4.18-stable review patch. If anyone has any objections, please let me know.
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From: H. Peter Anvin hpa@zytor.com
commit 991a25194097006ec1e0d2e0814ff920e59e3465 upstream.
On architectures with CBAUDEX == 0 (Alpha and PowerPC), the code in tty_baudrate.c does not do any limit checking on the tty_baudrate[] array, and in fact a buffer overrun is possible on both architectures. Add a limit check to prevent that situation.
This will be followed by a much bigger cleanup/simplification patch.
Signed-off-by: H. Peter Anvin (Intel) hpa@zytor.com Requested-by: Cc: Johan Hovold johan@kernel.org Cc: Jiri Slaby jslaby@suse.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Richard Henderson rth@twiddle.net Cc: Ivan Kokshaysky ink@jurassic.park.msu.ru Cc: Matt Turner mattst88@gmail.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Kate Stewart kstewart@linuxfoundation.org Cc: Philippe Ombredanne pombredanne@nexb.com Cc: Eugene Syromiatnikov esyr@redhat.com Cc: Alan Cox alan@lxorguk.ukuu.org.uk Cc: stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/tty/tty_baudrate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/tty/tty_baudrate.c +++ b/drivers/tty/tty_baudrate.c @@ -77,7 +77,7 @@ speed_t tty_termios_baud_rate(struct kte else cbaud += 15; } - return baud_table[cbaud]; + return cbaud >= n_baud_table ? 0 : baud_table[cbaud]; } EXPORT_SYMBOL(tty_termios_baud_rate);
@@ -113,7 +113,7 @@ speed_t tty_termios_input_baud_rate(stru else cbaud += 15; } - return baud_table[cbaud]; + return cbaud >= n_baud_table ? 0 : baud_table[cbaud]; #else return tty_termios_baud_rate(termios); #endif