dhcpcd: dumping lease uses control socket to get the lease

Thanks to privsep it's hard to know where the lease is now stored.
As such, the only true location is from the running dhcpcd process.
The ability to read a raw lease from stdin has been dropped.

1 files changed, 139 insertions, 80 deletions

diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index bd2556ea..d70ff37b 100644
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -1458,7 +1458,7 @@ dhcpcd_getinterfaces(void *arg)
 	TAILQ_FOREACH(ifp, fd->ctx->ifaces, next) {
 		if (!ifp->active)
 			continue;
-		if (send_interface(fd, ifp) == -1)
+		if (send_interface(fd, ifp, AF_UNSPEC) == -1)
 			logerr(__func__);
 	}
 }
@@ -1469,7 +1469,7 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd,
 {
 	struct interface *ifp;
 	unsigned long long opts;
-	int opt, oi, do_reboot, do_renew;
+	int opt, oi, do_reboot, do_renew, af = AF_UNSPEC;
 	size_t len, l;
 	char *tmp, *p;
 
@@ -1492,12 +1492,6 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd,
 		return 0;
 	}
 
-	/* Only privileged users can control dhcpcd via the socket. */
-	if (fd->flags & FD_UNPRIV) {
-		errno = EPERM;
-		return -1;
-	}
-
 	/* Log the command */
 	len = 1;
 	for (opt = 0; opt < argc; opt++)
@@ -1542,9 +1536,50 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd,
 		case 'N':
 			do_renew = 1;
 			break;
+		case 'U':
+			opts |= DHCPCD_DUMPLEASE;
+			break;
+		case '4':
+			af = AF_INET;
+			break;
+		case '6':
+			af = AF_INET6;
+			break;
 		}
 	}
 
+	if (opts & DHCPCD_DUMPLEASE) {
+		ctx->options |= DHCPCD_DUMPLEASE;
+		size_t nifaces = 0;
+
+		for (oi = optind; oi < argc; oi++) {
+			if ((ifp = if_find(ctx->ifaces, argv[oi])) == NULL)
+				continue;
+			if (!ifp->active)
+				continue;
+			opt = send_interface(NULL, ifp, af);
+			if (opt != -1)
+				nifaces += (size_t)opt;
+		}
+		if (write(fd->fd, &nifaces, sizeof(nifaces)) != sizeof(nifaces))
+			return -1;
+		for (oi = optind; oi < argc; oi++) {
+			if ((ifp = if_find(ctx->ifaces, argv[oi])) == NULL)
+				continue;
+			if (!ifp->active)
+				continue;
+			send_interface(fd, ifp, af);
+		}
+		ctx->options &= ~DHCPCD_DUMPLEASE;
+		return 0;
+	}
+
+	/* Only privileged users can control dhcpcd via the socket. */
+	if (fd->flags & FD_UNPRIV) {
+		errno = EPERM;
+		return -1;
+	}
+
 	if (opts & (DHCPCD_EXITING | DHCPCD_RELEASE)) {
 		if (optind == argc) {
 			stop_all_interfaces(ctx, opts);
@@ -1583,6 +1618,86 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd,
 	return 0;
 }
 
+static int
+dhcpcd_readdump(struct dhcpcd_ctx *ctx)
+{
+	int error = 0;
+	size_t nifaces, buflen = 0, dlen;
+	ssize_t len;
+	char *buf = NULL, *dp, *de;
+	bool print;
+
+again1:
+	len = read(ctx->control_fd, &nifaces, sizeof(nifaces));
+	if (len == -1) {
+		if (errno == EAGAIN)
+			goto again1;
+		return -1;
+	}
+	if (len != sizeof(nifaces)) {
+		errno = EINVAL;
+		return -1;
+	}
+	for (; nifaces > 0; nifaces--) {
+again2:
+		len = read(ctx->control_fd, &dlen, sizeof(dlen));
+		if (len == -1) {
+			if (errno == EAGAIN)
+				goto again2;
+			error = -1;
+			goto out;
+		}
+		if (len != sizeof(dlen)) {
+			errno = EINVAL;
+			goto out;
+		}
+		if (dlen > buflen) {
+			char *nbuf = realloc(buf, dlen);
+			if (nbuf == NULL) {
+				error = -1;
+				goto out;
+			}
+			buf = nbuf;
+			buflen = dlen;
+		}
+again3:
+		if (read(ctx->control_fd, buf, dlen) != (ssize_t)dlen) {
+			if (errno == EAGAIN)
+				goto again3;
+			error = -1;
+			goto out;
+		}
+		dp = buf;
+		de = dp + dlen;
+		while (dp < de) {
+			if (dp + 6 >= de) /* _new and = something */
+				break;
+			if (dp[0] == 'n' && dp[3] == '_') {
+				if (dp[1] == 'e' && dp[2] == 'w') {
+					print = true;
+					dp += 4;
+				} else if (dp[1] == 'd' &&
+				    isdigit((unsigned char)dp[2]))
+					print = true;
+			} else
+				print = false;
+			while (dp < de && *dp != '\0') {
+				if (print)
+					putchar(*dp);
+				dp++;
+			}
+			if (print)
+				putchar('\n');
+			dp++;
+		}
+		fflush(stdout);
+	}
+
+out:
+	free(buf);
+	return error;
+}
+
 static void
 dhcpcd_fork_cb(void *arg)
 {
@@ -1891,74 +2006,7 @@ printpidfile:
 		logerr("%s: eloop_signal_mask", __func__);
 		goto exit_failure;
 	}
-#endif
 
-	if (ctx.options & DHCPCD_DUMPLEASE) {
-		/* Open sockets so we can dump something about
-		 * valid interfaces. */
-		if (if_opensockets(&ctx) == -1) {
-			logerr("%s: if_opensockets", __func__);
-			goto exit_failure;
-		}
-		if (optind != argc) {
-			/* We need to try and find the interface so we can load
-			 * the hardware address to compare automated IAID */
-			ctx.ifaces = if_discover(&ctx, &ifaddrs,
-			    argc - optind, argv + optind);
-		} else {
-			if ((ctx.ifaces = malloc(sizeof(*ctx.ifaces))) != NULL)
-				TAILQ_INIT(ctx.ifaces);
-		}
-		if (ctx.ifaces == NULL) {
-			logerr("%s: if_discover", __func__);
-			goto exit_failure;
-		}
-		ifp = if_find(ctx.ifaces, argv[optind]);
-		if (ifp == NULL) {
-			ifp = calloc(1, sizeof(*ifp));
-			if (ifp == NULL) {
-				logerr(__func__);
-				goto exit_failure;
-			}
-			if (optind != argc)
-				strlcpy(ctx.pidfile, argv[optind],
-				    sizeof(ctx.pidfile));
-			ifp->ctx = &ctx;
-			TAILQ_INSERT_HEAD(ctx.ifaces, ifp, next);
-			if (family == 0) {
-				if (ctx.pidfile[0] != '\0' &&
-				    ctx.pidfile[strlen(ctx.pidfile) - 1] == '6')
-					family = AF_INET6;
-				else
-					family = AF_INET;
-			}
-		}
-		configure_interface(ifp, ctx.argc, ctx.argv, 0);
-		i = 0;
-		if (family == 0 || family == AF_INET) {
-#ifdef INET
-			if (dhcp_dump(ifp) == -1)
-				i = -1;
-#else
-			if (family == AF_INET)
-				logerrx("No INET support");
-#endif
-		}
-		if (family == 0 || family == AF_INET6) {
-#ifdef DHCP6
-			if (dhcp6_dump(ifp) == -1)
-				i = -1;
-#else
-			if (family == AF_INET6)
-				logerrx("No DHCP6 support");
-#endif
-		}
-		if (i == -1)
-			goto exit_failure;
-		goto exit_success;
-	}
-
-#ifdef USE_SIGNALS
 	/* Test against siga instead of sig to avoid gcc
 	 * warning about a bogus potential signed overflow.
 	 * The end result will be the same. */
@@ -1972,18 +2020,30 @@ printpidfile:
 		if (ctx.control_fd == -1)
 			ctx.control_fd = control_open(NULL);
 		if (ctx.control_fd != -1) {
-			loginfox("sending commands to master dhcpcd process");
+			if (!(ctx.options & DHCPCD_DUMPLEASE))
+				loginfox("sending commands to dhcpcd process");
 			len = control_send(&ctx, argc, argv);
-			if (len > 0) {
+			if (len > 0)
 				logdebugx("send OK");
-				goto exit_success;
-			} else {
+			else {
 				logerr("%s: control_send", __func__);
 				goto exit_failure;
 			}
+			if (ctx.options & DHCPCD_DUMPLEASE) {
+				if (dhcpcd_readdump(&ctx) == -1) {
+					logerr("%s: dhcpcd_readdump", __func__);
+					goto exit_failure;
+				}
+			}
+			goto exit_success;
 		} else {
 			if (errno != ENOENT)
 				logerr("%s: control_open", __func__);
+			if (ctx.options & DHCPCD_DUMPLEASE) {
+				if (errno == ENOENT)
+					logerrx("dhcpcd is not running");
+				goto exit_failure;
+			}
 		}
 		ctx.options &= ~DHCPCD_FORKED;
 #ifdef USE_SIGNALS
@@ -2312,7 +2372,6 @@ exit1:
 	eloop_free(ctx.ps_eloop);
 #endif
 	eloop_free(ctx.eloop);
-
 	if (ctx.options & DHCPCD_STARTED && !(ctx.options & DHCPCD_FORKED))
 		loginfox(PACKAGE " exited");
 	logclose();