RISC-V: Protect all kernel sections including init early

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Currently, .init.text & .init.data are intermixed which makes it impossible
apply different permissions to them. .init.data shouldn't need exec
permissions while .init.text shouldn't have write permission. Moreover,
the strict permission are only enforced /init starts. This leaves the
kernel vulnerable from possible buggy built-in modules.

Keep .init.text & .data in separate sections so that different permissions
are applied to each section. Apply permissions to individual sections as
early as possible. This improves the kernel protection under
CONFIG_STRICT_KERNEL_RWX. We also need to restore the permissions for the
entire _init section after it is freed so that those pages can be used
for other purpose.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

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Atish Patra 2020-11-04 16:04:38 -08:00 • committed by Palmer Dabbelt

parent b6566dc1ac

commit 19a0086902

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6 changed files with 67 additions and 27 deletions

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2

arch/riscv/include/asm/sections.h

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4

arch/riscv/include/asm/set_memory.h

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12

arch/riscv/kernel/setup.c

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51

arch/riscv/kernel/vmlinux.lds.S

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21

arch/riscv/mm/init.c

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6

arch/riscv/mm/pageattr.c

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