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linux_dsm_epyc7002/include/net/9p/client.h
Tomas Bortoli 728356dede 9p: Add refcount to p9_req_t 
To avoid use-after-free(s), use a refcount to keep track of the
usable references to any instantiated struct p9_req_t.

This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as
wrappers to kref_put(), kref_get() and kref_get_unless_zero().
These are used by the client and the transports to keep track of
valid requests' references.

p9_free_req() is added back and used as callback by kref_put().

Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by
kmem_cache_free() will not be reused for another type until the rcu
synchronisation period is over, so an address gotten under rcu read
lock is safe to inc_ref() without corrupting random memory while
the lock is held.

Link: http://lkml.kernel.org/r/1535626341-20693-1-git-send-email-asmadeus@codewreck.org
Co-developed-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+467050c1ce275af2a5b8@syzkaller.appspotmail.com
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-08 01:39:47 +09:00

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/*
* include/net/9p/client.h
*
* 9P Client Definitions
*
* Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#ifndef NET_9P_CLIENT_H
#define NET_9P_CLIENT_H
#include <linux/utsname.h>
#include <linux/idr.h>
/* Number of requests per row */
#define P9_ROW_MAXTAG 255
/** enum p9_proto_versions - 9P protocol versions
* @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
* @p9_proto_2000u: 9P2000.u extension
* @p9_proto_2000L: 9P2000.L extension
*/
enum p9_proto_versions{
p9_proto_legacy,
p9_proto_2000u,
p9_proto_2000L,
};
/**
* enum p9_trans_status - different states of underlying transports
* @Connected: transport is connected and healthy
* @Disconnected: transport has been disconnected
* @Hung: transport is connected by wedged
*
* This enumeration details the various states a transport
* instatiation can be in.
*/
enum p9_trans_status {
Connected,
BeginDisconnect,
Disconnected,
Hung,
};
/**
* enum p9_req_status_t - status of a request
* @REQ_STATUS_ALLOC: request has been allocated but not sent
* @REQ_STATUS_UNSENT: request waiting to be sent
* @REQ_STATUS_SENT: request sent to server
* @REQ_STATUS_RCVD: response received from server
* @REQ_STATUS_FLSHD: request has been flushed
* @REQ_STATUS_ERROR: request encountered an error on the client side
*/
enum p9_req_status_t {
REQ_STATUS_ALLOC,
REQ_STATUS_UNSENT,
REQ_STATUS_SENT,
REQ_STATUS_RCVD,
REQ_STATUS_FLSHD,
REQ_STATUS_ERROR,
};
/**
* struct p9_req_t - request slots
* @status: status of this request slot
* @t_err: transport error
* @wq: wait_queue for the client to block on for this request
* @tc: the request fcall structure
* @rc: the response fcall structure
* @aux: transport specific data (provided for trans_fd migration)
* @req_list: link for higher level objects to chain requests
*/
struct p9_req_t {
int status;
int t_err;
struct kref refcount;
wait_queue_head_t wq;
struct p9_fcall tc;
struct p9_fcall rc;
void *aux;
struct list_head req_list;
};
/**
* struct p9_client - per client instance state
* @lock: protect @fids and @reqs
* @msize: maximum data size negotiated by protocol
* @proto_version: 9P protocol version to use
* @trans_mod: module API instantiated with this client
* @status: connection state
* @trans: tranport instance state and API
* @fids: All active FID handles
* @reqs: All active requests.
* @name: node name used as client id
*
* The client structure is used to keep track of various per-client
* state that has been instantiated.
*/
struct p9_client {
spinlock_t lock;
unsigned int msize;
unsigned char proto_version;
struct p9_trans_module *trans_mod;
enum p9_trans_status status;
void *trans;
struct kmem_cache *fcall_cache;
union {
struct {
int rfd;
int wfd;
} fd;
struct {
u16 port;
bool privport;
} tcp;
} trans_opts;
struct idr fids;
struct idr reqs;
char name[__NEW_UTS_LEN + 1];
};
/**
* struct p9_fid - file system entity handle
* @clnt: back pointer to instantiating &p9_client
* @fid: numeric identifier for this handle
* @mode: current mode of this fid (enum?)
* @qid: the &p9_qid server identifier this handle points to
* @iounit: the server reported maximum transaction size for this file
* @uid: the numeric uid of the local user who owns this handle
* @rdir: readdir accounting structure (allocated on demand)
* @dlist: per-dentry fid tracking
*
* TODO: This needs lots of explanation.
*/
struct p9_fid {
struct p9_client *clnt;
u32 fid;
int mode;
struct p9_qid qid;
u32 iounit;
kuid_t uid;
void *rdir;
struct hlist_node dlist; /* list of all fids attached to a dentry */
};
/**
* struct p9_dirent - directory entry structure
* @qid: The p9 server qid for this dirent
* @d_off: offset to the next dirent
* @d_type: type of file
* @d_name: file name
*/
struct p9_dirent {
struct p9_qid qid;
u64 d_off;
unsigned char d_type;
char d_name[256];
};
struct iov_iter;
int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
const char *name);
int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
struct p9_fid *newdirfid, const char *new_name);
struct p9_client *p9_client_create(const char *dev_name, char *options);
void p9_client_destroy(struct p9_client *clnt);
void p9_client_disconnect(struct p9_client *clnt);
void p9_client_begin_disconnect(struct p9_client *clnt);
struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
const char *uname, kuid_t n_uname, const char *aname);
struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
const unsigned char * const *wnames, int clone);
int p9_client_open(struct p9_fid *fid, int mode);
int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
char *extension);
int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, const char *newname);
int p9_client_symlink(struct p9_fid *fid, const char *name, const char *symname,
kgid_t gid, struct p9_qid *qid);
int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
kgid_t gid, struct p9_qid *qid);
int p9_client_clunk(struct p9_fid *fid);
int p9_client_fsync(struct p9_fid *fid, int datasync);
int p9_client_remove(struct p9_fid *fid);
int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
int p9dirent_read(struct p9_client *clnt, char *buf, int len,
struct p9_dirent *dirent);
struct p9_wstat *p9_client_stat(struct p9_fid *fid);
int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
u64 request_mask);
int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
dev_t rdev, kgid_t gid, struct p9_qid *);
int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
kgid_t gid, struct p9_qid *);
int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
void p9_fcall_fini(struct p9_fcall *fc);
struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
static inline void p9_req_get(struct p9_req_t *r)
{
kref_get(&r->refcount);
}
static inline int p9_req_try_get(struct p9_req_t *r)
{
return kref_get_unless_zero(&r->refcount);
}
int p9_req_put(struct p9_req_t *r);
void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
int p9stat_read(struct p9_client *, char *, int, struct p9_wstat *);
void p9stat_free(struct p9_wstat *);
int p9_is_proto_dotu(struct p9_client *clnt);
int p9_is_proto_dotl(struct p9_client *clnt);
struct p9_fid *p9_client_xattrwalk(struct p9_fid *, const char *, u64 *);
int p9_client_xattrcreate(struct p9_fid *, const char *, u64, int);
int p9_client_readlink(struct p9_fid *fid, char **target);
int p9_client_init(void);
void p9_client_exit(void);
#endif /* NET_9P_CLIENT_H */
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