Commit e2a666d5 authored by Rusty Russell's avatar Rusty Russell Committed by Linus Torvalds

kbuild: sign the modules at install time

Linus deleted the old code and put signing on the install command,
I fixed it to extract the keyid and signer-name within sign-file
and cleaned up that script now it always signs in-place.

Some enthusiast should convert sign-key to perl and pull
x509keyid into it.
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c9623de4
......@@ -719,6 +719,17 @@ endif # INSTALL_MOD_STRIP
export mod_strip_cmd
ifeq ($(CONFIG_MODULE_SIG),y)
MODSECKEY = ./signing_key.priv
MODPUBKEY = ./signing_key.x509
export MODPUBKEY
mod_sign_cmd = sh $(srctree)/scripts/sign-file $(MODSECKEY) $(MODPUBKEY) $(srctree)/scripts/x509keyid
else
mod_sign_cmd = true
endif
export mod_sign_cmd
ifeq ($(KBUILD_EXTMOD),)
core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
......
......@@ -17,7 +17,7 @@ __modinst: $(modules)
@:
quiet_cmd_modules_install = INSTALL $@
cmd_modules_install = mkdir -p $(2); cp $@ $(2) ; $(mod_strip_cmd) $(2)/$(notdir $@)
cmd_modules_install = mkdir -p $(2); cp $@ $(2) ; $(mod_strip_cmd) $(2)/$(notdir $@) ; $(mod_sign_cmd) $(2)/$(notdir $@)
# Modules built outside the kernel source tree go into extra by default
INSTALL_MOD_DIR ?= extra
......
......@@ -14,8 +14,7 @@
# 3) create one <module>.mod.c file pr. module
# 4) create one Module.symvers file with CRC for all exported symbols
# 5) compile all <module>.mod.c files
# 6) final link of the module to a <module.ko> (or <module.unsigned>) file
# 7) signs the modules to a <module.ko> file
# 6) final link of the module to a <module.ko> file
# Step 3 is used to place certain information in the module's ELF
# section, including information such as:
......@@ -33,8 +32,6 @@
# Step 4 is solely used to allow module versioning in external modules,
# where the CRC of each module is retrieved from the Module.symvers file.
# Step 7 is dependent on CONFIG_MODULE_SIG being enabled.
# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
# symbols in the final module linking stage
# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
......@@ -119,7 +116,6 @@ $(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
targets += $(modules:.ko=.mod.o)
# Step 6), final link of the modules
ifneq ($(CONFIG_MODULE_SIG),y)
quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o = $(LD) -r $(LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
......@@ -129,78 +125,7 @@ $(modules): %.ko :%.o %.mod.o FORCE
$(call if_changed,ld_ko_o)
targets += $(modules)
else
quiet_cmd_ld_ko_unsigned_o = LD [M] $@
cmd_ld_ko_unsigned_o = \
$(LD) -r $(LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
-o $@ $(filter-out FORCE,$^) \
$(if $(AFTER_LINK),; $(AFTER_LINK))
$(modules:.ko=.ko.unsigned): %.ko.unsigned :%.o %.mod.o FORCE
$(call if_changed,ld_ko_unsigned_o)
targets += $(modules:.ko=.ko.unsigned)
# Step 7), sign the modules
MODSECKEY = ./signing_key.priv
MODPUBKEY = ./signing_key.x509
ifeq ($(wildcard $(MODSECKEY))+$(wildcard $(MODPUBKEY)),$(MODSECKEY)+$(MODPUBKEY))
ifeq ($(KBUILD_SRC),)
# no O= is being used
SCRIPTS_DIR := scripts
else
SCRIPTS_DIR := $(KBUILD_SRC)/scripts
endif
SIGN_MODULES := 1
else
SIGN_MODULES := 0
endif
# only sign if it's an in-tree module
ifneq ($(KBUILD_EXTMOD),)
SIGN_MODULES := 0
endif
# We strip the module as best we can - note that using both strip and eu-strip
# results in a smaller module than using either alone.
EU_STRIP = $(shell which eu-strip || echo true)
quiet_cmd_sign_ko_stripped_ko_unsigned = STRIP [M] $@
cmd_sign_ko_stripped_ko_unsigned = \
cp $< $@ && \
strip -x -g $@ && \
$(EU_STRIP) $@
ifeq ($(SIGN_MODULES),1)
quiet_cmd_genkeyid = GENKEYID $@
cmd_genkeyid = \
perl $(SCRIPTS_DIR)/x509keyid $< $<.signer $<.keyid
%.signer %.keyid: %
$(call if_changed,genkeyid)
KEYRING_DEP := $(MODSECKEY) $(MODPUBKEY) $(MODPUBKEY).signer $(MODPUBKEY).keyid
quiet_cmd_sign_ko_ko_stripped = SIGN [M] $@
cmd_sign_ko_ko_stripped = \
sh $(SCRIPTS_DIR)/sign-file $(MODSECKEY) $(MODPUBKEY) $< $@
else
KEYRING_DEP :=
quiet_cmd_sign_ko_ko_unsigned = NO SIGN [M] $@
cmd_sign_ko_ko_unsigned = \
cp $< $@
endif
$(modules): %.ko :%.ko.stripped $(KEYRING_DEP) FORCE
$(call if_changed,sign_ko_ko_stripped)
$(patsubst %.ko,%.ko.stripped,$(modules)): %.ko.stripped :%.ko.unsigned FORCE
$(call if_changed,sign_ko_stripped_ko_unsigned)
targets += $(modules)
endif
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
......
#!/bin/sh
#!/bin/bash
#
# Sign a module file using the given key.
#
# Format: sign-file <key> <x509> <src-file> <dst-file>
# Format: sign-file <key> <x509> <keyid-script> <module>
#
scripts=`dirname $0`
......@@ -15,8 +15,8 @@ fi
key="$1"
x509="$2"
src="$3"
dst="$4"
keyid_script="$3"
mod="$4"
if [ ! -r "$key" ]
then
......@@ -29,16 +29,6 @@ then
echo "Can't read X.509 certificate" >&2
exit 2
fi
if [ ! -r "$x509.signer" ]
then
echo "Can't read Signer name" >&2
exit 2;
fi
if [ ! -r "$x509.keyid" ]
then
echo "Can't read Key identifier" >&2
exit 2;
fi
#
# Signature parameters
......@@ -83,33 +73,35 @@ fi
(
perl -e "binmode STDOUT; print pack(\"C*\", $prologue)" || exit $?
openssl dgst $dgst -binary $src || exit $?
) >$src.dig || exit $?
openssl dgst $dgst -binary $mod || exit $?
) >$mod.dig || exit $?
#
# Generate the binary signature, which will be just the integer that comprises
# the signature with no metadata attached.
#
openssl rsautl -sign -inkey $key -keyform PEM -in $src.dig -out $src.sig || exit $?
signerlen=`stat -c %s $x509.signer`
keyidlen=`stat -c %s $x509.keyid`
siglen=`stat -c %s $src.sig`
openssl rsautl -sign -inkey $key -keyform PEM -in $mod.dig -out $mod.sig || exit $?
SIGNER="`perl $keyid_script $x509 signer-name`"
KEYID="`perl $keyid_script $x509 keyid`"
keyidlen=${#KEYID}
siglen=${#SIGNER}
#
# Build the signed binary
#
(
cat $src || exit $?
cat $mod || exit $?
echo '~Module signature appended~' || exit $?
cat $x509.signer $x509.keyid || exit $?
echo -n "$SIGNER" || exit $?
echo -n "$KEYID" || exit $?
# Preface each signature integer with a 2-byte BE length
perl -e "binmode STDOUT; print pack(\"n\", $siglen)" || exit $?
cat $src.sig || exit $?
cat $mod.sig || exit $?
# Generate the information block
perl -e "binmode STDOUT; print pack(\"CCCCCxxxN\", $algo, $hash, $id_type, $signerlen, $keyidlen, $siglen + 2)" || exit $?
) >$dst~ || exit $?
) >$mod~ || exit $?
# Permit in-place signing
mv $dst~ $dst || exit $?
mv $mod~ $mod || exit $?
......@@ -22,7 +22,7 @@ use strict;
my $raw_data;
die "Need three filenames\n" if ($#ARGV != 2);
die "Need a filename [keyid|signer-name]\n" if ($#ARGV != 1);
my $src = $ARGV[0];
......@@ -259,10 +259,10 @@ die $src, ": ", "X.509: Couldn't find the Subject Key Identifier extension\n"
my $id_key_id = asn1_retrieve($subject_key_id->[1]);
open(OUTFD, ">$ARGV[1]") || die $ARGV[1];
print OUTFD $id_name;
close OUTFD || die $ARGV[1];
open(OUTFD, ">$ARGV[2]") || die $ARGV[2];
print OUTFD $id_key_id;
close OUTFD || die $ARGV[2];
if ($ARGV[1] eq "signer-name") {
print $id_name;
} elsif ($ARGV[1] eq "keyid") {
print $id_key_id;
} else {
die "Unknown arg";
}
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