Commit 549f90db authored by Borislav Petkov's avatar Borislav Petkov Committed by Ingo Molnar
Browse files

x86/boot: Simplify pointer casting in choose_random_location() 



Pass them down as 'unsigned long' directly and get rid of more casting and
assignments.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: bhe@redhat.com
Cc: dyoung@redhat.com
Cc: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org
Cc: vgoyal@redhat.com
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20160506115015.GI24044@pd.tnic


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9dc1969c

arch/x86/boot/compressed/kaslr.c

+6 −11
Original line number Diff line number Diff line
@@ -350,20 +350,15 @@ static unsigned long find_random_addr(unsigned long minimum, 
	return slots_fetch_random();

}



unsigned char *choose_random_location(unsigned char *input_ptr,

/*

 * Since this function examines addresses much more numerically,

 * it takes the input and output pointers as 'unsigned long'.

 */

unsigned char *choose_random_location(unsigned long input,

				      unsigned long input_size,

				      unsigned char *output_ptr,

				      unsigned long output,

				      unsigned long output_size)

{

	/*

	 * The caller of choose_random_location() uses unsigned char * for

	 * buffer pointers since it performs decompression, elf parsing, etc.

	 * Since this code examines addresses much more numerically,

	 * unsigned long is used internally here. Instead of sprinkling

	 * more casts into extract_kernel, do them here and at return.

	 */

	unsigned long input = (unsigned long)input_ptr;

	unsigned long output = (unsigned long)output_ptr;

	unsigned long choice = output;

	unsigned long random_addr;

arch/x86/boot/compressed/misc.c

+2 −1
Original line number Diff line number Diff line
@@ -366,7 +366,8 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, 
	 * the entire decompressed kernel plus relocation table, or the

	 * entire decompressed kernel plus .bss and .brk sections.

	 */

	output = choose_random_location(input_data, input_len, output,

	output = choose_random_location((unsigned long)input_data, input_len,

					(unsigned long)output,

					max(output_len, kernel_total_size));



	/* Validate memory location choices. */

arch/x86/boot/compressed/misc.h

+5 −5
Original line number Diff line number Diff line
@@ -67,20 +67,20 @@ int cmdline_find_option_bool(const char *option); 


#if CONFIG_RANDOMIZE_BASE

/* kaslr.c */

unsigned char *choose_random_location(unsigned char *input_ptr,

unsigned char *choose_random_location(unsigned long input_ptr,

				      unsigned long input_size,

				      unsigned char *output_ptr,

				      unsigned long output_ptr,

				      unsigned long output_size);

/* cpuflags.c */

bool has_cpuflag(int flag);

#else

static inline

unsigned char *choose_random_location(unsigned char *input_ptr,

unsigned char *choose_random_location(unsigned long input_ptr,

				      unsigned long input_size,

				      unsigned char *output_ptr,

				      unsigned long output_ptr,

				      unsigned long output_size)

{

	return output_ptr;

	return (unsigned char *)output_ptr;

}

#endif

CRA Git | Maintained and supported by SUSTech CRA and CCSE