Commit ccd58205 authored by Guo Weikang's avatar Guo Weikang Committed by Andrew Morton
Browse files

mm/early_ioremap: add null pointer checks to prevent NULL-pointer dereference 

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@gmail.com


Signed-off-by: default avatarGuo Weikang <guoweikang.kernel@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8ad946eb

arch/x86/kernel/setup.c

+4 −1
Original line number Diff line number Diff line
@@ -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",

drivers/acpi/acpi_extlog.c

+14 −0
Original line number Diff line number Diff line
@@ -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 @@ static int __init extlog_init(void) 
	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;

include/asm-generic/early_ioremap.h

+1 −1
Original line number Diff line number Diff line
@@ -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

mm/early_ioremap.c

+7 −1
Original line number Diff line number Diff line
@@ -245,7 +245,10 @@ early_memremap_prot(resource_size_t phys_addr, unsigned long size, 


#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 *dest, phys_addr_t src, unsigned long size) 
		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 */