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From 395915dae1571e10e2766c999974de864655ea3a Mon Sep 17 00:00:00 2001
From: ikerexxe <ipedrosa@redhat.com>
Date: Mon, 15 Jun 2020 09:52:11 +0200
Subject: [PATCH] pam_faillock: change /run/faillock/$USER permissions to 0660
Nowadays, /run/faillock/$USER files have user:root ownership and 0600
permissions. This forces the process that writes to these files to have
CAP_DAC_OVERRIDE capabilites. Just by changing the permissions to 0660
the capability can be removed, which leads to a more secure system.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1661822
---
modules/pam_faillock/faillock.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/modules/pam_faillock/faillock.c b/modules/pam_faillock/faillock.c
index e492f5f9..4ea94cbe 100644
--- a/modules/pam_faillock/faillock.c
+++ b/modules/pam_faillock/faillock.c
@@ -76,7 +76,7 @@ open_tally (const char *dir, const char *user, uid_t uid, int create)
flags |= O_CREAT;
}
- fd = open(path, flags, 0600);
+ fd = open(path, flags, 0660);
free(path);
@@ -88,6 +88,18 @@ open_tally (const char *dir, const char *user, uid_t uid, int create)
if (st.st_uid != uid) {
ignore_return(fchown(fd, uid, -1));
}
+
+ /*
+ * If umask is set to 022, as will probably in most systems, then the
+ * group will not be able to write to the file. So, change the file
+ * permissions just in case.
+ * Note: owners of this file are user:root, so if the permissions are
+ * not changed the root process writing to this file will require
+ * CAP_DAC_OVERRIDE.
+ */
+ if (!(st.st_mode & S_IWGRP)) {
+ ignore_return(fchmod(fd, 0660));
+ }
}
}
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