From 9ac650401ffc2fb05c9328d26e76a5e7ae39152a Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Mon, 11 Dec 2023 23:31:22 +0800
Subject: Fix test for multiuser kernels
getuid() succeeds even on non-multiuser kernels. Instead
getgroups() is a valid test.
Fixes #214 on github
---
common-session.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/common-session.c
+++ b/common-session.c
@@ -71,10 +71,13 @@ void common_session_init(int sock_in, in
#if !DROPBEAR_SVR_MULTIUSER
/* A sanity check to prevent an accidental configuration option
leaving multiuser systems exposed */
- errno = 0;
- getuid();
- if (errno != ENOSYS) {
- dropbear_exit("Non-multiuser Dropbear requires a non-multiuser kernel");
+ {
+ int ret;
+ errno = 0;
+ ret = getgroups(0, NULL);
+ if (!(ret == -1 && errno == ENOSYS)) {
+ dropbear_exit("Non-multiuser Dropbear requires a non-multiuser kernel");
+ }
}
#endif