entropy_config *cfg,
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struct ottery_entropy_state *state,
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uint8_t *out, size_t outlen)
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{
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int err;
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uint32_t *up = (uint32_t *) out;
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(void) cfg;
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(void) state;
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if (! (ottery_get_cpu_capabilities_() & OTTERY_CPUCAP_RAND))
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return OTTERY_ERR_INIT_STRONG_RNG;
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while (outlen >= 4) {
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if ((err = rdrand(up)))
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return err;
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up += 1;
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outlen -= 4;
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}
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if (outlen) {
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uint32_t tmp;
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if ((err = rdrand(&tmp)))
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return err;
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memcpy(up, &tmp, outlen);
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}
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return 0;
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}
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#define ENTROPY_SOURCE_RDRAND \
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{ ottery_get_entropy_rdrand, SRC(RDRAND)|DOM(CPU)|FL(FAST)|FL(STRONG) }
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#endif
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