The patch titled
Subject: mm/early_ioremap: add null pointer checks to prevent NULL-pointer dereference
has been added to the -mm mm-unstable branch. Its filename is
mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Guo Weikang <guoweikang.kernel@xxxxxxxxx>
Subject: mm/early_ioremap: add null pointer checks to prevent NULL-pointer dereference
Date: Thu, 12 Dec 2024 18:10:00 +0800
The early_ioremap interface can fail and return NULL in certain cases. To
prevent NULL-pointer dereference crashes, fixed issues in the acpi_extlog
and copy_early_mem interfaces, improving robustness when handling early
memory.
Link: https://lkml.kernel.org/r/20241212101004.1544070-1-guoweikang.kernel@xxxxxxxxx
Signed-off-by: Guo Weikang <guoweikang.kernel@xxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jason A. Donenfeld <Jason@xxxxxxxxx>
Cc: Julian Stecklina <julian.stecklina@xxxxxxxxxxxxxxxxxxxxx>
Cc: Kevin Loughlin <kevinloughlin@xxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Xin Li (Intel) <xin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/setup.c | 5 ++++-
drivers/acpi/acpi_extlog.c | 14 ++++++++++++++
include/asm-generic/early_ioremap.h | 2 +-
mm/early_ioremap.c | 8 +++++++-
4 files changed, 26 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/setup.c~mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference
+++ a/arch/x86/kernel/setup.c
@@ -259,6 +259,7 @@ static void __init relocate_initrd(void)
u64 ramdisk_image = get_ramdisk_image();
u64 ramdisk_size = get_ramdisk_size();
u64 area_size = PAGE_ALIGN(ramdisk_size);
+ int ret = 0;
/* We need to move the initrd down into directly mapped mem */
u64 relocated_ramdisk = memblock_phys_alloc_range(area_size, PAGE_SIZE, 0,
@@ -272,7 +273,9 @@ static void __init relocate_initrd(void)
printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
- copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
+ ret = copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
+ if (ret)
+ panic("Copy RAMDISK failed\n");
printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
" [mem %#010llx-%#010llx]\n",
--- a/drivers/acpi/acpi_extlog.c~mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference
+++ a/drivers/acpi/acpi_extlog.c
@@ -251,6 +251,10 @@ static int __init extlog_init(void)
}
extlog_l1_hdr = acpi_os_map_iomem(l1_dirbase, l1_hdr_size);
+ if (!extlog_l1_hdr) {
+ rc = -ENOMEM;
+ goto err_release_l1_hdr;
+ }
l1_head = (struct extlog_l1_head *)extlog_l1_hdr;
l1_size = l1_head->total_len;
l1_percpu_entry = l1_head->entries;
@@ -268,6 +272,10 @@ static int __init extlog_init(void)
goto err;
}
extlog_l1_addr = acpi_os_map_iomem(l1_dirbase, l1_size);
+ if (!extlog_l1_addr) {
+ rc = -ENOMEM;
+ goto err_release_l1_dir;
+ }
l1_entry_base = (u64 *)((u8 *)extlog_l1_addr + l1_hdr_size);
/* remap elog table */
@@ -279,6 +287,10 @@ static int __init extlog_init(void)
goto err_release_l1_dir;
}
elog_addr = acpi_os_map_iomem(elog_base, elog_size);
+ if (!elog_addr) {
+ rc = -ENOMEM;
+ goto err_release_elog;
+ }
rc = -ENOMEM;
/* allocate buffer to save elog record */
@@ -300,6 +312,8 @@ err_release_l1_dir:
if (extlog_l1_addr)
acpi_os_unmap_iomem(extlog_l1_addr, l1_size);
release_mem_region(l1_dirbase, l1_size);
+err_release_l1_hdr:
+ release_mem_region(l1_dirbase, l1_hdr_size);
err:
pr_warn(FW_BUG "Extended error log disabled because of problems parsing f/w tables\n");
return rc;
--- a/include/asm-generic/early_ioremap.h~mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference
+++ a/include/asm-generic/early_ioremap.h
@@ -35,7 +35,7 @@ extern void early_ioremap_reset(void);
/*
* Early copy from unmapped memory to kernel mapped memory.
*/
-extern void copy_from_early_mem(void *dest, phys_addr_t src,
+extern int copy_from_early_mem(void *dest, phys_addr_t src,
unsigned long size);
#else
--- a/mm/early_ioremap.c~mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference
+++ a/mm/early_ioremap.c
@@ -245,7 +245,10 @@ early_memremap_prot(resource_size_t phys
#define MAX_MAP_CHUNK (NR_FIX_BTMAPS << PAGE_SHIFT)
-void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
+/*
+ * If no empty slot, handle that and return -ENOMEM.
+ */
+int __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
{
unsigned long slop, clen;
char *p;
@@ -256,12 +259,15 @@ void __init copy_from_early_mem(void *de
if (clen > MAX_MAP_CHUNK - slop)
clen = MAX_MAP_CHUNK - slop;
p = early_memremap(src & PAGE_MASK, clen + slop);
+ if (!p)
+ return -ENOMEM;
memcpy(dest, p + slop, clen);
early_memunmap(p, clen + slop);
dest += clen;
src += clen;
size -= clen;
}
+ return 0;
}
#else /* CONFIG_MMU */
_
Patches currently in -mm which might be from guoweikang.kernel@xxxxxxxxx are
mm-shmem-refactor-to-reuse-vfs_parse_monolithic_sep-for-option-parsing.patch
mm-early_ioremap-add-null-pointer-checks-to-prevent-null-pointer-dereference.patch
