linux-kernel - [PATCH v4 1/3] kasan: move checks to do_strncpy_from

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241016131802.3115788-2-snovitoll@gmail.com>
Date: Wed, 16 Oct 2024 18:18:00 +0500
From: Sabyrzhan Tasbolatov <snovitoll@...il.com>
To: andreyknvl@...il.com
Cc: 2023002089@...k.tyut.edu.cn,
	akpm@...ux-foundation.org,
	alexs@...nel.org,
	corbet@....net,
	dvyukov@...gle.com,
	elver@...gle.com,
	glider@...gle.com,
	kasan-dev@...glegroups.com,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	ryabinin.a.a@...il.com,
	siyanteng@...ngson.cn,
	snovitoll@...il.com,
	vincenzo.frascino@....com,
	workflows@...r.kernel.org
Subject: [PATCH v4 1/3] kasan: move checks to do_strncpy_from_user

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.

Fixes: 2865baf54077 ("x86: support user address masking instead of non-speculative conditional")
Reviewed-by: Andrey Konovalov <andreyknvl@...il.com>
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@...il.com>
---
 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 989a12a6787..6dc234913dd 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();
-- 
2.34.1