This adds an addition layer of protection for the saved copy of LUKS
volume 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 | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 0611fd83858e..f3d51c38a1c9 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -557,9 +557,25 @@ static void kexec_mark_crashkres(bool protect)
kexec_mark_range(control, crashk_res.end, protect);
}
+static void kexec_mark_luks_volume_key_inaccessible(void)
+{
+ unsigned long start, end;
+ struct page *page;
+ unsigned int nr_pages;
+
+ if (kexec_crash_image->luks_volume_key_addr) {
+ start = kexec_crash_image->luks_volume_key_addr;
+ end = start + kexec_crash_image->luks_volume_key_sz - 1;
+ page = pfn_to_page(start >> PAGE_SHIFT);
+ nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
+ set_memory_np((unsigned long)page_address(page), nr_pages);
+ }
+}
+
void arch_kexec_protect_crashkres(void)
{
kexec_mark_crashkres(true);
+ kexec_mark_luks_volume_key_inaccessible();
}
void arch_kexec_unprotect_crashkres(void)
--
2.37.3
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