diff options
| author | Kees Cook <keescook@chromium.org> | 2022-05-03 13:55:02 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-05-08 01:33:07 -0700 |
| commit | be2b34fa9be31c60a95989f984c9a5d40cd781b6 (patch) | |
| tree | a1b5f247ac20de2866d52ea68930b47268366efc /scripts | |
| parent | 613f4b3ed7902d1dbbc6ade6401e452a63dfbc21 (diff) | |
randstruct: Move seed generation into scripts/basic/
To enable Clang randstruct support, move the structure layout
randomization seed generation out of scripts/gcc-plugins/ into
scripts/basic/ so it happens early enough that it can be used by either
compiler implementation. The gcc-plugin still builds its own header file,
but now does so from the common "randstruct.seed" file.
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-6-keescook@chromium.org
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/basic/.gitignore | 1 | ||||
| -rw-r--r-- | scripts/basic/Makefile | 11 | ||||
| -rw-r--r-- | scripts/gcc-plugins/Makefile | 15 | ||||
| -rwxr-xr-x | scripts/gcc-plugins/gen-random-seed.sh | 9 | ||||
| -rwxr-xr-x | scripts/gen-randstruct-seed.sh | 7 |
5 files changed, 29 insertions, 14 deletions
diff --git a/scripts/basic/.gitignore b/scripts/basic/.gitignore index 961c91c8a884..07c195f605a1 100644 --- a/scripts/basic/.gitignore +++ b/scripts/basic/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only /fixdep +/randstruct.seed diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile index eeb6a38c5551..dd289a6725ac 100644 --- a/scripts/basic/Makefile +++ b/scripts/basic/Makefile @@ -3,3 +3,14 @@ # fixdep: used to generate dependency information during build process hostprogs-always-y += fixdep + +# randstruct: the seed is needed before building the gcc-plugin or +# before running a Clang kernel build. +gen-randstruct-seed := $(srctree)/scripts/gen-randstruct-seed.sh +quiet_cmd_create_randstruct_seed = GENSEED $@ +cmd_create_randstruct_seed = \ + $(CONFIG_SHELL) $(gen-randstruct-seed) \ + $@ $(objtree)/include/generated/randstruct_hash.h +$(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE + $(call if_changed,create_randstruct_seed) +always-$(CONFIG_RANDSTRUCT) += randstruct.seed diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index 1952d3bb80c6..148f4639cf09 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -1,12 +1,17 @@ # SPDX-License-Identifier: GPL-2.0 -$(obj)/randomize_layout_plugin.so: $(objtree)/$(obj)/randomize_layout_seed.h -quiet_cmd_create_randomize_layout_seed = GENSEED $@ +$(obj)/randomize_layout_plugin.so: $(obj)/randomize_layout_seed.h +quiet_cmd_create_randomize_layout_seed = SEEDHDR $@ cmd_create_randomize_layout_seed = \ - $(CONFIG_SHELL) $(srctree)/$(src)/gen-random-seed.sh $@ $(objtree)/include/generated/randomize_layout_hash.h -$(objtree)/$(obj)/randomize_layout_seed.h: FORCE + SEED=$$(cat $(filter-out FORCE,$^) </dev/null); \ + echo '/*' > $@; \ + echo ' * This file is automatically generated. Keep it private.' >> $@; \ + echo ' * Exposing this value will expose the layout of randomized structures.' >> $@; \ + echo ' */' >> $@; \ + echo "const char *randstruct_seed = \"$$SEED\";" >> $@ +$(obj)/randomize_layout_seed.h: $(objtree)/scripts/basic/randstruct.seed FORCE $(call if_changed,create_randomize_layout_seed) -targets += randomize_layout_seed.h randomize_layout_hash.h +targets += randomize_layout_seed.h # Build rules for plugins # diff --git a/scripts/gcc-plugins/gen-random-seed.sh b/scripts/gcc-plugins/gen-random-seed.sh deleted file mode 100755 index 68af5cc20a64..000000000000 --- a/scripts/gcc-plugins/gen-random-seed.sh +++ /dev/null @@ -1,9 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0 - -if [ ! -f "$1" ]; then - SEED=`od -A n -t x8 -N 32 /dev/urandom | tr -d ' \n'` - echo "const char *randstruct_seed = \"$SEED\";" > "$1" - HASH=`echo -n "$SEED" | sha256sum | cut -d" " -f1 | tr -d ' \n'` - echo "#define RANDSTRUCT_HASHED_SEED \"$HASH\"" > "$2" -fi diff --git a/scripts/gen-randstruct-seed.sh b/scripts/gen-randstruct-seed.sh new file mode 100755 index 000000000000..61017b36c464 --- /dev/null +++ b/scripts/gen-randstruct-seed.sh @@ -0,0 +1,7 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +SEED=$(od -A n -t x8 -N 32 /dev/urandom | tr -d ' \n') +echo "$SEED" > "$1" +HASH=$(echo -n "$SEED" | sha256sum | cut -d" " -f1) +echo "#define RANDSTRUCT_HASHED_SEED \"$HASH\"" > "$2" |