The patch titled Subject: ima: verify the previous kernel's IMA buffer lies in addressable RAM has been added to the -mm mm-nonmm-unstable branch. Its filename is ima-verify-the-previous-kernels-ima-buffer-lies-in-addressable-ram.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

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: ima: verify the previous kernel's IMA buffer lies in addressable RAM Date: Tue, 30 Dec 2025 22:16:07 -0800

Patch series "Address page fault in ima_restore_measurement_list()", v3.

When the second-stage kernel is booted via kexec with a limiting command line such as "mem=<size>" we observe a pafe fault that happens.

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

This happens on x86_64 only, as this is already fixed in aarch64 in commit: cbf9c4b9617b ("of: check previous kernel's ima-kexec-buffer against memory bounds")

This patch (of 3):

When the second-stage kernel is booted with a limiting command line (e.g. "mem=<size>"), the IMA measurement buffer handed over from the previous kernel may fall outside the addressable RAM of the new kernel. Accessing such a buffer can fault during early restore.

Introduce a small generic helper, ima_validate_range(), which verifies that a physical [start, end] range for the previous-kernel IMA buffer lies within addressable memory: - On x86, use pfn_range_is_mapped(). - On OF based architectures, use page_is_ram().

Link: https://lkml.kernel.org/r/20251231061609.907170-1-harshit.m.mogalapalli@orac... Link: https://lkml.kernel.org/r/20251231061609.907170-2-harshit.m.mogalapalli@orac... Signed-off-by: Harshit Mogalapalli harshit.m.mogalapalli@oracle.com Cc: Alexander Graf graf@amazon.com Cc: Ard Biesheuvel ardb@kernel.org 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: Mimi Zohar zohar@linux.ibm.com Cc: Paul Webb paul.x.webb@oracle.com 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: Baoquan He bhe@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

include/linux/ima.h | 1 security/integrity/ima/ima_kexec.c | 35 +++++++++++++++++++++++++++ 2 files changed, 36 insertions(+)

--- a/include/linux/ima.h~ima-verify-the-previous-kernels-ima-buffer-lies-in-addressable-ram +++ a/include/linux/ima.h @@ -69,6 +69,7 @@ static inline int ima_measure_critical_d #ifdef CONFIG_HAVE_IMA_KEXEC int __init ima_free_kexec_buffer(void); int __init ima_get_kexec_buffer(void **addr, size_t *size); +int ima_validate_range(phys_addr_t phys, size_t size); #endif

#ifdef CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT --- a/security/integrity/ima/ima_kexec.c~ima-verify-the-previous-kernels-ima-buffer-lies-in-addressable-ram +++ a/security/integrity/ima/ima_kexec.c @@ -12,6 +12,8 @@ #include <linux/kexec.h> #include <linux/of.h> #include <linux/ima.h> +#include <linux/mm.h> +#include <linux/overflow.h> #include <linux/reboot.h> #include <asm/page.h> #include "ima.h" @@ -294,3 +296,36 @@ void __init ima_load_kexec_buffer(void) pr_debug("Error restoring the measurement list: %d\n", rc); } } + +/* + * ima_validate_range - verify a physical buffer lies in addressable RAM + * @phys: physical start address of the buffer from previous kernel + * @size: size of the buffer + * + * On success return 0. On failure returns -EINVAL so callers can skip + * restoring. + */ +int ima_validate_range(phys_addr_t phys, size_t size) +{ + unsigned long start_pfn, end_pfn; + phys_addr_t end_phys; + + if (check_add_overflow(phys, (phys_addr_t)size - 1, &end_phys)) + return -EINVAL; + + start_pfn = PHYS_PFN(phys); + end_pfn = PHYS_PFN(end_phys); + +#ifdef CONFIG_X86 + if (!pfn_range_is_mapped(start_pfn, end_pfn)) +#else + if (!page_is_ram(start_pfn) || !page_is_ram(end_pfn)) +#endif + { + pr_warn("IMA: previous kernel measurement buffer %pa (size 0x%zx) lies outside available memory\n", + &phys, size); + return -EINVAL; + } + + return 0; +} _

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