2fb18b5d30
This brings in several patches needed to add support for a memfd_create() syscall into kernel version 3.4 from kernel version 3.17. This is required for running lxc >= 3.1.0-r1 with security patch that fixes CVE-2019-5736. In short, security issue was: in a privileged container root process could overwrite lxc-start executable by opening its file descriptor and rewriting executable contents. This is where memfd comes to help: you can create an in-memory file, copy your executable there, and place a set of SEALS to protect it from modifying at a deep level. Then you fexecve() that fd and you're safe. For example, pulseaudio also can benefit from having memfd_create() implemented. This backports the following commits from upstream linux: - dd37978c50bc8b354e5c4633f69387f16572fdac: cache the value of file_inode() in struct file commit from linux-3.10 to have an f_inode member inside struct file and a helper function file_inode() that is used in some of the following commits - 40e041a2c858b3caefc757e26cb85bfceae5062b shm: add sealing API from 3.17: security measure called SEALS, that you can put on memfd file to restrict operations on it - 9183df25fe7b194563db3fec6dc3202a5855839c shm: add memfd_create() syscall also from 3.17 - 503e6636b6f96056210062be703356f4253b6db9 asm-generic: add memfd_create system call to unistd.h - e57e41931134e09fc6c03c8d4eb19d516cc6e59b ARM: wire up memfd_create syscall The last two are needed to make the syscall visible/usable from userspace, one in generic context, other for ARM arch. The test program (https://github.com/minlexx/test_memfd/) was written to verify that this works. [ci:skip-build]: already built successfully in CI
42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
From c4dd412e68ccbe2e759d6517e902a6f3e7d8f700 Mon Sep 17 00:00:00 2001
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From: Russell King <rmk+kernel@arm.linux.org.uk>
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Date: Tue, 2 Jul 2019 02:57:25 +0300
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Subject: [PATCH 5/5] ARM: wire up memfd_create syscall
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Add the memfd_create syscall to ARM.
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Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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---
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arch/arm/include/asm/unistd.h | 2 ++
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arch/arm/kernel/calls.S | 2 ++
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2 files changed, 4 insertions(+)
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diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
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index 6ef9635a174..9b81e87e683 100644
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--- a/arch/arm/include/asm/unistd.h
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+++ b/arch/arm/include/asm/unistd.h
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@@ -405,6 +405,8 @@
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#define __NR_process_vm_readv (__NR_SYSCALL_BASE+376)
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#define __NR_process_vm_writev (__NR_SYSCALL_BASE+377)
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#define __NR_seccomp (__NR_SYSCALL_BASE+383)
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+/*#define __NR_getrandom (__NR_SYSCALL_BASE+384) not ported yet */
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+#define __NR_memfd_create (__NR_SYSCALL_BASE+385)
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/*
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* The following SWIs are ARM private.
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diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
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index d01eb013b0a..957e262aa86 100644
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--- a/arch/arm/kernel/calls.S
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+++ b/arch/arm/kernel/calls.S
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@@ -393,6 +393,8 @@
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CALL(sys_ni_syscall)
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CALL(sys_ni_syscall)
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CALL(sys_seccomp)
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+ CALL(sys_ni_syscall) /* no sys_getrandom yet */
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+/* 385 */ CALL(sys_memfd_create)
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#ifndef syscalls_counted
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.equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
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#define syscalls_counted
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--
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2.20.1
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