| From f9c0d4ae8e655a311176b1ad1b10e29d40d8a645 Mon Sep 17 00:00:00 2001 |
| From: Jessica Yu <jeyu@kernel.org> |
| Date: Tue, 23 Jul 2019 15:26:28 +0200 |
| Subject: modules: always page-align module section allocations |
| |
| [ Upstream commit 38f054d549a869f22a02224cd276a27bf14b6171 ] |
| |
| 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: Sasha Levin <sashal@kernel.org> |
| --- |
| kernel/module.c | 7 +------ |
| 1 file changed, 1 insertion(+), 6 deletions(-) |
| |
| diff --git a/kernel/module.c b/kernel/module.c |
| index 3fda10c549a25..2dec3d4a9b627 100644 |
| --- a/kernel/module.c |
| +++ b/kernel/module.c |
| @@ -76,14 +76,9 @@ |
| |
| /* |
| * 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)) |
| -- |
| 2.20.1 |
| |
