From 352e209804c70b991feededc0a45762929840ace Mon Sep 17 00:00:00 2001 From: Colin Guthrie Date: Mon, 12 Jan 2015 20:40:14 +0000 Subject: [PATCH] random-seed: avoid errors when we cannot write random-seed file When we call 'systemd-random-seed load' with a read-only /var/lib/systemd, the cleanup code (which rewrites the random-seed file) will fail and exit. Arguably, if the filesystem is read-only and the random-seed file exists then this will be possibly be quite bad for entroy on subsequent reboots but it should still not make the unit fail. --- src/random-seed/random-seed.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/src/random-seed/random-seed.c b/src/random-seed/random-seed.c index 06c123960..ce1bd195d 100644 --- a/src/random-seed/random-seed.c +++ b/src/random-seed/random-seed.c @@ -38,6 +38,7 @@ int main(int argc, char *argv[]) { ssize_t k; int r; FILE *f; + bool cleanup_seed_file = true; if (argc != 2) { log_error("This program requires one argument."); @@ -90,6 +91,7 @@ int main(int argc, char *argv[]) { r = -errno; goto finish; } + cleanup_seed_file = false; } random_fd = open("/dev/urandom", O_RDWR|O_CLOEXEC|O_NOCTTY, 0600); @@ -140,20 +142,22 @@ int main(int argc, char *argv[]) { goto finish; } - /* 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. */ - fchmod(seed_fd, 0600); - fchown(seed_fd, 0, 0); + if (cleanup_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. */ + fchmod(seed_fd, 0600); + fchown(seed_fd, 0, 0); - k = loop_read(random_fd, buf, 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); - if (r < 0) - log_error_errno(r, "Failed to write new random seed file: %m"); + k = loop_read(random_fd, buf, 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); + if (r < 0) + log_error_errno(r, "Failed to write new random seed file: %m"); + } } finish: -- 2.30.2