4891d713fb
s_read_urandom has a while loop to handle read() that returns less than the full buffer (either due to EINTR or because more than the atomic guarantee from urandom was requested). However, the target of the read was always the base pointer p instead of the updated pointer q, so in the end less than the requested randomness is returned. Use q instead of p in the read() call. Upstream pull request: https://github.com/libtom/libtommath/pull/512 Signed-off-by: Arnout Vandecappelle <arnout@mind.be>
169 lines
4.1 KiB
C
169 lines
4.1 KiB
C
#include "tommath_private.h"
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#ifdef BN_S_MP_RAND_PLATFORM_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/* First the OS-specific special cases
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* - *BSD
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* - Windows
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*/
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#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
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#define BN_S_READ_ARC4RANDOM_C
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static mp_err s_read_arc4random(void *p, size_t n)
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{
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arc4random_buf(p, n);
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return MP_OKAY;
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}
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#endif
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#if defined(_WIN32) || defined(_WIN32_WCE)
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#define BN_S_READ_WINCSP_C
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#ifndef _WIN32_WINNT
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#define _WIN32_WINNT 0x0400
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#endif
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#ifdef _WIN32_WCE
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#define UNDER_CE
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#define ARM
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#endif
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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#include <wincrypt.h>
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static mp_err s_read_wincsp(void *p, size_t n)
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{
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static HCRYPTPROV hProv = 0;
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if (hProv == 0) {
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HCRYPTPROV h = 0;
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if (!CryptAcquireContext(&h, NULL, MS_DEF_PROV, PROV_RSA_FULL,
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(CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET)) &&
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!CryptAcquireContext(&h, NULL, MS_DEF_PROV, PROV_RSA_FULL,
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CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET | CRYPT_NEWKEYSET)) {
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return MP_ERR;
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}
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hProv = h;
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}
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return CryptGenRandom(hProv, (DWORD)n, (BYTE *)p) == TRUE ? MP_OKAY : MP_ERR;
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}
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#endif /* WIN32 */
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#if !defined(BN_S_READ_WINCSP_C) && defined(__linux__) && defined(__GLIBC_PREREQ)
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#if __GLIBC_PREREQ(2, 25)
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#define BN_S_READ_GETRANDOM_C
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#include <sys/random.h>
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#include <errno.h>
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static mp_err s_read_getrandom(void *p, size_t n)
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{
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char *q = (char *)p;
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while (n > 0u) {
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ssize_t ret = getrandom(q, n, 0);
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if (ret < 0) {
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if (errno == EINTR) {
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continue;
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}
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return MP_ERR;
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}
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q += ret;
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n -= (size_t)ret;
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}
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return MP_OKAY;
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}
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#endif
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#endif
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/* We assume all platforms besides windows provide "/dev/urandom".
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* In case yours doesn't, define MP_NO_DEV_URANDOM at compile-time.
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*/
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#if !defined(BN_S_READ_WINCSP_C) && !defined(MP_NO_DEV_URANDOM)
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#define BN_S_READ_URANDOM_C
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#ifndef MP_DEV_URANDOM
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#define MP_DEV_URANDOM "/dev/urandom"
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#endif
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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static mp_err s_read_urandom(void *p, size_t n)
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{
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int fd;
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char *q = (char *)p;
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do {
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fd = open(MP_DEV_URANDOM, O_RDONLY);
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} while ((fd == -1) && (errno == EINTR));
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if (fd == -1) return MP_ERR;
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while (n > 0u) {
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ssize_t ret = read(fd, q, n);
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if (ret < 0) {
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if (errno == EINTR) {
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continue;
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}
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close(fd);
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return MP_ERR;
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}
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q += ret;
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n -= (size_t)ret;
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}
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close(fd);
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return MP_OKAY;
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}
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#endif
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#if defined(MP_PRNG_ENABLE_LTM_RNG)
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#define BN_S_READ_LTM_RNG
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unsigned long (*ltm_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
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void (*ltm_rng_callback)(void);
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static mp_err s_read_ltm_rng(void *p, size_t n)
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{
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unsigned long res;
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if (ltm_rng == NULL) return MP_ERR;
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res = ltm_rng(p, n, ltm_rng_callback);
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if (res != n) return MP_ERR;
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return MP_OKAY;
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}
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#endif
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#ifdef BN_S_READ_ARC4RANDOM_C
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mp_err s_read_arc4random(void *p, size_t n);
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#endif
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#ifdef BN_S_READ_WINCSP_C
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mp_err s_read_wincsp(void *p, size_t n);
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#endif
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#ifdef BN_S_READ_GETRANDOM_C
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mp_err s_read_getrandom(void *p, size_t n);
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#endif
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#ifdef BN_S_READ_URANDOM_C
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mp_err s_read_urandom(void *p, size_t n);
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#endif
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#ifdef BN_S_READ_LTM_RNG
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mp_err s_read_ltm_rng(void *p, size_t n);
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#endif
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mp_err s_mp_rand_platform(void *p, size_t n)
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{
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mp_err err = MP_ERR;
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#ifdef BN_S_READ_ARC4RANDOM_C
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if ((err != MP_OKAY) && MP_HAS(S_READ_ARC4RANDOM)) err = s_read_arc4random(p, n);
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#endif
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#ifdef BN_S_READ_WINCSP_C
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if ((err != MP_OKAY) && MP_HAS(S_READ_WINCSP)) err = s_read_wincsp(p, n);
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#endif
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#ifdef BN_S_READ_GETRANDOM_C
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if ((err != MP_OKAY) && MP_HAS(S_READ_GETRANDOM)) err = s_read_getrandom(p, n);
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#endif
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#ifdef BN_S_READ_URANDOM_C
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if ((err != MP_OKAY) && MP_HAS(S_READ_URANDOM)) err = s_read_urandom(p, n);
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#endif
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#ifdef BN_S_READ_LTM_RNG
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if ((err != MP_OKAY) && MP_HAS(S_READ_LTM_RNG)) err = s_read_ltm_rng(p, n);
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#endif
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return err;
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}
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#endif
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