KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> writes:
>> > +static int
>> > +__negative_fpos_check(struct file *file, loff_t pos, size_t count)
>> > +{
>> > + /*
>> > + * pos or pos+count is negative here, check overflow.
>> > + * too big "count" will be caught in rw_verify_area().
>> > + */
>> > + if ((pos < 0) && (pos + count < pos))
>> > + return -EOVERFLOW;
>> > + if (file->f_mode & FMODE_NEG_OFFSET)
>> > + return 0;
>> > + return -EINVAL;
>> > +}
>> > +
>> > /*
>> > * rw_verify_area doesn't like huge counts. We limit
>> > * them to something that fits in "int" so that others
>> > @@ -222,8 +236,11 @@ int rw_verify_area(int read_write, struc
>> > if (unlikely((ssize_t) count < 0))
>> > return retval;
>> > pos = *ppos;
>> > - if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
>> > - return retval;
>> > + if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) {
>> > + retval = __negative_fpos_check(file, pos, count);
>> > + if (retval)
>> > + return retval;
>> > + }
>> >
>> > if (unlikely(inode->i_flock && mandatory_lock(inode))) {
>> > retval = locks_mandatory_area(
>>
>> Um... How do lseek() work? It sounds like to violate error code range.
>
> This is for read-write. As far as I know,
> - generic_file_llseek,
> - default_llseek
> - no_llseek
>
> doesn't call this function.
It seems to allow to set negative value to ->f_pos, right? So, lseek()
returns (uses) it?
Thanks.
--
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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