forked from pool/systemd
122 lines
5.2 KiB
Diff
122 lines
5.2 KiB
Diff
Simply writing /var/lib/systemd/random-seed back to /dev/(u)random does not
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increase the entropy bit count. Therefore use the RNDADDENTROPY ioctl to
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write back the bytes and increase the entropy bit counter.
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Related to bnc#892096
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---
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systemd-210/src/random-seed/random-seed.c | 66 +++++++++++++++++++++++++++---
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1 file changed, 61 insertions(+), 5 deletions(-)
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--- systemd-210/src/random-seed/random-seed.c
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+++ systemd-210/src/random-seed/random-seed.c 2014-08-27 11:58:59.022526580 +0000
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@@ -22,7 +22,9 @@
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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+#include <linux/random.h>
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#include <string.h>
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+#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include "log.h"
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@@ -32,8 +34,9 @@
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#define POOL_SIZE_MIN 512
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int main(int argc, char *argv[]) {
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- _cleanup_close_ int seed_fd = -1, random_fd = -1;
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+ _cleanup_close_ int seed_fd = -1, random_fd = -1, entropy_fd = -1;
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_cleanup_free_ void* buf = NULL;
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+ size_t entropy_count = 0;
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size_t buf_size = 0;
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ssize_t k;
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int r;
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@@ -82,6 +85,23 @@ int main(int argc, char *argv[]) {
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if (streq(argv[1], "load")) {
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+ entropy_fd = open(RANDOM_SEED_DIR "entropy_count", O_RDONLY|O_CLOEXEC|O_NOCTTY, 0600);
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+ if (entropy_fd < 0) {
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+ entropy_count = 0;
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+ if (errno != ENOENT) {
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+ log_error("Failed to open " RANDOM_SEED "/entropy_count: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ } else {
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+ r = read(entropy_fd, &entropy_count, sizeof(entropy_count));
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+ if (r < 0) {
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+ log_error("Failed to read entropy count file: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ }
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+
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seed_fd = open(RANDOM_SEED, O_RDWR|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
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if (seed_fd < 0) {
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seed_fd = open(RANDOM_SEED, O_RDONLY|O_CLOEXEC|O_NOCTTY);
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@@ -113,16 +133,37 @@ int main(int argc, char *argv[]) {
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} else {
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lseek(seed_fd, 0, SEEK_SET);
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- k = loop_write(random_fd, buf, (size_t) k, false);
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- if (k <= 0) {
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- log_error("Failed to write seed to /dev/urandom: %s", r < 0 ? strerror(-r) : "short write");
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+ if (entropy_count && (size_t) k == buf_size) {
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+ struct rand_pool_info entropy = {
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+ .entropy_count = entropy_count,
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+ .buf_size = buf_size,
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+ };
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+ entropy.buf[0] = ((__u32*)buf)[0];
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+ r = ioctl(random_fd, RNDADDENTROPY, &entropy);
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+ if (r < 0) {
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+ log_error("Failed to write seed to /dev/urandom: %m");
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+ r = -errno;
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+ }
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+ } else {
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+ k = loop_write(random_fd, buf, (size_t) k, false);
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+ if (k <= 0) {
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+ log_error("Failed to write seed to /dev/urandom: %s", r < 0 ? strerror(-r) : "short write");
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- r = k == 0 ? -EIO : (int) k;
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+ r = k == 0 ? -EIO : (int) k;
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+ }
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}
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}
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} else if (streq(argv[1], "save")) {
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+ /* Read available entropy count, if possible */
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+ f = fopen("/proc/sys/kernel/random/entropy_avail", "re");
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+ if (f) {
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+ if (fscanf(f, "%zu", &entropy_count) < 0)
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+ entropy_count = 0;
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+ fclose(f);
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+ }
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+
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seed_fd = open(RANDOM_SEED, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
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if (seed_fd < 0) {
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log_error("Failed to open " RANDOM_SEED ": %m");
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@@ -137,6 +178,21 @@ int main(int argc, char *argv[]) {
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goto finish;
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}
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+ if (entropy_count) {
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+ entropy_fd = open(RANDOM_SEED_DIR "entropy_count", O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
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+ if (seed_fd < 0) {
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+ log_error("Failed to open " RANDOM_SEED_DIR "entropy_count: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ r = write(entropy_fd, &entropy_count, sizeof(entropy_count));
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+ if (r < 0) {
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+ log_error("Failed to write entropy count file: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ }
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+
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} else {
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log_error("Unknown verb %s.", argv[1]);
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r = -EINVAL;
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