Attachment 630992 Details for Bug 926169

[patch] use-rndaddentropy-ioctl-to-load-random-seed.patch

use-rndaddentropy-ioctl-to-load-random-seed.patch (text/plain), 6.63 KB, created by Dr. Werner Fink on 2015-04-14 12:02:48 UTC

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Creator: Dr. Werner Fink

Created: 2015-04-14 12:02:48 UTC

Size: 6.63 KB

patch

obsolete

>Simply writing /var/lib/systemd/random-seed back to /dev/(u)random does not
>increase the entropy bit count.  Therefore use the RNDADDENTROPY ioctl to
>write back the bytes and increase the entropy bit counter.
>
>Related to bnc#892096
>
>---
> systemd-210/src/random-seed/random-seed.c |   73 +++++++++++++++++++++++++-----
> 1 file changed, 62 insertions(+), 11 deletions(-)
>
>--- systemd-210/src/random-seed/random-seed.c
>+++ systemd-210/src/random-seed/random-seed.c	2015-04-14 11:38:08.617519434 +0000
>@@ -22,7 +22,9 @@
> #include <unistd.h>
> #include <fcntl.h>
> #include <errno.h>
>+#include <linux/random.h>
> #include <string.h>
>+#include <sys/ioctl.h>
> #include <sys/stat.h>
> 
> #include "log.h"
>@@ -32,8 +34,8 @@
> #define POOL_SIZE_MIN 512
> 
> int main(int argc, char *argv[]) {
>-        _cleanup_close_ int seed_fd = -1, random_fd = -1;
>-        _cleanup_free_ void* buf = NULL;
>+        _cleanup_close_ int seed_fd = -1, random_fd = -1, entropy_fd = -1;
>+        _cleanup_free_ struct rand_pool_info *entropy = NULL;
>         size_t buf_size = 0;
>         ssize_t k;
>         int r;
>@@ -64,11 +66,12 @@ int main(int argc, char *argv[]) {
>         if (buf_size <= POOL_SIZE_MIN)
>                 buf_size = POOL_SIZE_MIN;
> 
>-        buf = malloc(buf_size);
>-        if (!buf) {
>+        entropy = (struct rand_pool_info*) malloc(sizeof(struct rand_pool_info) + buf_size);
>+        if (!entropy) {
>                 r = log_oom();
>                 goto finish;
>         }
>+        entropy->buf_size = buf_size;
> 
>         r = mkdir_parents_label(RANDOM_SEED, 0755);
>         if (r < 0) {
>@@ -82,6 +85,23 @@ int main(int argc, char *argv[]) {
> 
>         if (streq(argv[1], "load")) {
> 
>+                entropy_fd = open(RANDOM_SEED_DIR "entropy_count", O_RDONLY|O_CLOEXEC|O_NOCTTY, 0600);
>+                if (entropy_fd < 0) {
>+                         entropy->entropy_count = 0;                    
>+                         if (errno != ENOENT) {
>+                                log_error("Failed to open " RANDOM_SEED "/entropy_count: %m");
>+                                r = -errno;
>+                                goto finish;
>+                         }
>+                } else {
>+                        r = read(entropy_fd, &entropy->entropy_count, sizeof(entropy->entropy_count));
>+                        if (r < 0) {
>+                                log_error("Failed to read entropy count file: %m");
>+                                r = -errno;
>+                                goto finish;
>+                        }
>+                }
>+
>                 seed_fd = open(RANDOM_SEED, O_RDWR|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
>                 if (seed_fd < 0) {
>                         seed_fd = open(RANDOM_SEED, O_RDONLY|O_CLOEXEC|O_NOCTTY);
>@@ -102,7 +122,7 @@ int main(int argc, char *argv[]) {
>                         }
>                 }
> 
>-                k = loop_read(seed_fd, buf, buf_size, false);
>+                k = loop_read(seed_fd, entropy->buf, entropy->buf_size, false);
>                 if (k <= 0) {
> 
>                         if (r != 0)
>@@ -113,16 +133,32 @@ int main(int argc, char *argv[]) {
>                 } else {
>                         lseek(seed_fd, 0, SEEK_SET);
> 
>-                        k = loop_write(random_fd, buf, (size_t) k, false);
>-                        if (k <= 0) {
>-                                log_error("Failed to write seed to /dev/urandom: %s", r < 0 ? strerror(-r) : "short write");
>+                        if (entropy->entropy_count && (size_t) k == entropy->buf_size) {
>+                                r = ioctl(random_fd, RNDADDENTROPY, entropy);
>+                                if (r < 0) {
>+                                        log_error("Failed to write seed to /dev/urandom: %m");
>+                                        r = -errno;
>+                                }
>+                        } else {
>+                                k = loop_write(random_fd, entropy->buf, (size_t) k, false);
>+                                if (k <= 0) {
>+                                        log_error("Failed to write seed to /dev/urandom: %s", r < 0 ? strerror(-r) : "short write");
> 
>-                                r = k == 0 ? -EIO : (int) k;
>+                                        r = k == 0 ? -EIO : (int) k;
>+                                }
>                         }
>                 }
> 
>         } else if (streq(argv[1], "save")) {
> 
>+                /* Read available entropy count, if possible */
>+                f = fopen("/proc/sys/kernel/random/entropy_avail", "re");
>+                if (f) {
>+                        if (fscanf(f, "%zu", &entropy->entropy_count) < 0)
>+                                entropy->entropy_count = 0;
>+                        fclose(f);
>+                }
>+
>                 seed_fd = open(RANDOM_SEED, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
>                 if (seed_fd < 0) {
>                         log_error("Failed to open " RANDOM_SEED ": %m");
>@@ -137,6 +173,21 @@ int main(int argc, char *argv[]) {
>                         goto finish;
>                 }
> 
>+                if (entropy->entropy_count) {
>+                        entropy_fd = open(RANDOM_SEED_DIR "entropy_count", O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
>+                        if (seed_fd < 0) {
>+                                log_error("Failed to open " RANDOM_SEED_DIR "entropy_count: %m");
>+                                r = -errno;
>+                                goto finish;
>+                        }
>+                        r = write(entropy_fd, &entropy->entropy_count, sizeof(entropy->entropy_count));
>+                        if (r < 0) {
>+                                log_error("Failed to write entropy count file: %m");
>+                                r = -errno;
>+                                goto finish;
>+                        }
>+                }
>+
>         } else {
>                 log_error("Unknown verb %s.", argv[1]);
>                 r = -EINVAL;
>@@ -149,12 +200,12 @@ int main(int argc, char *argv[]) {
>         fchmod(seed_fd, 0600);
>         fchown(seed_fd, 0, 0);
> 
>-        k = loop_read(random_fd, buf, buf_size, false);
>+        k = loop_read(random_fd, entropy->buf, entropy->buf_size, false);
>         if (k <= 0) {
>                 log_error("Failed to read new seed from /dev/urandom: %s", r < 0 ? strerror(-r) : "EOF");
>                 r = k == 0 ? -EIO : (int) k;
>         } else {
>-                r = loop_write(seed_fd, buf, (size_t) k, false);
>+                r = loop_write(seed_fd, entropy->buf, (size_t) k, false);
>                 if (r <= 0) {
>                         log_error("Failed to write new random seed file: %s", r < 0 ? strerror(-r) : "short write");
>                         r = r == 0 ? -EIO : r;

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Attachments on bug 926169: 630158 | 630231 | 630992