From: "Serge E. Hallyn" <serge@hallyn.com>
To: Paul Moore <paul@paul-moore.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
"Andrew G. Morgan" <morgan@kernel.org>,
Gaosheng Cui <cuigaosheng1@huawei.com>,
akpm@linux-foundation.org, ezk@cs.sunysb.edu,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
Date: Thu, 3 Nov 2022 08:24:34 -0500 [thread overview]
Message-ID: <20221103132434.GA30946@mail.hallyn.com> (raw)
In-Reply-To: <CAHC9VhSMFgifrUdMvogne+DC+gx_B9dW5mGsNZ8vstHpUsupOQ@mail.gmail.com>
On Thu, Nov 03, 2022 at 07:57:45AM -0400, Paul Moore wrote:
> On Tue, Nov 1, 2022 at 12:30 AM Serge E. Hallyn <serge@hallyn.com> wrote:
> > On Mon, Oct 31, 2022 at 07:18:54AM -0700, Andrew G. Morgan wrote:
> > > Acked-by: Andrew G. Morgan <morgan@kernel.org>
> > >
> > >
> > > On Mon, Oct 31, 2022 at 4:25 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
> > > >
> > > > Shifting signed 32-bit value by 31 bits is undefined, so changing
> > > > significant bit to unsigned. The UBSAN warning calltrace like below:
> > > >
> > > > UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
> > > > left shift of 1 by 31 places cannot be represented in type 'int'
> > > > Call Trace:
> > > > <TASK>
> > > > dump_stack_lvl+0x7d/0xa5
> > > > dump_stack+0x15/0x1b
> > > > ubsan_epilogue+0xe/0x4e
> > > > __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> > > > cap_task_prctl+0x561/0x6f0
> > > > security_task_prctl+0x5a/0xb0
> > > > __x64_sys_prctl+0x61/0x8f0
> > > > do_syscall_64+0x58/0x80
> > > > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > > > </TASK>
> > > >
> > > > Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
> > > > Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> >
> > Reviewed-by: Serge Hallyn <serge@hallyn.com>
> >
> > Paul, do you mind including this in your lsm tree?
>
> Sure, although just a warning that it might not happen until next
> week. Maybe I'll get some time this weekend but I can't be certain.
Ok, thanks.
I wouldn't mind putting up a capability tree if number of patches were
going to start ramping up, but historically that has not been worth it.
next prev parent reply other threads:[~2022-11-03 13:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 11:25 [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK Gaosheng Cui
2022-10-31 14:18 ` Andrew G. Morgan
2022-11-01 4:30 ` Serge E. Hallyn
2022-11-03 11:57 ` Paul Moore
2022-11-03 13:24 ` Serge E. Hallyn [this message]
2022-11-05 5:33 ` Paul Moore
2022-11-05 5:30 ` Paul Moore
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