+ x86-kexec-add-a-sanity-check-on-previous-kernels-ima-kexec-buffer.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

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The patch titled
     Subject: x86/kexec: add a sanity check on previous kernel's ima kexec buffer
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     x86-kexec-add-a-sanity-check-on-previous-kernels-ima-kexec-buffer.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/x86-kexec-add-a-sanity-check-on-previous-kernels-ima-kexec-buffer.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Subject: x86/kexec: add a sanity check on previous kernel's ima kexec buffer
Date: Tue, 30 Dec 2025 22:16:09 -0800

When the second-stage kernel is booted via kexec with a limiting command
line such as "mem=<size>", the physical range that contains the carried
over IMA measurement list may fall outside the truncated RAM leading to a
kernel panic.

    BUG: unable to handle page fault for address: ffff97793ff47000
    RIP: ima_restore_measurement_list+0xdc/0x45a
    #PF: error_code(0x0000) – not-present page

Other architectures already validate the range with page_is_ram(), as done
in commit cbf9c4b9617b ("of: check previous kernel's ima-kexec-buffer
against memory bounds") do a similar check on x86.

Without carrying the measurement list across kexec, the attestation
would fail.

Link: https://lkml.kernel.org/r/20251231061609.907170-4-harshit.m.mogalapalli@oracle.com
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Fixes: b69a2afd5afc ("x86/kexec: Carry forward IMA measurement log on kexec")
Reported-by: Paul Webb <paul.x.webb@oracle.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: guoweikang <guoweikang.kernel@gmail.com>
Cc: Henry Willard <henry.willard@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: Jonathan McDowell <noodles@fb.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Yifei Liu <yifei.l.liu@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/kernel/setup.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/arch/x86/kernel/setup.c~x86-kexec-add-a-sanity-check-on-previous-kernels-ima-kexec-buffer
+++ a/arch/x86/kernel/setup.c
@@ -439,9 +439,15 @@ int __init ima_free_kexec_buffer(void)
 
 int __init ima_get_kexec_buffer(void **addr, size_t *size)
 {
+	int ret;
+
 	if (!ima_kexec_buffer_size)
 		return -ENOENT;
 
+	ret = ima_validate_range(ima_kexec_buffer_phys, ima_kexec_buffer_size);
+	if (ret)
+		return ret;
+
 	*addr = __va(ima_kexec_buffer_phys);
 	*size = ima_kexec_buffer_size;
 
_

Patches currently in -mm which might be from harshit.m.mogalapalli@oracle.com are

ima-verify-the-previous-kernels-ima-buffer-lies-in-addressable-ram.patch
of-kexec-refactor-ima_get_kexec_buffer-to-use-ima_validate_range.patch
x86-kexec-add-a-sanity-check-on-previous-kernels-ima-kexec-buffer.patch