On 01/22/2018, 09:44 AM, Greg Kroah-Hartman wrote:
4.14-stable review patch. If anyone has any objections, please let me know.
From: Li Jinyue lijinyue@huawei.com
commit fbe0e839d1e22d88810f3ee3e2f1479be4c0aa4a upstream.
UBSAN reports signed integer overflow in kernel/futex.c:
UBSAN: Undefined behaviour in kernel/futex.c:2041:18 signed integer overflow: 0 - -2147483648 cannot be represented in type 'int'
Add a sanity check to catch negative values of nr_wake and nr_requeue.
Signed-off-by: Li Jinyue lijinyue@huawei.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: peterz@infradead.org Cc: dvhart@infradead.org Link: https://lkml.kernel.org/r/1513242294-31786-1-git-send-email-lijinyue@huawei.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
kernel/futex.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/kernel/futex.c +++ b/kernel/futex.c @@ -1878,6 +1878,9 @@ static int futex_requeue(u32 __user *uad struct futex_q *this, *next; DEFINE_WAKE_Q(wake_q);
- if (nr_wake < 0 || nr_requeue < 0)
return -EINVAL;
This breaks strace's test suite on 4.14.15 (and is present in upstream obviously too): futex(0x7ff568b44ffc, 0x3, 0xfacefeed, 0xbadda7a0ca7b100d, 0x7ff568b44ffc, 0x9caffee1) = -1: Invalid argument
strace uses weird values in the testkit to pass down to futex as can be seen. I think like in: commit e78c38f6bdd900b2ad9ac9df8eff58b745dc5b3c Author: Jiri Slaby jslaby@suse.cz Date: Mon Oct 23 13:41:51 2017 +0200
futex: futex_wake_op, do not fail on invalid op
something similar should be done here too. Maybe: if (nr_wake < 0) nr_wake = 0; if (nr_requeue < 0) nr_requeue = 0; ?
Maybe also with some pr_info_ratelimited like in the above commit?
thanks,