linux-kernel - [patch V4 08/12] uaccess: Provide put/get_user

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20251022103112.358808928@linutronix.de>
Date: Wed, 22 Oct 2025 14:49:11 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
cc: kernel test robot <lkp@...el.com>,
 Russell King <linux@...linux.org.uk>,
 linux-arm-kernel@...ts.infradead.org,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 x86@...nel.org,
 Madhavan Srinivasan <maddy@...ux.ibm.com>,
 Michael Ellerman <mpe@...erman.id.au>,
 Nicholas Piggin <npiggin@...il.com>,
 Christophe Leroy <christophe.leroy@...roup.eu>,
 linuxppc-dev@...ts.ozlabs.org,
 Paul Walmsley <pjw@...nel.org>,
 Palmer Dabbelt <palmer@...belt.com>,
 linux-riscv@...ts.infradead.org,
 Heiko Carstens <hca@...ux.ibm.com>,
 Christian Borntraeger <borntraeger@...ux.ibm.com>,
 Sven Schnelle <svens@...ux.ibm.com>,
 linux-s390@...r.kernel.org,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Andrew Cooper <andrew.cooper3@...rix.com>,
 David Laight <david.laight.linux@...il.com>,
 Julia Lawall <Julia.Lawall@...ia.fr>,
 Nicolas Palix <nicolas.palix@...g.fr>,
 Peter Zijlstra <peterz@...radead.org>,
 Darren Hart <dvhart@...radead.org>,
 Davidlohr Bueso <dave@...olabs.net>,
 André Almeida <andrealmeid@...lia.com>,
 Alexander Viro <viro@...iv.linux.org.uk>,
 Christian Brauner <brauner@...nel.org>,
 Jan Kara <jack@...e.cz>,
 linux-fsdevel@...r.kernel.org
Subject: [patch V4 08/12] uaccess: Provide put/get_user_scoped()

Provide conveniance wrappers around scoped user access similiar to
put/get_user(), which reduce the usage sites to:

       if (!get_user_scoped(val, ptr))
       		return -EFAULT;

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
V4: Rename to scoped
---
 include/linux/uaccess.h |   44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -825,6 +825,50 @@ for (bool done = false; !done; done = tr
 #define scoped_user_rw_access(uptr, elbl)				\
 	scoped_user_rw_access_size(uptr, sizeof(*(uptr)), elbl)
 
+/**
+ * get_user_scoped - Read user data with scoped access
+ * @val:	The variable to store the value read from user memory
+ * @usrc:	Pointer to the user space memory to read from
+ *
+ * Return: true if successful, false when faulted
+ */
+#define get_user_scoped(val, usrc)				\
+({								\
+	__label__ efault;					\
+	typeof(usrc) _tmpsrc = usrc;				\
+	bool _ret = true;					\
+								\
+	scoped_user_read_access(_tmpsrc, efault)		\
+		unsafe_get_user(val, _tmpsrc, efault);		\
+	if (0) {						\
+	efault:							\
+		_ret = false;					\
+	}							\
+	_ret;							\
+})
+
+/**
+ * put_user_scoped - Write to user memory with scoped access
+ * @val:	The value to write
+ * @udst:	Pointer to the user space memory to write to
+ *
+ * Return: true if successful, false when faulted
+ */
+#define put_user_scoped(val, udst)				\
+({								\
+	__label__ efault;					\
+	typeof(udst) _tmpdst = udst;				\
+	bool _ret = true;					\
+								\
+	scoped_user_write_access(_tmpdst, efault)		\
+		unsafe_put_user(val, _tmpdst, efault);		\
+	if (0) {						\
+	efault:							\
+		_ret = false;					\
+	}							\
+	_ret;							\
+})
+
 #ifdef CONFIG_HARDENED_USERCOPY
 void __noreturn usercopy_abort(const char *name, const char *detail,
 			       bool to_user, unsigned long offset,