On Mon, Oct 01, 2018 at 03:45:00PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > > Teach callers of inode->i_op->get_link in the vfs code to check for a > NULL return value and return an error status instead of blindly > dereferencing the returned NULL pointer. Is that better than having the get_link method return ERR_PTR(-EUCLEAN) itself? > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > --- > fs/namei.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/namei.c b/fs/namei.c > index 0cab6494978c..0744ab981fa0 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -4737,6 +4737,8 @@ int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen) > if (IS_ERR(link)) > return PTR_ERR(link); > } > + if (!link) > + return -EUCLEAN; > res = readlink_copy(buffer, buflen, link); > do_delayed_call(&done); > return res; > @@ -4763,6 +4765,8 @@ const char *vfs_get_link(struct dentry *dentry, struct delayed_call *done) > res = ERR_PTR(security_inode_readlink(dentry)); > if (!res) > res = inode->i_op->get_link(dentry, inode, done); > + if (!res) > + return ERR_PTR(-EUCLEAN); > } > return res; > }
