The 'output' variable is passed from decompress_kernel to check_ipl_parmblock before it is initialized. That disables the safe guard against the overwrite of the ipl parameter block. Fix this by passing the correct value to check_ipl_parmblock. Reported-by: David Binderman <dcb314@hotmail.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
		
			
				
	
	
		
			163 lines
		
	
	
	
		
			3.6 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			163 lines
		
	
	
	
		
			3.6 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Definitions and wrapper functions for kernel decompressor
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 *
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 * Copyright IBM Corp. 2010
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 *
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 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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 */
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#include <asm/uaccess.h>
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#include <asm/page.h>
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#include <asm/ipl.h>
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#include "sizes.h"
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/*
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 * gzip declarations
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 */
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#define STATIC static
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#undef memset
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#undef memcpy
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#undef memmove
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#define memzero(s, n) memset((s), 0, (n))
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/* Symbols defined by linker scripts */
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extern char input_data[];
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extern int input_len;
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extern char _text, _end;
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extern char _bss, _ebss;
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static void error(char *m);
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static unsigned long free_mem_ptr;
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static unsigned long free_mem_end_ptr;
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#ifdef CONFIG_HAVE_KERNEL_BZIP2
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#define HEAP_SIZE	0x400000
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#else
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#define HEAP_SIZE	0x10000
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#endif
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#ifdef CONFIG_KERNEL_GZIP
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#include "../../../../lib/decompress_inflate.c"
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#endif
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#ifdef CONFIG_KERNEL_BZIP2
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#include "../../../../lib/decompress_bunzip2.c"
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#endif
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#ifdef CONFIG_KERNEL_LZMA
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#include "../../../../lib/decompress_unlzma.c"
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#endif
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#ifdef CONFIG_KERNEL_LZO
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#include "../../../../lib/decompress_unlzo.c"
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#endif
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extern _sclp_print_early(const char *);
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int puts(const char *s)
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{
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	_sclp_print_early(s);
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	return 0;
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}
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void *memset(void *s, int c, size_t n)
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{
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	char *xs;
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	if (c == 0)
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		return __builtin_memset(s, 0, n);
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	xs = (char *) s;
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	if (n > 0)
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		do {
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			*xs++ = c;
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		} while (--n > 0);
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	return s;
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}
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void *memcpy(void *__dest, __const void *__src, size_t __n)
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{
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	return __builtin_memcpy(__dest, __src, __n);
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}
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void *memmove(void *__dest, __const void *__src, size_t __n)
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{
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	char *d;
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	const char *s;
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	if (__dest <= __src)
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		return __builtin_memcpy(__dest, __src, __n);
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	d = __dest + __n;
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	s = __src + __n;
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	while (__n--)
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		*--d = *--s;
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	return __dest;
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}
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static void error(char *x)
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{
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	unsigned long long psw = 0x000a0000deadbeefULL;
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	puts("\n\n");
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	puts(x);
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	puts("\n\n -- System halted");
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	asm volatile("lpsw %0" : : "Q" (psw));
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}
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/*
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 * Safe guard the ipl parameter block against a memory area that will be
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 * overwritten. The validity check for the ipl parameter block is complex
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 * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
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 * the ipl parameter block intersects with the passed memory area we can
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 * safely assume that we can read from that memory. In that case just copy
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 * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
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 * block.
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 */
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static void check_ipl_parmblock(void *start, unsigned long size)
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{
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	void *src, *dst;
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	src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
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	if (src + PAGE_SIZE <= start || src >= start + size)
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		return;
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	dst = (void *) IPL_PARMBLOCK_ORIGIN;
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	memmove(dst, src, PAGE_SIZE);
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	S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
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}
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unsigned long decompress_kernel(void)
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{
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	unsigned long output_addr;
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	unsigned char *output;
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	output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
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	check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
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	memset(&_bss, 0, &_ebss - &_bss);
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	free_mem_ptr = (unsigned long)&_end;
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	free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
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	output = (unsigned char *) output_addr;
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#ifdef CONFIG_BLK_DEV_INITRD
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	/*
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	 * Move the initrd right behind the end of the decompressed
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	 * kernel image.
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	 */
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	if (INITRD_START && INITRD_SIZE &&
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	    INITRD_START < (unsigned long) output + SZ__bss_start) {
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		check_ipl_parmblock(output + SZ__bss_start,
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				    INITRD_START + INITRD_SIZE);
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		memmove(output + SZ__bss_start,
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			(void *) INITRD_START, INITRD_SIZE);
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		INITRD_START = (unsigned long) output + SZ__bss_start;
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	}
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#endif
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	puts("Uncompressing Linux... ");
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	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
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	puts("Ok, booting the kernel.\n");
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	return (unsigned long) output;
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}
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