ceph: avoid possible null deref in readdir after dir llseek

last may be NULL, but we dereference it in the else branch without
checking.  Normally it doesn't trigger because last == NULL when fpos == 2,
but it could happen on a newly opened dir if the user seeks forward.

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2010-11-22 22:58:06 -08:00
parent 3561d43fd2
commit 884ea89276

View file

@ -114,8 +114,8 @@ static int __dcache_readdir(struct file *filp,
spin_lock(&dcache_lock);
/* start at beginning? */
if (filp->f_pos == 2 || (last &&
filp->f_pos < ceph_dentry(last)->offset)) {
if (filp->f_pos == 2 || last == NULL ||
filp->f_pos < ceph_dentry(last)->offset) {
if (list_empty(&parent->d_subdirs))
goto out_unlock;
p = parent->d_subdirs.prev;