From 38bd49064a1ecb67baad33598e3d824448ab11ec Mon Sep 17 00:00:00 2001 From: Sachin Prabhu Date: Fri, 3 Mar 2017 15:41:38 -0800 Subject: Handle mismatched open calls A signal can interrupt a SendReceive call which result in incoming responses to the call being ignored. This is a problem for calls such as open which results in the successful response being ignored. This results in an open file resource on the server. The patch looks into responses which were cancelled after being sent and in case of successful open closes the open fids. For this patch, the check is only done in SendReceive2() RH-bz: 1403319 Signed-off-by: Sachin Prabhu Reviewed-by: Pavel Shilovsky Cc: Stable --- fs/cifs/connect.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'fs/cifs/connect.c') diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 9ae695a..0c7596c 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -904,10 +904,19 @@ cifs_demultiplex_thread(void *p) server->lstrp = jiffies; if (mid_entry != NULL) { + if ((mid_entry->mid_flags & MID_WAIT_CANCELLED) && + mid_entry->mid_state == MID_RESPONSE_RECEIVED && + server->ops->handle_cancelled_mid) + server->ops->handle_cancelled_mid( + mid_entry->resp_buf, + server); + if (!mid_entry->multiRsp || mid_entry->multiEnd) mid_entry->callback(mid_entry); - } else if (!server->ops->is_oplock_break || - !server->ops->is_oplock_break(buf, server)) { + } else if (server->ops->is_oplock_break && + server->ops->is_oplock_break(buf, server)) { + cifs_dbg(FYI, "Received oplock break\n"); + } else { cifs_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n", atomic_read(&midCount)); cifs_dump_mem("Received Data is: ", buf, -- cgit v1.1 From 40920c2bb119fd49ba03e2f97a172171781be442 Mon Sep 17 00:00:00 2001 From: Mark Syms Date: Tue, 29 Nov 2016 11:36:46 +0000 Subject: CIFS: handle guest access errors to Windows shares Commit 1a967d6c9b39c226be1b45f13acd4d8a5ab3dc44 ("correctly to anonymous authentication for the NTLM(v2) authentication") introduces a regression in handling errors related to attempting a guest connection to a Windows share which requires authentication. This should result in a permission denied error but actually causes the kernel module to enter a never-ending loop trying to follow a DFS referal which doesn't exist. The base cause of this is the failure now occurs later in the process during tree connect and not at the session setup setup and all errors in tree connect are interpreted as needing to follow the DFS paths which isn't in this case correct. So, check the returned error against EACCES and fail if this is returned error. Feedback from Aurelien: PS> net user guest /activate:no PS> mkdir C:\guestshare PS> icacls C:\guestshare /grant 'Everyone:(OI)(CI)F' PS> new-smbshare -name guestshare -path C:\guestshare -fullaccess Everyone I've tested v3.10, v4.4, master, master+your patch using default options (empty or no user "NU") and user=abc (U). NT_LOGON_FAILURE in session setup: LF This is what you seem to have in 3.10. NT_ACCESS_DENIED in tree connect to the share: AD This is what you get before your infinite loop. | NU U -------------------------------- 3.10 | LF LF 4.4 | LF LF master | AD LF master+patch | AD LF No infinite DFS loop :( All these issues result in mount failing very fast with permission denied. I guess it could be from either the Windows version or the share/folder ACL. A deeper analysis of the packets might reveal more. In any case I did not notice any issues for on a basic DFS setup with the patch so I don't think it introduced any regressions, which is probably all that matters. It still bothers me a little I couldn't hit the bug. I've included kernel output w/ debugging output and network capture of my tests if anyone want to have a look at it. (master+patch = ml-guestfix). Signed-off-by: Mark Syms Reviewed-by: Aurelien Aptel Tested-by: Aurelien Aptel Acked-by: Pavel Shilovsky Signed-off-by: Steve French --- fs/cifs/connect.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/cifs/connect.c') diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 0c7596c..d82467c 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -3753,6 +3753,9 @@ try_mount_again: if (IS_ERR(tcon)) { rc = PTR_ERR(tcon); tcon = NULL; + if (rc == -EACCES) + goto mount_fail_check; + goto remote_path_check; } -- cgit v1.1