qemuarm64 fails to kexec secondary kernel with following message: setup_2nd_dtb: kaslr-seed is not wiped to 0. kexec: setup_2nd_dtb failed. kexec: load failed.
It happens because kaslr-seed is not wiped in case when CONFIG_RANDOMIZE_BASE is not set and qemu generates chosen/kaslr-seed property. Solution is to remove check in kexec-tools that kaslr-seed is 0. Signed-off-by: Alexander Kamensky <[email protected]> --- ...bled-check-if-kaslr-seed-dtb-propert.patch | 67 +++++++++++++++++++ .../kexec/kexec-tools_2.0.20.bb | 1 + 2 files changed, 68 insertions(+) create mode 100644 meta/recipes-kernel/kexec/kexec-tools/0001-arm64-kexec-disabled-check-if-kaslr-seed-dtb-propert.patch diff --git a/meta/recipes-kernel/kexec/kexec-tools/0001-arm64-kexec-disabled-check-if-kaslr-seed-dtb-propert.patch b/meta/recipes-kernel/kexec/kexec-tools/0001-arm64-kexec-disabled-check-if-kaslr-seed-dtb-propert.patch new file mode 100644 index 0000000000..c2301e711d --- /dev/null +++ b/meta/recipes-kernel/kexec/kexec-tools/0001-arm64-kexec-disabled-check-if-kaslr-seed-dtb-propert.patch @@ -0,0 +1,67 @@ +From d48ec5e1a5fb7907520dee71b1d94045486a0c29 Mon Sep 17 00:00:00 2001 +From: Alexander Kamensky <[email protected]> +Date: Thu, 12 Nov 2020 12:56:46 -0800 +Subject: [PATCH] arm64: kexec: disabled check if kaslr-seed dtb property was + wiped + +Kexec when loading arm64 kernel checks if chosen/kaslr-seed dtb property is +wiped. It's a good assertion to verify proper behavior of kernel. However, +if bootloader creates and fills kaslr-seed property and kernel is not +configured with CONFIG_RANDOMIZE_BASE then logic of reading and wiping +kaslr-seed does not run. As a result kaslr-seed property is not zero and when +kexec tries to load secondary kernel it fails with the following message: + +setup_2nd_dtb: kaslr-seed is not wiped to 0. +kexec: setup_2nd_dtb failed. +kexec: load failed. + +This was observed on Yocto Project on qemuarm64 machine with 5.8 kernel, +qemu 5.1.0. Qemu created kaslr-seed property but kernel was not configured +with CONFIG_RANDOMIZE_BASE. + +Although check has some value, there is a use-case where it breaks kexec, +this patch removes it. + +Note in described use-case the fact that kaslr-seed is not wiped and user +readable through /sys/firmware/fdt or +/sys/firmware/devicetree/base/chosen/kaslr-seed is not a security problem +as kaslr is disabled anyway. + +Signed-off-by: Alexander Kamensky <[email protected]> +Upstream-Status: Submitted [http://lists.infradead.org/pipermail/kexec/2020-November/021740.html] +--- + kexec/arch/arm64/kexec-arm64.c | 14 +------------- + 1 file changed, 1 insertion(+), 13 deletions(-) + +Index: kexec-tools-2.0.20/kexec/arch/arm64/kexec-arm64.c +=================================================================== +--- kexec-tools-2.0.20.orig/kexec/arch/arm64/kexec-arm64.c ++++ kexec-tools-2.0.20/kexec/arch/arm64/kexec-arm64.c +@@ -428,7 +428,7 @@ static int setup_2nd_dtb(struct dtb *dtb + int len, range_len; + int nodeoffset; + int new_size; +- int result, kaslr_seed; ++ int result; + + result = fdt_check_header(dtb->buf); + +@@ -499,18 +499,6 @@ static int setup_2nd_dtb(struct dtb *dtb + return result; + } + } else { +- kaslr_seed = fdt64_to_cpu(*prop); +- +- /* kaslr_seed must be wiped clean by primary +- * kernel during boot +- */ +- if (kaslr_seed != 0) { +- dbgprintf("%s: kaslr-seed is not wiped to 0.\n", +- __func__); +- result = -EINVAL; +- goto on_error; +- } +- + /* + * Invoke the getrandom system call with + * GRND_NONBLOCK, to make sure we diff --git a/meta/recipes-kernel/kexec/kexec-tools_2.0.20.bb b/meta/recipes-kernel/kexec/kexec-tools_2.0.20.bb index 1e81ecc2c7..69d2e9bfba 100644 --- a/meta/recipes-kernel/kexec/kexec-tools_2.0.20.bb +++ b/meta/recipes-kernel/kexec/kexec-tools_2.0.20.bb @@ -21,6 +21,7 @@ SRC_URI = "${KERNELORG_MIRROR}/linux/utils/kernel/kexec/kexec-tools-${PV}.tar.gz file://0006-kexec-arm-undefine-__NR_kexec_file_load-for-arm.patch \ file://0007-kexec-un-break-the-build-on-32-bit-x86.patch \ file://0001-kexec-Fix-build-with-fno-common.patch \ + file://0001-arm64-kexec-disabled-check-if-kaslr-seed-dtb-propert.patch \ " SRC_URI[md5sum] = "46724b67f32501c5d3e778161347cad9" -- 2.26.2
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