there is an overflow in the code :
cyz_polling_cycle = (arg * HZ) / 1000,
the multiplicator arg comes from user, so it may be an overflow if
arg is a big number. And the value of cyc_polling_cycle will be
wrong when it is used next time.
Reported-by: Qixue Xiao <xiaoqixu...@163.com>
Suggested-by: Yongjian Xu <xuyongjia...@gmail.com>
Suggested-by: Yu Chen <chy...@gmail.com>
Signed-off-by: Qixue Xiao <xiaoqixu...@163.com>
---
drivers/tty/cyclades.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index 33f83fe..a57bb5a 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -2709,6 +2709,8 @@ cy_ioctl(struct tty_struct *tty,
break;
#ifndef CONFIG_CYZ_INTR
case CYZSETPOLLCYCLE:
+ if (arg > LONG_MAX / HZ)
+ return -ENODEV;
cyz_polling_cycle = (arg * HZ) / 1000;
break;
case CYZGETPOLLCYCLE:
--
1.7.9.5
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