diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/machine-id-setup.c | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/src/machine-id-setup.c b/src/machine-id-setup.c index 98e288e1b5..be51d0dec7 100644 --- a/src/machine-id-setup.c +++ b/src/machine-id-setup.c @@ -32,16 +32,28 @@ #include "util.h" #include "log.h" +static void make_v4_uuid(unsigned char *id) { + /* Stolen from generate_random_uuid() of drivers/char/random.c + * in the kernel sources */ + + /* Set UUID version to 4 --- truly random generation */ + id[6] = (id[6] & 0x0F) | 0x40; + + /* Set the UUID variant to DCE */ + id[8] = (id[8] & 0x3F) | 0x80; +} + static int generate(char id[34]) { int fd; - char buf[16]; - char *p, *q; + unsigned char buf[16], *p; + char *q; ssize_t k; assert(id); /* First, try reading the D-Bus machine id, unless it is a symlink */ - if ((fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW)) >= 0) { + fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); + if (fd >= 0) { k = loop_read(fd, id, 33, false); close_nointr_nofail(fd); @@ -56,7 +68,8 @@ static int generate(char id[34]) { } /* If that didn't work, generate a random machine id */ - if ((fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) { + fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fd < 0) { log_error("Failed to open /dev/urandom: %m"); return -errno; } @@ -69,6 +82,11 @@ static int generate(char id[34]) { return k < 0 ? (int) k : -EIO; } + /* Turn this into a valid v4 UUID, to be nice. Note that we + * only guarantee this for newly generated UUIDs, not for + * pre-existing ones.*/ + make_v4_uuid(buf); + for (p = buf, q = id; p < buf + sizeof(buf); p++, q += 2) { q[0] = hexchar(*p >> 4); q[1] = hexchar(*p & 15); @@ -96,10 +114,12 @@ int machine_id_setup(void) { * will be owned by root it doesn't matter much, but maybe * people look. */ - if ((fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444)) >= 0) + fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); + if (fd >= 0) writable = true; else { - if ((fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) { + fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fd < 0) { umask(m); log_error("Cannot open /etc/machine-id: %m"); return -errno; @@ -126,7 +146,8 @@ int machine_id_setup(void) { /* Hmm, so, the id currently stored is not useful, then let's * generate one */ - if ((r = generate(id)) < 0) + r = generate(id); + if (r < 0) goto finish; if (S_ISREG(st.st_mode) && writable) { @@ -146,7 +167,8 @@ int machine_id_setup(void) { mkdir_p("/run/systemd", 0755); - if ((r = write_one_line_file("/run/systemd/machine-id", id)) < 0) { + r = write_one_line_file("/run/systemd/machine-id", id); + if (r < 0) { log_error("Cannot write /run/systemd/machine-id: %s", strerror(-r)); unlink("/run/systemd/machine-id"); |