lkml.org 
[lkml]   [2016]   [May]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/boot] x86/boot: Simplify pointer casting in choose_random_location()
Commit-ID:  549f90db68c9f8e21a40ec21c8047441984e7164
Gitweb: http://git.kernel.org/tip/549f90db68c9f8e21a40ec21c8047441984e7164
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Fri, 6 May 2016 13:50:15 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 7 May 2016 07:38:38 +0200

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 <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: Ingo Molnar <mingo@kernel.org>
---
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 6392f00..ff12277 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 9536d77..f14db4e 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 1f23d02..0112005a 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

\
 
 \ /
  Last update: 2016-05-07 09:01    [W:0.065 / U:0.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site