diff options
Diffstat (limited to 'fs/overlayfs/inode.c')
-rw-r--r-- | fs/overlayfs/inode.c | 50 |
1 files changed, 35 insertions, 15 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index ba0db2638946..0bb8347c0d8b 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -45,17 +45,36 @@ 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; - upperdentry = ovl_dentry_upper(dentry); - if (upperdentry) { + err = ovl_copy_up(dentry); + if (!err) { + upperdentry = ovl_dentry_upper(dentry); + mutex_lock(&upperdentry->d_inode->i_mutex); + + if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) + attr->ia_valid &= ~ATTR_MODE; + err = notify_change(upperdentry, attr, NULL); + if (!err) + ovl_copyattr(upperdentry->d_inode, dentry->d_inode); mutex_unlock(&upperdentry->d_inode->i_mutex); - } else { - err = ovl_copy_up_last(dentry, attr, false); } ovl_drop_write(dentry); out: @@ -202,8 +221,7 @@ static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz) return realinode->i_op->readlink(realpath.dentry, buf, bufsiz); } - -static bool ovl_is_private_xattr(const char *name) +bool ovl_is_private_xattr(const char *name) { return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0; } @@ -261,7 +279,8 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) struct path realpath; enum ovl_path_type type = ovl_path_real(dentry, &realpath); ssize_t res; - int off; + size_t len; + char *s; res = vfs_listxattr(realpath.dentry, list, size); if (res <= 0 || size == 0) @@ -271,17 +290,19 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) return res; /* filter out private xattrs */ - for (off = 0; off < res;) { - char *s = list + off; - size_t slen = strlen(s) + 1; + for (s = list, len = res; len;) { + size_t slen = strnlen(s, len) + 1; - BUG_ON(off + slen > res); + /* underlying fs providing us with an broken xattr list? */ + if (WARN_ON(slen > len)) + return -EIO; + len -= slen; if (ovl_is_private_xattr(s)) { res -= slen; - memmove(s, s + slen, res - off); + memmove(s, s + slen, len); } else { - off += slen; + s += slen; } } @@ -396,12 +417,11 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, if (!inode) return NULL; - mode &= S_IFMT; - inode->i_ino = get_next_ino(); inode->i_mode = mode; inode->i_flags |= S_NOATIME | S_NOCMTIME; + mode &= S_IFMT; switch (mode) { case S_IFDIR: inode->i_private = oe; |