From 38f054d549a869f22a02224cd276a27bf14b6171 Mon Sep 17 00:00:00 2001 From: Jessica Yu Date: Tue, 23 Jul 2019 15:26:28 +0200 Subject: modules: always page-align module section allocations 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 Reported-by: Bartosz Golaszewski Tested-by: David Lechner Tested-by: Martin Kaiser Tested-by: Bartosz Golaszewski Signed-off-by: Jessica Yu --- kernel/module.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 5933395af9a0..cd8df516666d 100644 --- 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)) -- cgit v1.2.3 From 3b5be16c7e90a69c93349d210766250fffcb54bd Mon Sep 17 00:00:00 2001 From: He Zhe Date: Tue, 20 Aug 2019 22:53:10 +0800 Subject: modules: page-align module section allocations only for arches supporting strict module rwx We should keep the case of "#define debug_align(X) (X)" for all arches without CONFIG_HAS_STRICT_MODULE_RWX ability, which would save people, who are sensitive to system size, a lot of memory when using modules, especially for embedded systems. This is also the intention of the original #ifdef... statement and still valid for now. Note that this still keeps the effect of the fix of the following commit, 38f054d549a8 ("modules: always page-align module section allocations"), since when CONFIG_ARCH_HAS_STRICT_MODULE_RWX is enabled, module pages are aligned. Signed-off-by: He Zhe Signed-off-by: Jessica Yu --- kernel/module.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/module.c b/kernel/module.c index cd8df516666d..9ee93421269c 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -64,9 +64,14 @@ /* * Modules' sections will be aligned on page boundaries - * to ensure complete separation of code and data + * to ensure complete separation of code and data, but + * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y */ +#ifdef CONFIG_ARCH_HAS_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)) -- cgit v1.2.3