From 9ef65e0f4c697eade80ca5986ca1964ce42d0347 Mon Sep 17 00:00:00 2001
From: MadMaurice <madmaurice@zom.bi>
Date: Fri, 15 Jan 2021 20:22:22 +0100
Subject: [PATCH] Drop group rights first
We might not be able to drop group rights after dropping user rights
so do group rights first.
---
main.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/main.c b/main.c
index 7a241a0..23a60c4 100644
--- a/main.c
+++ b/main.c
@@ -14,15 +14,9 @@ pid_t pid_child;
void drop_root(void)
{
- uid_t uid = getuid();
- // Drop root privileges
- if (setresuid(-1,uid,uid) == -1)
- {
- int err = errno;
- printf("Failed to drop root privileges with setresuid (%d)\n", err);
- exit(err);
- }
-
+ /// Drop root privileges
+ // First group then user because we might not
+ // be able to drop group once we dropped user
gid_t gid = getgid();
if (setresgid(-1,gid,gid) == -1)
{
@@ -31,6 +25,14 @@ void drop_root(void)
exit(err);
}
+ uid_t uid = getuid();
+ if (setresuid(-1,uid,uid) == -1)
+ {
+ int err = errno;
+ printf("Failed to drop root privileges with setresuid (%d)\n", err);
+ exit(err);
+ }
+
// sanity check
if (seteuid(0) != -1)
{