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| author | Christopher Oo <t-chriso@microsoft.com> | 2015-06-25 16:10:48 -0700 |
|---|---|---|
| committer | Steve French <smfrench@gmail.com> | 2015-08-20 10:19:25 -0500 |
| commit | 5fb4e288a025af1abc5c67ecebf30fbf6b3edad1 (patch) | |
| tree | 751d20a93eb2f92415213fc068e6daa95e839119 /fs/cifs/cifssmb.c | |
| parent | 0a6d0b64120759df8b9291af92d998ed1cbefc9d (diff) | |
| download | linux-5fb4e288a025af1abc5c67ecebf30fbf6b3edad1.tar.bz2 | |
cifs: Fix use-after-free on mid_q_entry
With CIFS_DEBUG_2 enabled, additional debug information is tracked inside each
mid_q_entry struct, however cifs_save_when_sent may use the mid_q_entry after it
has been freed from the appropriate callback if the transport layer has very low
latency. Holding the srv_mutex fixes this use-after-free, as cifs_save_when_sent
is called while the srv_mutex is held while the request is sent.
Signed-off-by: Christopher Oo <t-chriso@microsoft.com>
Diffstat (limited to 'fs/cifs/cifssmb.c')
| -rw-r--r-- | fs/cifs/cifssmb.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 672ef35c9f73..90b4f9f7de66 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -696,7 +696,9 @@ cifs_echo_callback(struct mid_q_entry *mid) { struct TCP_Server_Info *server = mid->callback_data; + mutex_lock(&server->srv_mutex); DeleteMidQEntry(mid); + mutex_unlock(&server->srv_mutex); add_credits(server, 1, CIFS_ECHO_OP); } @@ -1572,7 +1574,9 @@ cifs_readv_callback(struct mid_q_entry *mid) } queue_work(cifsiod_wq, &rdata->work); + mutex_lock(&server->srv_mutex); DeleteMidQEntry(mid); + mutex_unlock(&server->srv_mutex); add_credits(server, 1, 0); } @@ -2032,6 +2036,7 @@ cifs_writev_callback(struct mid_q_entry *mid) { struct cifs_writedata *wdata = mid->callback_data; struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink); + struct TCP_Server_Info *server = tcon->ses->server; unsigned int written; WRITE_RSP *smb = (WRITE_RSP *)mid->resp_buf; @@ -2068,7 +2073,9 @@ cifs_writev_callback(struct mid_q_entry *mid) } queue_work(cifsiod_wq, &wdata->work); + mutex_lock(&server->srv_mutex); DeleteMidQEntry(mid); + mutex_unlock(&server->srv_mutex); add_credits(tcon->ses->server, 1, 0); } |