From 4a3956c790290efeb647bbb0c3a90476bb57800e Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 1 Oct 2010 14:20:22 -0700 Subject: vfs: introduce FMODE_UNSIGNED_OFFSET for allowing negative f_pos Now, rw_verify_area() checsk f_pos is negative or not. And if negative, returns -EINVAL. But, some special files as /dev/(k)mem and /proc//mem etc.. has negative offsets. And we can't do any access via read/write to the file(device). So introduce FMODE_UNSIGNED_OFFSET to allow negative file offsets. Signed-off-by: Wu Fengguang Signed-off-by: KAMEZAWA Hiroyuki Cc: Al Viro Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/proc/base.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/proc/base.c') diff --git a/fs/proc/base.c b/fs/proc/base.c index dc5d5f51f3fe..fb2a5abd4e4f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -771,6 +771,8 @@ static const struct file_operations proc_single_file_operations = { static int mem_open(struct inode* inode, struct file* file) { file->private_data = (void*)((long)current->self_exec_id); + /* OK to pass negative loff_t, we can catch out-of-range */ + file->f_mode |= FMODE_UNSIGNED_OFFSET; return 0; } -- cgit v1.2.3