linux-kernel - [PATCH v3 7/7] x86/crash: make the page that stores the dm crypt keys inaccessible

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240425100434.198925-8-coxu@redhat.com>
Date: Thu, 25 Apr 2024 18:04:31 +0800
From: Coiby Xu <coxu@...hat.com>
To: kexec@...ts.infradead.org
Cc: Ondrej Kozina <okozina@...hat.com>,
	Milan Broz <gmazyland@...il.com>,
	Thomas Staudt <tstaudt@...ibm.com>,
	Daniel P . Berrangé <berrange@...hat.com>,
	Kairui Song <ryncsn@...il.com>,
	dm-devel@...hat.com,
	Jan Pazdziora <jpazdziora@...hat.com>,
	Pingfan Liu <kernelfans@...il.com>,
	Baoquan He <bhe@...hat.com>,
	Dave Young <dyoung@...hat.com>,
	linux-kernel@...r.kernel.org,
	x86@...nel.org,
	Dave Hansen <dave.hansen@...el.com>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v3 7/7] x86/crash: make the page that stores the dm crypt keys inaccessible

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@...il.com>
Signed-off-by: Coiby Xu <coxu@...hat.com>
---
 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);
 }
 
 void arch_kexec_unprotect_crashkres(void)
 {
+	kexec_mark_dm_crypt_keys(false);
 	kexec_mark_crashkres(false);
 }
 #endif
-- 
2.44.0