Messages in this thread Patch in this message | | | From | xqx12 <> | Subject | [PATCH] tty: an overflow of multiplication in drivers/tty/cyclades.c | Date | Wed, 18 Dec 2013 09:00:29 +0800 |
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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 <xiaoqixue_1@163.com> Suggested-by: Yongjian Xu <xuyongjiande@gmail.com> Suggested-by: Yu Chen <chyyuu@gmail.com> Signed-off-by: Qixue Xiao <xiaoqixue_1@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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