4dcb3d8ab2
[ Upstream commit c73aa4102f5b9f261a907c3b3df94cd2c478504d ]
Fix the ->get handlers for the afs.cell and afs.volume xattrs to pass the
source data size to memcpy() rather than target buffer size.
Overcopying the source data occasionally causes the kernel to oops.
Fixes: d3e3b7eac8 ("afs: Add metadata xattrs")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
121 lines
3 KiB
C
121 lines
3 KiB
C
/* Extended attribute handling for AFS. We use xattrs to get and set metadata
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* instead of providing pioctl().
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*
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* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/xattr.h>
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#include "internal.h"
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static const char afs_xattr_list[] =
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"afs.cell\0"
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"afs.fid\0"
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"afs.volume";
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/*
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* Retrieve a list of the supported xattrs.
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*/
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ssize_t afs_listxattr(struct dentry *dentry, char *buffer, size_t size)
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{
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if (size == 0)
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return sizeof(afs_xattr_list);
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if (size < sizeof(afs_xattr_list))
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return -ERANGE;
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memcpy(buffer, afs_xattr_list, sizeof(afs_xattr_list));
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return sizeof(afs_xattr_list);
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}
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/*
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* Get the name of the cell on which a file resides.
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*/
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static int afs_xattr_get_cell(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_cell *cell = vnode->volume->cell;
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size_t namelen;
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namelen = cell->name_len;
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, cell->name, namelen);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_cell_handler = {
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.name = "afs.cell",
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.get = afs_xattr_get_cell,
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};
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/*
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* Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of
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* hex numbers separated by colons.
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*/
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static int afs_xattr_get_fid(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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char text[8 + 1 + 8 + 1 + 8 + 1];
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size_t len;
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len = sprintf(text, "%x:%x:%x",
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vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
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if (size == 0)
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return len;
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if (len > size)
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return -ERANGE;
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memcpy(buffer, text, len);
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return len;
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}
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static const struct xattr_handler afs_xattr_afs_fid_handler = {
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.name = "afs.fid",
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.get = afs_xattr_get_fid,
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};
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/*
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* Get the name of the volume on which a file resides.
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*/
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static int afs_xattr_get_volume(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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const char *volname = vnode->volume->name;
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size_t namelen;
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namelen = strlen(volname);
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, volname, namelen);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_volume_handler = {
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.name = "afs.volume",
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.get = afs_xattr_get_volume,
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};
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const struct xattr_handler *afs_xattr_handlers[] = {
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&afs_xattr_afs_cell_handler,
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&afs_xattr_afs_fid_handler,
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&afs_xattr_afs_volume_handler,
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NULL
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};
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