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 | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 1a3e2c05a8a5..c9c814b934b8 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -546,14 +546,32 @@ static void kexec_mark_crashkres(bool protect)
kexec_mark_range(control, crashk_res.end, protect);
}
+static void kexec_mark_dm_crypt_key(bool protect)
+{
+ unsigned long start_paddr, end_paddr;
+ unsigned int nr_pages;
+
+ if (kexec_crash_image->dm_crypt_key_addr) {
+ start_paddr = kexec_crash_image->dm_crypt_key_addr;
+ end_paddr = start_paddr + kexec_crash_image->dm_crypt_key_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_rw((unsigned long)phys_to_virt(start_paddr), nr_pages);
+ }
+}
+
void arch_kexec_protect_crashkres(void)
{
kexec_mark_crashkres(true);
+ kexec_mark_dm_crypt_key(true);
}
void arch_kexec_unprotect_crashkres(void)
{
kexec_mark_crashkres(false);
+ kexec_mark_dm_crypt_key(false);
}
/*
--
2.43.0
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