commit b0b0b186f5f9e57bfe93ed96c8c3a1e9fc4f192b
author Michael Jumper <mjumper@apache.org> Tue Jul 17 21:55:46 2018 -0700
committer Michael Jumper <mjumper@apache.org> Tue Jul 17 21:55:46 2018 -0700
tree 1fa0c0ae787cb7c11615d933f623a0757dea390d
parent f5b5ac718396b24352290d2fac976260f4b3829e

GUACAMOLE-573: Ensure scrollback buffer bounds cannot be exceeded. Remove incorrect bounds checks.

src/terminal/buffer.c

diff --git a/src/terminal/buffer.c b/src/terminal/buffer.c
index 2985592..4ecc5ba 100644
--- a/src/terminal/buffer.c
+++ b/src/terminal/buffer.c
@@ -83,12 +83,10 @@
     guac_terminal_char* first;
     guac_terminal_buffer_row* buffer_row;
 
-    /* Calculate scrollback row index */
-    int index = buffer->top + row;
+    /* Normalize row index into a scrollback buffer index */
+    int index = (buffer->top + row) % buffer->available;
     if (index < 0)
         index += buffer->available;
-    else if (index >= buffer->available)
-        index -= buffer->available;
 
     /* Get row */
     buffer_row = &(buffer->rows[index]);

src/terminal/select.c

diff --git a/src/terminal/select.c b/src/terminal/select.c
index 131b5f6..20fc3cd 100644
--- a/src/terminal/select.c
+++ b/src/terminal/select.c
@@ -149,12 +149,6 @@
 
     int start_column = *column;
 
-    /* If requested row is outside the bounds of the current terminal or
-     * scrollback, assume the character is 1 column wide */
-    if (row >= terminal->term_height
-            || row < terminal->term_height - terminal->buffer->length)
-        return 1;
-
     guac_terminal_buffer_row* buffer_row = guac_terminal_buffer_get_row(terminal->buffer, row, 0);
     if (start_column < buffer_row->length) {
 
@@ -291,12 +285,6 @@
     char buffer[1024];
     int i = start;
 
-    /* If requested row is outside the bounds of the current terminal or
-     * scrollback, do nothing */
-    if (row >= terminal->term_height
-            || row < terminal->term_height - terminal->buffer->length)
-        return;
-
     guac_terminal_buffer_row* buffer_row =
         guac_terminal_buffer_get_row(terminal->buffer, row, 0);
 

src/terminal/terminal/buffer.h

diff --git a/src/terminal/terminal/buffer.h b/src/terminal/terminal/buffer.h
index db2a4a1..0e08226 100644
--- a/src/terminal/terminal/buffer.h
+++ b/src/terminal/terminal/buffer.h
@@ -70,7 +70,10 @@
     guac_terminal_buffer_row* rows;
 
     /**
-     * The row to replace when adding a new row to the buffer.
+     * The index of the first row in the buffer (the row which represents row 0
+     * with respect to the terminal display). This is also the index of the row
+     * to replace when insufficient space remains in the buffer to add a new
+     * row.
      */
     int top;