From 549f90db68c9f8e21a40ec21c8047441984e7164 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 6 May 2016 13:50:15 +0200 Subject: [PATCH] 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: Borislav Petkov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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: Ingo Molnar --- arch/x86/boot/compressed/kaslr.c | 17 ++++++----------- arch/x86/boot/compressed/misc.c | 3 ++- arch/x86/boot/compressed/misc.h | 10 +++++----- 3 files changed, 13 insertions(+), 17 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 6392f0041b8a..ff1227746c72 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -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; diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 9536d778149e..f14db4e21654 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -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. */ diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 1f23d022d241..0112005a3f23 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -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 -- 2.39.2