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| author | Miklos Szeredi <miklos@szeredi.hu> | 2015-12-11 18:30:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-25 23:01:24 +0300 |
| commit | 8373f6590f6b371bff2c5f2c0581548eb0192014 (patch) | |
| tree | f2d9f8ef550d2d58b8624a889d63e05f02be032b /fs/overlayfs/inode.c | |
| parent | 7193e802960f884e0ae6c40711c4e3c70fa3b070 (diff) | |
| download | linux-8373f6590f6b371bff2c5f2c0581548eb0192014.tar.xz | |
ovl: setattr: check permissions before copy-up
commit cf9a6784f7c1b5ee2b9159a1246e327c331c5697 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/overlayfs/inode.c')
| -rw-r--r-- | fs/overlayfs/inode.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 4060ffde8722..b29036aa8d7c 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -42,6 +42,19 @@ 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; |