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x86, build: replace Perl script with Shell script 

Commit e6023367d7 ("x86, kaslr: Prevent .bss from overlaping initrd")
added Perl to the required build environment.  This reimplements in
shell the Perl script used to find the size of the kernel with bss and
brk added.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Rob Landley <rob@landley.net>
Acked-by: Rob Landley <rob@landley.net>
Cc: Anca Emanuel <anca.emanuel@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kees Cook 2015-01-26 12:58:35 -08:00 committed by Linus Torvalds
parent 9879de7373
commit d69911a68c
3 changed files with 43 additions and 40 deletions
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2
arch/x86/boot/compressed/Makefile
View File

@ -90,7 +90,7 @@ suffix-$(CONFIG_KERNEL_LZO) := lzo
suffix-$(CONFIG_KERNEL_LZ4) := lz4
RUN_SIZE = $(shell $(OBJDUMP) -h vmlinux | \
perl $(srctree)/arch/x86/tools/calc_run_size.pl)
$(CONFIG_SHELL) $(srctree)/arch/x86/tools/calc_run_size.sh)
quiet_cmd_mkpiggy = MKPIGGY $@
cmd_mkpiggy = $(obj)/mkpiggy $< $(RUN_SIZE) > $@ || ( rm -f $@ ; false )

39
arch/x86/tools/calc_run_size.pl
View File

@ -1,39 +0,0 @@
#!/usr/bin/perl
#
# Calculate the amount of space needed to run the kernel, including room for
# the .bss and .brk sections.
#
# Usage:
# objdump -h a.out | perl calc_run_size.pl
use strict;
my $mem_size = 0;
my $file_offset = 0;
my $sections=" *[0-9]+ \.(?:bss|brk) +";
while (<>) {
if (/^$sections([0-9a-f]+) +(?:[0-9a-f]+ +){2}([0-9a-f]+)/) {
my $size = hex($1);
my $offset = hex($2);
$mem_size += $size;
if ($file_offset == 0) {
$file_offset = $offset;
} elsif ($file_offset != $offset) {
# BFD linker shows the same file offset in ELF.
# Gold linker shows them as consecutive.
next if ($file_offset + $mem_size == $offset + $size);
printf STDERR "file_offset: 0x%lx\n", $file_offset;
printf STDERR "mem_size: 0x%lx\n", $mem_size;
printf STDERR "offset: 0x%lx\n", $offset;
printf STDERR "size: 0x%lx\n", $size;
die ".bss and .brk are non-contiguous\n";
}
}
}
if ($file_offset == 0) {
die "Never found .bss or .brk file offset\n";
}
printf("%d\n", $mem_size + $file_offset);

42
arch/x86/tools/calc_run_size.sh Normal file
View File

@ -0,0 +1,42 @@
#!/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