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2021-03-03cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting cifs_sb->prepath.Shyam Prasad N
[ Upstream commit a738c93fb1c17e386a09304b517b1c6b2a6a5a8b ] While debugging another issue today, Steve and I noticed that if a subdir for a file share is already mounted on the client, any new mount of any other subdir (or the file share root) of the same share results in sharing the cifs superblock, which e.g. can result in incorrect device name. While setting prefix path for the root of a cifs_sb, CIFS_MOUNT_USE_PREFIX_PATH flag should also be set. Without it, prepath is not even considered in some places, and output of "mount" and various /proc/<>/*mount* related options can be missing part of the device name. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-02-10cifs: report error instead of invalid when revalidating a dentry failsAurelien Aptel
commit 21b200d091826a83aafc95d847139b2b0582f6d1 upstream. Assuming - //HOST/a is mounted on /mnt - //HOST/b is mounted on /mnt/b On a slow connection, running 'df' and killing it while it's processing /mnt/b can make cifs_get_inode_info() returns -ERESTARTSYS. This triggers the following chain of events: => the dentry revalidation fail => dentry is put and released => superblock associated with the dentry is put => /mnt/b is unmounted This patch makes cifs_d_revalidate() return the error instead of 0 (invalid) when cifs_revalidate_dentry() fails, except for ENOENT (file deleted) and ESTALE (file recreated). Signed-off-by: Aurelien Aptel <aaptel@suse.com> Suggested-by: Shyam Prasad N <nspmangalore@gmail.com> Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com> CC: stable@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-11cifs: fix potential use-after-free in cifs_echo_request()Paulo Alcantara
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) <pc@cjr.nz> CC: Stable <stable@vger.kernel.org> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-18Convert trailing spaces and periods in path componentsBoris Protopopov
commit 57c176074057531b249cf522d90c22313fa74b0b upstream. When converting trailing spaces and periods in paths, do so for every component of the path, not just the last component. If the conversion is not done for every path component, then subsequent operations in directories with trailing spaces or periods (e.g. create(), mkdir()) will fail with ENOENT. This is because on the server, the directory will have a special symbol in its name, and the client needs to provide the same. Signed-off-by: Boris Protopopov <pboris@amazon.com> Acked-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-29cifs: remove bogus debug codeDan Carpenter
commit d367cb960ce88914898cbfa43645c2e43ede9465 upstream. The "end" pointer is either NULL or it points to the next byte to parse. If there isn't a next byte then dereferencing "end" is an off-by-one out of bounds error. And, of course, if it's NULL that leads to an Oops. Printing "*end" doesn't seem very useful so let's delete this code. Also for the last debug statement, I noticed that it should be printing "sequence_end" instead of "end" so fix that as well. Reported-by: Dominik Maier <dmaier@sect.tu-berlin.de> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-01cifs: Fix double add page to memcg when cifs_readpagesZhang Xiaoxu
[ Upstream commit 95a3d8f3af9b0d63b43f221b630beaab9739d13a ] When xfstests generic/451, there is an BUG at mm/memcontrol.c: page:ffffea000560f2c0 refcount:2 mapcount:0 mapping:000000008544e0ea index:0xf mapping->aops:cifs_addr_ops dentry name:"tst-aio-dio-cycle-write.451" flags: 0x2fffff80000001(locked) raw: 002fffff80000001 ffffc90002023c50 ffffea0005280088 ffff88815cda0210 raw: 000000000000000f 0000000000000000 00000002ffffffff ffff88817287d000 page dumped because: VM_BUG_ON_PAGE(page->mem_cgroup) page->mem_cgroup:ffff88817287d000 ------------[ cut here ]------------ kernel BUG at mm/memcontrol.c:2659! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 2038 Comm: xfs_io Not tainted 5.8.0-rc1 #44 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_ 073836-buildvm-ppc64le-16.ppc.4 RIP: 0010:commit_charge+0x35/0x50 Code: 0d 48 83 05 54 b2 02 05 01 48 89 77 38 c3 48 c7 c6 78 4a ea ba 48 83 05 38 b2 02 05 01 e8 63 0d9 RSP: 0018:ffffc90002023a50 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff88817287d000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88817ac97ea0 RDI: ffff88817ac97ea0 RBP: ffffea000560f2c0 R08: 0000000000000203 R09: 0000000000000005 R10: 0000000000000030 R11: ffffc900020237a8 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000001 R15: ffff88815a1272c0 FS: 00007f5071ab0800(0000) GS:ffff88817ac80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055efcd5ca000 CR3: 000000015d312000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mem_cgroup_charge+0x166/0x4f0 __add_to_page_cache_locked+0x4a9/0x710 add_to_page_cache_locked+0x15/0x20 cifs_readpages+0x217/0x1270 read_pages+0x29a/0x670 page_cache_readahead_unbounded+0x24f/0x390 __do_page_cache_readahead+0x3f/0x60 ondemand_readahead+0x1f1/0x470 page_cache_async_readahead+0x14c/0x170 generic_file_buffered_read+0x5df/0x1100 generic_file_read_iter+0x10c/0x1d0 cifs_strict_readv+0x139/0x170 new_sync_read+0x164/0x250 __vfs_read+0x39/0x60 vfs_read+0xb5/0x1e0 ksys_pread64+0x85/0xf0 __x64_sys_pread64+0x22/0x30 do_syscall_64+0x69/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5071fcb1af Code: Bad RIP value. RSP: 002b:00007ffde2cdb8e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000011 RAX: ffffffffffffffda RBX: 00007ffde2cdb990 RCX: 00007f5071fcb1af RDX: 0000000000001000 RSI: 000055efcd5ca000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000293 R12: 0000000000000001 R13: 000000000009f000 R14: 0000000000000000 R15: 0000000000001000 Modules linked in: ---[ end trace 725fa14a3e1af65c ]--- Since commit 3fea5a499d57 ("mm: memcontrol: convert page cache to a new mem_cgroup_charge() API") not cancel the page charge, the pages maybe double add to pagecache: thread1 | thread2 cifs_readpages readpages_get_pages add_to_page_cache_locked(head,index=n)=0 | readpages_get_pages | add_to_page_cache_locked(head,index=n+1)=0 add_to_page_cache_locked(head, index=n+1)=-EEXIST then, will next loop with list head page's index=n+1 and the page->mapping not NULL readpages_get_pages add_to_page_cache_locked(head, index=n+1) commit_charge VM_BUG_ON_PAGE So, we should not do the next loop when any page add to page cache failed. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com> Acked-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01CIFS: Properly process SMB3 lease breaksPavel Shilovsky
[ Upstream commit 9bd4540836684013aaad6070a65d6fcdd9006625 ] Currenly we doesn't assume that a server may break a lease from RWH to RW which causes us setting a wrong lease state on a file and thus mistakenly flushing data and byte-range locks and purging cached data on the client. This leads to performance degradation because subsequent IOs go directly to the server. Fix this by propagating new lease state and epoch values to the oplock break handler through cifsFileInfo structure and removing the use of cifsInodeInfo flags for that. It allows to avoid some races of several lease/oplock breaks using those flags in parallel. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-21smb3: warn on confusing error scenario with sec=krb5Steve French
commit 0a018944eee913962bce8ffebbb121960d5125d9 upstream. When mounting with Kerberos, users have been confused about the default error returned in scenarios in which either keyutils is not installed or the user did not properly acquire a krb5 ticket. Log a warning message in the case that "ENOKEY" is returned from the get_spnego_key upcall so that users can better understand why mount failed in those two cases. CC: Stable <stable@vger.kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-31Revert "cifs: Fix the target file was deleted when rename failed."Steve French
commit 0e6705182d4e1b77248a93470d6d7b3013d59b30 upstream. This reverts commit 9ffad9263b467efd8f8dc7ae1941a0a655a2bab2. Upon additional testing with older servers, it was found that the original commit introduced a regression when using the old SMB1 dialect and rsyncing over an existing file. The patch will need to be respun to address this, likely including a larger refactoring of the SMB1 and SMB3 rename code paths to make it less confusing and also to address some additional rename error cases that SMB3 may be able to workaround. Signed-off-by: Steve French <stfrench@microsoft.com> Reported-by: Patrick Fernie <patrick.fernie@gmail.com> CC: Stable <stable@vger.kernel.org> Acked-by: Ronnie Sahlberg <lsahlber@redhat.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Acked-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-22cifs: update ctime and mtime during truncateZhang Xiaoxu
[ Upstream commit 5618303d8516f8ac5ecfe53ee8e8bc9a40eaf066 ] As the man description of the truncate, if the size changed, then the st_ctime and st_mtime fields should be updated. But in cifs, we doesn't do it. It lead the xfstests generic/313 failed. So, add the ATTR_MTIME|ATTR_CTIME flags on attrs when change the file size Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-09cifs: Fix the target file was deleted when rename failed.Zhang Xiaoxu
commit 9ffad9263b467efd8f8dc7ae1941a0a655a2bab2 upstream. When xfstest generic/035, we found the target file was deleted if the rename return -EACESS. In cifs_rename2, we unlink the positive target dentry if rename failed with EACESS or EEXIST, even if the target dentry is positived before rename. Then the existing file was deleted. We should just delete the target file which created during the rename. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-09SMB3: Honor persistent/resilient handle flags for multiuser mountsPaul Aurich
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 <paul@darkrain42.org> CC: Stable <stable@vger.kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-09SMB3: Honor 'seal' flag for multiuser mountsPaul Aurich
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 <paul@darkrain42.org> CC: Stable <stable@vger.kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-30cifs/smb3: Fix data inconsistent when zero file rangeZhang Xiaoxu
[ Upstream commit 6b69040247e14b43419a520f841f2b3052833df9 ] CIFS implements the fallocate(FALLOC_FL_ZERO_RANGE) with send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. It just set the range of the remote file to zero, but local page cache not update, then the data inconsistent with server, which leads the xfstest generic/008 failed. So we need to remove the local page caches before send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. After next read, it will re-cache it. Fixes: 30175628bf7f5 ("[SMB3] Enable fallocate -z support for SMB3 mounts") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Cc: stable@vger.kernel.org # v3.17 Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-30cifs/smb3: Fix data inconsistent when punch holeZhang Xiaoxu
[ Upstream commit acc91c2d8de4ef46ed751c5f9df99ed9a109b100 ] When punch hole success, we also can read old data from file: # strace -e trace=pread64,fallocate xfs_io -f -c "pread 20 40" \ -c "fpunch 20 40" -c"pread 20 40" file pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40 fallocate(3, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 20, 40) = 0 pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40 CIFS implements the fallocate(FALLOCATE_FL_PUNCH_HOLE) with send SMB ioctl(FSCTL_SET_ZERO_DATA) to server. It just set the range of the remote file to zero, but local page caches not updated, then the local page caches inconsistent with server. Also can be found by xfstests generic/316. So, we need to remove the page caches before send the SMB ioctl(FSCTL_SET_ZERO_DATA) to server. Fixes: 31742c5a33176 ("enable fallocate punch hole ("fallocate -p") for SMB3") Suggested-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Cc: stable@vger.kernel.org # v3.17 Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-03cifs: Fix null pointer check in cifs_readSteve French
[ Upstream commit 9bd21d4b1a767c3abebec203342f3820dcb84662 ] Coverity scan noted a redundant null check Coverity-id: 728517 Reported-by: Coverity <scan-admin@coverity.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-20cifs: Fix a race condition with cifs_echo_requestRonnie Sahlberg
[ 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 <lsahlber@redhat.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-20cifs: Check for timeout on Negotiate stageSamuel Cabrero
[ 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 <scabrero@suse.de> Reviewed-by: Aurélien Aptel <aaptel@suse.de> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-10cifs: protect updating server->dstaddr with a spinlockRonnie Sahlberg
[ 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 <lsahlber@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-03-20cifs_atomic_open(): fix double-put on late allocation failureAl Viro
commit d9a9f4849fe0c9d560851ab22a85a666cddfdd24 upstream. several iterations of ->atomic_open() calling conventions ago, we used to need fput() if ->atomic_open() failed at some point after successful finish_open(). Now (since 2016) it's not needed - struct file carries enough state to make fput() work regardless of the point in struct file lifecycle and discarding it on failure exits in open() got unified. Unfortunately, I'd missed the fact that we had an instance of ->atomic_open() (cifs one) that used to need that fput(), as well as the stale comment in finish_open() demanding such late failure handling. Trivially fixed... Fixes: fe9ec8291fca "do_last(): take fput() on error after opening to out:" Cc: stable@kernel.org # v4.7+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-11cifs: don't leak -EAGAIN for stat() during reconnectRonnie Sahlberg
commit fc513fac56e1b626ae48a74d7551d9c35c50129e upstream. If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected it is possible we will leak -EAGAIN back to the application even for system calls such as stat() where this is not a valid error. Fix this by re-trying the operation from within cifs_revalidate_dentry_attr() if cifs_get_inode_info*() returns -EAGAIN. This fixes stat() and possibly also other system calls that uses cifs_revalidate_dentry*(). Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-11cifs: Fix mode output in debugging statementsFrank Sorenson
[ 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 <sorenson@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-28cifs: fix NULL dereference in match_prepathRonnie Sahlberg
[ Upstream commit fe1292686333d1dadaf84091f585ee903b9ddb84 ] RHBZ: 1760879 Fix an oops in match_prepath() by making sure that the prepath string is not NULL before we pass it into strcmp(). This is similar to other checks we make for example in cifs_root_iget() Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-14cifs: fail i/o on soft mounts if sessionsetup errors outRonnie Sahlberg
commit b0dd940e582b6a60296b9847a54012a4b080dc72 upstream. RHBZ: 1579050 If we have a soft mount we should fail commands for session-setup failures (such as the password having changed/ account being deleted/ ...) and return an error back to the application. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-29signal: Allow cifs and drbd to receive their terminating signalsEric W. Biederman
[ 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 <ronniesahlberg@gmail.com> Reported-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Cc: Steve French <smfrench@gmail.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: David Laight <David.Laight@ACULAB.COM> 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" <ebiederm@xmission.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-29cifs: fix rmmod regression in cifs.ko caused by force_sig changesSteve French
[ 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 <stfrench@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> CC: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-29signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sigEric W. Biederman
[ Upstream commit 72abe3bcf0911d69b46c1e8bdb5612675e0ac42c ] The locking in force_sig_info is not prepared to deal with a task that exits or execs (as sighand may change). The is not a locking problem in force_sig as force_sig is only built to handle synchronous exceptions. Further the function force_sig_info changes the signal state if the signal is ignored, or blocked or if SIGNAL_UNKILLABLE will prevent the delivery of the signal. The signal SIGKILL can not be ignored and can not be blocked and SIGNAL_UNKILLABLE won't prevent it from being delivered. So using force_sig rather than send_sig for SIGKILL is confusing and pointless. Because it won't impact the sending of the signal and and because using force_sig is wrong, replace force_sig with send_sig. Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Jeff Layton <jlayton@primarydata.com> Cc: Steve French <smfrench@gmail.com> Fixes: a5c3e1c725af ("Revert "cifs: No need to send SIGKILL to demux_thread during umount"") Fixes: e7ddee9037e7 ("cifs: disable sharing session and tcon and add new TCP sharing code") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-23cifs: Adjust indentation in smb2_open_fileNathan Chancellor
commit 7935799e041ae10d380d04ea23868240f082bd11 upstream. Clang warns: ../fs/cifs/smb2file.c:70:3: warning: misleading indentation; statement is not part of the previous 'if' [-Wmisleading-indentation] if (oparms->tcon->use_resilient) { ^ ../fs/cifs/smb2file.c:66:2: note: previous statement is here if (rc) ^ 1 warning generated. This warning occurs because there is a space after the tab on this line. Remove it so that the indentation is consistent with the Linux kernel coding style and clang no longer warns. Fixes: 592fafe644bf ("Add resilienthandles mount parm") Link: https://github.com/ClangBuiltLinux/linux/issues/826 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-21CIFS: Respect O_SYNC and O_DIRECT flags during reconnectPavel Shilovsky
commit 44805b0e62f15e90d233485420e1847133716bdc upstream. Currently the client translates O_SYNC and O_DIRECT flags into corresponding SMB create options when openning a file. The problem is that on reconnect when the file is being re-opened the client doesn't set those flags and it causes a server to reject re-open requests because create options don't match. The latter means that any subsequent system call against that open file fail until a share is re-mounted. Fix this by properly setting SMB create options when re-openning files after reconnects. Fixes: 1013e760d10e6: ("SMB3: Don't ignore O_SYNC/O_DSYNC and O_DIRECT flags") Cc: Stable <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-21CIFS: Fix SMB2 oplock break processingPavel Shilovsky
commit fa9c2362497fbd64788063288dc4e74daf977ebb upstream. Even when mounting modern protocol version the server may be configured without supporting SMB2.1 leases and the client uses SMB2 oplock to optimize IO performance through local caching. However there is a problem in oplock break handling that leads to missing a break notification on the client who has a file opened. It latter causes big latencies to other clients that are trying to open the same file. The problem reproduces when there are multiple shares from the same server mounted on the client. The processing code tries to match persistent and volatile file ids from the break notification with an open file but it skips all share besides the first one. Fix this by looking up in all shares belonging to the server that issued the oplock break. Cc: Stable <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-21CIFS: Fix NULL-pointer dereference in smb2_push_mandatory_locksPavel Shilovsky
commit 6f582b273ec23332074d970a7fb25bef835df71f upstream. Currently when the client creates a cifsFileInfo structure for a newly opened file, it allocates a list of byte-range locks with a pointer to the new cfile and attaches this list to the inode's lock list. The latter happens before initializing all other fields, e.g. cfile->tlink. Thus a partially initialized cifsFileInfo structure becomes available to other threads that walk through the inode's lock list. One example of such a thread may be an oplock break worker thread that tries to push all cached byte-range locks. This causes NULL-pointer dereference in smb2_push_mandatory_locks() when accessing cfile->tlink: [598428.945633] BUG: kernel NULL pointer dereference, address: 0000000000000038 ... [598428.945749] Workqueue: cifsoplockd cifs_oplock_break [cifs] [598428.945793] RIP: 0010:smb2_push_mandatory_locks+0xd6/0x5a0 [cifs] ... [598428.945834] Call Trace: [598428.945870] ? cifs_revalidate_mapping+0x45/0x90 [cifs] [598428.945901] cifs_oplock_break+0x13d/0x450 [cifs] [598428.945909] process_one_work+0x1db/0x380 [598428.945914] worker_thread+0x4d/0x400 [598428.945921] kthread+0x104/0x140 [598428.945925] ? process_one_work+0x380/0x380 [598428.945931] ? kthread_park+0x80/0x80 [598428.945937] ret_from_fork+0x35/0x40 Fix this by reordering initialization steps of the cifsFileInfo structure: initialize all the fields first and then add the new byte-range lock list to the inode's lock list. Cc: Stable <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-10cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occursDave Wysochanski
[ Upstream commit d46b0da7a33dd8c99d969834f682267a45444ab3 ] There's a deadlock that is possible and can easily be seen with a test where multiple readers open/read/close of the same file and a disruption occurs causing reconnect. The deadlock is due a reader thread inside cifs_strict_readv calling down_read and obtaining lock_sem, and then after reconnect inside cifs_reopen_file calling down_read a second time. If in between the two down_read calls, a down_write comes from another process, deadlock occurs. CPU0 CPU1 ---- ---- cifs_strict_readv() down_read(&cifsi->lock_sem); _cifsFileInfo_put OR cifs_new_fileinfo down_write(&cifsi->lock_sem); cifs_reopen_file() down_read(&cifsi->lock_sem); Fix the above by changing all down_write(lock_sem) calls to down_write_trylock(lock_sem)/msleep() loop, which in turn makes the second down_read call benign since it will never block behind the writer while holding lock_sem. Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed--by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-06fs: cifs: mute -Wunused-const-variable messageAustin Kim
[ Upstream commit dd19c106a36690b47bb1acc68372f2b472b495b8 ] After 'Initial git repository build' commit, 'mapping_table_ERRHRD' variable has not been used. So 'mapping_table_ERRHRD' const variable could be removed to mute below warning message: fs/cifs/netmisc.c:120:40: warning: unused variable 'mapping_table_ERRHRD' [-Wunused-const-variable] static const struct smb_to_posix_error mapping_table_ERRHRD[] = { ^ Signed-off-by: Austin Kim <austindh.kim@gmail.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-29CIFS: avoid using MID 0xFFFFRoberto Bergantinos Corpas
commit 03d9a9fe3f3aec508e485dd3dcfa1e99933b4bdb upstream. According to MS-CIFS specification MID 0xFFFF should not be used by the CIFS client, but we actually do. Besides, this has proven to cause races leading to oops between SendReceive2/cifs_demultiplex_thread. On SMB1, MID is a 2 byte value easy to reach in CurrentMid which may conflict with an oplock break notification request coming from server Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-17CIFS: Force reval dentry if LOOKUP_REVAL flag is setPavel Shilovsky
commit 0b3d0ef9840f7be202393ca9116b857f6f793715 upstream. Mark inode for force revalidation if LOOKUP_REVAL flag is set. This tells the client to actually send a QueryInfo request to the server to obtain the latest metadata in case a directory or a file were changed remotely. Only do that if the client doesn't have a lease for the file to avoid unneeded round trips to the server. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-17CIFS: Force revalidate inode when dentry is stalePavel Shilovsky
commit c82e5ac7fe3570a269c0929bf7899f62048e7dbc upstream. Currently the client indicates that a dentry is stale when inode numbers or type types between a local inode and a remote file don't match. If this is the case attributes is not being copied from remote to local, so, it is already known that the local copy has stale metadata. That's why the inode needs to be marked for revalidation in order to tell the VFS to lookup the dentry again before openning a file. This prevents unexpected stale errors to be returned to the user space when openning a file. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-17CIFS: Gracefully handle QueryInfo errors during openPavel Shilovsky
commit 30573a82fb179420b8aac30a3a3595aa96a93156 upstream. Currently if the client identifies problems when processing metadata returned in CREATE response, the open handle is being leaked. This causes multiple problems like a file missing a lease break by that client which causes high latencies to other clients accessing the file. Another side-effect of this is that the file can't be deleted. Fix this by closing the file after the client hits an error after the file was opened and the open descriptor wasn't returned to the user space. Also convert -ESTALE to -EOPENSTALE to allow the VFS to revalidate a dentry and retry the open. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05CIFS: Fix oplock handling for SMB 2.1+ protocolsPavel Shilovsky
commit a016e2794fc3a245a91946038dd8f34d65e53cc3 upstream. There may be situations when a server negotiates SMB 2.1 protocol version or higher but responds to a CREATE request with an oplock rather than a lease. Currently the client doesn't handle such a case correctly: when another CREATE comes in the server sends an oplock break to the initial CREATE and the client doesn't send an ack back due to a wrong caching level being set (READ instead of RWH). Missing an oplock break ack makes the server wait until the break times out which dramatically increases the latency of the second CREATE. Fix this by properly detecting oplocks when using SMB 2.1 protocol version and higher. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05CIFS: fix max ea value sizeMurphy Zhou
commit 63d37fb4ce5ae7bf1e58f906d1bf25f036fe79b2 upstream. It should not be larger then the slab max buf size. If user specifies a larger size, it passes this check and goes straightly to SMB2_set_info_init performing an insecure memcpy. Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-21cifs: Use kzfree() to zero out the passwordDan Carpenter
[ Upstream commit 478228e57f81f6cb60798d54fc02a74ea7dd267e ] It's safer to zero out the password so that it can never be disclosed. Fixes: 0c219f5799c7 ("cifs: set domainName when a domain-key is used in multiuser") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-21cifs: set domainName when a domain-key is used in multiuserRonnie Sahlberg
[ Upstream commit f2aee329a68f5a907bcff11a109dfe17c0b41aeb ] RHBZ: 1710429 When we use a domain-key to authenticate using multiuser we must also set the domainnmame for the new volume as it will be used and passed to the server in the NTLMSSP Domain-name. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-25smb3: send CAP_DFS capability during session setupSteve French
commit 8d33096a460d5b9bd13300f01615df5bb454db10 upstream. We had a report of a server which did not do a DFS referral because the session setup Capabilities field was set to 0 (unlike negotiate protocol where we set CAP_DFS). Better to send it session setup in the capabilities as well (this also more closely matches Windows client behavior). Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-25SMB3: Fix deadlock in validate negotiate hits reconnectPavel Shilovsky
commit e99c63e4d86d3a94818693147b469fa70de6f945 upstream. Currently we skip SMB2_TREE_CONNECT command when checking during reconnect because Tree Connect happens when establishing an SMB session. For SMB 3.0 protocol version the code also calls validate negotiate which results in SMB2_IOCL command being sent over the wire. This may deadlock on trying to acquire a mutex when checking for reconnect. Fix this by skipping SMB2_IOCL command when doing the reconnect check. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-11CIFS: cifs_read_allocate_pages: don't iterate through whole page array on ENOMEMRoberto Bergantinos Corpas
commit 31fad7d41e73731f05b8053d17078638cf850fa6 upstream. In cifs_read_allocate_pages, in case of ENOMEM, we go through whole rdata->pages array but we have failed the allocation before nr_pages, therefore we may end up calling put_page with NULL pointer, causing oops Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-25cifs: fix strcat buffer overflow and reduce raciness in smb21_set_oplock_level()Christoph Probst
commit 6a54b2e002c9d00b398d35724c79f9fe0d9b38fb upstream. Change strcat to strncpy in the "None" case to fix a buffer overflow when cinode->oplock is reset to 0 by another thread accessing the same cinode. It is never valid to append "None" to any other message. Consolidate multiple writes to cinode->oplock to reduce raciness. Signed-off-by: Christoph Probst <kernel@probst.it> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-02cifs: do not attempt cifs operation on smb2+ rename errorFrank Sorenson
commit 652727bbe1b17993636346716ae5867627793647 upstream. A path-based rename returning EBUSY will incorrectly try opening the file with a cifs (NT Create AndX) operation on an smb2+ mount, which causes the server to force a session close. If the mount is smb2+, skip the fallback. Signed-off-by: Frank Sorenson <sorenson@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-27CIFS: keep FileInfo handle live during oplock breakAurelien Aptel
commit b98749cac4a695f084a5ff076f4510b23e353ecd upstream. In the oplock break handler, writing pending changes from pages puts the FileInfo handle. If the refcount reaches zero it closes the handle and waits for any oplock break handler to return, thus causing a deadlock. To prevent this situation: * We add a wait flag to cifsFileInfo_put() to decide whether we should wait for running/pending oplock break handlers * We keep an additionnal reference of the SMB FileInfo handle so that for the rest of the handler putting the handle won't close it. - The ref is bumped everytime we queue the handler via the cifs_queue_oplock_break() helper. - The ref is decremented at the end of the handler This bug was triggered by xfstest 464. Also important fix to address the various reports of oops in smb2_push_mandatory_locks Signed-off-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-20cifs: fallback to older infolevels on findfirst queryinfo retrySteve French
[ Upstream commit 3b7960caceafdfc2cdfe2850487f8d091eb41144 ] In cases where queryinfo fails, we have cases in cifs (vers=1.0) where with backupuid mounts we retry the query info with findfirst. This doesn't work to some NetApp servers which don't support WindowsXP (and later) infolevel 261 (SMB_FIND_FILE_ID_FULL_DIR_INFO) so in this case use other info levels (in this case it will usually be level 257, SMB_FIND_FILE_DIRECTORY_INFO). (Also fixes some indentation) See kernel bugzilla 201435 Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-04-20fix incorrect error code mapping for OBJECTID_NOT_FOUNDSteve French
[ Upstream commit 85f9987b236cf46e06ffdb5c225cf1f3c0acb789 ] It was mapped to EIO which can be confusing when user space queries for an object GUID for an object for which the server file system doesn't support (or hasn't saved one). As Amir Goldstein suggested this is similar to ENOATTR (equivalently ENODATA in Linux errno definitions) so changing NT STATUS code mapping for OBJECTID_NOT_FOUND to ENODATA. Signed-off-by: Steve French <stfrench@microsoft.com> CC: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-04-05cifs: Fix NULL pointer dereference of devnameYao Liu
[ Upstream commit 68e2672f8fbd1e04982b8d2798dd318bf2515dd2 ] There is a NULL pointer dereference of devname in strspn() The oops looks something like: CIFS: Attempting to mount (null) BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... RIP: 0010:strspn+0x0/0x50 ... Call Trace: ? cifs_parse_mount_options+0x222/0x1710 [cifs] ? cifs_get_volume_info+0x2f/0x80 [cifs] cifs_setup_volume_info+0x20/0x190 [cifs] cifs_get_volume_info+0x50/0x80 [cifs] cifs_smb3_do_mount+0x59/0x630 [cifs] ? ida_alloc_range+0x34b/0x3d0 cifs_do_mount+0x11/0x20 [cifs] mount_fs+0x52/0x170 vfs_kern_mount+0x6b/0x170 do_mount+0x216/0xdc0 ksys_mount+0x83/0xd0 __x64_sys_mount+0x25/0x30 do_syscall_64+0x65/0x220 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix this by adding a NULL check on devname in cifs_parse_devname() Signed-off-by: Yao Liu <yotta.liu@ucloud.cn> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>