svn commit: r287777 - stable/9/sys/teken

[Ed Schouten]

Author: ed
Date: Mon Sep 14 09:31:00 2015
New Revision: 287777
URL: https://svnweb.freebsd.org/changeset/base/287777

Log:
  MFC r286798 and r286827:
  
    Stop parsing digits if the value already exceeds UINT_MAX / 100.
  
    There is no need for us to support parsing values that are larger than
    the maximum terminal window size. In this case that would be the maximum
    of unsigned short.
  
    The problem with parsing larger values is that they can cause integer
    overflows when adjusting the cursor position, leading to all sorts of
    failing assertions.
  
  MFC r286981 and r287098:
  
    Don't truncate cursor arithmetic to 16 bits.
  
    When updating the row number when the cursor position escape sequence is
    issued, we should make sure to store the intermediate result in a 32-bit
    integer. If we fail to do this, the cursor may be set above the origin
    region, which is bad.
  
    This could cause libteken to crash when INVARIANTS is enabled, due to
    the strict set of assertions that libteken has.
  
  PR:		202326, 202540, 202612
  Submitted by:	kwcu csie org

Modified:
  stable/9/sys/teken/teken.c
  stable/9/sys/teken/teken_subr.h
Directory Properties:
  stable/9/   (props changed)
  stable/9/sys/   (props changed)

Modified: stable/9/sys/teken/teken.c
==============================================================================
--- stable/9/sys/teken/teken.c	Mon Sep 14 09:12:28 2015	(r287776)
+++ stable/9/sys/teken/teken.c	Mon Sep 14 09:31:00 2015	(r287777)
@@ -29,12 +29,14 @@
 #include <sys/cdefs.h>
 #if defined(__FreeBSD__) && defined(_KERNEL)
 #include <sys/param.h>
+#include <sys/limits.h>
 #include <sys/lock.h>
 #include <sys/systm.h>
 #define	teken_assert(x)		MPASS(x)
 #else /* !(__FreeBSD__ && _KERNEL) */
 #include <sys/types.h>
 #include <assert.h>
+#include <limits.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -405,18 +407,24 @@ teken_state_numbers(teken_t *t, teken_ch
 	teken_assert(t->t_curnum < T_NUMSIZE);
 
 	if (c >= '0' && c <= '9') {
-		/*
-		 * Don't do math with the default value of 1 when a
-		 * custom number is inserted.
-		 */
 		if (t->t_stateflags & TS_FIRSTDIGIT) {
+			/* First digit. */
 			t->t_stateflags &= ~TS_FIRSTDIGIT;
-			t->t_nums[t->t_curnum] = 0;
-		} else {
-			t->t_nums[t->t_curnum] *= 10;
+			t->t_nums[t->t_curnum] = c - '0';
+		} else if (t->t_nums[t->t_curnum] < UINT_MAX / 100) {
+			/*
+			 * There is no need to continue parsing input
+			 * once the value exceeds the size of the
+			 * terminal. It would only allow for integer
+			 * overflows when performing arithmetic on the
+			 * cursor position.
+			 *
+			 * Ignore any further digits if the value is
+			 * already UINT_MAX / 100.
+			 */
+			t->t_nums[t->t_curnum] =
+			    t->t_nums[t->t_curnum] * 10 + c - '0';
 		}
-
-		t->t_nums[t->t_curnum] += c - '0';
 		return (1);
 	} else if (c == ';') {
 		if (t->t_stateflags & TS_FIRSTDIGIT)

Modified: stable/9/sys/teken/teken_subr.h
==============================================================================
--- stable/9/sys/teken/teken_subr.h	Mon Sep 14 09:12:28 2015	(r287776)
+++ stable/9/sys/teken/teken_subr.h	Mon Sep 14 09:31:00 2015	(r287777)
@@ -324,13 +324,13 @@ static void
 teken_subr_cursor_position(teken_t *t, unsigned int row, unsigned int col)
 {
 
-	t->t_cursor.tp_row = t->t_originreg.ts_begin + row - 1;
-	if (t->t_cursor.tp_row >= t->t_originreg.ts_end)
-		t->t_cursor.tp_row = t->t_originreg.ts_end - 1;
-
-	t->t_cursor.tp_col = col - 1;
-	if (t->t_cursor.tp_col >= t->t_winsize.tp_col)
-		t->t_cursor.tp_col = t->t_winsize.tp_col - 1;
+	row = row - 1 + t->t_originreg.ts_begin;
+	t->t_cursor.tp_row = row < t->t_originreg.ts_end ?
+	    row : t->t_originreg.ts_end - 1;
+
+	col--;
+	t->t_cursor.tp_col = col < t->t_winsize.tp_col ?
+	    col : t->t_winsize.tp_col - 1;
 
 	t->t_stateflags &= ~TS_WRAPPED;
 	teken_funcs_cursor(t);
@@ -583,9 +583,9 @@ static void
 teken_subr_horizontal_position_absolute(teken_t *t, unsigned int col)
 {
 
-	t->t_cursor.tp_col = col - 1;
-	if (t->t_cursor.tp_col >= t->t_winsize.tp_col)
-		t->t_cursor.tp_col = t->t_winsize.tp_col - 1;
+	col--;
+	t->t_cursor.tp_col = col < t->t_winsize.tp_col ?
+	    col : t->t_winsize.tp_col - 1;
 
 	t->t_stateflags &= ~TS_WRAPPED;
 	teken_funcs_cursor(t);
@@ -1297,9 +1297,9 @@ static void
 teken_subr_vertical_position_absolute(teken_t *t, unsigned int row)
 {
 
-	t->t_cursor.tp_row = t->t_originreg.ts_begin + row - 1;
-	if (t->t_cursor.tp_row >= t->t_originreg.ts_end)
-		t->t_cursor.tp_row = t->t_originreg.ts_end - 1;
+	row = row - 1 + t->t_originreg.ts_begin;
+	t->t_cursor.tp_row = row < t->t_originreg.ts_end ?
+	    row : t->t_originreg.ts_end - 1;
 
 	t->t_stateflags &= ~TS_WRAPPED;
 	teken_funcs_cursor(t);