Attachment 2726 Details for Bug 2478 – Patch v2

[patch] Patch v2

0001-ANSI-terminal-escape-sequences-do-not-affect-process.patch (text/plain), 3.25 KB, created by Alex Dowad on 2015-10-13 17:22:59 AEDT

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Creator: Alex Dowad

Created: 2015-10-13 17:22:59 AEDT

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patch

obsolete

>From c4f36769ef97e5159cbd69eba4057bfab88da667 Mon Sep 17 00:00:00 2001
>From: Alex Dowad <alexinbeijing@gmail.com>
>Date: Mon, 12 Oct 2015 20:38:00 +0200
>Subject: [PATCH] ANSI terminal escape sequences do not affect processing of
> SSH escapes
>
>Even when the user has not pressed a key, ANSI-compatible terminal emulators
>can send escape sequences to ssh's stdin at any time. For example, any time that
>the server sends an "<ESC>[6n" (query cursor position) sequence, an ANSI-compatible
>terminal will send back "<ESC>[<ROW>;<COLUMN>R". ssh sees these escape sequences
>just as if they were characters typed in by the user. This causes problems if the
>user is attempting to type an SSH escape sequence, starting with "<ENTER>~".
>
>Therefore, when scanning user input for SSH escape sequences, skip over any
>ANSI terminal control sequences which appear in the input.
>---
> clientloop.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
>diff --git a/clientloop.c b/clientloop.c
>index 87ceb3d..c45c523 100644
>--- a/clientloop.c
>+++ b/clientloop.c
>@@ -154,6 +154,7 @@ volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
> static int escape_char1;	/* Escape character. (proto1 only) */
> static int escape_pending1;	/* Last character was an escape (proto1 only) */
> static int last_was_cr;		/* Last character was a newline. */
>+static int last_was_ansi;	/* Last character was part of an ANSI escape. */
> static int exit_status;		/* Used to store the command exit status. */
> static int stdin_eof;		/* EOF has been encountered on stderr. */
> static Buffer stdin_buffer;	/* Buffer for stdin data. */
>@@ -1096,7 +1097,14 @@ process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
> 		/* Get one character at a time. */
> 		ch = buf[i];
> 
>-		if (*escape_pendingp) {
>+		/* ANSI terminal escape sequences may appear anywhere in input stream. */
>+		/* They do not affect our processing of our own escapes. */
>+		if (ch == 0x1B) {
>+			last_was_ansi = 1;
>+		} else if (last_was_ansi) {
>+			if (ch != '[' && ch != ';' && !isdigit(ch))
>+				last_was_ansi = 0;
>+		} else if (*escape_pendingp) {
> 			/* We have previously seen an escape character. */
> 			/* Clear the flag now. */
> 			*escape_pendingp = 0;
>@@ -1276,6 +1284,10 @@ process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
> 					buffer_put_char(bin, escape_char);
> 					bytes++;
> 				}
>+
>+				/* Record whether escaped character was a newline. */
>+				last_was_cr = (ch == '\r' || ch == '\n');
>+
> 				/* Escaped characters fall through here */
> 				break;
> 			}
>@@ -1292,13 +1304,12 @@ process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
> 				*escape_pendingp = 1;
> 				continue;
> 			}
>+
>+			/* It wasn't an escape, was it a newline? */
>+			last_was_cr = (ch == '\r' || ch == '\n');
> 		}
> 
>-		/*
>-		 * Normal character.  Record whether it was a newline,
>-		 * and append it to the buffer.
>-		 */
>-		last_was_cr = (ch == '\r' || ch == '\n');
>+		/* Normal character.  Append it to the buffer. */
> 		buffer_put_char(bin, ch);
> 		bytes++;
> 	}
>@@ -1495,6 +1506,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
> 	/* Initialize variables. */
> 	escape_pending1 = 0;
> 	last_was_cr = 1;
>+	last_was_ansi = 0;
> 	exit_status = -1;
> 	stdin_eof = 0;
> 	buffer_high = 64 * 1024;
>-- 
>2.0.0.GIT
>

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