Commit-ID: 7de828dfe607013546ece7ce25aa9839e8f93a66 Gitweb: http://git.kernel.org/tip/7de828dfe607013546ece7ce25aa9839e8f93a66 Author: Kees Cook <[email protected]> AuthorDate: Mon, 18 Apr 2016 09:42:14 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 19 Apr 2016 10:30:51 +0200
x86/KASLR: Clarify purpose of kaslr.c The name "choose_kernel_location" isn't specific enough, and doesn't describe the primary thing it does: choosing a random location. This patch renames it to "choose_random_location", and clarifies the what routines are contained in the kaslr.c source file. Suggested-by: Ingo Molnar <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/boot/compressed/kaslr.c | 13 ++++++++++++- arch/x86/boot/compressed/misc.c | 2 +- arch/x86/boot/compressed/misc.h | 4 ++-- 3 files changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index a51ec84..9e03190 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -1,3 +1,14 @@ +/* + * kaslr.c + * + * This contains the routines needed to generate a reasonable level of + * entropy to choose a randomized kernel base address offset in support + * of Kernel Address Space Layout Randomization (KASLR). Additionally + * handles walking the physical memory maps (and tracking memory regions + * to avoid) in order to select a physical memory location that can + * contain the entire properly aligned running kernel image. + * + */ #include "misc.h" #include <asm/msr.h> @@ -295,7 +306,7 @@ static unsigned long find_random_addr(unsigned long minimum, return slots_fetch_random(); } -unsigned char *choose_kernel_location(unsigned char *input, +unsigned char *choose_random_location(unsigned char *input, unsigned long input_size, unsigned char *output, unsigned long output_size) diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 0d69e80..ad8c01a 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -431,7 +431,7 @@ 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_kernel_location(input_data, input_len, output, + output = choose_random_location(input_data, input_len, output, output_len > run_size ? output_len : run_size); diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 1f750a51..9887e0d 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -67,7 +67,7 @@ int cmdline_find_option_bool(const char *option); #if CONFIG_RANDOMIZE_BASE /* kaslr.c */ -unsigned char *choose_kernel_location(unsigned char *input, +unsigned char *choose_random_location(unsigned char *input, unsigned long input_size, unsigned char *output, unsigned long output_size); @@ -75,7 +75,7 @@ unsigned char *choose_kernel_location(unsigned char *input, bool has_cpuflag(int flag); #else static inline -unsigned char *choose_kernel_location(unsigned char *input, +unsigned char *choose_random_location(unsigned char *input, unsigned long input_size, unsigned char *output, unsigned long output_size)
