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