kernel.git/fs/cifs/connect.c, branch linux-4.4.y

cifs: fix incorrect check for null pointer in header_assemble

2021-10-06T08:22:23Z

commit 9ed38fd4a15417cac83967360cf20b853bfab9b6 upstream. Although very unlikely that the tlink pointer would be null in this case, get_next_mid function can in theory return null (but not an error) so need to check for null (not for IS_ERR, which can not be returned here). Address warning: fs/smbfs_client/connect.c:2392 cifs_match_super() warn: 'tlink' isn't an ERR_PTR Pointed out by Dan Carpenter via smatch code analysis tool CC: stable@vger.kernel.org Reported-by: Dan Carpenter Acked-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

cifs: fix potential use-after-free in cifs_echo_request()

2020-12-11T12:36:45Z

commit 212253367dc7b49ed3fc194ce71b0992eacaecf2 upstream. This patch fixes a potential use-after-free bug in cifs_echo_request(). For instance, thread 1 -------- cifs_demultiplex_thread() clean_demultiplex_info() kfree(server) thread 2 (workqueue) -------- apic_timer_interrupt() smp_apic_timer_interrupt() irq_exit() __do_softirq() run_timer_softirq() call_timer_fn() cifs_echo_request() <- use-after-free in server ptr Signed-off-by: Paulo Alcantara (SUSE) CC: Stable Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

SMB3: Honor persistent/resilient handle flags for multiuser mounts

2020-07-09T07:35:09Z

commit 00dfbc2f9c61185a2e662f27c45a0bb29b2a134f upstream. Without this: - persistent handles will only be enabled for per-user tcons if the server advertises the 'Continuous Availabity' capability - resilient handles would never be enabled for per-user tcons Signed-off-by: Paul Aurich CC: Stable Signed-off-by: Steve French Reviewed-by: Aurelien Aptel Signed-off-by: Greg Kroah-Hartman

SMB3: Honor 'seal' flag for multiuser mounts

2020-07-09T07:35:09Z

commit cc15461c73d7d044d56c47e869a215e49bd429c8 upstream. Ensure multiuser SMB3 mounts use encryption for all users' tcons if the mount options are configured to require encryption. Without this, only the primary tcon and IPC tcons are guaranteed to be encrypted. Per-user tcons would only be encrypted if the server was configured to require encryption. Signed-off-by: Paul Aurich CC: Stable Signed-off-by: Steve French Reviewed-by: Aurelien Aptel Signed-off-by: Greg Kroah-Hartman

cifs: Fix a race condition with cifs_echo_request

2020-05-20T06:11:44Z

[ Upstream commit f2caf901c1b7ce65f9e6aef4217e3241039db768 ] There is a race condition with how we send (or supress and don't send) smb echos that will cause the client to incorrectly think the server is unresponsive and thus needs to be reconnected. Summary of the race condition: 1) Daisy chaining scheduling creates a gap. 2) If traffic comes unfortunate shortly after the last echo, the planned echo is suppressed. 3) Due to the gap, the next echo transmission is delayed until after the timeout, which is set hard to twice the echo interval. This is fixed by changing the timeouts from 2 to three times the echo interval. Detailed description of the bug: https://lutz.donnerhacke.de/eng/Blog/Groundhog-Day-with-SMB-remount Signed-off-by: Ronnie Sahlberg Reviewed-by: Pavel Shilovsky Signed-off-by: Steve French Signed-off-by: Sasha Levin

cifs: Check for timeout on Negotiate stage

2020-05-20T06:11:43Z

[ Upstream commit 76e752701a8af4404bbd9c45723f7cbd6e4a251e ] Some servers seem to accept connections while booting but never send the SMBNegotiate response neither close the connection, causing all processes accessing the share hang on uninterruptible sleep state. This happens when the cifs_demultiplex_thread detects the server is unresponsive so releases the socket and start trying to reconnect. At some point, the faulty server will accept the socket and the TCP status will be set to NeedNegotiate. The first issued command accessing the share will start the negotiation (pid 5828 below), but the response will never arrive so other commands will be blocked waiting on the mutex (pid 55352). This patch checks for unresponsive servers also on the negotiate stage releasing the socket and reconnecting if the response is not received and checking again the tcp state when the mutex is acquired. PID: 55352 TASK: ffff880fd6cc02c0 CPU: 0 COMMAND: "ls" #0 [ffff880fd9add9f0] schedule at ffffffff81467eb9 #1 [ffff880fd9addb38] __mutex_lock_slowpath at ffffffff81468fe0 #2 [ffff880fd9addba8] mutex_lock at ffffffff81468b1a #3 [ffff880fd9addbc0] cifs_reconnect_tcon at ffffffffa042f905 [cifs] #4 [ffff880fd9addc60] smb_init at ffffffffa042faeb [cifs] #5 [ffff880fd9addca0] CIFSSMBQPathInfo at ffffffffa04360b5 [cifs] .... Which is waiting a mutex owned by: PID: 5828 TASK: ffff880fcc55e400 CPU: 0 COMMAND: "xxxx" #0 [ffff880fbfdc19b8] schedule at ffffffff81467eb9 #1 [ffff880fbfdc1b00] wait_for_response at ffffffffa044f96d [cifs] #2 [ffff880fbfdc1b60] SendReceive at ffffffffa04505ce [cifs] #3 [ffff880fbfdc1bb0] CIFSSMBNegotiate at ffffffffa0438d79 [cifs] #4 [ffff880fbfdc1c50] cifs_negotiate_protocol at ffffffffa043b383 [cifs] #5 [ffff880fbfdc1c80] cifs_reconnect_tcon at ffffffffa042f911 [cifs] #6 [ffff880fbfdc1d20] smb_init at ffffffffa042faeb [cifs] #7 [ffff880fbfdc1d60] CIFSSMBQFSInfo at ffffffffa0434eb0 [cifs] .... Signed-off-by: Samuel Cabrero Reviewed-by: Aurélien Aptel Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Sasha Levin

cifs: protect updating server->dstaddr with a spinlock

2020-05-10T08:26:11Z

[ Upstream commit fada37f6f62995cc449b36ebba1220594bfe55fe ] We use a spinlock while we are reading and accessing the destination address for a server. We need to also use this spinlock to protect when we are modifying this address from reconn_set_ipaddr(). Signed-off-by: Ronnie Sahlberg Reviewed-by: Jeff Layton Signed-off-by: Steve French Signed-off-by: Sasha Levin

cifs: Fix mode output in debugging statements

2020-03-11T06:51:12Z

[ Upstream commit f52aa79df43c4509146140de0241bc21a4a3b4c7 ] A number of the debug statements output file or directory mode in hex. Change these to print using octal. Signed-off-by: Frank Sorenson Signed-off-by: Steve French Signed-off-by: Sasha Levin

signal: Allow cifs and drbd to receive their terminating signals

2020-01-29T09:21:47Z

[ Upstream commit 33da8e7c814f77310250bb54a9db36a44c5de784 ] My recent to change to only use force_sig for a synchronous events wound up breaking signal reception cifs and drbd. I had overlooked the fact that by default kthreads start out with all signals set to SIG_IGN. So a change I thought was safe turned out to have made it impossible for those kernel thread to catch their signals. Reverting the work on force_sig is a bad idea because what the code was doing was very much a misuse of force_sig. As the way force_sig ultimately allowed the signal to happen was to change the signal handler to SIG_DFL. Which after the first signal will allow userspace to send signals to these kernel threads. At least for wake_ack_receiver in drbd that does not appear actively wrong. So correct this problem by adding allow_kernel_signal that will allow signals whose siginfo reports they were sent by the kernel through, but will not allow userspace generated signals, and update cifs and drbd to call allow_kernel_signal in an appropriate place so that their thread can receive this signal. Fixing things this way ensures that userspace won't be able to send signals and cause problems, that it is clear which signals the threads are expecting to receive, and it guarantees that nothing else in the system will be affected. This change was partly inspired by similar cifs and drbd patches that added allow_signal. Reported-by: ronnie sahlberg Reported-by: Christoph Böhmwalder Tested-by: Christoph Böhmwalder Cc: Steve French Cc: Philipp Reisner Cc: David Laight Fixes: 247bc9470b1e ("cifs: fix rmmod regression in cifs.ko caused by force_sig changes") Fixes: 72abe3bcf091 ("signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig") Fixes: fee109901f39 ("signal/drbd: Use send_sig not force_sig") Fixes: 3cf5d076fb4d ("signal: Remove task parameter from force_sig") Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin

cifs: fix rmmod regression in cifs.ko caused by force_sig changes

2020-01-29T09:21:46Z

[ Upstream commit 247bc9470b1eeefc7b58cdf2c39f2866ba651509 ] Fixes: 72abe3bcf091 ("signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig") The global change from force_sig caused module unloading of cifs.ko to fail (since the cifsd process could not be killed, "rmmod cifs" now would always fail) Signed-off-by: Steve French Reviewed-by: Ronnie Sahlberg CC: Eric W. Biederman Signed-off-by: Sasha Levin