Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 177 insertions, 0 deletions

diff --git a/src/random-seed/random-seed.c b/src/random-seed/random-seed.c
new file mode 100644
index 0000000..0c5f329
--- /dev/null
+++ b/src/random-seed/random-seed.c
@@ -0,0 +1,177 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "sd-id128.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "log.h"
+#include "main-func.h"
+#include "mkdir.h"
+#include "string-util.h"
+#include "util.h"
+
+#define POOL_SIZE_MIN 512
+#define POOL_SIZE_MAX (10*1024*1024)
+
+static int run(int argc, char *argv[]) {
+        _cleanup_close_ int seed_fd = -1, random_fd = -1;
+        bool read_seed_file, write_seed_file;
+        _cleanup_free_ void* buf = NULL;
+        size_t buf_size = 0;
+        struct stat st;
+        ssize_t k;
+        FILE *f;
+        int r;
+
+        log_setup_service();
+
+        if (argc != 2)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "This program requires one argument.");
+
+        umask(0022);
+
+        /* Read pool size, if possible */
+        f = fopen("/proc/sys/kernel/random/poolsize", "re");
+        if (f) {
+                if (fscanf(f, "%zu", &buf_size) > 0)
+                        /* poolsize is in bits on 2.6, but we want bytes */
+                        buf_size /= 8;
+
+                fclose(f);
+        }
+
+        if (buf_size < POOL_SIZE_MIN)
+                buf_size = POOL_SIZE_MIN;
+
+        r = mkdir_parents_label(RANDOM_SEED, 0755);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create directory " RANDOM_SEED_DIR ": %m");
+
+        /* When we load the seed we read it and write it to the device and then immediately update the saved seed with
+         * new data, to make sure the next boot gets seeded differently. */
+
+        if (streq(argv[1], "load")) {
+                int open_rw_error;
+
+                seed_fd = open(RANDOM_SEED, O_RDWR|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
+                open_rw_error = -errno;
+                if (seed_fd < 0) {
+                        write_seed_file = false;
+
+                        seed_fd = open(RANDOM_SEED, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+                        if (seed_fd < 0) {
+                                bool missing = errno == ENOENT;
+
+                                log_full_errno(missing ? LOG_DEBUG : LOG_ERR,
+                                               open_rw_error, "Failed to open " RANDOM_SEED " for writing: %m");
+                                r = log_full_errno(missing ? LOG_DEBUG : LOG_ERR,
+                                                   errno, "Failed to open " RANDOM_SEED " for reading: %m");
+                                return missing ? 0 : r;
+                        }
+                } else
+                        write_seed_file = true;
+
+                random_fd = open("/dev/urandom", O_RDWR|O_CLOEXEC|O_NOCTTY, 0600);
+                if (random_fd < 0) {
+                        write_seed_file = false;
+
+                        random_fd = open("/dev/urandom", O_WRONLY|O_CLOEXEC|O_NOCTTY, 0600);
+                        if (random_fd < 0)
+                                return log_error_errno(errno, "Failed to open /dev/urandom: %m");
+                }
+
+                read_seed_file = true;
+
+        } else if (streq(argv[1], "save")) {
+
+                random_fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+                if (random_fd < 0)
+                        return log_error_errno(errno, "Failed to open /dev/urandom: %m");
+
+                seed_fd = open(RANDOM_SEED, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
+                if (seed_fd < 0)
+                        return log_error_errno(errno, "Failed to open " RANDOM_SEED ": %m");
+
+                read_seed_file = false;
+                write_seed_file = true;
+
+        } else
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Unknown verb '%s'.", argv[1]);
+
+        if (fstat(seed_fd, &st) < 0)
+                return log_error_errno(errno, "Failed to stat() seed file " RANDOM_SEED ": %m");
+
+        /* If the seed file is larger than what we expect, then honour the existing size and save/restore as much as it says */
+        if ((uint64_t) st.st_size > buf_size)
+                buf_size = MIN(st.st_size, POOL_SIZE_MAX);
+
+        buf = malloc(buf_size);
+        if (!buf)
+                return log_oom();
+
+        if (read_seed_file) {
+                sd_id128_t mid;
+                int z;
+
+                k = loop_read(seed_fd, buf, buf_size, false);
+                if (k < 0)
+                        r = log_error_errno(k, "Failed to read seed from " RANDOM_SEED ": %m");
+                else if (k == 0) {
+                        r = 0;
+                        log_debug("Seed file " RANDOM_SEED " not yet initialized, proceeding.");
+                } else {
+                        (void) lseek(seed_fd, 0, SEEK_SET);
+
+                        r = loop_write(random_fd, buf, (size_t) k, false);
+                        if (r < 0)
+                                log_error_errno(r, "Failed to write seed to /dev/urandom: %m");
+                }
+
+                /* Let's also write the machine ID into the random seed. Why? As an extra protection against "golden
+                 * images" that are put together sloppily, i.e. images which are duplicated on multiple systems but
+                 * where the random seed file is not properly reset. Frequently the machine ID is properly reset on
+                 * those systems however (simply because it's easier to notice, if it isn't due to address clashes and
+                 * so on, while random seed equivalence is generally not noticed easily), hence let's simply write the
+                 * machined ID into the random pool too. */
+                z = sd_id128_get_machine(&mid);
+                if (z < 0)
+                        log_debug_errno(z, "Failed to get machine ID, ignoring: %m");
+                else {
+                        z = loop_write(random_fd, &mid, sizeof(mid), false);
+                        if (z < 0)
+                                log_debug_errno(z, "Failed to write machine ID to /dev/urandom, ignoring: %m");
+                }
+        }
+
+        if (write_seed_file) {
+                /* This is just a safety measure. Given that we are root and
+                 * most likely created the file ourselves the mode and owner
+                 * should be correct anyway. */
+                (void) fchmod(seed_fd, 0600);
+                (void) fchown(seed_fd, 0, 0);
+
+                k = loop_read(random_fd, buf, buf_size, false);
+                if (k < 0)
+                        return log_error_errno(k, "Failed to read new seed from /dev/urandom: %m");
+                if (k == 0)
+                        return log_error_errno(SYNTHETIC_ERRNO(EIO),
+                                               "Got EOF while reading from /dev/urandom.");
+
+                r = loop_write(seed_fd, buf, (size_t) k, false);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to write new random seed file: %m");
+        }
+
+        return r;
+}
+
+DEFINE_MAIN_FUNCTION(run);