From: Akinobu Mita <akinobu.mita@xxxxxxxxx>
[ Upstream commit 2e41f274f9aa71cdcc69dc1f26a3f9304a651804 ]
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@xxxxxxxxx
Link: https://lkml.kernel.org/r/20220919172418.45257-2-akinobu.mita@xxxxxxxxx
Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()")
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Reported-by: Zhao Gongyi <zhaogongyi@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
Cc: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/libfs.c | 22 +++++++++++++++++++---
include/linux/fs.h | 12 ++++++++++--
2 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/fs/libfs.c b/fs/libfs.c
index 83618c21c216..251bf5004919 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -864,8 +864,8 @@ ssize_t simple_attr_read(struct file *file, char __user *buf,
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;
@@ -886,7 +886,10 @@ 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);
@@ -896,8 +899,21 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
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
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1084f1335c9f..ff0a992846a3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3280,7 +3280,7 @@ 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); \
@@ -3291,10 +3291,16 @@ 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, ...)
{
@@ -3309,6 +3315,8 @@ 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 proc_nr_files(struct ctl_table *table, int write,
--
2.35.1
