From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <593FB839.2070804@huawei.com> Date: Tue, 13 Jun 2017 18:02:33 +0800 From: zhong jiang MIME-Version: 1.0 To: Jiri Slaby CC: , , Jeff Layton , "J. Bruce Fields" , , Xishi Qiu Subject: Re: [PATCH] fs: fcntl, avoid undefined behaviour References: <20161014092342.25546-1-jslaby@suse.cz> <593E20A1.10608@huawei.com> <53f29baf-4da1-f2db-aec4-32291dc8db7d@suse.cz> In-Reply-To: <53f29baf-4da1-f2db-aec4-32291dc8db7d@suse.cz> Content-Type: text/plain; charset="ISO-8859-2" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 2017/6/13 17:29, Jiri Slaby wrote: > On 06/12/2017, 07:03 AM, zhong jiang wrote: >> On 2016/10/14 17:23, Jiri Slaby wrote: >>> fcntl(0, F_SETOWN, 0x80000000) triggers: >>> UBSAN: Undefined behaviour in fs/fcntl.c:118:7 >>> negation of -2147483648 cannot be represented in type 'int': >>> CPU: 1 PID: 18261 Comm: syz-executor Not tainted 4.8.1-0-syzkaller #1 >>> ... >>> Call Trace: >>> ... >>> [] ? f_setown+0x1d8/0x200 >>> [] ? SyS_fcntl+0x999/0xf30 >>> [] ? entry_SYSCALL_64_fastpath+0x23/0xc1 >>> >>> Fix that by checking the arg parameter properly (against INT_MAX) and >>> return immediatelly in case it is wrong. No error is returned, the >>> same as in other cases. >>> >>> Signed-off-by: Jiri Slaby >>> Cc: Jeff Layton >>> Cc: "J. Bruce Fields" >>> Cc: Alexander Viro >>> Cc: linux-fsdevel@vger.kernel.org >>> --- >>> fs/fcntl.c | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/fs/fcntl.c b/fs/fcntl.c >>> index 350a2c8cfd28..bfc3b040d956 100644 >>> --- a/fs/fcntl.c >>> +++ b/fs/fcntl.c >>> @@ -112,6 +112,10 @@ void f_setown(struct file *filp, unsigned long arg, int force) >>> enum pid_type type; >>> struct pid *pid; >>> int who = arg; >>> + >>> + if (arg > INT_MAX) >>> + return; >>> + >>> type = PIDTYPE_PID; >>> if (who < 0 >>> type = PIDTYPE_PGID; >> Hi, Jiri >> >> I hit the same issue, but I see the upstream is still not changed. Had any problem? > Hi, it needed an update which I have just sent. So let's see if that > gets applied. > > thanks, I have updated in newest kernel version. but it fails to get the change. Can you look at that? Thanks zhongjiang