From ae193dd79398970ee760e0c8129ac42ef8f5c6ff Mon Sep 17 00:00:00 2001 From: Sabyrzhan Tasbolatov Date: Wed, 16 Oct 2024 18:18:00 +0500 Subject: [PATCH] kasan: move checks to do_strncpy_from_user Patch series "kasan: migrate the last module test to kunit", v4. copy_user_test() is the last KUnit-incompatible test with CONFIG_KASAN_MODULE_TEST requirement, which we are going to migrate to KUnit framework and delete the former test and Kconfig as well. In this patch series: - [1/3] move kasan_check_write() and check_object_size() to do_strncpy_from_user() to cover with KASAN checks with multiple conditions in strncpy_from_user(). - [2/3] migrated copy_user_test() to KUnit, where we can also test strncpy_from_user() due to [1/4]. KUnits have been tested on: - x86_64 with CONFIG_KASAN_GENERIC. Passed - arm64 with CONFIG_KASAN_SW_TAGS. 1 fail. See [1] - arm64 with CONFIG_KASAN_HW_TAGS. 1 fail. See [1] [1] https://lore.kernel.org/linux-mm/CACzwLxj21h7nCcS2-KA_q7ybe+5pxH0uCDwu64q_9pPsydneWQ@mail.gmail.com/ - [3/3] delete CONFIG_KASAN_MODULE_TEST and documentation occurrences. This patch (of 3): Since in the commit 2865baf54077("x86: support user address masking instead of non-speculative conditional") do_strncpy_from_user() is called from multiple places, we should sanitize the kernel *dst memory and size which were done in strncpy_from_user() previously. Link: https://lkml.kernel.org/r/20241016131802.3115788-1-snovitoll@gmail.com Link: https://lkml.kernel.org/r/20241016131802.3115788-2-snovitoll@gmail.com Fixes: 2865baf54077 ("x86: support user address masking instead of non-speculative conditional") Signed-off-by: Sabyrzhan Tasbolatov Reviewed-by: Andrey Konovalov Cc: Alexander Potapenko Cc: Alex Shi Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Hu Haowen <2023002089@link.tyut.edu.cn> Cc: Jonathan Corbet Cc: Marco Elver Cc: Vincenzo Frascino Cc: Yanteng Si Signed-off-by: Andrew Morton --- lib/strncpy_from_user.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index 989a12a67872..6dc234913dd5 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -120,6 +120,9 @@ long strncpy_from_user(char *dst, const char __user *src, long count) if (unlikely(count <= 0)) return 0; + kasan_check_write(dst, count); + check_object_size(dst, count, false); + if (can_do_masked_user_access()) { long retval; @@ -142,8 +145,6 @@ long strncpy_from_user(char *dst, const char __user *src, long count) if (max > count) max = count; - kasan_check_write(dst, count); - check_object_size(dst, count, false); if (user_read_access_begin(src, max)) { retval = do_strncpy_from_user(dst, src, count, max); user_read_access_end();