1009-tools-xenconsole-replace-ESC-char-on-xenconsole-outp.patch

From e952a87a9869f87f8cb6183d7c2d4ab4e5d234f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Sun, 10 Feb 2019 02:11:50 +0100
Subject: [PATCH] tools/xenconsole: replace ESC char on xenconsole output by
 default
MIME-Version: 1.0
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And add --no-replace-escape option to disable it.
This is done to prevent domU from exploiting hypothetical bug in
terminal emulator.

Add an -r/--no-replace-escape option to xenconsole client to disable
replacing ESC. Carry it from xl command through env variable.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
---
 tools/console/client/main.c | 21 ++++++++++++++++++---
 tools/xl/xl_cmdtable.c      |  3 ++-
 tools/xl/xl_console.c       |  7 ++++++-
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/tools/console/client/main.c b/tools/console/client/main.c
index d2dcc3ddcac3..3d6cea805908 100644
--- a/tools/console/client/main.c
+++ b/tools/console/client/main.c
@@ -78,6 +78,7 @@ static void usage(const char *program) {
 	       "  --type TYPE      console type. must be 'pv', 'serial' or 'vuart'\n"
 	       "  --start-notify-fd N file descriptor used to notify parent\n"
 	       "  --escape E       escape sequence to exit console\n"
+	       "  -r, --no-replace-escape Do not replace ESC character with dot\n"
 	       , program);
 }
 
@@ -175,7 +176,8 @@ static void restore_term(int fd, struct termios *old)
 }
 
 static int console_loop(int fd, struct xs_handle *xs, char *pty_path,
-			bool interactive, char escape_character)
+			bool interactive, char escape_character,
+			bool replace_escape)
 {
 	int ret, xs_fd = xs_fileno(xs), max_fd = -1;
 
@@ -249,6 +251,12 @@ static int console_loop(int fd, struct xs_handle *xs, char *pty_path,
 				fd = -1;
 				continue;
 			}
+			if (replace_escape) {
+				int i;
+				for (i = 0; i < len; i++)
+					if (msg[i] == '\033')
+						msg[i] = '.';
+			}
 
 			if (!write_sync(STDOUT_FILENO, msg, len)) {
 				perror("write() failed");
@@ -325,7 +333,7 @@ int main(int argc, char **argv)
 {
 	struct termios attr;
 	int domid;
-	const char *sopt = "hn:";
+	const char *sopt = "hn:r";
 	int ch;
 	unsigned int num = 0;
 	int opt_ind=0;
@@ -337,6 +345,7 @@ int main(int argc, char **argv)
 		{ "start-notify-fd", 1, 0, 's' },
 		{ "interactive", 0, 0, 'i' },
 		{ "escape",  1, 0, 'e' },
+		{ "no-replace-escape", 0, 0, 'r' },
 		{ 0 },
 
 	};
@@ -346,9 +355,13 @@ int main(int argc, char **argv)
 	char *end;
 	console_type type = CONSOLE_INVAL;
 	bool interactive = 0;
+	bool replace_escape = 1;
 	const char *console_names = "serial, pv, vuart";
 	char escape_character = DEFAULT_ESCAPE_CHARACTER;
 
+	if (getenv("XEN_CONSOLE_REPLACE_ESCAPE"))
+		replace_escape = atoi(getenv("XEN_CONSOLE_REPLACE_ESCAPE"));
+
 	while((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 		switch(ch) {
 		case 'h':
@@ -387,6 +400,8 @@ int main(int argc, char **argv)
 				fprintf(stderr, "Invalid escape argument\n");
 				exit(EINVAL);
 			}
+		case 'r':
+			replace_escape = 0;
 			break;
 		default:
 			fprintf(stderr, "Invalid argument\n");
@@ -506,7 +521,7 @@ int main(int argc, char **argv)
 		close(start_notify_fd);
 	}
 
-	console_loop(spty, xs, path, interactive, escape_character);
+	console_loop(spty, xs, path, interactive, escape_character, replace_escape);
 
 	free(path);
 	free(dom_path);
diff --git a/tools/xl/xl_cmdtable.c b/tools/xl/xl_cmdtable.c
index 42751228c1d1..2185777525d2 100644
--- a/tools/xl/xl_cmdtable.c
+++ b/tools/xl/xl_cmdtable.c
@@ -142,7 +142,8 @@ const struct cmd_spec cmd_table[] = {
       "[options] <Domain>\n"
       "-t <type>       console type, pv , serial or vuart\n"
       "-n <number>     console number\n"
-      "-e <escape>     escape character"
+      "-e <escape>     escape character\n"
+      "-r              do not replace ESC character with dot"
     },
     { "vncviewer",
       &main_vncviewer, 0, 0,
diff --git a/tools/xl/xl_console.c b/tools/xl/xl_console.c
index 5633c6f6f7e6..0d8b3e858303 100644
--- a/tools/xl/xl_console.c
+++ b/tools/xl/xl_console.c
@@ -27,10 +27,11 @@ int main_console(int argc, char **argv)
     uint32_t domid;
     int opt = 0, num = 0;
     libxl_console_type type = 0;
+    bool replace_escape = true;
     const char *console_names = "pv, serial, vuart";
     char* escape_character = NULL;
 
-    SWITCH_FOREACH_OPT(opt, "n:t:e:", NULL, "console", 1) {
+    SWITCH_FOREACH_OPT(opt, "n:t:e:r", NULL, "console", 1) {
     case 't':
         if (!strcmp(optarg, "pv"))
             type = LIBXL_CONSOLE_TYPE_PV;
@@ -48,9 +49,13 @@ int main_console(int argc, char **argv)
         break;
     case 'e':
         escape_character = optarg;
+    case 'r':
+        replace_escape = false;
         break;
     }
 
+    setenv("XEN_CONSOLE_REPLACE_ESCAPE", replace_escape ? "1" : "0", 1);
+
     domid = find_domain(argv[optind]);
     if (!type)
         libxl_primary_console_exec(ctx, domid, -1, escape_character);
-- 
2.44.0