From 720c13fa4884d8bd691a2c32795b9bc2230ed4e7 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@kth.se>
Date: Mon, 22 Feb 2021 15:35:10 +0100
Subject: Make libpassphrase optional
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Signed-off-by: Mattias Andrée <maandree@kth.se>
---
 DEPENDENCIES |  4 ++--
 config.mk    |  4 +++-
 file2key.c   | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 76 insertions(+), 4 deletions(-)

diff --git a/DEPENDENCIES b/DEPENDENCIES
index af6600c..ee2bbd7 100644
--- a/DEPENDENCIES
+++ b/DEPENDENCIES
@@ -1,7 +1,7 @@
 RUNTIME DEPENDENCIES:
 
 	libc
-	libpassphrase
+	libpassphrase (opt-in)
 	libkeccak
 
 
@@ -11,7 +11,7 @@ BUILD DEPENDENCIES:
 	make
 	cc
 	libc
-	libpassphrase
+	libpassphrase (opt-in)
 	libkeccak
 
 
diff --git a/config.mk b/config.mk
index 42aeeb4..b8c111e 100644
--- a/config.mk
+++ b/config.mk
@@ -3,4 +3,6 @@ MANPREFIX = $(CONFIGFILE)
 
 CFLAGS   = -std=c99 -Wall -Wextra -O2
 CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700
-LDFLAGS  = -s -lpassphrase -lkeccak
+LDFLAGS  = -s -lkeccak
+
+# To use libpassphrase, add -DWITH_LIBPASSPHRASE to CPPFLAGS and -lpassphrase to LDFLAGS
diff --git a/file2key.c b/file2key.c
index 77b9fc3..8781330 100644
--- a/file2key.c
+++ b/file2key.c
@@ -4,9 +4,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#ifndef WITH_LIBPASSPHRASE
+# include <termios.h>
+#endif
 #include <unistd.h>
 
-#include <passphrase.h>
+#ifdef WITH_LIBPASSPHRASE
+# include <passphrase.h>
+#endif
 #include <libkeccak.h>
 
 #include "config.h"
@@ -53,12 +58,20 @@ static char *argv0;
 static int
 get_passphrase(char **passphrasep)
 {
+#ifndef WITH_LIBPASSPHRASE
+	struct termios stty, stty_saved;
+	char *passphrase = NULL, *new;
+	size_t len = 0, size = 0;
+	ssize_t r;
+#endif
 	int ttyfd;
 	ttyfd = open("/dev/tty", O_RDONLY);
 	if (ttyfd < 0) {
 		perror(argv0);
 		return 2;
 	}
+
+#ifdef WITH_LIBPASSPHRASE
 	passphrase_disable_echo1(ttyfd);
 	fprintf(stderr, "%s", PASSPHRASE_PROMPT_STRING);
 	fflush(stderr);
@@ -68,6 +81,55 @@ get_passphrase(char **passphrasep)
 	passphrase_reenable_echo1(ttyfd);
 	close(ttyfd);
 	return *passphrasep ? 0 : 2;
+
+#else
+	memset(&stty, 0, sizeof(stty));
+	if (tcgetattr(ttyfd, &stty)) {
+		perror(argv0);
+		close(ttyfd);
+		return 2;
+	}
+	memcpy(&stty_saved, &stty, sizeof(stty));
+	stty.c_lflag &= (tcflag_t)~ECHO;
+	tcsetattr(ttyfd, TCSAFLUSH, &stty);
+	fprintf(stderr, "%s", PASSPHRASE_PROMPT_STRING);
+	fflush(stderr);
+
+	for (;;) {
+		if (len == size) {
+			new = realloc(passphrase, size += 32);
+			if (!new) {
+				perror(argv0);
+				close(ttyfd);
+				if (passphrase) {
+					memset(passphrase, 0, len);
+					free(passphrase);
+				}
+				return 2;
+			}
+			passphrase = new;
+		}
+		r = read(ttyfd, &passphrase[len], 1);
+		if (r < 0) {
+			perror(argv0);
+			memset(passphrase, 0, len);
+			free(passphrase);
+			close(ttyfd);
+			return 2;
+		} else if (!r || passphrase[len] == '\n') {
+			passphrase[len] = 0;
+			break;
+		} else {
+			len += 1;
+		}
+	}
+
+	fprintf(stderr, "\n");
+	tcsetattr(ttyfd, TCSAFLUSH, &stty_saved);
+	close(ttyfd);
+	*passphrasep = passphrase;
+	return 0;
+#endif
 }
 
 
@@ -188,7 +250,11 @@ main(int argc, char *argv[])
 		goto fail;
 	if (libkeccak_update(&state, passphrase, strlen(passphrase)))
 		goto pfail;
+#ifdef WITH_LIBPASSPHRASE
 	passphrase_wipe(passphrase, strlen(passphrase));
+#else
+	memset(passphrase, 0, strlen(passphrase));
+#endif
 	free(passphrase);
 	passphrase = NULL;
 
@@ -238,7 +304,11 @@ pfail:
 	perror(*argv);
 fail:
 	if (passphrase) {
+#ifdef WITH_LIBPASSPHRASE
 		passphrase_wipe(passphrase, strlen(passphrase));
+#else
+		memset(passphrase, 0, strlen(passphrase));
+#endif
 		free(passphrase);
 	}
 done:
-- 
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