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This makes it harder for accidental or malicious changes to v9fs_xattr_user_handler, v9fs_xattr_trusted_handler, v9fs_xattr_security_handler, or v9fs_xattr_handlers at runtime. Cc: Eric Van Hensbergen <ericvh@kernel.org> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Christian Schoenebeck <linux_oss@crudebyte.com> Cc: v9fs@lists.linux.dev Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20230930050033.41174-4-wedsonaf@gmail.com Acked-by: Dominique Martinet <asmadeus@codewreck.org> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
193 lines
4.9 KiB
C
193 lines
4.9 KiB
C
// SPDX-License-Identifier: LGPL-2.1
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/*
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* Copyright IBM Corporation, 2010
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* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/uio.h>
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#include <linux/posix_acl_xattr.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include "fid.h"
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#include "xattr.h"
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ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
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void *buffer, size_t buffer_size)
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{
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ssize_t retval;
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u64 attr_size;
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struct p9_fid *attr_fid;
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struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
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struct iov_iter to;
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int err;
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iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size);
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attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
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if (IS_ERR(attr_fid)) {
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retval = PTR_ERR(attr_fid);
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p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
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retval);
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return retval;
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}
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if (attr_size > buffer_size) {
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if (buffer_size)
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retval = -ERANGE;
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else if (attr_size > SSIZE_MAX)
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retval = -EOVERFLOW;
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else /* request to get the attr_size */
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retval = attr_size;
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} else {
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iov_iter_truncate(&to, attr_size);
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retval = p9_client_read(attr_fid, 0, &to, &err);
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if (err)
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retval = err;
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}
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p9_fid_put(attr_fid);
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return retval;
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}
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/*
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* v9fs_xattr_get()
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*
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* Copy an extended attribute into the buffer
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* provided, or compute the buffer size required.
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* Buffer is NULL to compute the size of the buffer required.
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*
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* Returns a negative error number on failure, or the number of bytes
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* used / required on success.
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*/
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ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
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void *buffer, size_t buffer_size)
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{
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struct p9_fid *fid;
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int ret;
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p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n",
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name, buffer_size);
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fid = v9fs_fid_lookup(dentry);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
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p9_fid_put(fid);
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return ret;
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}
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/*
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* v9fs_xattr_set()
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*
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* Create, replace or remove an extended attribute for this inode. Buffer
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* is NULL to remove an existing extended attribute, and non-NULL to
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* either replace an existing extended attribute, or create a new extended
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* attribute. The flags XATTR_REPLACE and XATTR_CREATE
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* specify that an extended attribute must exist and must not exist
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* previous to the call, respectively.
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*
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* Returns 0, or a negative error number on failure.
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*/
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int v9fs_xattr_set(struct dentry *dentry, const char *name,
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const void *value, size_t value_len, int flags)
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{
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int ret;
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struct p9_fid *fid;
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fid = v9fs_fid_lookup(dentry);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
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p9_fid_put(fid);
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return ret;
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}
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int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
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const void *value, size_t value_len, int flags)
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{
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struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
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struct iov_iter from;
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int retval, err;
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iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len);
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p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
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name, value_len, flags);
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/* Clone it */
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fid = clone_fid(fid);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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/*
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* On success fid points to xattr
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*/
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retval = p9_client_xattrcreate(fid, name, value_len, flags);
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if (retval < 0)
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p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
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retval);
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else
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p9_client_write(fid, 0, &from, &retval);
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err = p9_fid_put(fid);
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if (!retval && err)
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retval = err;
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return retval;
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}
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ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
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{
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return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
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}
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static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
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struct dentry *dentry, struct inode *inode,
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const char *name, void *buffer, size_t size)
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{
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const char *full_name = xattr_full_name(handler, name);
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return v9fs_xattr_get(dentry, full_name, buffer, size);
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}
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static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
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struct mnt_idmap *idmap,
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struct dentry *dentry, struct inode *inode,
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const char *name, const void *value,
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size_t size, int flags)
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{
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const char *full_name = xattr_full_name(handler, name);
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return v9fs_xattr_set(dentry, full_name, value, size, flags);
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}
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static const struct xattr_handler v9fs_xattr_user_handler = {
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.prefix = XATTR_USER_PREFIX,
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.get = v9fs_xattr_handler_get,
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.set = v9fs_xattr_handler_set,
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};
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static const struct xattr_handler v9fs_xattr_trusted_handler = {
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.prefix = XATTR_TRUSTED_PREFIX,
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.get = v9fs_xattr_handler_get,
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.set = v9fs_xattr_handler_set,
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};
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#ifdef CONFIG_9P_FS_SECURITY
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static const struct xattr_handler v9fs_xattr_security_handler = {
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.prefix = XATTR_SECURITY_PREFIX,
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.get = v9fs_xattr_handler_get,
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.set = v9fs_xattr_handler_set,
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};
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#endif
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const struct xattr_handler * const v9fs_xattr_handlers[] = {
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&v9fs_xattr_user_handler,
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&v9fs_xattr_trusted_handler,
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#ifdef CONFIG_9P_FS_SECURITY
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&v9fs_xattr_security_handler,
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#endif
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NULL
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};
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