From: Jessica Yu jeyu@kernel.org
commit 38f054d549a869f22a02224cd276a27bf14b6171 upstream.
Some arches (e.g., arm64, x86) have moved towards non-executable module_alloc() allocations for security hardening reasons. That means that the module loader will need to set the text section of a module to executable, regardless of whether or not CONFIG_STRICT_MODULE_RWX is set.
When CONFIG_STRICT_MODULE_RWX=y, module section allocations are always page-aligned to handle memory rwx permissions. On some arches with CONFIG_STRICT_MODULE_RWX=n however, when setting the module text to executable, the BUG_ON() in frob_text() gets triggered since module section allocations are not page-aligned when CONFIG_STRICT_MODULE_RWX=n. Since the set_memory_* API works with pages, and since we need to call set_memory_x() regardless of whether CONFIG_STRICT_MODULE_RWX is set, we might as well page-align all module section allocations for ease of managing rwx permissions of module sections (text, rodata, etc).
Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n") Reported-by: Martin Kaiser lists@kaiser.cx Reported-by: Bartosz Golaszewski brgl@bgdev.pl Tested-by: David Lechner david@lechnology.com Tested-by: Martin Kaiser martin@kaiser.cx Tested-by: Bartosz Golaszewski bgolaszewski@baylibre.com Signed-off-by: Jessica Yu jeyu@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/module.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)
--- a/kernel/module.c +++ b/kernel/module.c @@ -64,14 +64,9 @@
/* * Modules' sections will be aligned on page boundaries - * to ensure complete separation of code and data, but - * only when CONFIG_STRICT_MODULE_RWX=y + * to ensure complete separation of code and data */ -#ifdef CONFIG_STRICT_MODULE_RWX # define debug_align(X) ALIGN(X, PAGE_SIZE) -#else -# define debug_align(X) (X) -#endif
/* If this is set, the section belongs in the init part of the module */ #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))