tty vt: fix character insertion overflow
authorNicolas Pitre <nicolas.pitre@linaro.org>
Mon, 25 Feb 2013 01:06:09 +0000 (20:06 -0500)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 25 Feb 2013 01:29:49 +0000 (17:29 -0800)
commita883b70d8e0a88278c0a1f80753b4dc99962b541
tree923e2b4d21eecff2561b02e841638ae82467e74c
parent77be36de8b07027a70fbc8f02703ccd76cd16d09
tty vt: fix character insertion overflow

Commit 81732c3b2fed ("tty vt: Fix line garbage in virtual console on
command line edition") broke insert_char() in multiple ways.  Then
commit b1a925f44a3a ("tty vt: Fix a regression in command line edition")
partially fixed it.  However, the buffer being moved is still too large
and overflowing beyond the end of the current line, corrupting existing
characters on the next line.

Example test case:

echo -e "abc\nde\x1b[A\x1b[4h \x1b[4l\x1b[B"

Expected result:

ab c
de

Current result:

ab c
 e

Needless to say that this is very annoying when inserting words in the
middle of paragraphs with certain text editors.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Cc: Jean-Fran├žois Moine <moinejf@free.fr>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/tty/vt/vt.c