From ca918f63b7a98442d2925c0a668c911d8140215b Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 13 Apr 2023 10:49:15 +0200
Subject: [PATCH] udev,sd-device: use CMSG_FIND_DATA() more

---
 src/libsystemd/sd-device/device-monitor.c | 6 ++----
 src/udev/udev-ctrl.c                      | 8 ++------
 2 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
index af093385da8..a23b5e78470 100644
--- a/src/libsystemd/sd-device/device-monitor.c
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -503,7 +503,6 @@ int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret) {
                 .msg_name = &snl,
                 .msg_namelen = sizeof(snl),
         };
-        struct cmsghdr *cmsg;
         struct ucred *cred;
         size_t offset;
         ssize_t n;
@@ -559,12 +558,11 @@ int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret) {
                                                  snl.nl.nl_pid);
         }
 
-        cmsg = CMSG_FIRSTHDR(&smsg);
-        if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS)
+        cred = CMSG_FIND_DATA(&smsg, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
+        if (!cred)
                 return log_monitor_errno(m, SYNTHETIC_ERRNO(EAGAIN),
                                          "No sender credentials received, ignoring message.");
 
-        cred = (struct ucred*) CMSG_DATA(cmsg);
         if (!check_sender_uid(m, cred->uid))
                 return log_monitor_errno(m, SYNTHETIC_ERRNO(EAGAIN),
                                          "Sender uid="UID_FMT", message ignored.", cred->uid);
diff --git a/src/udev/udev-ctrl.c b/src/udev/udev-ctrl.c
index 24180f9418f..7d9a8c018f0 100644
--- a/src/udev/udev-ctrl.c
+++ b/src/udev/udev-ctrl.c
@@ -161,7 +161,6 @@ static int udev_ctrl_connection_event_handler(sd_event_source *s, int fd, uint32
                 .msg_control = &control,
                 .msg_controllen = sizeof(control),
         };
-        struct cmsghdr *cmsg;
         struct ucred *cred;
         ssize_t size;
 
@@ -185,15 +184,12 @@ static int udev_ctrl_connection_event_handler(sd_event_source *s, int fd, uint32
 
         cmsg_close_all(&smsg);
 
-        cmsg = CMSG_FIRSTHDR(&smsg);
-
-        if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) {
+        cred = CMSG_FIND_DATA(&smsg, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
+        if (!cred) {
                 log_error("No sender credentials received, ignoring message");
                 return 0;
         }
 
-        cred = (struct ucred *) CMSG_DATA(cmsg);
-
         if (cred->uid != 0) {
                 log_error("Invalid sender uid "UID_FMT", ignoring message", cred->uid);
                 return 0;