From: Huacai Chen <chenhuacai@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Huacai Chen <chenhuacai@loongson.cn>,
loongarch@lists.linux.dev,
Linux-Arch <linux-arch@vger.kernel.org>,
Xuefeng Li <lixuefeng@loongson.cn>, guoren <guoren@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn,
stable@vger.kernel.org
Subject: Re: [PATCH] LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h
Date: Sat, 11 May 2024 22:28:37 +0800 [thread overview]
Message-ID: <CAAhV-H5kn2xPLqgop0iOyg-tc5kAYcuNo3cd+f3yCdkN=cJDug@mail.gmail.com> (raw)
In-Reply-To: <f92e23be-3f3f-4bc6-8711-3bcf6beb7fa2@app.fastmail.com>
Hi, Arnd,
On Sat, May 11, 2024 at 8:17 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Sat, May 11, 2024, at 12:01, Huacai Chen wrote:
> > Chromium sandbox apparently wants to deny statx [1] so it could properly
> > inspect arguments after the sandboxed process later falls back to fstat.
> > Because there's currently not a "fd-only" version of statx, so that the
> > sandbox has no way to ensure the path argument is empty without being
> > able to peek into the sandboxed process's memory. For architectures able
> > to do newfstatat though, glibc falls back to newfstatat after getting
> > -ENOSYS for statx, then the respective SIGSYS handler [2] takes care of
> > inspecting the path argument, transforming allowed newfstatat's into
> > fstat instead which is allowed and has the same type of return value.
> >
> > But, as LoongArch is the first architecture to not have fstat nor
> > newfstatat, the LoongArch glibc does not attempt falling back at all
> > when it gets -ENOSYS for statx -- and you see the problem there!
>
> My main objection here is that this is inconsistent with 32-bit
> architectures: we normally have newfstatat() on 64-bit
> architectures but fstatat64() on 32-bit ones. While loongarch64
> is the first 64-bit one that is missing newfstatat(), we have
> riscv32 already without fstatat64().
Then how to move forward? Xuerui said that he wants to improve
seccomp, but a long time has already passed. And I think we should
solve this problem before Debian loong64 ports become usable.
>
> Importantly, we can't just add fstatat64() on riscv32 because
> there is no time64 version for it other than statx(), and I don't
> want the architectures to diverge more than necessary.
> I would not mind adding a variant of statx() that works for
> both riscv32 and loongarch64 though, if it gets added to all
> architectures.
As far as I know, Ren Guo is trying to implement riscv64 kernel +
riscv32 userspace, so I think riscv32 kernel won't be widely used?
Huacai
>
> Arnd
>
next prev parent reply other threads:[~2024-05-11 14:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 10:01 [PATCH] LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h Huacai Chen
2024-05-11 12:17 ` Arnd Bergmann
2024-05-11 14:28 ` Huacai Chen [this message]
2024-05-11 15:38 ` Arnd Bergmann
2024-05-12 3:11 ` Huacai Chen
2024-05-12 7:52 ` Arnd Bergmann
2024-06-15 8:52 ` Huacai Chen
2024-06-15 8:55 ` Xi Ruoyao
2024-06-15 9:29 ` Huacai Chen
2024-06-15 11:47 ` Arnd Bergmann
2024-06-15 12:12 ` Xi Ruoyao
2024-06-15 13:12 ` Xi Ruoyao
2024-06-17 6:35 ` Arnd Bergmann
2024-06-17 6:45 ` Xi Ruoyao
2024-06-17 6:53 ` Arnd Bergmann
2024-06-22 7:45 ` Huacai Chen
2024-06-22 11:04 ` Xi Ruoyao
2024-05-15 9:30 ` maobibo
2024-05-15 14:25 ` Arnd Bergmann
2024-05-16 2:52 ` maobibo
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