summaryrefslogtreecommitdiff
path: root/fs/overlayfs/inode.c
diff options
context:
space:
mode:
authorMiklos Szeredi <miklos@szeredi.hu>2015-12-11 16:30:49 +0100
committerMiklos Szeredi <miklos@szeredi.hu>2015-12-11 16:30:49 +0100
commitcf9a6784f7c1b5ee2b9159a1246e327c331c5697 (patch)
tree00479d7bda053b037fe13c7408e3540365f907bf /fs/overlayfs/inode.c
parented06e069775ad9236087594a1c1667367e983fb5 (diff)
ovl: setattr: check permissions before copy-up
Without this copy-up of a file can be forced, even without actually being allowed to do anything on the file. [Arnd Bergmann] include <linux/pagemap.h> for PAGE_CACHE_SIZE (used by MAX_LFS_FILESIZE definition). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
Diffstat (limited to 'fs/overlayfs/inode.c')
-rw-r--r--fs/overlayfs/inode.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 76546314e35f..213a726cff96 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -45,6 +45,19 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
int err;
struct dentry *upperdentry;
+ /*
+ * Check for permissions before trying to copy-up. This is redundant
+ * since it will be rechecked later by ->setattr() on upper dentry. But
+ * without this, copy-up can be triggered by just about anybody.
+ *
+ * We don't initialize inode->size, which just means that
+ * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
+ * check for a swapfile (which this won't be anyway).
+ */
+ err = inode_change_ok(dentry->d_inode, attr);
+ if (err)
+ return err;
+
err = ovl_want_write(dentry);
if (err)
goto out;