On Fri, Jun 07, 2024 at 06:00:44PM +0800, Baoquan He wrote:
On 05/23/24 at 01:04pm, Coiby Xu wrote:This adds an addition layer of protection for the saved copy of dm crypt key. Trying to access the saved copy will cause page fault. Suggested-by: Pingfan Liu <kernelfans@xxxxxxxxx> Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx> --- arch/x86/kernel/machine_kexec_64.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index b180d8e497c3..fc0a80f4254e 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -545,13 +545,34 @@ static void kexec_mark_crashkres(bool protect) kexec_mark_range(control, crashk_res.end, protect); } +static void kexec_mark_dm_crypt_keys(bool protect) +{ + unsigned long start_paddr, end_paddr; + unsigned int nr_pages; + + if (kexec_crash_image->dm_crypt_keys_addr) { + start_paddr = kexec_crash_image->dm_crypt_keys_addr; + end_paddr = start_paddr + kexec_crash_image->dm_crypt_keys_sz - 1; + nr_pages = (PAGE_ALIGN(end_paddr) - PAGE_ALIGN_DOWN(start_paddr))/PAGE_SIZE; + if (protect) + set_memory_np((unsigned long)phys_to_virt(start_paddr), nr_pages); + else + __set_memory_prot( + (unsigned long)phys_to_virt(start_paddr), + nr_pages, + __pgprot(_PAGE_PRESENT | _PAGE_NX | _PAGE_RW)); + } +} + void arch_kexec_protect_crashkres(void) { kexec_mark_crashkres(true); + kexec_mark_dm_crypt_keys(true);Isn't crashkernel region covering crypt keys' storing region? Do we need mark it again specifically? Not sure if I miss anything.
kexec_mark_crashkres only makes the page read-only whereas kexec_mark_dm_crypt_keys makes the memory inaccessible. I've added a comment for this function in v5 and hopefully no one will be confused by it. -- Best regards, Coiby _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
