From: Florian Weimer <fweimer@redhat.com>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: libc-alpha@sourceware.org, Jeremy Linton <jeremy.linton@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Brown <broonie@kernel.org>,
Kees Cook <keescook@chromium.org>,
Salvatore Mesoraca <s.mesoraca16@gmail.com>,
Lennart Poettering <mzxreary@0pointer.de>,
Topi Miettinen <toiwoton@gmail.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
kernel-hardening@lists.openwall.com,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH 3/4] aarch64: Use mmap to add PROT_BTI instead of mprotect [BZ #26831]
Date: Tue, 03 Nov 2020 11:34:22 +0100 [thread overview]
Message-ID: <87v9embufl.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <f5eaa74cb7538382b2fd2439755386ac68f7c8db.1604393169.git.szabolcs.nagy@arm.com> (Szabolcs Nagy's message of "Tue, 3 Nov 2020 10:26:29 +0000")
* Szabolcs Nagy:
> Re-mmap executable segments if possible instead of using mprotect
> to add PROT_BTI. This allows using BTI protection with security
> policies that prevent mprotect with PROT_EXEC.
>
> If the fd of the ELF module is not available because it was kernel
> mapped then mprotect is used and failures are ignored. It is
> expected that linux kernel will add PROT_BTI when mapping a module
> (current linux as of version 5.9 does not do this).
>
> Computing the mapping parameters follows the logic of
> _dl_map_object_from_fd more closely now.
What's the performance of this on execve-heavy workloads, such as kernel
or glibc builds? Hopefully it's cheap because these mappings have not
been faulted in yet.
Thanks,
Florian
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next prev parent reply other threads:[~2020-11-03 10:34 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-03 10:25 [PATCH 0/4] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) [BZ #26831] Szabolcs Nagy
2020-11-03 10:25 ` [PATCH 1/4] elf: Pass the fd to note processing " Szabolcs Nagy
2020-11-03 10:26 ` [PATCH 2/4] elf: Move note processing after l_phdr is updated " Szabolcs Nagy
2020-11-03 10:38 ` Florian Weimer
2020-11-03 12:36 ` H.J. Lu
2020-11-03 15:04 ` Szabolcs Nagy
2020-11-03 15:27 ` H.J. Lu
2020-11-03 10:26 ` [PATCH 3/4] aarch64: Use mmap to add PROT_BTI instead of mprotect " Szabolcs Nagy
2020-11-03 10:34 ` Florian Weimer [this message]
2020-11-03 10:26 ` [PATCH 4/4] aarch64: Remove the bti link_map field " Szabolcs Nagy
2020-11-03 17:34 ` [PATCH 0/4] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) " Mark Brown
2020-11-04 5:41 ` Jeremy Linton
2020-11-04 8:57 ` Szabolcs Nagy
2020-11-04 14:41 ` Catalin Marinas
2020-11-04 14:45 ` Florian Weimer
2020-11-04 10:50 ` Mark Brown
2020-11-04 18:47 ` Jeremy Linton
2020-11-04 18:53 ` Mark Brown
2020-11-04 9:02 ` Topi Miettinen
2020-11-04 9:20 ` Will Deacon
2020-11-04 9:29 ` Florian Weimer
2020-11-04 9:55 ` Topi Miettinen
2020-11-04 14:35 ` Catalin Marinas
2020-11-04 15:19 ` Topi Miettinen
2020-11-04 16:08 ` Szabolcs Nagy
2020-11-04 15:20 ` Mark Rutland
2020-11-04 18:59 ` Jeremy Linton
2020-11-05 11:31 ` Szabolcs Nagy
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