diff options
| -rw-r--r-- | src/core/manager.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/src/core/manager.c b/src/core/manager.c index 5253cb3712..c1dce62a18 100644 --- a/src/core/manager.c +++ b/src/core/manager.c @@ -1720,16 +1720,15 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t return 0; } - n = recvmsg(m->notify_fd, &msghdr, MSG_DONTWAIT|MSG_CMSG_CLOEXEC); + n = recvmsg(m->notify_fd, &msghdr, MSG_DONTWAIT|MSG_CMSG_CLOEXEC|MSG_TRUNC); if (n < 0) { - if (!IN_SET(errno, EAGAIN, EINTR)) - log_error("Failed to receive notification message: %m"); + if (IN_SET(errno, EAGAIN, EINTR)) + return 0; /* Spurious wakeup, try again */ - /* It's not an option to return an error here since it - * would disable the notification handler entirely. Services - * wouldn't be able to send the WATCHDOG message for - * example... */ - return 0; + /* If this is any other, real error, then let's stop processing this socket. This of course means we + * won't take notification messages anymore, but that's still better than busy looping around this: + * being woken up over and over again but being unable to actually read the message off the socket. */ + return log_error_errno(errno, "Failed to receive notification message: %m"); } CMSG_FOREACH(cmsg, &msghdr) { @@ -1762,13 +1761,19 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t return 0; } - if ((size_t) n >= sizeof(buf)) { + if ((size_t) n >= sizeof(buf) || (msghdr.msg_flags & MSG_TRUNC)) { log_warning("Received notify message exceeded maximum size. Ignoring."); return 0; } - /* The message should be a string. Here we make sure it's NUL-terminated, - * but only the part until first NUL will be used anyway. */ + /* As extra safety check, let's make sure the string we get doesn't contain embedded NUL bytes. We permit one + * trailing NUL byte in the message, but don't expect it. */ + if (n > 1 && memchr(buf, 0, n-1)) { + log_warning("Received notify message with embedded NUL bytes. Ignoring."); + return 0; + } + + /* Make sure it's NUL-terminated. */ buf[n] = 0; /* Notify every unit that might be interested, but try @@ -1941,14 +1946,17 @@ static int manager_dispatch_signal_fd(sd_event_source *source, int fd, uint32_t for (;;) { n = read(m->signal_fd, &sfsi, sizeof(sfsi)); if (n != sizeof(sfsi)) { + if (n >= 0) { + log_warning("Truncated read from signal fd (%zu bytes)!", n); + return 0; + } - if (n >= 0) - return -EIO; - - if (errno == EINTR || errno == EAGAIN) + if (IN_SET(errno, EINTR, EAGAIN)) break; - return -errno; + /* We return an error here, which will kill this handler, + * to avoid a busy loop on read error. */ + return log_error_errno(errno, "Reading from signal fd failed: %m"); } log_received_signal(sfsi.ssi_signo == SIGCHLD || |