linux-hardening - [RFC v1 05/17] uaccess: add non-caching copy_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: <20250712192202.707192-6-gatlin.newhouse@gmail.com>
Date: Sat, 12 Jul 2025 19:21:50 +0000
From: Gatlin Newhouse <gatlin.newhouse@...il.com>
To: linux-hardening@...r.kernel.org
Cc: Gatlin Newhouse <gatlin.newhouse@...il.com>
Subject: [RFC v1 05/17] uaccess: add non-caching copy_from_user functions

---
 include/linux/uaccess.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 7c06f4795670..d6d80bb9e0fa 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -186,6 +186,26 @@ _inline_copy_from_user(void *to, const void __user *from, unsigned long n)
 extern __must_check unsigned long
 _copy_from_user(void *, const void __user *, unsigned long);
 
+#ifdef CONFIG_SAFEFETCH
+static inline __must_check unsigned long
+_copy_from_user_no_dfcache(void *to, const void __user *from, unsigned long n)
+{
+	unsigned long res = n;
+
+	might_fault();
+	if (!should_fail_usercopy() && likely(access_ok(from, n))) {
+		instrument_copy_from_user_before(to, from, n);
+		res = raw_copy_from_user_no_dfcache(to, from, n);
+		instrument_copy_from_user_after(to, from, n, res);
+	}
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
+}
+extern __must_check unsigned long
+_copy_from_user_no_dfcache(void *, const void __user *, unsigned long);
+#endif
+
 static inline __must_check unsigned long
 _inline_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
@@ -213,6 +233,16 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
 #endif
 }
 
+#ifdef CONFIG_SAFEFETCH
+static __always_inline unsigned long __must_check
+copy_from_user_no_dfcache(void *to, const void __user *from, unsigned long n)
+{
+	if (likely(check_copy_size(to, n, false)))
+		n = _copy_from_user_no_dfcache(to, from, n);
+	return n;
+}
+#endif
+
 static __always_inline unsigned long __must_check
 copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-- 
2.25.1