xemu/hw/9pfs/9p-xattr.h
Greg Kurz 72f0d0bf51 9pfs: local: lremovexattr: don't follow symlinks
The local_lremovexattr() callback is vulnerable to symlink attacks because
it calls lremovexattr() which follows symbolic links in all path elements
but the rightmost one.

This patch introduces a helper to emulate the non-existing fremovexattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lremovexattr().

local_lremovexattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00

77 lines
3.0 KiB
C

/*
* 9p
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#ifndef QEMU_9P_XATTR_H
#define QEMU_9P_XATTR_H
#include "qemu/xattr.h"
typedef struct xattr_operations
{
const char *name;
ssize_t (*getxattr)(FsContext *ctx, const char *path,
const char *name, void *value, size_t size);
ssize_t (*listxattr)(FsContext *ctx, const char *path,
char *name, void *value, size_t size);
int (*setxattr)(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags);
int (*removexattr)(FsContext *ctx,
const char *path, const char *name);
} XattrOperations;
ssize_t local_getxattr_nofollow(FsContext *ctx, const char *path,
const char *name, void *value, size_t size);
ssize_t local_setxattr_nofollow(FsContext *ctx, const char *path,
const char *name, void *value, size_t size,
int flags);
ssize_t local_removexattr_nofollow(FsContext *ctx, const char *path,
const char *name);
extern XattrOperations mapped_user_xattr;
extern XattrOperations passthrough_user_xattr;
extern XattrOperations mapped_pacl_xattr;
extern XattrOperations mapped_dacl_xattr;
extern XattrOperations passthrough_acl_xattr;
extern XattrOperations none_acl_xattr;
extern XattrOperations *mapped_xattr_ops[];
extern XattrOperations *passthrough_xattr_ops[];
extern XattrOperations *none_xattr_ops[];
ssize_t v9fs_get_xattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size);
ssize_t v9fs_list_xattr(FsContext *ctx, const char *path, void *value,
size_t vsize);
int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags);
int v9fs_remove_xattr(FsContext *ctx, const char *path, const char *name);
ssize_t pt_listxattr(FsContext *ctx, const char *path, char *name, void *value,
size_t size);
ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size);
int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
size_t size, int flags);
int pt_removexattr(FsContext *ctx, const char *path, const char *name);
ssize_t notsup_getxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size);
int notsup_setxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags);
ssize_t notsup_listxattr(FsContext *ctx, const char *path, char *name,
void *value, size_t size);
int notsup_removexattr(FsContext *ctx, const char *path, const char *name);
#endif