From 860721558837441ab45019858e710a2625ffa46e Mon Sep 17 00:00:00 2001 From: Matt Johnston Date: Wed, 7 Dec 2022 13:04:10 +0800 Subject: Allow users's own gid in pty permission check This allows non-root Dropbear to work even without devpts gid=5 mount option on Linux. --- sshpty.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/sshpty.c +++ b/sshpty.c @@ -380,7 +380,9 @@ pty_setowner(struct passwd *pw, const ch tty_name, strerror(errno)); } - if (st.st_uid != pw->pw_uid || st.st_gid != gid) { + /* Allow either "tty" gid or user's own gid. On Linux with openpty() + * this varies depending on the devpts mount options */ + if (st.st_uid != pw->pw_uid || !(st.st_gid == gid || st.st_gid == pw->pw_gid)) { if (chown(tty_name, pw->pw_uid, gid) < 0) { if (errno == EROFS && (st.st_uid == pw->pw_uid || st.st_uid == 0)) {