diff options
| -rw-r--r-- | package/system/urandom-seed/Makefile | 5 | ||||
| -rwxr-xr-x | package/system/urandom-seed/files/etc/init.d/urandom_seed | 2 | ||||
| -rw-r--r-- | package/system/urandom-seed/files/lib/preinit/81_urandom_seed | 16 | ||||
| -rwxr-xr-x | package/system/urandom-seed/files/sbin/urandom_seed | 20 | ||||
| -rw-r--r-- | package/system/urandom-seed/seedrng.c | 434 |
5 files changed, 35 insertions, 442 deletions
diff --git a/package/system/urandom-seed/Makefile b/package/system/urandom-seed/Makefile index 0c8d77f445..7c5524a9db 100644 --- a/package/system/urandom-seed/Makefile +++ b/package/system/urandom-seed/Makefile @@ -9,6 +9,7 @@ include $(INCLUDE_DIR)/package.mk define Package/urandom-seed SECTION:=base CATEGORY:=Base system + DEPENDS:=+getrandom TITLE:=/etc/urandom.seed handling for OpenWrt URL:=https://openwrt.org/ endef @@ -18,15 +19,11 @@ define Build/Prepare endef define Build/Compile/Default - $(TARGET_CC) $(TARGET_CFLAGS) $(TARGET_CPPFLAGS) $(TARGET_LDFLAGS) \ - -std=gnu99 -o $(PKG_BUILD_DIR)/seedrng seedrng.c endef Build/Compile = $(Build/Compile/Default) define Package/urandom-seed/install $(CP) ./files/* $(1)/ - $(INSTALL_DIR) $(1)/sbin - $(CP) $(PKG_BUILD_DIR)/seedrng $(1)/sbin/ endef $(eval $(call BuildPackage,urandom-seed)) diff --git a/package/system/urandom-seed/files/etc/init.d/urandom_seed b/package/system/urandom-seed/files/etc/init.d/urandom_seed index d6e81c6079..17d9c13400 100755 --- a/package/system/urandom-seed/files/etc/init.d/urandom_seed +++ b/package/system/urandom-seed/files/etc/init.d/urandom_seed @@ -5,7 +5,7 @@ USE_PROCD=1 start_service() { procd_open_instance "urandom_seed" - procd_set_param command "/sbin/seedrng" + procd_set_param command "/sbin/urandom_seed" procd_set_param stdout 1 procd_set_param stderr 1 procd_close_instance diff --git a/package/system/urandom-seed/files/lib/preinit/81_urandom_seed b/package/system/urandom-seed/files/lib/preinit/81_urandom_seed index b3014daeaf..2adc6c47f0 100644 --- a/package/system/urandom-seed/files/lib/preinit/81_urandom_seed +++ b/package/system/urandom-seed/files/lib/preinit/81_urandom_seed @@ -2,11 +2,21 @@ log_urandom_seed() { echo "urandom-seed: $1" > /dev/kmsg } +_do_urandom_seed() { + [ -f "$1" ] || { log_urandom_seed "Seed file not found ($1)"; return; } + [ -O "$1" -a -G "$1" -a ! -x "$1" ] || { log_urandom_seed "Wrong owner / permissions for $1"; return; } + + log_urandom_seed "Seeding with $1" + cat "$1" > /dev/urandom +} + do_urandom_seed() { [ -c /dev/urandom ] || { log_urandom_seed "Something is wrong with /dev/urandom"; return; } - seedrng 2>&1 | while read -r line; do - log_urandom_seed "$line" - done + + _do_urandom_seed "/etc/urandom.seed" + + SEED="$(uci -q get system.@system[0].urandom_seed)" + [ "${SEED:0:1}" = "/" -a "$SEED" != "/etc/urandom.seed" ] && _do_urandom_seed "$SEED" } boot_hook_add preinit_main do_urandom_seed diff --git a/package/system/urandom-seed/files/sbin/urandom_seed b/package/system/urandom-seed/files/sbin/urandom_seed new file mode 100755 index 0000000000..7043e8af4e --- /dev/null +++ b/package/system/urandom-seed/files/sbin/urandom_seed @@ -0,0 +1,20 @@ +#!/bin/sh +set -e + +trap '[ "$?" -eq 0 ] || echo "An error occured" >&2' EXIT + +save() { + touch "$1.tmp" + chown root:root "$1.tmp" + chmod 600 "$1.tmp" + getrandom 512 > "$1.tmp" + mv "$1.tmp" "$1" + echo "Seed saved ($1)" +} + +SEED="$(uci -q get system.@system[0].urandom_seed || true)" +[ "${SEED:0:1}" = "/" ] && save "$SEED" + +SEED=/etc/urandom.seed +[ ! -f $SEED ] && save "$SEED" +true diff --git a/package/system/urandom-seed/seedrng.c b/package/system/urandom-seed/seedrng.c deleted file mode 100644 index 9a2cb10f55..0000000000 --- a/package/system/urandom-seed/seedrng.c +++ /dev/null @@ -1,434 +0,0 @@ -// SPDX-License-Identifier: (GPL-2.0 OR MIT OR Apache-2.0) -/* - * Copyright (C) 2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. - */ - -#include <linux/random.h> -#include <sys/random.h> -#include <sys/ioctl.h> -#include <sys/file.h> -#include <sys/stat.h> -#include <sys/types.h> -#include <fcntl.h> -#include <poll.h> -#include <unistd.h> -#include <time.h> -#include <errno.h> -#include <endian.h> -#include <stdbool.h> -#include <stdint.h> -#include <string.h> -#include <stdio.h> -#include <stdlib.h> - -#define SEED_DIR "/etc/seedrng" -#define CREDITABLE_SEED SEED_DIR "/seed.credit" -#define NON_CREDITABLE_SEED SEED_DIR "/seed.no-credit" -#define LOCK_FILE "/tmp/run/seedrng.lock" - -enum blake2s_lengths { - BLAKE2S_BLOCK_LEN = 64, - BLAKE2S_HASH_LEN = 32, - BLAKE2S_KEY_LEN = 32 -}; - -enum seedrng_lengths { - MAX_SEED_LEN = 512, - MIN_SEED_LEN = BLAKE2S_HASH_LEN -}; - -struct blake2s_state { - uint32_t h[8]; - uint32_t t[2]; - uint32_t f[2]; - uint8_t buf[BLAKE2S_BLOCK_LEN]; - unsigned int buflen; - unsigned int outlen; -}; - -#define le32_to_cpup(a) le32toh(*(a)) -#define cpu_to_le32(a) htole32(a) -#ifndef ARRAY_SIZE -#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) -#endif -#ifndef DIV_ROUND_UP -#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) -#endif - -static inline void cpu_to_le32_array(uint32_t *buf, unsigned int words) -{ - while (words--) { - *buf = cpu_to_le32(*buf); - ++buf; - } -} - -static inline void le32_to_cpu_array(uint32_t *buf, unsigned int words) -{ - while (words--) { - *buf = le32_to_cpup(buf); - ++buf; - } -} - -static inline uint32_t ror32(uint32_t word, unsigned int shift) -{ - return (word >> (shift & 31)) | (word << ((-shift) & 31)); -} - -static const uint32_t blake2s_iv[8] = { - 0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL, - 0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL -}; - -static const uint8_t blake2s_sigma[10][16] = { - { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }, - { 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 }, - { 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 }, - { 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 }, - { 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 }, - { 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 }, - { 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 }, - { 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 }, - { 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 }, - { 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 }, -}; - -static void blake2s_set_lastblock(struct blake2s_state *state) -{ - state->f[0] = -1; -} - -static void blake2s_increment_counter(struct blake2s_state *state, const uint32_t inc) -{ - state->t[0] += inc; - state->t[1] += (state->t[0] < inc); -} - -static void blake2s_init_param(struct blake2s_state *state, const uint32_t param) -{ - int i; - - memset(state, 0, sizeof(*state)); - for (i = 0; i < 8; ++i) - state->h[i] = blake2s_iv[i]; - state->h[0] ^= param; -} - -static void blake2s_init(struct blake2s_state *state, const size_t outlen) -{ - blake2s_init_param(state, 0x01010000 | outlen); - state->outlen = outlen; -} - -static void blake2s_compress(struct blake2s_state *state, const uint8_t *block, size_t nblocks, const uint32_t inc) -{ - uint32_t m[16]; - uint32_t v[16]; - int i; - - while (nblocks > 0) { - blake2s_increment_counter(state, inc); - memcpy(m, block, BLAKE2S_BLOCK_LEN); - le32_to_cpu_array(m, ARRAY_SIZE(m)); - memcpy(v, state->h, 32); - v[ 8] = blake2s_iv[0]; - v[ 9] = blake2s_iv[1]; - v[10] = blake2s_iv[2]; - v[11] = blake2s_iv[3]; - v[12] = blake2s_iv[4] ^ state->t[0]; - v[13] = blake2s_iv[5] ^ state->t[1]; - v[14] = blake2s_iv[6] ^ state->f[0]; - v[15] = blake2s_iv[7] ^ state->f[1]; - -#define G(r, i, a, b, c, d) do { \ - a += b + m[blake2s_sigma[r][2 * i + 0]]; \ - d = ror32(d ^ a, 16); \ - c += d; \ - b = ror32(b ^ c, 12); \ - a += b + m[blake2s_sigma[r][2 * i + 1]]; \ - d = ror32(d ^ a, 8); \ - c += d; \ - b = ror32(b ^ c, 7); \ -} while (0) - -#define ROUND(r) do { \ - G(r, 0, v[0], v[ 4], v[ 8], v[12]); \ - G(r, 1, v[1], v[ 5], v[ 9], v[13]); \ - G(r, 2, v[2], v[ 6], v[10], v[14]); \ - G(r, 3, v[3], v[ 7], v[11], v[15]); \ - G(r, 4, v[0], v[ 5], v[10], v[15]); \ - G(r, 5, v[1], v[ 6], v[11], v[12]); \ - G(r, 6, v[2], v[ 7], v[ 8], v[13]); \ - G(r, 7, v[3], v[ 4], v[ 9], v[14]); \ -} while (0) - ROUND(0); - ROUND(1); - ROUND(2); - ROUND(3); - ROUND(4); - ROUND(5); - ROUND(6); - ROUND(7); - ROUND(8); - ROUND(9); - -#undef G -#undef ROUND - - for (i = 0; i < 8; ++i) - state->h[i] ^= v[i] ^ v[i + 8]; - - block += BLAKE2S_BLOCK_LEN; - --nblocks; - } -} - -static void blake2s_update(struct blake2s_state *state, const void *inp, size_t inlen) -{ - const size_t fill = BLAKE2S_BLOCK_LEN - state->buflen; - const uint8_t *in = inp; - - if (!inlen) - return; - if (inlen > fill) { - memcpy(state->buf + state->buflen, in, fill); - blake2s_compress(state, state->buf, 1, BLAKE2S_BLOCK_LEN); - state->buflen = 0; - in += fill; - inlen -= fill; - } - if (inlen > BLAKE2S_BLOCK_LEN) { - const size_t nblocks = DIV_ROUND_UP(inlen, BLAKE2S_BLOCK_LEN); - blake2s_compress(state, in, nblocks - 1, BLAKE2S_BLOCK_LEN); - in += BLAKE2S_BLOCK_LEN * (nblocks - 1); - inlen -= BLAKE2S_BLOCK_LEN * (nblocks - 1); - } - memcpy(state->buf + state->buflen, in, inlen); - state->buflen += inlen; -} - -static void blake2s_final(struct blake2s_state *state, uint8_t *out) -{ - blake2s_set_lastblock(state); - memset(state->buf + state->buflen, 0, BLAKE2S_BLOCK_LEN - state->buflen); - blake2s_compress(state, state->buf, 1, state->buflen); - cpu_to_le32_array(state->h, ARRAY_SIZE(state->h)); - memcpy(out, state->h, state->outlen); -} - -static size_t determine_optimal_seed_len(void) -{ - size_t ret = 0; - char poolsize_str[11] = { 0 }; - int fd = open("/proc/sys/kernel/random/poolsize", O_RDONLY); - - if (fd < 0 || read(fd, poolsize_str, sizeof(poolsize_str) - 1) < 0) { - fprintf(stderr, "WARNING: Unable to determine pool size, falling back to %u bits: %s\n", MIN_SEED_LEN * 8, strerror(errno)); - ret = MIN_SEED_LEN; - } else - ret = DIV_ROUND_UP(strtoul(poolsize_str, NULL, 10), 8); - if (fd >= 0) - close(fd); - if (ret < MIN_SEED_LEN) - ret = MIN_SEED_LEN; - else if (ret > MAX_SEED_LEN) - ret = MAX_SEED_LEN; - return ret; -} - -static int read_new_seed(uint8_t *seed, size_t len, bool *is_creditable) -{ - ssize_t ret; - int urandom_fd; - - *is_creditable = false; - ret = getrandom(seed, len, GRND_NONBLOCK); - if (ret == (ssize_t)len) { - *is_creditable = true; - return 0; - } else if (ret < 0 && errno == ENOSYS) { - struct pollfd random_fd = { - .fd = open("/dev/random", O_RDONLY), - .events = POLLIN - }; - if (random_fd.fd < 0) - return -errno; - *is_creditable = poll(&random_fd, 1, 0) == 1; - close(random_fd.fd); - } else if (getrandom(seed, len, GRND_INSECURE) == (ssize_t)len) - return 0; - urandom_fd = open("/dev/urandom", O_RDONLY); - if (urandom_fd < 0) - return -errno; - ret = read(urandom_fd, seed, len); - if (ret == (ssize_t)len) - ret = 0; - else - ret = -errno ? -errno : -EIO; - close(urandom_fd); - return ret; -} - -static int seed_rng(uint8_t *seed, size_t len, bool credit) -{ - struct { - int entropy_count; - int buf_size; - uint8_t buffer[MAX_SEED_LEN]; - } req = { - .entropy_count = credit ? len * 8 : 0, - .buf_size = len - }; - int random_fd, ret; - - if (len > sizeof(req.buffer)) - return -EFBIG; - memcpy(req.buffer, seed, len); - - random_fd = open("/dev/random", O_RDWR); - if (random_fd < 0) - return -errno; - ret = ioctl(random_fd, RNDADDENTROPY, &req); - if (ret) - ret = -errno ? -errno : -EIO; - close(random_fd); - return ret; -} - -static int seed_from_file_if_exists(const char *filename, bool credit, struct blake2s_state *hash) -{ - uint8_t seed[MAX_SEED_LEN]; - ssize_t seed_len; - int fd, dfd, ret = 0; - - fd = open(filename, O_RDONLY); - if (fd < 0 && errno == ENOENT) - return 0; - else if (fd < 0) { - ret = -errno; - fprintf(stderr, "ERROR: Unable to open seed file: %s\n", strerror(errno)); - return ret; - } - dfd = open(SEED_DIR, O_DIRECTORY | O_RDONLY); - if (dfd < 0) { - ret = -errno; - close(fd); - fprintf(stderr, "ERROR: Unable to open seed directory: %s\n", strerror(errno)); - return ret; - } - seed_len = read(fd, seed, sizeof(seed)); - if (seed_len < 0) { - ret = -errno; - fprintf(stderr, "ERROR: Unable to read seed file: %s\n", strerror(errno)); - } - close(fd); - if (ret) { - close(dfd); - return ret; - } - if ((unlink(filename) < 0 || fsync(dfd) < 0) && seed_len) { - ret = -errno; - fprintf(stderr, "ERROR: Unable to remove seed after reading, so not seeding: %s\n", strerror(errno)); - } - close(dfd); - if (ret) - return ret; - if (!seed_len) - return 0; - - blake2s_update(hash, &seed_len, sizeof(seed_len)); - blake2s_update(hash, seed, seed_len); - - fprintf(stdout, "Seeding %zd bits %s crediting\n", seed_len * 8, credit ? "and" : "without"); - ret = seed_rng(seed, seed_len, credit); - if (ret < 0) - fprintf(stderr, "ERROR: Unable to seed: %s\n", strerror(-ret)); - return ret; -} - -static bool skip_credit(void) -{ - const char *skip = getenv("SEEDRNG_SKIP_CREDIT"); - return skip && (!strcmp(skip, "1") || !strcasecmp(skip, "true") || - !strcasecmp(skip, "yes") || !strcasecmp(skip, "y")); -} - -int main(int argc __attribute__((unused)), char *argv[] __attribute__((unused))) -{ - static const char seedrng_prefix[] = "SeedRNG v1 Old+New Prefix"; - static const char seedrng_failure[] = "SeedRNG v1 No New Seed Failure"; - int ret, fd = -1, lock, program_ret = 0; - uint8_t new_seed[MAX_SEED_LEN]; - size_t new_seed_len; - bool new_seed_creditable; - struct timespec realtime = { 0 }, boottime = { 0 }; - struct blake2s_state hash; - - umask(0077); - if (getuid()) { - fprintf(stderr, "ERROR: This program requires root\n"); - return 1; - } - - blake2s_init(&hash, BLAKE2S_HASH_LEN); - blake2s_update(&hash, seedrng_prefix, strlen(seedrng_prefix)); - clock_gettime(CLOCK_REALTIME, &realtime); - clock_gettime(CLOCK_BOOTTIME, &boottime); - blake2s_update(&hash, &realtime, sizeof(realtime)); - blake2s_update(&hash, &boottime, sizeof(boottime)); - - if (mkdir(SEED_DIR, 0700) < 0 && errno != EEXIST) { - fprintf(stderr, "ERROR: Unable to create \"%s\" directory: %s\n", SEED_DIR, strerror(errno)); - return 1; - } - - lock = open(LOCK_FILE, O_WRONLY | O_CREAT, 0000); - if (lock < 0 || flock(lock, LOCK_EX) < 0) { - fprintf(stderr, "ERROR: Unable to open lock file: %s\n", strerror(errno)); - program_ret = 1; - goto out; - } - - ret = seed_from_file_if_exists(NON_CREDITABLE_SEED, false, &hash); - if (ret < 0) - program_ret |= 1 << 1; - ret = seed_from_file_if_exists(CREDITABLE_SEED, !skip_credit(), &hash); - if (ret < 0) - program_ret |= 1 << 2; - - new_seed_len = determine_optimal_seed_len(); - ret = read_new_seed(new_seed, new_seed_len, &new_seed_creditable); - if (ret < 0) { - fprintf(stderr, "ERROR: Unable to read new seed: %s\n", strerror(-ret)); - new_seed_len = BLAKE2S_HASH_LEN; - strncpy((char *)new_seed, seedrng_failure, new_seed_len); - program_ret |= 1 << 3; - } - blake2s_update(&hash, &new_seed_len, sizeof(new_seed_len)); - blake2s_update(&hash, new_seed, new_seed_len); - blake2s_final(&hash, new_seed + new_seed_len - BLAKE2S_HASH_LEN); - - fprintf(stdout, "Saving %zu bits of %s seed for next boot\n", new_seed_len * 8, new_seed_creditable ? "creditable" : "non-creditable"); - fd = open(NON_CREDITABLE_SEED, O_WRONLY | O_CREAT | O_TRUNC, 0400); - if (fd < 0) { - fprintf(stderr, "ERROR: Unable to open seed file for writing: %s\n", strerror(errno)); - program_ret |= 1 << 4; - goto out; - } - if (write(fd, new_seed, new_seed_len) != (ssize_t)new_seed_len || fsync(fd) < 0) { - fprintf(stderr, "ERROR: Unable to write seed file: %s\n", strerror(errno)); - program_ret |= 1 << 5; - goto out; - } - if (new_seed_creditable && rename(NON_CREDITABLE_SEED, CREDITABLE_SEED) < 0) { - fprintf(stderr, "WARNING: Unable to make new seed creditable: %s\n", strerror(errno)); - program_ret |= 1 << 6; - } -out: - if (fd >= 0) - close(fd); - if (lock >= 0) - close(lock); - return program_ret; -} |