loadpin: Prevent SECURITY_LOADPIN_ENFORCE=y without module decompression

If modules are built compressed, and LoadPin is enforcing by default, we
must have in-kernel module decompression enabled (MODULE_DECOMPRESS).
Modules will fail to load without decompression built into the kernel
because they'll be blocked by LoadPin. Add a depends on clause to
prevent this combination.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20240514224839.2526112-1-swboyd@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/security/loadpin/Kconfig b/security/loadpin/Kconfig
index 6724eaba3d36471239e814bfafccad48fa0c045b..848f8b4a6019064badc5eb888fa20360aec909f2 100644 (file)
--- a/security/loadpin/Kconfig
+++ b/security/loadpin/Kconfig
@@ -14,6 +14,9 @@ config SECURITY_LOADPIN
 config SECURITY_LOADPIN_ENFORCE
        bool "Enforce LoadPin at boot"
        depends on SECURITY_LOADPIN
+       # Module compression breaks LoadPin unless modules are decompressed in
+       # the kernel.
+       depends on !MODULES || (MODULE_COMPRESS_NONE || MODULE_DECOMPRESS)
        help
          If selected, LoadPin will enforce pinning at boot. If not
          selected, it can be enabled at boot with the kernel parameter