The patch titled
Subject: kasan: move checks to do_strncpy_from_user
has been added to the -mm mm-unstable branch. Its filename is
kasan-move-checks-to-do_strncpy_from_user.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-move-checks-to-do_strncpy_from_user.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx>
Subject: kasan: move checks to do_strncpy_from_user
Date: Wed, 16 Oct 2024 18:18:00 +0500
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@xxxxxxxxxxxxxx/
- [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@xxxxxxxxx
Link: https://lkml.kernel.org/r/20241016131802.3115788-2-snovitoll@xxxxxxxxx
Fixes: 2865baf54077 ("x86: support user address masking instead of non-speculative conditional")
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx>
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alex Shi <alexs@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Hu Haowen <2023002089@xxxxxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Yanteng Si <siyanteng@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/strncpy_from_user.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/lib/strncpy_from_user.c~kasan-move-checks-to-do_strncpy_from_user
+++ a/lib/strncpy_from_user.c
@@ -120,6 +120,9 @@ long strncpy_from_user(char *dst, const
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
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();
_
Patches currently in -mm which might be from snovitoll@xxxxxxxxx are
x86-traps-move-kmsan-check-after-instrumentation_begin.patch
mm-kasan-kmsan-copy_from-to_kernel_nofault.patch
kasan-move-checks-to-do_strncpy_from_user.patch
kasan-migrate-copy_user_test-to-kunit.patch
kasan-delete-config_kasan_module_test.patch
