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libfs: add DEFINE_SIMPLE_ATTRIBUTE_SIGNED for signed value

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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
488dac0c92 ("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
488dac0c92 ("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: 488dac0c92 ("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>
This commit is contained in:
Akinobu Mita 2022-09-20 02:24:16 +09:00 committed by Andrew Morton
parent 7b9cbc7701
commit 2e41f274f9
2 changed files with 29 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
fs/libfs.c
View File

@ -995,8 +995,8 @@ 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;
@ -1017,7 +1017,10 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
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);
@ -1027,8 +1030,21 @@ 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

12
include/linux/fs.h
View File

@ -3485,7 +3485,7 @@ void simple_transaction_set(struct file *file, size_t n);
* 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); \
@ -3496,10 +3496,16 @@ static const struct file_operations __fops = { \
.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, ...)
{
@ -3514,6 +3520,8 @@ ssize_t simple_attr_read(struct file *file, char __user *buf,
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 __init list_bdev_fs_names(char *buf, size_t size);