From 2e41f274f9aa71cdcc69dc1f26a3f9304a651804 Mon Sep 17 00:00:00 2001

From: Akinobu Mita <akinobu.mita@gmail.com>

Date: Tue, 20 Sep 2022 02:24:16 +0900

Subject: [PATCH] libfs: add DEFINE_SIMPLE_ATTRIBUTE_SIGNED for signed value

Git-commit: 2e41f274f9aa71cdcc69dc1f26a3f9304a651804

Patch-mainline: v6.2-rc1

References: git-fixes

Patch series "fix error when writing negative value to simple attribute

files".

The simple attribute files do not accept a negative value since the commit

488dac0c9237 ("libfs: fix error cast of negative value in

simple_attr_write()"), but some attribute files want to accept a negative

value.

This patch (of 3):

The simple attribute files do not accept a negative value since the commit

488dac0c9237 ("libfs: fix error cast of negative value in

simple_attr_write()"), so we have to use a 64-bit value to write a

negative value.

This adds DEFINE_SIMPLE_ATTRIBUTE_SIGNED for a signed value.

Link: https://lkml.kernel.org/r/20220919172418.45257-1-akinobu.mita@gmail.com

Link: https://lkml.kernel.org/r/20220919172418.45257-2-akinobu.mita@gmail.com

Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()")

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

Reported-by: Zhao Gongyi <zhaogongyi@huawei.com>

Reviewed-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Cc: Alexander Viro <viro@zeniv.linux.org.uk>

Cc: Jonathan Corbet <corbet@lwn.net>

Cc: Oscar Salvador <osalvador@suse.de>

Cc: Rafael J. Wysocki <rafael@kernel.org>

Cc: Shuah Khan <shuah@kernel.org>

Cc: Wei Yongjun <weiyongjun1@huawei.com>

Cc: Yicong Yang <yangyicong@hisilicon.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 fs/libfs.c         |   22 +++++++++++++++++++---

 include/linux/fs.h |   12 ++++++++++--

 2 files changed, 29 insertions(+), 5 deletions(-)

--- a/fs/libfs.c

+++ b/fs/libfs.c

@@ -967,8 +967,8 @@ out:

 EXPORT_SYMBOL_GPL(simple_attr_read);

 /* interpret the buffer as a number to call the set function with */

-ssize_t simple_attr_write(struct file *file, const char __user *buf,

-			  size_t len, loff_t *ppos)

+static ssize_t simple_attr_write_xsigned(struct file *file, const char __user *buf,

+			  size_t len, loff_t *ppos, bool is_signed)

 {

 	struct simple_attr *attr;

 	unsigned long long val;

@@ -989,7 +989,10 @@ ssize_t simple_attr_write(struct file *f

 		goto out;

 	attr->set_buf[size] = '\0';

-	ret = kstrtoull(attr->set_buf, 0, &val;;

+	if (is_signed)

+		ret = kstrtoll(attr->set_buf, 0, &val;;

+	else

+		ret = kstrtoull(attr->set_buf, 0, &val;;

 	if (ret)

 		goto out;

 	ret = attr->set(attr->data, val);

@@ -999,8 +1002,21 @@ out:

 	mutex_unlock(&attr->mutex);

 	return ret;

 }

+

+ssize_t simple_attr_write(struct file *file, const char __user *buf,

+			  size_t len, loff_t *ppos)

+{

+	return simple_attr_write_xsigned(file, buf, len, ppos, false);

+}

 EXPORT_SYMBOL_GPL(simple_attr_write);

+ssize_t simple_attr_write_signed(struct file *file, const char __user *buf,

+			  size_t len, loff_t *ppos)

+{

+	return simple_attr_write_xsigned(file, buf, len, ppos, true);

+}

+EXPORT_SYMBOL_GPL(simple_attr_write_signed);

+

 /**

  * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation

  * @sb:		filesystem to do the file handle conversion on

--- a/include/linux/fs.h

+++ b/include/linux/fs.h

@@ -3631,7 +3631,7 @@ void simple_transaction_set(struct file

  * All attributes contain a text representation of a numeric value

  * that are accessed with the get() and set() functions.

  */

-#define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)		\

+#define DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, __is_signed)	\

 static int __fops ## _open(struct inode *inode, struct file *file)	\

 {									\

 	__simple_attr_check_format(__fmt, 0ull);			\

@@ -3642,10 +3642,16 @@ static const struct file_operations __fo

 	.open	 = __fops ## _open,					\

 	.release = simple_attr_release,					\

 	.read	 = simple_attr_read,					\

-	.write	 = simple_attr_write,					\

+	.write	 = (__is_signed) ? simple_attr_write_signed : simple_attr_write,	\

 	.llseek	 = generic_file_llseek,					\

 }

+#define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)		\

+	DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, false)

+

+#define DEFINE_SIMPLE_ATTRIBUTE_SIGNED(__fops, __get, __set, __fmt)	\

+	DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, true)

+

 static inline __printf(1, 2)

 void __simple_attr_check_format(const char *fmt, ...)

 {

@@ -3660,6 +3666,8 @@ ssize_t simple_attr_read(struct file *fi

 			 size_t len, loff_t *ppos);

 ssize_t simple_attr_write(struct file *file, const char __user *buf,

 			  size_t len, loff_t *ppos);

+ssize_t simple_attr_write_signed(struct file *file, const char __user *buf,

+				 size_t len, loff_t *ppos);

 struct ctl_table;

 int proc_nr_files(struct ctl_table *table, int write,