control: remove unprivileged socket

src/control.h

@@ -66,16 +66,19 @@ struct fd_list {
 TAILQ_HEAD(fd_list_head, fd_list);
 
 #define FD_LISTEN  0x01U
-#define FD_UNPRIV  0x02U
-#define FD_SENDLEN 0x04U
+#define FD_COMMAND 0x02U
+#define FD_PRIV	   0x04U
+#define FD_SENDLEN 0x08U
 
 int control_start(struct dhcpcd_ctx *, const char *, sa_family_t);
 int control_stop(struct dhcpcd_ctx *);
-int control_open(const char *, sa_family_t, bool);
+int control_open(const char *, sa_family_t);
 ssize_t control_send(struct dhcpcd_ctx *, int, char *const *);
+struct fd_list *control_find(struct dhcpcd_ctx *, int);
 struct fd_list *control_new(struct dhcpcd_ctx *, int, unsigned int);
 void control_free(struct fd_list *);
 void control_delete(struct fd_list *);
-int control_queue(struct fd_list *, void *, size_t);
-int control_recvdata(struct fd_list *fd, char *, size_t);
+int control_queue(struct fd_list *, const void *, size_t);
+int control_recvmsg(struct fd_list *, struct msghdr *, size_t);
+int control_user_ispriv(struct dhcpcd_ctx *ctx, uid_t uid, gid_t gid);
 #endif

src/defs.h

@@ -29,7 +29,7 @@
 #define DEFS_H
 
 #define PACKAGE "dhcpcd"
-#define VERSION "10.3.2"
+#define VERSION "10.5.0"
 
 #ifndef PRIVSEP_USER
 #define PRIVSEP_USER "_" PACKAGE

src/dhcpcd.8.in

@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd May 8, 2025
+.Dd July 5, 2026
 .Dt DHCPCD 8
 .Os
 .Sh NAME
@@ -861,12 +861,8 @@ running on the
 .Ar interface .
 .It Pa @RUNDIR@/sock
 Control socket to the manager daemon.
-.It Pa @RUNDIR@/unpriv.sock
-Unprivileged socket to the manager daemon, only allows state retrieval.
 .It Pa @RUNDIR@/ Ns Ar interface Ns .sock
 Control socket to per interface daemon.
-.It Pa @RUNDIR@/ Ns Ar interface Ns .unpriv.sock
-Unprivileged socket to per interface daemon, only allows state retrieval.
 .El
 .Sh SEE ALSO
 .Xr fnmatch 3 ,

src/dhcpcd.c

@@ -1593,13 +1593,16 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd, int argc,
 	 * write callback on the fd */
 	/* Make any change here in privsep-control.c as well. */
 	if (strcmp(*argv, "--version") == 0) {
-		return control_queue(fd, UNCONST(VERSION), strlen(VERSION) + 1);
+		return control_queue(fd, VERSION, strlen(VERSION) + 1);
 	} else if (strcmp(*argv, "--getconfigfile") == 0) {
-		return control_queue(fd, UNCONST(fd->ctx->cffile),
+		return control_queue(fd, fd->ctx->cffile,
 		    strlen(fd->ctx->cffile) + 1);
 	} else if (strcmp(*argv, "--getinterfaces") == 0) {
 		oifind = argc = 0;
 		goto dumplease;
+	} else if (strcmp(*argv, "--isprivileged") == 0) {
+		const char *ret = fd->flags & FD_PRIV ? "true" : "false";
+		return control_queue(fd, ret, strlen(ret) + 1);
 	} else if (strcmp(*argv, "--listen") == 0) {
 		fd->flags |= FD_LISTEN;
 		return 0;
@@ -1682,8 +1685,10 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd, int argc,
 				nifaces += (size_t)opt;
 			}
 		}
-		if (write(fd->fd, &nifaces, sizeof(nifaces)) != sizeof(nifaces))
+		fd->flags &= ~FD_SENDLEN;
+		if (control_queue(fd, &nifaces, sizeof(nifaces)) == -1)
 			goto dumperr;
+		fd->flags |= FD_SENDLEN;
 		TAILQ_FOREACH(ifp, ctx->ifaces, next) {
 			if (!ifp->active)
 				continue;
@@ -1704,7 +1709,7 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd, int argc,
 	}
 
 	/* Only privileged users can control dhcpcd via the socket. */
-	if (fd->flags & FD_UNPRIV) {
+	if (!(fd->flags & FD_PRIV)) {
 		errno = EPERM;
 		return -1;
 	}
@@ -2078,7 +2083,7 @@ main(int argc, char **argv, char **envp)
 	ifo = NULL;
 	ctx.cffile = CONFIG;
 	ctx.script = UNCONST(dhcpcd_default_script);
-	ctx.control_fd = ctx.control_unpriv_fd = ctx.link_fd = -1;
+	ctx.control_fd = ctx.link_fd = -1;
 	ctx.pf_inet_fd = -1;
 #ifdef PF_LINK
 	ctx.pf_link_fd = -1;
@@ -2421,20 +2426,12 @@ main(int argc, char **argv, char **envp)
 	if (!(ctx.options & DHCPCD_TEST)) {
 		ctx.options |= DHCPCD_FORKED; /* avoid socket unlink */
 		if (!(ctx.options & DHCPCD_MANAGER))
-			ctx.control_fd = control_open(argv[optind], family,
-			    ctx.options & DHCPCD_DUMPLEASE);
+			ctx.control_fd = control_open(argv[optind], family);
 		if (!(ctx.options & DHCPCD_MANAGER) && ctx.control_fd == -1)
-			ctx.control_fd = control_open(argv[optind], AF_UNSPEC,
-			    ctx.options & DHCPCD_DUMPLEASE);
+			ctx.control_fd = control_open(argv[optind], AF_UNSPEC);
 		if (ctx.control_fd == -1)
-			ctx.control_fd = control_open(NULL, AF_UNSPEC,
-			    ctx.options & DHCPCD_DUMPLEASE);
+			ctx.control_fd = control_open(NULL, AF_UNSPEC);
 		if (ctx.control_fd != -1) {
-#ifdef PRIVSEP
-			if (IN_PRIVSEP(&ctx) &&
-			    ps_managersandbox(&ctx, NULL) == -1)
-				goto exit_failure;
-#endif
 			if (!(ctx.options & DHCPCD_DUMPLEASE))
 				loginfox("sending commands to dhcpcd process");
 			len = control_send(&ctx, argc, argv);
@@ -2580,6 +2577,8 @@ main(int argc, char **argv, char **envp)
 	logdebugx("spawned manager process on PID %d", (int)getpid());
 
 start_manager:
+
+	logdebugx("spawned manager process on PID %d", (int)getpid());
 	ctx.options |= DHCPCD_STARTED;
 	if ((pid = pidfile_lock(ctx.pidfile)) != 0) {
 		logerr("%s: pidfile_lock %d", __func__, (int)pid);

src/dhcpcd.h

@@ -174,10 +174,8 @@ struct dhcpcd_ctx {
 	size_t io_buflen;
 
 	int control_fd;
-	int control_unpriv_fd;
 	struct fd_list_head control_fds;
 	char control_sock[sizeof(CONTROLSOCKET) + IF_NAMESIZE];
-	char control_sock_unpriv[sizeof(CONTROLSOCKET) + IF_NAMESIZE + 7];
 	gid_t control_group;
 
 	/* DHCP Enterprise options, RFC3925 */
@@ -199,13 +197,12 @@ struct dhcpcd_ctx {
 	struct ps_process *ps_root;
 	struct ps_process *ps_inet;
 	struct ps_process *ps_ctl;
-	int ps_data_fd;			   /* data returned from processes */
-	int ps_log_fd;			   /* chroot logging */
-	int ps_log_root_fd;		   /* outside chroot log reader */
-	struct fd_list *ps_control;	   /* Queue for the above */
-	struct fd_list *ps_control_client; /* Queue for the above */
-	void *ps_buf;			   /* IPC buffer */
-	size_t ps_buflen;		   /* IPC buffer length */
+	int ps_data_fd;		    /* data returned from processes */
+	int ps_log_fd;		    /* chroot logging */
+	int ps_log_root_fd;	    /* outside chroot log reader */
+	struct fd_list *ps_control; /* Queue for the above */
+	void *ps_buf;		    /* IPC buffer */
+	size_t ps_buflen;	    /* IPC buffer length */
 #endif
 
 #ifdef INET