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.
Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") Reported-by: Zhao Gongyi zhaogongyi@huawei.com Signed-off-by: Akinobu Mita akinobu.mita@gmail.com --- 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 31b0ddf01c31..76fb29a103a2 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -994,8 +994,8 @@ 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; @@ -1016,7 +1016,10 @@ 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); @@ -1026,8 +1029,21 @@ 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 9eced4cc286e..c79138818922 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3471,7 +3471,7 @@ 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); \ @@ -3482,10 +3482,16 @@ 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, ...) { @@ -3500,6 +3506,8 @@ 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);