On Fri, Feb 23, 2018 at 6:46 PM, Luis R. Rodriguez <mcgrof@xxxxxxxxxx> wrote:
> When a kernel is not built with:
>
> CONFIG_HAS_FW_LOADER_USER_HELPER_FALLBACK=y
>
> We don't currently enable testing fw_fallback.sh. For kernels that
> still enable the fallback mechanism, its possible to use the async
> request firmware API call request_firmware_nowait() using the custom
> interface to use the fallback mechanism, so we should be able to test
> this but we currently cannot.
>
> We can enable testing without CONFIG_HAS_FW_LOADER_USER_HELPER_FALLBACK=y
> by relying on /proc/config.gz (CONFIG_IKCONFIG_PROC), if present. If you
> don't have this we'll have no option but to rely on old heuristics for now.
>
> Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
> ---
> tools/testing/selftests/firmware/config | 4 +++
> tools/testing/selftests/firmware/fw_fallback.sh | 45 ++++++++++++++++++++++++-
> 2 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/firmware/config b/tools/testing/selftests/firmware/config
> index c8137f70e291..bf634dda0720 100644
> --- a/tools/testing/selftests/firmware/config
> +++ b/tools/testing/selftests/firmware/config
> @@ -1 +1,5 @@
> CONFIG_TEST_FIRMWARE=y
> +CONFIG_FW_LOADER=y
> +CONFIG_FW_LOADER_USER_HELPER=y
> +CONFIG_IKCONFIG=y
> +CONFIG_IKCONFIG_PROC=y
> diff --git a/tools/testing/selftests/firmware/fw_fallback.sh b/tools/testing/selftests/firmware/fw_fallback.sh
> index 722cad91df74..a42e437363d9 100755
> --- a/tools/testing/selftests/firmware/fw_fallback.sh
> +++ b/tools/testing/selftests/firmware/fw_fallback.sh
> @@ -6,7 +6,46 @@
> # won't find so that we can do the load ourself manually.
> set -e
>
> +PROC_CONFIG="/proc/config.gz"
> +TEST_DIR=$(dirname $0)
> +
> modprobe test_firmware
> +if [ ! -f $PROC_CONFIG ]; then
> + if modprobe configs 2>/dev/null; then
> + echo "Loaded configs module"
> + if [ ! -f $PROC_CONFIG ]; then
> + echo "You must have the following enabled in your kernel:" >&2
> + cat $TEST_DIR/config >&2
> + echo "Resorting to old heuristics" >&2
> + fi
> + else
> + echo "Failed to load configs module, using old heuristics" >&2
> + fi
> +fi
> +
> +kconfig_has()
> +{
> + if [ -f $PROC_CONFIG ]; then
> + if zgrep -q $1 $PROC_CONFIG 2>/dev/null; then
> + echo "yes"
> + else
> + echo "no"
> + fi
> + else
> + # We currently don't have easy heuristics to infer this
> + # so best we can do is just try to use the kernel assuming
> + # you had enabled it. This matches the old behaviour.
> + if [ "$1" = "CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y" ]; then
> + echo "yes"
> + elif [ "$1" = "CONFIG_FW_LOADER_USER_HELPER=y" ]; then
> + if [ -d /sys/class/firmware/ ]; then
> + echo yes
> + else
> + echo no
> + fi
> + fi
> + fi
> +}
Some day when we have more formalized CONFIG-scanning for selftests,
we can probably describe all of this better in a cleaner way. In the
meantime, yeah, this seems fine.
>
> DIR=/sys/devices/virtual/misc/test_firmware
>
> @@ -14,6 +53,7 @@ DIR=/sys/devices/virtual/misc/test_firmware
> # These days no one enables CONFIG_FW_LOADER_USER_HELPER so check for that
> # as an indicator for CONFIG_FW_LOADER_USER_HELPER.
> HAS_FW_LOADER_USER_HELPER=$(if [ -d /sys/class/firmware/ ]; then echo yes; else echo no; fi)
> +HAS_FW_LOADER_USER_HELPER_FALLBACK=$(kconfig_has CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y)
>
> if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
> OLD_TIMEOUT=$(cat /sys/class/firmware/timeout)
> @@ -286,7 +326,10 @@ run_sysfs_custom_load_tests()
> fi
> }
>
> -run_sysfs_main_tests
> +if [ "$HAS_FW_LOADER_USER_HELPER_FALLBACK" = "yes" ]; then
> + run_sysfs_main_tests
> +fi
> +
> run_sysfs_custom_load_tests
>
> exit 0
> --
> 2.16.2
>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
-Kees
--
Kees Cook
Pixel Security
