65 lines
2.6 KiB
Diff
65 lines
2.6 KiB
Diff
From e342e4d5c3093d8dd9e2d622e46d36f67bfb4925 Mon Sep 17 00:00:00 2001
|
|
From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
|
|
Date: Mon, 10 Jan 2022 12:34:42 +0100
|
|
Subject: [PATCH] Add root group writeable flag to log file
|
|
|
|
Some systems strips even root process capability of writing to different
|
|
users file. That include systemd under Fedora. When
|
|
log-facility=/var/log/dnsmasq.log is used, log file with mode 0640
|
|
is created. But restart then fails, because such log file can be used
|
|
only when created new. Existing file cannot be opened by root when
|
|
starting, causing fatal error. Avoid that by adding root group writeable flag.
|
|
|
|
Ensure group is always root when granting write access. If it is
|
|
anything else, administrator has to configure correct rights.
|
|
|
|
(cherry picked from commit 1f8f78a49b8fd6b2862a3882053b1c6e6e111e5c)
|
|
---
|
|
src/log.c | 23 ++++++++++++++++++-----
|
|
1 file changed, 18 insertions(+), 5 deletions(-)
|
|
|
|
diff --git a/src/log.c b/src/log.c
|
|
index 1ec3447..bcd6e52 100644
|
|
--- a/src/log.c
|
|
+++ b/src/log.c
|
|
@@ -100,10 +100,23 @@ int log_start(struct passwd *ent_pw, int errfd)
|
|
/* If we're running as root and going to change uid later,
|
|
change the ownership here so that the file is always owned by
|
|
the dnsmasq user. Then logrotate can just copy the owner.
|
|
- Failure of the chown call is OK, (for instance when started as non-root) */
|
|
- if (log_to_file && !log_stderr && ent_pw && ent_pw->pw_uid != 0 &&
|
|
- fchown(log_fd, ent_pw->pw_uid, -1) != 0)
|
|
- ret = errno;
|
|
+ Failure of the chown call is OK, (for instance when started as non-root).
|
|
+
|
|
+ If we've created a file with group-id root, we also make
|
|
+ the file group-writable. This gives processes in the root group
|
|
+ write access to the file and avoids the problem that on some systems,
|
|
+ once the file is owned by the dnsmasq user, it can't be written
|
|
+ whilst dnsmasq is running as root during startup.
|
|
+ */
|
|
+ if (log_to_file && !log_stderr && ent_pw && ent_pw->pw_uid != 0)
|
|
+ {
|
|
+ struct stat ls;
|
|
+ if (getgid() == 0 && fstat(log_fd, &ls) == 0 && ls.st_gid == 0 &&
|
|
+ (ls.st_mode & S_IWGRP) == 0)
|
|
+ (void)fchmod(log_fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
|
|
+ if (fchown(log_fd, ent_pw->pw_uid, -1) != 0)
|
|
+ ret = errno;
|
|
+ }
|
|
|
|
return ret;
|
|
}
|
|
@@ -118,7 +131,7 @@ int log_reopen(char *log_file)
|
|
/* NOTE: umask is set to 022 by the time this gets called */
|
|
|
|
if (log_file)
|
|
- log_fd = open(log_file, O_WRONLY|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR|S_IRGRP);
|
|
+ log_fd = open(log_file, O_WRONLY|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR|S_IRGRP);
|
|
else
|
|
{
|
|
#if defined(HAVE_SOLARIS_NETWORK) || defined(__ANDROID__)
|
|
--
|
|
2.40.1
|
|
|