From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Florian Weimer <fweimer@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
systemd-devel@lists.freedesktop.org,
Kees Cook <keescook@chromium.org>,
libc-alpha@sourceware.org, Will Deacon <will.deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mark Brown <broonie@kernel.org>,
Topi Miettinen <toiwoton@gmail.com>,
Lennart Poettering <mzxreary@0pointer.de>,
Dave Martin <dave.martin@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [systemd-devel] BTI interaction between seccomp filters in systemd and glibc mprotect calls, causing service failures
Date: Fri, 23 Oct 2020 07:13:17 +0100 [thread overview]
Message-ID: <20201023061316.GR3819@arm.com> (raw)
In-Reply-To: <20201022093104.GB1229@gaia>
The 10/22/2020 10:31, Catalin Marinas wrote:
> IIUC, the problem is with the main executable which is mapped by the
> kernel without PROT_BTI. The dynamic loader wants to set PROT_BTI but
> does not have the original file descriptor to be able to remap. Its only
> choice is mprotect() and this fails because of the MDWX policy.
>
> Not sure whether the kernel has the right information but could it map
> the main executable with PROT_BTI if the corresponding PT_GNU_PROPERTY
> is found? The current ABI states it only sets PROT_BTI for the
> interpreter who'd be responsible for setting the PROT_BTI on the main
> executable. I can't tell whether it would break anything but it's worth
> a try:
i think it would work, but now i can't easily
tell from the libc if i have to do the mprotect
on the main exe or not.
i guess i can just always mprotect and ignore
the failure?
>
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 4784011cecac..0a08fb9133e8 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -730,14 +730,6 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void)
> int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
> bool has_interp, bool is_interp)
> {
> - /*
> - * For dynamically linked executables the interpreter is
> - * responsible for setting PROT_BTI on everything except
> - * itself.
> - */
> - if (is_interp != has_interp)
> - return prot;
> -
> if (!(state->flags & ARM64_ELF_BTI))
> return prot;
>
>
> --
> Catalin
--
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next prev parent reply other threads:[~2020-10-23 6:14 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8584c14f-5c28-9d70-c054-7c78127d84ea@arm.com>
2020-10-22 7:18 ` [systemd-devel] BTI interaction between seccomp filters in systemd and glibc mprotect calls, causing service failures 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 [this message]
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
[not found] ` <20201022075447.GO3819@arm.com>
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
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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