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authorMiklos Szeredi <mszeredi@redhat.com>2016-10-04 14:40:45 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2016-10-14 11:16:47 +0200
commit7764235becf3b72bd124400fbffe670531322135 (patch)
tree9377570db6422ab76c10617bea548a1f4e41311e
parentd60874cd58fcb21372f2df698c20f8cf2f78fdcb (diff)
downloadlinux-7764235becf3b72bd124400fbffe670531322135.tar.bz2
ovl: use vfs_get_link()
Resulting in a complete removal of a function basically implementing the inverse of vfs_readlink(). As a bonus, now the proper security hook is also called. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--fs/overlayfs/copy_up.c46
-rw-r--r--fs/overlayfs/inode.c10
2 files changed, 7 insertions, 49 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 796d06fafd09..e9d4013ed3c6 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -177,40 +177,6 @@ out_fput:
return error;
}
-static char *ovl_read_symlink(struct dentry *realdentry)
-{
- int res;
- char *buf;
- struct inode *inode = realdentry->d_inode;
- mm_segment_t old_fs;
-
- res = -EINVAL;
- if (!inode->i_op->readlink)
- goto err;
-
- res = -ENOMEM;
- buf = (char *) __get_free_page(GFP_KERNEL);
- if (!buf)
- goto err;
-
- old_fs = get_fs();
- set_fs(get_ds());
- /* The cast to a user pointer is valid due to the set_fs() */
- res = inode->i_op->readlink(realdentry,
- (char __user *)buf, PAGE_SIZE - 1);
- set_fs(old_fs);
- if (res < 0) {
- free_page((unsigned long) buf);
- goto err;
- }
- buf[res] = '\0';
-
- return buf;
-
-err:
- return ERR_PTR(res);
-}
-
static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
{
struct iattr attr = {
@@ -342,18 +308,20 @@ out_cleanup:
int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
struct path *lowerpath, struct kstat *stat)
{
+ DEFINE_DELAYED_CALL(done);
struct dentry *workdir = ovl_workdir(dentry);
int err;
struct kstat pstat;
struct path parentpath;
+ struct dentry *lowerdentry = lowerpath->dentry;
struct dentry *upperdir;
struct dentry *upperdentry;
- char *link = NULL;
+ const char *link = NULL;
if (WARN_ON(!workdir))
return -EROFS;
- ovl_do_check_copy_up(lowerpath->dentry);
+ ovl_do_check_copy_up(lowerdentry);
ovl_path_upper(parent, &parentpath);
upperdir = parentpath.dentry;
@@ -363,7 +331,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
return err;
if (S_ISLNK(stat->mode)) {
- link = ovl_read_symlink(lowerpath->dentry);
+ link = vfs_get_link(lowerdentry, &done);
if (IS_ERR(link))
return PTR_ERR(link);
}
@@ -388,9 +356,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
}
out_unlock:
unlock_rename(workdir, upperdir);
-
- if (link)
- free_page((unsigned long) link);
+ do_delayed_call(&done);
return err;
}
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 50dc214c44f2..bc6d261db669 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -156,22 +156,14 @@ static const char *ovl_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
- struct dentry *realdentry;
- struct inode *realinode;
const struct cred *old_cred;
const char *p;
if (!dentry)
return ERR_PTR(-ECHILD);
- realdentry = ovl_dentry_real(dentry);
- realinode = realdentry->d_inode;
-
- if (WARN_ON(!realinode->i_op->get_link))
- return ERR_PTR(-EPERM);
-
old_cred = ovl_override_creds(dentry->d_sb);
- p = realinode->i_op->get_link(realdentry, realinode, done);
+ p = vfs_get_link(ovl_dentry_real(dentry), done);
revert_creds(old_cred);
return p;
}