Commit 5b710aa8 authored by WANG Rui's avatar WANG Rui Committed by Huacai Chen
Browse files

LoongArch: Avoid initrd overlap during kernel relocation 



Validate the relocation address against the initrd region specified via
"initrd=" or "initrdmem=" on the command line. Reject relocation targets
that overlap the initrd to prevent memory corruption during early boot.

Acked-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarWANG Rui <wangrui@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 08ade00f

arch/loongarch/kernel/relocate.c

+38 −0
Original line number Diff line number Diff line
@@ -222,14 +222,52 @@ static inline void __init *determine_relocation_address(void) 
	return RELOCATED_KASLR(destination);

}



static unsigned long __init determine_initrd_address(unsigned long *size)

{

	unsigned long start = 0;

	unsigned long key_length;

	char *p, *endp, *key = "initrd=";



	key_length = strlen(key);

	p = strstr(boot_command_line, key);



	if (!p) {

		key = "initrdmem=";

		key_length = strlen(key);

		p = strstr(boot_command_line, key);

	}



	if (p == boot_command_line || (p > boot_command_line && *(p - 1) == ' ')) {

		p += key_length;

		start = memparse(p, &endp);

		if (*endp == ',')

			*size = memparse(endp + 1, NULL);

	}



	return start;

}



static inline int __init relocation_addr_valid(void *location_new)

{

	unsigned long kernel_start, kernel_size;

	unsigned long initrd_start, initrd_size = 0;



	if ((unsigned long)location_new & 0x00000ffff)

		return 0; /* Inappropriately aligned new location */



	if ((unsigned long)location_new < (unsigned long)_end)

		return 0; /* New location overlaps original kernel */



	initrd_start = determine_initrd_address(&initrd_size);

	if (initrd_start && initrd_size) {

		kernel_start = PHYSADDR(location_new);

		kernel_size = (unsigned long)_end - (unsigned long)_text;



		if (kernel_start < (initrd_start + initrd_size) &&

			initrd_start < (kernel_start + kernel_size))

			return 0; /* initrd/initramfs overlaps kernel */

	}



	return 1;

}

#endif