Prompt for the password

Supplying the password on the command line is not safe.  This patch
adds support for prompting the user to enter the password.  At some
point, supplying the pasword on the command line should be deprecated.

Prior to this patch, the password could be specified with a blank in
between the '-p' option and the password.  With this patch, the
password now must be adjacent

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

src/evmctl.c

@@ -54,6 +54,7 @@
 #include <getopt.h>
 #include <keyutils.h>
 #include <ctype.h>
+#include <termios.h>
 
 #include <openssl/sha.h>
 #include <openssl/pem.h>
@@ -1468,15 +1469,15 @@ struct command cmds[] = {
 	{"--version", NULL, 0, ""},
 	{"help", cmd_help, 0, "<command>"},
 	{"import", cmd_import, 0, "[--rsa] pubkey keyring", "Import public key into the keyring.\n"},
-	{"sign", cmd_sign_evm, 0, "[-r] [--imahash | --imasig ] [--key key] [--pass password] file", "Sign file metadata.\n"},
+	{"sign", cmd_sign_evm, 0, "[-r] [--imahash | --imasig ] [--key key] [--pass [password] file", "Sign file metadata.\n"},
 	{"verify", cmd_verify_evm, 0, "file", "Verify EVM signature (for debugging).\n"},
-	{"ima_sign", cmd_sign_ima, 0, "[--sigfile] [--key key] [--pass password] file", "Make file content signature.\n"},
+	{"ima_sign", cmd_sign_ima, 0, "[--sigfile] [--key key] [--pass [password] file", "Make file content signature.\n"},
 	{"ima_verify", cmd_verify_ima, 0, "file", "Verify IMA signature (for debugging).\n"},
 	{"ima_hash", cmd_hash_ima, 0, "file", "Make file content hash.\n"},
 	{"ima_measurement", cmd_ima_measurement, 0, "file", "Verify measurement list (experimental).\n"},
 	{"ima_fix", cmd_ima_fix, 0, "[-t fdsxm] path", "Recursively fix IMA/EVM xattrs in fix mode.\n"},
 	{"ima_clear", cmd_ima_clear, 0, "[-t fdsxm] path", "Recursively remove IMA/EVM xattrs.\n"},
-	{"sign_hash", cmd_sign_hash, 0, "[--key key] [--pass password]", "Sign hashes from shaXsum output.\n"},
+	{"sign_hash", cmd_sign_hash, 0, "[--key key] [--pass [password]", "Sign hashes from shaXsum output.\n"},
 #ifdef DEBUG
 	{"hmac", cmd_hmac_evm, 0, "[--imahash | --imasig ] file", "Sign file metadata with HMAC using symmetric key (for testing purpose).\n"},
 #endif
@@ -1488,7 +1489,7 @@ static struct option opts[] = {
 	{"imasig", 0, 0, 's'},
 	{"imahash", 0, 0, 'd'},
 	{"hashalgo", 1, 0, 'a'},
-	{"pass", 1, 0, 'p'},
+	{"pass", 2, 0, 'p'},
 	{"sigfile", 0, 0, 'f'},
 	{"uuid", 2, 0, 'u'},
 	{"rsa", 0, 0, '1'},
@@ -1503,6 +1504,40 @@ static struct option opts[] = {
 
 };
 
+static char *get_password(void)
+{
+	struct termios flags, tmp_flags;
+	char *password, *pwd;
+	int passlen = 64;
+
+	password = malloc(passlen);
+	if (!password) {
+		perror("malloc");
+		return NULL;
+	}
+
+	tcgetattr(fileno(stdin), &flags);
+	tmp_flags = flags;
+	tmp_flags.c_lflag &= ~ECHO;
+	tmp_flags.c_lflag |= ECHONL;
+
+	if (tcsetattr(fileno(stdin), TCSANOW, &tmp_flags) != 0) {
+		perror("tcsetattr");
+		return NULL;
+	}
+
+	printf("PEM password: ");
+	pwd = fgets(password, passlen, stdin);
+
+	/* restore terminal */
+	if (tcsetattr(fileno(stdin), TCSANOW, &flags) != 0) {
+		perror("tcsetattr");
+		return NULL;
+	}
+
+	return pwd;
+}
+
 int main(int argc, char *argv[])
 {
 	int err = 0, c, lind;
@@ -1511,7 +1546,7 @@ int main(int argc, char *argv[])
 	g_argc = argc;
 
 	while (1) {
-		c = getopt_long(argc, argv, "hvnsda:p:fu::k:t:ri", opts, &lind);
+		c = getopt_long(argc, argv, "hvnsda:p::fu::k:t:ri", opts, &lind);
 		if (c == -1)
 			break;
 
@@ -1538,7 +1573,10 @@ int main(int argc, char *argv[])
 			params.hash_algo = optarg;
 			break;
 		case 'p':
-			params.keypass = optarg;
+			if (optarg)
+				params.keypass = optarg;
+			else
+				params.keypass = get_password();
 			break;
 		case 'f':
 			sigfile = 1;