From: Florian Weimer <fweimer@redhat.com>
To: Dave Martin via Libc-alpha <libc-alpha@sourceware.org>
Cc: Dave Martin <Dave.Martin@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
systemd-devel@lists.freedesktop.org,
Kees Cook <keescook@chromium.org>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Jeremy Linton <jeremy.linton@arm.com>,
Mark Brown <broonie@kernel.org>,
toiwoton@gmail.com,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: BTI interaction between seccomp filters in systemd and glibc mprotect calls, causing service failures
Date: Tue, 27 Oct 2020 15:41:16 +0100 [thread overview]
Message-ID: <877drb68ab.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <20201027142218.GE27285@arm.com> (Dave Martin via Libc-alpha's message of "Tue, 27 Oct 2020 14:22:19 +0000")
* Dave Martin via Libc-alpha:
> On Mon, Oct 26, 2020 at 05:45:42PM +0100, Florian Weimer via Libc-alpha wrote:
>> * Dave Martin via Libc-alpha:
>>
>> > Would it now help to add something like:
>> >
>> > int mchangeprot(void *addr, size_t len, int old_flags, int new_flags)
>> > {
>> > int ret = -EINVAL;
>> > mmap_write_lock(current->mm);
>> > if (all vmas in [addr .. addr + len) have
>> > their mprotect flags set to old_flags) {
>> >
>> > ret = mprotect(addr, len, new_flags);
>> > }
>> >
>> > mmap_write_unlock(current->mm);
>> > return ret;
>> > }
>>
>> I suggested something similar as well. Ideally, the interface would
>> subsume pkey_mprotect, though, and have a separate flags argument from
>> the protection flags. But then we run into argument list length limits.
>>
>> Thanks,
>> Florian
>
> I suppose. Assuming that a syscall filter can inspect memory, we might
> be able to bundle arguments into a struct if necessary.
But that leads to a discussion about batch mmap/mprotect/munmap, and
that's again incompatible with seccomp (it would need a checking loop).
Thanks,
Florian
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next prev parent reply other threads:[~2020-10-27 14:41 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 3:44 Jeremy Linton
2020-10-22 7:18 ` [systemd-devel] " Lennart Poettering
2020-10-22 7:54 ` Florian Weimer
2020-10-22 8:17 ` Topi Miettinen
2020-10-22 8:25 ` Florian Weimer
2020-10-22 8:29 ` Szabolcs Nagy
2020-10-22 8:38 ` Lennart Poettering
2020-10-22 9:31 ` Catalin Marinas
2020-10-22 10:12 ` Topi Miettinen
2020-10-22 10:27 ` Florian Weimer
2020-10-23 6:13 ` Szabolcs Nagy
2020-10-23 9:04 ` Catalin Marinas
2020-10-22 10:03 ` Topi Miettinen
2020-10-22 8:05 ` Szabolcs Nagy
2020-10-22 8:31 ` Lennart Poettering
2020-10-22 7:54 ` Szabolcs Nagy
2020-10-22 10:39 ` Topi Miettinen
2020-10-22 20:02 ` Kees Cook
2020-10-22 22:24 ` Topi Miettinen
2020-10-23 17:52 ` Salvatore Mesoraca
2020-10-24 11:34 ` Topi Miettinen
2020-10-24 14:12 ` Salvatore Mesoraca
2020-10-25 13:42 ` Jordan Glover
2020-10-23 9:02 ` Catalin Marinas
2020-10-24 11:01 ` Topi Miettinen
2020-10-26 14:52 ` Catalin Marinas
2020-10-26 15:56 ` Dave Martin
2020-10-26 16:51 ` Mark Brown
2020-10-26 16:31 ` Topi Miettinen
2020-10-26 16:24 ` Dave Martin
2020-10-26 16:39 ` Topi Miettinen
2020-10-26 16:45 ` Florian Weimer
2020-10-27 14:22 ` Dave Martin
2020-10-27 14:41 ` Florian Weimer [this message]
2020-10-26 16:57 ` Szabolcs Nagy
2020-10-26 17:52 ` Dave Martin
2020-10-26 22:39 ` Jeremy Linton
2020-10-27 14:15 ` Dave Martin
2020-10-29 11:02 ` Catalin Marinas
2020-11-04 12:18 ` Dave Martin
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