x86/KASLR: Clean up unused code from old 'run_size' and rename it to 'kernel_total_size'

Since 'run_size' is now calculated in misc.c, the old script and associated
argument passing is no longer needed. This patch removes them, and renames
'run_size' to the more descriptive 'kernel_total_size'.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
[ Rewrote the changelog, renamed 'run_size' to 'kernel_total_size' ]
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: lasse.collin@tukaani.org
Link: http://lkml.kernel.org/r/1461888548-32439-6-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 4599780..adef26d 100644 (file)
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -121,10 +121,8 @@ suffix-$(CONFIG_KERNEL_XZ) := xz
 suffix-$(CONFIG_KERNEL_LZO)    := lzo
 suffix-$(CONFIG_KERNEL_LZ4)    := lz4
 
-RUN_SIZE = $(shell $(OBJDUMP) -h vmlinux | \
-            $(CONFIG_SHELL) $(srctree)/arch/x86/tools/calc_run_size.sh)
 quiet_cmd_mkpiggy = MKPIGGY $@
-      cmd_mkpiggy = $(obj)/mkpiggy $< $(RUN_SIZE) > $@ || ( rm -f $@ ; false )
+      cmd_mkpiggy = $(obj)/mkpiggy $< > $@ || ( rm -f $@ ; false )
 
 targets += piggy.S
 $(obj)/piggy.S: $(obj)/vmlinux.bin.$(suffix-y) $(obj)/mkpiggy FORCE

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 8a95e2f..1038524 100644 (file)
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -238,7 +238,6 @@ relocated:
  * Do the extraction, and jump to the new kernel..
  */
                                /* push arguments for extract_kernel: */
-       pushl   $z_run_size     /* size of kernel with .bss and .brk */
        pushl   $z_output_len   /* decompressed length, end of relocs */
 
        movl    BP_init_size(%esi), %eax
@@ -254,7 +253,7 @@ relocated:
        pushl   %eax            /* heap area */
        pushl   %esi            /* real mode pointer */
        call    extract_kernel  /* returns kernel location in %eax */
-       addl    $28, %esp
+       addl    $24, %esp
 
 /*
  * Jump to the extracted kernel.

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 09cdc0c..7c04700 100644 (file)
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -415,8 +415,6 @@ relocated:
  * Do the extraction, and jump to the new kernel..
  */
        pushq   %rsi                    /* Save the real mode argument */
-       movq    $z_run_size, %r9        /* size of kernel with .bss and .brk */
-       pushq   %r9
        movq    %rsi, %rdi              /* real mode address */
        leaq    boot_heap(%rip), %rsi   /* malloc area for uncompression */
        leaq    input_data(%rip), %rdx  /* input_data */
@@ -424,7 +422,6 @@ relocated:
        movq    %rbp, %r8               /* output target address */
        movq    $z_output_len, %r9      /* decompressed length, end of relocs */
        call    extract_kernel          /* returns kernel location in %rax */
-       popq    %r9
        popq    %rsi
 
 /*

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index cda93d1..bee6238 100644 (file)
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -340,9 +340,9 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
                                  unsigned char *input_data,
                                  unsigned long input_len,
                                  unsigned char *output,
-                                 unsigned long output_len,
-                                 unsigned long run_size)
+                                 unsigned long output_len)
 {
+       const unsigned long kernel_total_size = VO__end - VO__text;
        unsigned char *output_orig = output;
 
        /* Retain x86 boot parameters pointer passed from startup_32/64. */
@@ -364,8 +364,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
        lines = boot_params->screen_info.orig_video_lines;
        cols = boot_params->screen_info.orig_video_cols;
 
-       run_size = VO__end - VO__text;
-
        console_init();
        debug_putstr("early console in extract_kernel\n");
 
@@ -377,7 +375,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
        debug_putaddr(input_len);
        debug_putaddr(output);
        debug_putaddr(output_len);
-       debug_putaddr(run_size);
+       debug_putaddr(kernel_total_size);
 
        /*
         * The memory hole needed for the kernel is the larger of either
@@ -385,8 +383,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
         * entire decompressed kernel plus .bss and .brk sections.
         */
        output = choose_random_location(input_data, input_len, output,
-                                       output_len > run_size ? output_len
-                                                             : run_size);
+                                       max(output_len, kernel_total_size));
 
        /* Validate memory location choices. */
        if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))

diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
index f095ed9..72bad2c 100644 (file)
--- a/arch/x86/boot/compressed/mkpiggy.c
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -34,13 +34,11 @@ int main(int argc, char *argv[])
 {
        uint32_t olen;
        long ilen;
-       unsigned long run_size;
        FILE *f = NULL;
        int retval = 1;
 
-       if (argc < 3) {
-               fprintf(stderr, "Usage: %s compressed_file run_size\n",
-                               argv[0]);
+       if (argc < 2) {
+               fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
                goto bail;
        }
 
@@ -65,15 +63,11 @@ int main(int argc, char *argv[])
        ilen = ftell(f);
        olen = get_unaligned_le32(&olen);
 
-       run_size = atoi(argv[2]);
-
        printf(".section \".rodata..compressed\",\"a\",@progbits\n");
        printf(".globl z_input_len\n");
        printf("z_input_len = %lu\n", ilen);
        printf(".globl z_output_len\n");
        printf("z_output_len = %lu\n", (unsigned long)olen);
-       printf(".globl z_run_size\n");
-       printf("z_run_size = %lu\n", run_size);
 
        printf(".globl input_data, input_data_end\n");
        printf("input_data:\n");

diff --git a/arch/x86/tools/calc_run_size.sh b/arch/x86/tools/calc_run_size.sh
deleted file mode 100644 (file)
index 1a4c17b..0000000
--- a/arch/x86/tools/calc_run_size.sh
+++ /dev/null
@@ -1,42 +0,0 @@
-#!/bin/sh
-#
-# Calculate the amount of space needed to run the kernel, including room for
-# the .bss and .brk sections.
-#
-# Usage:
-# objdump -h a.out | sh calc_run_size.sh
-
-NUM='\([0-9a-fA-F]*[ \t]*\)'
-OUT=$(sed -n 's/^[ \t0-9]*.b[sr][sk][ \t]*'"$NUM$NUM$NUM$NUM"'.*/\1\4/p')
-if [ -z "$OUT" ] ; then
-       echo "Never found .bss or .brk file offset" >&2
-       exit 1
-fi
-
-OUT=$(echo ${OUT# })
-sizeA=$(printf "%d" 0x${OUT%% *})
-OUT=${OUT#* }
-offsetA=$(printf "%d" 0x${OUT%% *})
-OUT=${OUT#* }
-sizeB=$(printf "%d" 0x${OUT%% *})
-OUT=${OUT#* }
-offsetB=$(printf "%d" 0x${OUT%% *})
-
-run_size=$(( $offsetA + $sizeA + $sizeB ))
-
-# BFD linker shows the same file offset in ELF.
-if [ "$offsetA" -ne "$offsetB" ] ; then
-       # Gold linker shows them as consecutive.
-       endB=$(( $offsetB + $sizeB ))
-       if [ "$endB" != "$run_size" ] ; then
-               printf "sizeA: 0x%x\n" $sizeA >&2
-               printf "offsetA: 0x%x\n" $offsetA >&2
-               printf "sizeB: 0x%x\n" $sizeB >&2
-               printf "offsetB: 0x%x\n" $offsetB >&2
-               echo ".bss and .brk are non-contiguous" >&2
-               exit 1
-       fi
-fi
-
-printf "%d\n" $run_size
-exit 0