From f2b20f6ee842313a0d681dbbf7f87b70291a6a3b Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 16 Sep 2016 12:44:20 +0200 Subject: vfs: move permission checking into notify_change() for utimes(NULL) This fixes a bug where the permission was not properly checked in overlayfs. The testcase is ltp/utimensat01. It is also cleaner and safer to do the permission checking in the vfs helper instead of the caller. This patch introduces an additional ia_valid flag ATTR_TOUCH (since touch(1) is the most obvious user of utimes(NULL)) that is passed into notify_change whenever the conditions for this special permission checking mode are met. Reported-by: Aihua Zhang Signed-off-by: Miklos Szeredi Tested-by: Aihua Zhang Cc: # v3.18+ --- fs/utimes.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) (limited to 'fs/utimes.c') diff --git a/fs/utimes.c b/fs/utimes.c index 794f5f5b1fb5..ba54b9e648c9 100644 --- a/fs/utimes.c +++ b/fs/utimes.c @@ -87,21 +87,7 @@ static int utimes_common(struct path *path, struct timespec *times) */ newattrs.ia_valid |= ATTR_TIMES_SET; } else { - /* - * If times is NULL (or both times are UTIME_NOW), - * then we need to check permissions, because - * inode_change_ok() won't do it. - */ - error = -EPERM; - if (IS_IMMUTABLE(inode)) - goto mnt_drop_write_and_out; - - error = -EACCES; - if (!inode_owner_or_capable(inode)) { - error = inode_permission(inode, MAY_WRITE); - if (error) - goto mnt_drop_write_and_out; - } + newattrs.ia_valid |= ATTR_TOUCH; } retry_deleg: inode_lock(inode); @@ -113,7 +99,6 @@ retry_deleg: goto retry_deleg; } -mnt_drop_write_and_out: mnt_drop_write(path->mnt); out: return error; -- cgit