68 lines
2.4 KiB
Diff
68 lines
2.4 KiB
Diff
From d48ec5e1a5fb7907520dee71b1d94045486a0c29 Mon Sep 17 00:00:00 2001
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From: Alexander Kamensky <alexander.kamensky42@gmail.com>
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Date: Thu, 12 Nov 2020 12:56:46 -0800
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Subject: [PATCH] arm64: kexec: disabled check if kaslr-seed dtb property was
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wiped
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Kexec when loading arm64 kernel checks if chosen/kaslr-seed dtb property is
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wiped. It's a good assertion to verify proper behavior of kernel. However,
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if bootloader creates and fills kaslr-seed property and kernel is not
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configured with CONFIG_RANDOMIZE_BASE then logic of reading and wiping
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kaslr-seed does not run. As a result kaslr-seed property is not zero and when
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kexec tries to load secondary kernel it fails with the following message:
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setup_2nd_dtb: kaslr-seed is not wiped to 0.
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kexec: setup_2nd_dtb failed.
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kexec: load failed.
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This was observed on Yocto Project on qemuarm64 machine with 5.8 kernel,
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qemu 5.1.0. Qemu created kaslr-seed property but kernel was not configured
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with CONFIG_RANDOMIZE_BASE.
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Although check has some value, there is a use-case where it breaks kexec,
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this patch removes it.
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Note in described use-case the fact that kaslr-seed is not wiped and user
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readable through /sys/firmware/fdt or
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/sys/firmware/devicetree/base/chosen/kaslr-seed is not a security problem
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as kaslr is disabled anyway.
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Signed-off-by: Alexander Kamensky <alexander.kamensky42@gmail.com>
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Upstream-Status: Submitted [http://lists.infradead.org/pipermail/kexec/2020-November/021740.html]
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---
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kexec/arch/arm64/kexec-arm64.c | 14 +-------------
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1 file changed, 1 insertion(+), 13 deletions(-)
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Index: kexec-tools-2.0.20/kexec/arch/arm64/kexec-arm64.c
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===================================================================
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--- kexec-tools-2.0.20.orig/kexec/arch/arm64/kexec-arm64.c
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+++ kexec-tools-2.0.20/kexec/arch/arm64/kexec-arm64.c
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@@ -428,7 +428,7 @@ static int setup_2nd_dtb(struct dtb *dtb
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int len, range_len;
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int nodeoffset;
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int new_size;
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- int result, kaslr_seed;
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+ int result;
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result = fdt_check_header(dtb->buf);
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@@ -499,18 +499,6 @@ static int setup_2nd_dtb(struct dtb *dtb
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return result;
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}
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} else {
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- kaslr_seed = fdt64_to_cpu(*prop);
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-
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- /* kaslr_seed must be wiped clean by primary
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- * kernel during boot
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- */
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- if (kaslr_seed != 0) {
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- dbgprintf("%s: kaslr-seed is not wiped to 0.\n",
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- __func__);
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- result = -EINVAL;
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- goto on_error;
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- }
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-
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/*
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* Invoke the getrandom system call with
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* GRND_NONBLOCK, to make sure we
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