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    Subject[PATCH 4.19 028/190] modules: always page-align module section allocations
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    [ 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


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