From 4ba830fc31c056aaada774ce29bb7d4e136b5dcd Mon Sep 17 00:00:00 2001 From: Matt Johnston Date: Sat, 8 Nov 2014 22:15:16 +0800 Subject: Make sure hostkeys are flushed to disk to avoid empty files if the power fails. Based on patch from Peter Korsgaard --- svr-kex.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'svr-kex.c') diff --git a/svr-kex.c b/svr-kex.c index 337c377..01c76e6 100644 --- a/svr-kex.c +++ b/svr-kex.c @@ -84,7 +84,25 @@ void recv_msg_kexdh_init() { TRACE(("leave recv_msg_kexdh_init")) } + #ifdef DROPBEAR_DELAY_HOSTKEY + +static void fsync_parent_dir(const char* fn) { +#ifdef HAVE_LIBGEN_H + char *fn_dir = m_strdup(fn); + char *dir = dirname(fn_dir); + /* some OSes need the fd to be writable for fsync */ + int dirfd = open(dir, O_RDWR); + + if (dirfd != -1) { + fsync(dirfd); + m_close(dirfd); + } + + free(fn_dir); +#endif +} + static void svr_ensure_hostkey() { const char* fn = NULL; @@ -142,6 +160,10 @@ static void svr_ensure_hostkey() { } } + /* ensure directory update is flushed to disk, otherwise we can end up + with zero-byte hostkey files if the power goes off */ + fsync_parent_dir(fn); + ret = readhostkey(fn, svr_opts.hostkey, &type); if (ret == DROPBEAR_SUCCESS) { -- cgit v1.2.3