| From | Ben Hutchings <> | Date | Sun, 03 Feb 2019 14:45:08 +0100 | Subject | [PATCH 3.16 164/305] termios, tty/tty_baudrate.c: fix buffer overrun |
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3.16.63-rc1 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/tty/tty_ioctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/tty/tty_ioctl.c +++ b/drivers/tty/tty_ioctl.c @@ -327,7 +327,7 @@ 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); @@ -363,7 +363,7 @@ 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
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