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2025-04-14ksmbd: Prevent integer overflow in calculation of deadtimeDenis Arefev
The user can set any value for 'deadtime'. This affects the arithmetic expression 'req->deadtime * SMB_ECHO_INTERVAL', which is subject to overflow. The added check makes the server behavior more predictable. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable@vger.kernel.org Signed-off-by: Denis Arefev <arefev@swemel.ru> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-14ksmbd: fix the warning from __kernel_write_iterNamjae Jeon
[ 2110.972290] ------------[ cut here ]------------ [ 2110.972301] WARNING: CPU: 3 PID: 735 at fs/read_write.c:599 __kernel_write_iter+0x21b/0x280 This patch doesn't allow writing to directory. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei <norbert@doyensec.com> Tested-by: Norbert Szetei <norbert@doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-14ksmbd: fix use-after-free in smb_break_all_levII_oplock()Namjae Jeon
There is a room in smb_break_all_levII_oplock that can cause racy issues when unlocking in the middle of the loop. This patch use read lock to protect whole loop. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei <norbert@doyensec.com> Tested-by: Norbert Szetei <norbert@doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-14ksmbd: fix use-after-free in __smb2_lease_break_noti()Namjae Jeon
Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei <norbert@doyensec.com> Tested-by: Norbert Szetei <norbert@doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-14ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING"Namjae Jeon
wait_event_timeout() will set the state of the current task to TASK_UNINTERRUPTIBLE, before doing the condition check. This means that ksmbd_durable_scavenger_alive() will try to acquire the mutex while already in a sleeping state. The scheduler warns us by giving the following warning: do not call blocking ops when !TASK_RUNNING; state=2 set at [<0000000061515a6f>] prepare_to_wait_event+0x9f/0x6c0 WARNING: CPU: 2 PID: 4147 at kernel/sched/core.c:10099 __might_sleep+0x12f/0x160 mutex lock is not needed in ksmbd_durable_scavenger_alive(). Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-14ksmbd: Fix dangling pointer in krb_authenticateSean Heelan
krb_authenticate frees sess->user and does not set the pointer to NULL. It calls ksmbd_krb5_authenticate to reinitialise sess->user but that function may return without doing so. If that happens then smb2_sess_setup, which calls krb_authenticate, will be accessing free'd memory when it later uses sess->user. Cc: stable@vger.kernel.org Signed-off-by: Sean Heelan <seanheelan@gmail.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-13Revert "smb: client: fix TCP timers deadlock after rmmod"Kuniyuki Iwashima
This reverts commit e9f2517a3e18a54a3943c098d2226b245d488801. Commit e9f2517a3e18 ("smb: client: fix TCP timers deadlock after rmmod") is intended to fix a null-ptr-deref in LOCKDEP, which is mentioned as CVE-2024-54680, but is actually did not fix anything; The issue can be reproduced on top of it. [0] Also, it reverted the change by commit ef7134c7fc48 ("smb: client: Fix use-after-free of network namespace.") and introduced a real issue by reviving the kernel TCP socket. When a reconnect happens for a CIFS connection, the socket state transitions to FIN_WAIT_1. Then, inet_csk_clear_xmit_timers_sync() in tcp_close() stops all timers for the socket. If an incoming FIN packet is lost, the socket will stay at FIN_WAIT_1 forever, and such sockets could be leaked up to net.ipv4.tcp_max_orphans. Usually, FIN can be retransmitted by the peer, but if the peer aborts the connection, the issue comes into reality. I warned about this privately by pointing out the exact report [1], but the bogus fix was finally merged. So, we should not stop the timers to finally kill the connection on our side in that case, meaning we must not use a kernel socket for TCP whose sk->sk_net_refcnt is 0. The kernel socket does not have a reference to its netns to make it possible to tear down netns without cleaning up every resource in it. For example, tunnel devices use a UDP socket internally, but we can destroy netns without removing such devices and let it complete during exit. Otherwise, netns would be leaked when the last application died. However, this is problematic for TCP sockets because TCP has timers to close the connection gracefully even after the socket is close()d. The lifetime of the socket and its netns is different from the lifetime of the underlying connection. If the socket user does not maintain the netns lifetime, the timer could be fired after the socket is close()d and its netns is freed up, resulting in use-after-free. Actually, we have seen so many similar issues and converted such sockets to have a reference to netns. That's why I converted the CIFS client socket to have a reference to netns (sk->sk_net_refcnt == 1), which is somehow mentioned as out-of-scope of CIFS and technically wrong in e9f2517a3e18, but **is in-scope and right fix**. Regarding the LOCKDEP issue, we can prevent the module unload by bumping the module refcount when switching the LOCKDDEP key in sock_lock_init_class_and_name(). [2] For a while, let's revert the bogus fix. Note that now we can use sk_net_refcnt_upgrade() for the socket conversion, but I'll do so later separately to make backport easy. Link: https://lore.kernel.org/all/20250402020807.28583-1-kuniyu@amazon.com/ #[0] Link: https://lore.kernel.org/netdev/c08bd5378da647a2a4c16698125d180a@huawei.com/ #[1] Link: https://lore.kernel.org/lkml/20250402005841.19846-1-kuniyu@amazon.com/ #[2] Fixes: e9f2517a3e18 ("smb: client: fix TCP timers deadlock after rmmod") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Cc: stable@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-13Revert "smb: client: Fix netns refcount imbalance causing leaks and ↵Kuniyuki Iwashima
use-after-free" This reverts commit 4e7f1644f2ac6d01dc584f6301c3b1d5aac4eaef. The commit e9f2517a3e18 ("smb: client: fix TCP timers deadlock after rmmod") is not only a bogus fix for LOCKDEP null-ptr-deref but also introduces a real issue, TCP sockets leak, which will be explained in detail in the next revert. Also, CNA assigned CVE-2024-54680 to it but is rejecting it. [0] Thus, we are reverting the commit and its follow-up commit 4e7f1644f2ac ("smb: client: Fix netns refcount imbalance causing leaks and use-after-free"). Link: https://lore.kernel.org/all/2025040248-tummy-smilingly-4240@gregkh/ #[0] Fixes: 4e7f1644f2ac ("smb: client: Fix netns refcount imbalance causing leaks and use-after-free") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Cc: stable@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-13smb3 client: fix open hardlink on deferred close file errorChunjie Zhu
The following Python script results in unexpected behaviour when run on a CIFS filesystem against a Windows Server: # Create file fd = os.open('test', os.O_WRONLY|os.O_CREAT) os.write(fd, b'foo') os.close(fd) # Open and close the file to leave a pending deferred close fd = os.open('test', os.O_RDONLY|os.O_DIRECT) os.close(fd) # Try to open the file via a hard link os.link('test', 'new') newfd = os.open('new', os.O_RDONLY|os.O_DIRECT) The final open returns EINVAL due to the server returning STATUS_INVALID_PARAMETER. The root cause of this is that the client caches lease keys per inode, but the spec requires them to be related to the filename which causes problems when hard links are involved: From MS-SMB2 section 3.3.5.9.11: "The server MUST attempt to locate a Lease by performing a lookup in the LeaseTable.LeaseList using the LeaseKey in the SMB2_CREATE_REQUEST_LEASE_V2 as the lookup key. If a lease is found, Lease.FileDeleteOnClose is FALSE, and Lease.Filename does not match the file name for the incoming request, the request MUST be failed with STATUS_INVALID_PARAMETER" On client side, we first check the context of file open, if it hits above conditions, we first close all opening files which are belong to the same inode, then we do open the hard link file. Cc: stable@vger.kernel.org Signed-off-by: Chunjie Zhu <chunjie.zhu@cloud.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09smb3: Add defines for two new FileSystemAttributesSteve French
Two new file system attributes were recently added. See MS-FSCC 2.5.1: FILE_SUPPORTS_POSIX_UNLINK_RENAME and FILE_RETURNS_CLEANUP_RESULT_INFO Update the missing defines for ksmbd and cifs.ko Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09cifs: Fix querying of WSL CHR and BLK reparse points over SMB1Pali Rohár
When reparse point in SMB1 query_path_info() callback was detected then query also for EA $LXDEV. In this EA are stored device major and minor numbers used by WSL CHR and BLK reparse points. Without major and minor numbers, stat() syscall does not work for char and block devices. Similar code is already in SMB2+ query_path_info() callback function. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09cifs: Split parse_reparse_point callback to functions: get buffer and parse ↵Pali Rohár
buffer Parsing reparse point buffer is generic for all SMB versions and is already implemented by global function parse_reparse_point(). Getting reparse point buffer from the SMB response is SMB version specific, so introduce for it a new callback get_reparse_point_buffer. This functionality split is needed for followup change - getting reparse point buffer without parsing it. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09cifs: Improve handling of name surrogate reparse points in reparse.cPali Rohár
Like previous changes for file inode.c, handle directory name surrogate reparse points generally also in reparse.c. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09cifs: Remove explicit handling of IO_REPARSE_TAG_MOUNT_POINT in inode.cPali Rohár
IO_REPARSE_TAG_MOUNT_POINT is just a specific case of directory Name Surrogate reparse point. As reparse_info_to_fattr() already handles all directory Name Surrogate reparse point (done by the previous change), there is no need to have explicit case for IO_REPARSE_TAG_MOUNT_POINT. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09cifs: Fix encoding of SMB1 Session Setup Kerberos Request in non-UNICODE modePali Rohár
Like in UNICODE mode, SMB1 Session Setup Kerberos Request contains oslm and domain strings. Extract common code into ascii_oslm_strings() and ascii_domain_string() functions (similar to unicode variants) and use these functions in non-UNICODE code path in sess_auth_kerberos(). Decision if non-UNICODE or UNICODE mode is used is based on the SMBFLG2_UNICODE flag in Flags2 packed field, and not based on the capabilities of server. Fix this check too. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-09smb: client: fix UAF in decryption with multichannelPaulo Alcantara
After commit f7025d861694 ("smb: client: allocate crypto only for primary server") and commit b0abcd65ec54 ("smb: client: fix UAF in async decryption"), the channels started reusing AEAD TFM from primary channel to perform synchronous decryption, but that can't done as there could be multiple cifsd threads (one per channel) simultaneously accessing it to perform decryption. This fixes the following KASAN splat when running fstest generic/249 with 'vers=3.1.1,multichannel,max_channels=4,seal' against Windows Server 2022: BUG: KASAN: slab-use-after-free in gf128mul_4k_lle+0xba/0x110 Read of size 8 at addr ffff8881046c18a0 by task cifsd/986 CPU: 3 UID: 0 PID: 986 Comm: cifsd Not tainted 6.15.0-rc1 #1 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 print_report+0x156/0x528 ? gf128mul_4k_lle+0xba/0x110 ? __virt_addr_valid+0x145/0x300 ? __phys_addr+0x46/0x90 ? gf128mul_4k_lle+0xba/0x110 kasan_report+0xdf/0x1a0 ? gf128mul_4k_lle+0xba/0x110 gf128mul_4k_lle+0xba/0x110 ghash_update+0x189/0x210 shash_ahash_update+0x295/0x370 ? __pfx_shash_ahash_update+0x10/0x10 ? __pfx_shash_ahash_update+0x10/0x10 ? __pfx_extract_iter_to_sg+0x10/0x10 ? ___kmalloc_large_node+0x10e/0x180 ? __asan_memset+0x23/0x50 crypto_ahash_update+0x3c/0xc0 gcm_hash_assoc_remain_continue+0x93/0xc0 crypt_message+0xe09/0xec0 [cifs] ? __pfx_crypt_message+0x10/0x10 [cifs] ? _raw_spin_unlock+0x23/0x40 ? __pfx_cifs_readv_from_socket+0x10/0x10 [cifs] decrypt_raw_data+0x229/0x380 [cifs] ? __pfx_decrypt_raw_data+0x10/0x10 [cifs] ? __pfx_cifs_read_iter_from_socket+0x10/0x10 [cifs] smb3_receive_transform+0x837/0xc80 [cifs] ? __pfx_smb3_receive_transform+0x10/0x10 [cifs] ? __pfx___might_resched+0x10/0x10 ? __pfx_smb3_is_transform_hdr+0x10/0x10 [cifs] cifs_demultiplex_thread+0x692/0x1570 [cifs] ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] ? rcu_is_watching+0x20/0x50 ? rcu_lockdep_current_cpu_online+0x62/0xb0 ? find_held_lock+0x32/0x90 ? kvm_sched_clock_read+0x11/0x20 ? local_clock_noinstr+0xd/0xd0 ? trace_irq_enable.constprop.0+0xa8/0xe0 ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] kthread+0x1fe/0x380 ? kthread+0x10f/0x380 ? __pfx_kthread+0x10/0x10 ? local_clock_noinstr+0xd/0xd0 ? ret_from_fork+0x1b/0x60 ? local_clock+0x15/0x30 ? lock_release+0x29b/0x390 ? rcu_is_watching+0x20/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Tested-by: David Howells <dhowells@redhat.com> Reported-by: Steve French <stfrench@microsoft.com> Closes: https://lore.kernel.org/r/CAH2r5mu6Yc0-RJXM3kFyBYUB09XmXBrNodOiCVR4EDrmxq5Szg@mail.gmail.com Fixes: f7025d861694 ("smb: client: allocate crypto only for primary server") Fixes: b0abcd65ec54 ("smb: client: fix UAF in async decryption") Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-08cifs: Fix support for WSL-style symlinksPali Rohár
MS-FSCC in section 2.1.2.7 LX SYMLINK REPARSE_DATA_BUFFER now contains documentation about WSL symlink reparse point buffers. https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/68337353-9153-4ee1-ac6b-419839c3b7ad Fix the struct reparse_wsl_symlink_data_buffer to reflect buffer fields according to the MS-FSCC documentation. Fix the Linux SMB client to correctly fill the WSL symlink reparse point buffer when creaing new WSL-style symlink. There was a mistake during filling the data part of the reparse point buffer. It should starts with bytes "\x02\x00\x00\x00" (which represents version 2) but this constant was written as number 0x02000000 encoded in little endian, which resulted bytes "\x00\x00\x00\x02". This change is fixing this mistake. Fixes: 4e2043be5c14 ("cifs: Add support for creating WSL-style symlinks") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-08Use try_lookup_noperm() instead of d_hash_and_lookup() outside of VFSNeilBrown
try_lookup_noperm() and d_hash_and_lookup() are nearly identical. The former does some validation of the name where the latter doesn't. Outside of the VFS that validation is likely valuable, and having only one exported function for this task is certainly a good idea. So make d_hash_and_lookup() local to VFS files and change all other callers to try_lookup_noperm(). Note that the arguments are swapped. Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250319031545.2999807-6-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-08VFS: rename lookup_one_len family to lookup_noperm and remove permission checkNeilBrown
The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-07VFS: improve interface for lookup_one functionsNeilBrown
The family of functions: lookup_one() lookup_one_unlocked() lookup_one_positive_unlocked() appear designed to be used by external clients of the filesystem rather than by filesystems acting on themselves as the lookup_one_len family are used. They are used by: btrfs/ioctl - which is a user-space interface rather than an internal activity exportfs - i.e. from nfsd or the open_by_handle_at interface overlayfs - at access the underlying filesystems smb/server - for file service They should be used by nfsd (more than just the exportfs path) and cachefs but aren't. It would help if the documentation didn't claim they should "not be called by generic code". Also the path component name is passed as "name" and "len" which are (confusingly?) separate by the "base". In some cases the len in simply "strlen" and so passing a qstr using QSTR() would make the calling clearer. Other callers do pass separate name and len which are stored in a struct. Sometimes these are already stored in a qstr, other times it easily could be. So this patch changes these three functions to receive a 'struct qstr *', and improves the documentation. QSTR_LEN() is added to make it easy to pass a QSTR containing a known len. [brauner@kernel.org: take a struct qstr pointer] Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-2-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-07smb311 client: fix missing tcon check when mounting with linux/posix extensionsSteve French
When mounting the same share twice, once with the "linux" mount parameter (or equivalently "posix") and then once without (or e.g. with "nolinux"), we were incorrectly reusing the same tree connection for both mounts. This meant that the first mount of the share on the client, would cause subsequent mounts of that same share on the same client to ignore that mount parm ("linux" vs. "nolinux") and incorrectly reuse the same tcon. Cc: stable@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-07cifs: Ensure that all non-client-specific reparse points are processed by ↵Pali Rohár
the server Fix regression in mounts to e.g. onedrive shares. Generally, reparse points are processed by the SMB server during the SMB OPEN request, but there are few reparse points which do not have OPEN-like meaning for the SMB server and has to be processed by the SMB client. Those are symlinks and special files (fifo, socket, block, char). For Linux SMB client, it is required to process also name surrogate reparse points as they represent another entity on the SMB server system. Linux client will mark them as separate mount points. Examples of name surrogate reparse points are NTFS junction points (e.g. created by the "mklink" tool on Windows servers). So after processing the name surrogate reparse points, clear the -EOPNOTSUPP error code returned from the parse_reparse_point() to let SMB server to process reparse points. And remove printing misleading error message "unhandled reparse tag:" as reparse points are handled by SMB server and hence unhandled fact is normal operation. Fixes: cad3fc0a4c8c ("cifs: Throw -EOPNOTSUPP error on unsupported reparse point type from parse_reparse_point()") Fixes: b587fd128660 ("cifs: Treat unhandled directory name surrogate reparse points as mount directory nodes") Cc: stable@vger.kernel.org Reported-by: Junwen Sun <sunjw8888@gmail.com> Tested-by: Junwen Sun <sunjw8888@gmail.com> Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-04Merge tag '6.15-rc-part2-smb3-client-fixes' of ↵Linus Torvalds
git://git.samba.org/sfrench/cifs-2.6 Pull more smb client updates from Steve French: - reconnect fixes: three for updating rsize/wsize and an SMB1 reconnect fix - RFC1001 fixes: fixing connections to nonstandard ports, and negprot retries - fix mfsymlinks to old servers - make mapping of open flags for SMB1 more accurate - permission fixes: adding retry on open for write, and one for stat to workaround unexpected access denied - add two new xattrs, one for retrieving SACL and one for retrieving owner (without having to retrieve the whole ACL) - fix mount parm validation for echo_interval - minor cleanup (including removing now unneeded cifs_truncate_page) * tag '6.15-rc-part2-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: update internal version number cifs: Implement is_network_name_deleted for SMB1 cifs: Remove cifs_truncate_page() as it should be superfluous cifs: Do not add FILE_READ_ATTRIBUTES when using GENERIC_READ/EXECUTE/ALL cifs: Improve SMB2+ stat() to work also without FILE_READ_ATTRIBUTES cifs: Add fallback for SMB2 CREATE without FILE_READ_ATTRIBUTES cifs: Fix querying and creating MF symlinks over SMB1 cifs: Fix access_flags_to_smbopen_mode cifs: Fix negotiate retry functionality cifs: Improve handling of NetBIOS packets cifs: Allow to disable or force initialization of NetBIOS session cifs: Add a new xattr system.smb3_ntsd_owner for getting or setting owner cifs: Add a new xattr system.smb3_ntsd_sacl for getting or setting SACLs smb: client: Update IO sizes after reconnection smb: client: Store original IO parameters and prevent zero IO sizes smb:client: smb: client: Add reverse mapping from tcon to superblocks cifs: remove unreachable code in cifs_get_tcp_session() cifs: fix integer overflow in match_server()
2025-04-02cifs: update internal version numberSteve French
To 2.52 Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-02cifs: Implement is_network_name_deleted for SMB1Pali Rohár
This change allows Linux SMB1 client to autoreconnect the share when it is modified on server by admin operation which removes and re-adds it. Implementation is reused from SMB2+ is_network_name_deleted callback. There are just adjusted checks for error codes and access to struct smb_hdr. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-02cifs: Remove cifs_truncate_page() as it should be superfluousDavid Howells
The calls to cifs_truncate_page() should be superfluous as the places that call it also call truncate_setsize() or cifs_setsize() and therefore truncate_pagecache() which should also clear the tail part of the folio containing the EOF marker. Further, smb3_simple_falloc() calls both cifs_setsize() and truncate_setsize() in addition to cifs_truncate_page(). Remove the superfluous calls. This gets rid of another function referring to struct page. [Should cifs_setsize() also set inode->i_blocks?] Signed-off-by: David Howells <dhowells@redhat.com> cc: Steve French <stfrench@microsoft.com> Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01ksmbd: fix null pointer dereference in alloc_preauth_hash()Namjae Jeon
The Client send malformed smb2 negotiate request. ksmbd return error response. Subsequently, the client can send smb2 session setup even thought conn->preauth_info is not allocated. This patch add KSMBD_SESS_NEED_SETUP status of connection to ignore session setup request if smb2 negotiate phase is not complete. Cc: stable@vger.kernel.org Tested-by: Steve French <stfrench@microsoft.com> Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-26505 Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Do not add FILE_READ_ATTRIBUTES when using GENERIC_READ/EXECUTE/ALLPali Rohár
Individual bits GENERIC_READ, GENERIC_EXECUTE and GENERIC_ALL have meaning which includes also access right for FILE_READ_ATTRIBUTES. So specifying FILE_READ_ATTRIBUTES bit together with one of those GENERIC (except GENERIC_WRITE) does not do anything. This change prevents calling additional (fallback) code and sending more requests without FILE_READ_ATTRIBUTES when the primary request fails on -EACCES, as it is not needed at all. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Improve SMB2+ stat() to work also without FILE_READ_ATTRIBUTESPali Rohár
If SMB2_OP_QUERY_INFO (called when POSIX extensions are not used) failed with STATUS_ACCESS_DENIED then it means that caller does not have permission to open the path with FILE_READ_ATTRIBUTES access and therefore cannot issue SMB2_OP_QUERY_INFO command. This will result in the -EACCES error from stat() sycall. There is an alternative way how to query limited information about path but still suitable for stat() syscall. SMB2 OPEN/CREATE operation returns in its successful response subset of query information. So try to open the path without FILE_READ_ATTRIBUTES but with MAXIMUM_ALLOWED access which will grant the maximum possible access to the file and the response will contain required query information for stat() syscall. This will improve smb2_query_path_info() to query also files which do not grant FILE_READ_ATTRIBUTES access to caller. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Add fallback for SMB2 CREATE without FILE_READ_ATTRIBUTESPali Rohár
Some operations, like WRITE, does not require FILE_READ_ATTRIBUTES access. So when FILE_READ_ATTRIBUTES is not explicitly requested for smb2_open_file() then first try to do SMB2 CREATE with FILE_READ_ATTRIBUTES access (like it was before) and then fallback to SMB2 CREATE without FILE_READ_ATTRIBUTES access (less common case). This change allows to complete WRITE operation to a file when it does not grant FILE_READ_ATTRIBUTES permission and its parent directory does not grant READ_DATA permission (parent directory READ_DATA is implicit grant of child FILE_READ_ATTRIBUTES permission). Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Fix querying and creating MF symlinks over SMB1Pali Rohár
Old SMB1 servers without CAP_NT_SMBS do not support CIFS_open() function and instead SMBLegacyOpen() needs to be used. This logic is already handled in cifs_open_file() function, which is server->ops->open callback function. So for querying and creating MF symlinks use open callback function instead of CIFS_open() function directly. This change fixes querying and creating new MF symlinks on Windows 98. Currently cifs_query_mf_symlink() is not able to detect MF symlink and cifs_create_mf_symlink() is failing with EIO error. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Fix access_flags_to_smbopen_modePali Rohár
When converting access_flags to SMBOPEN mode, check for all possible access flags, not only GENERIC_READ and GENERIC_WRITE flags. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Fix negotiate retry functionalityPali Rohár
SMB negotiate retry functionality in cifs_negotiate() is currently broken and does not work when doing socket reconnect. Caller of this function, which is cifs_negotiate_protocol() requires that tcpStatus after successful execution of negotiate callback stay in CifsInNegotiate. But if the CIFSSMBNegotiate() called from cifs_negotiate() fails due to connection issues then tcpStatus is changed as so repeated CIFSSMBNegotiate() call does not help. Fix this problem by moving retrying code from negotiate callback (which is either cifs_negotiate() or smb2_negotiate()) to cifs_negotiate_protocol() which is caller of those callbacks. This allows to properly handle and implement correct transistions between tcpStatus states as function cifs_negotiate_protocol() already handles it. With this change, cifs_negotiate_protocol() now handles also -EAGAIN error set by the RFC1002_NEGATIVE_SESSION_RESPONSE processing after reconnecting with NetBIOS session. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Improve handling of NetBIOS packetsPali Rohár
Now all NetBIOS session logic is handled in ip_rfc1001_connect() function, so cleanup is_smb_response() function which contains generic handling of incoming SMB packets. Note that function is_smb_response() is not used directly or indirectly (e.g. over cifs_demultiplex_thread() by ip_rfc1001_connect() function. Except the Negative Session Response and the Session Keep Alive packet, the cifs_demultiplex_thread() should not receive any NetBIOS session packets. And Session Keep Alive packet may be received only when the NetBIOS session was established by ip_rfc1001_connect() function. So treat any such packet as error and schedule reconnect. Negative Session Response packet is returned from Windows SMB server (from Windows 98 and also from Windows Server 2022) if client sent over port 139 SMB negotiate request without previously establishing a NetBIOS session. The common scenario is that Negative Session Response packet is returned for the SMB negotiate packet, which is the first one which SMB client sends (if it is not establishing a NetBIOS session). Note that server port 139 may be forwarded and mapped between virtual machines to different number. And Linux SMB client do not call function ip_rfc1001_connect() when prot is not 139. So nowadays when using port mapping or port forwarding between VMs, it is not so uncommon to see this error. Currently the logic on Negative Session Response packet changes server port to 445 and force reconnection. But this logic does not work when using non-standard port numbers and also does not help if the server on specified port is requiring establishing a NetBIOS session. Fix this Negative Session Response logic and instead of changing server port (on which server does not have to listen), force reconnection with establishing a NetBIOS session. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Allow to disable or force initialization of NetBIOS sessionPali Rohár
Currently SMB client always tries to initialize NetBIOS session when the server port is 139. This is useful for default cases, but nowadays when using non-standard routing or testing between VMs, it is common that servers are listening on non-standard ports. So add a new mount option -o nbsessinit and -o nonbsessinit which either forces initialization or disables initialization regardless of server port number. This allows Linux SMB client to connect to older SMB1 server listening on non-standard port, which requires initialization of NetBIOS session, by using additional mount options -o port= and -o nbsessinit. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Add a new xattr system.smb3_ntsd_owner for getting or setting ownerPali Rohár
Changing owner is controlled by DACL permission WRITE_OWNER. Changing DACL itself is controlled by DACL permisssion WRITE_DAC. Owner of the file has implicit WRITE_DAC permission even when it is not explicitly granted for owner by DACL. Reading DACL or owner is controlled only by one permission READ_CONTROL. WRITE_OWNER permission can be bypassed by the SeTakeOwnershipPrivilege, which is by default available for local administrators. So if the local administrator wants to access some file to which does not have access, it is required to first change owner to ourself and then change DACL permissions. Currently Linux SMB client does not support this because client does not provide a way to change owner without touching DACL permissions. Fix this problem by introducing a new xattr "system.smb3_ntsd_owner" for setting/changing only owner part of the security descriptor. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Add a new xattr system.smb3_ntsd_sacl for getting or setting SACLsPali Rohár
Access to SACL part of SMB security descriptor is granted by SACL privilege which by default is accessible only for local administrator. But it can be granted to any other user by local GPO or AD. SACL access is not granted by DACL permissions and therefore is it possible that some user would not have access to DACLs of some file, but would have access to SACLs of all files. So it means that for accessing SACLs (either getting or setting) in some cases requires not touching or asking for DACLs. Currently Linux SMB client does not allow to get or set SACLs without touching DACLs. Which means that user without DACL access is not able to get or set SACLs even if it has access to SACLs. Fix this problem by introducing a new xattr "system.smb3_ntsd_sacl" for accessing only SACLs part of the security descriptor (therefore without DACLs and OWNER/GROUP). Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01ksmbd: validate zero num_subauth before sub_auth is accessedNorbert Szetei
Access psid->sub_auth[psid->num_subauth - 1] without checking if num_subauth is non-zero leads to an out-of-bounds read. This patch adds a validation step to ensure num_subauth != 0 before sub_auth is accessed. Cc: stable@vger.kernel.org Signed-off-by: Norbert Szetei <norbert@doyensec.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01ksmbd: fix overflow in dacloffset bounds checkNorbert Szetei
The dacloffset field was originally typed as int and used in an unchecked addition, which could overflow and bypass the existing bounds check in both smb_check_perm_dacl() and smb_inherit_dacl(). This could result in out-of-bounds memory access and a kernel crash when dereferencing the DACL pointer. This patch converts dacloffset to unsigned int and uses check_add_overflow() to validate access to the DACL. Cc: stable@vger.kernel.org Signed-off-by: Norbert Szetei <norbert@doyensec.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01ksmbd: fix session use-after-free in multichannel connectionNamjae Jeon
There is a race condition between session setup and ksmbd_sessions_deregister. The session can be freed before the connection is added to channel list of session. This patch check reference count of session before freeing it. Cc: stable@vger.kernel.org Reported-by: Sean Heelan <seanheelan@gmail.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31smb: client: Update IO sizes after reconnectionWang Zhaolong
When a SMB connection is reset and reconnected, the negotiated IO parameters (rsize/wsize) can become out of sync with the server's current capabilities. This can lead to suboptimal performance or even IO failures if the server's limits have changed. This patch implements automatic IO size renegotiation: 1. Adds cifs_renegotiate_iosize() function to update all superblocks associated with a tree connection 2. Updates each mount's rsize/wsize based on current server capabilities 3. Calls this function after successful tree connection reconnection With this change, all mount points will automatically maintain optimal and reliable IO parameters after network disruptions, using the bidirectional mapping added in previous patches. This completes the series improving connection resilience by keeping mount parameters synchronized with server capabilities. Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31smb: client: Store original IO parameters and prevent zero IO sizesWang Zhaolong
During mount option processing and negotiation with the server, the original user-specified rsize/wsize values were being modified directly. This makes it impossible to recover these values after a connection reset, leading to potential degraded performance after reconnection. The other problem is that When negotiating read and write sizes, there are cases where the negotiated values might calculate to zero, especially during reconnection when server->max_read or server->max_write might be reset. In general, these values come from the negotiation response. According to MS-SMB2 specification, these values should be at least 65536 bytes. This patch improves IO parameter handling: 1. Adds vol_rsize and vol_wsize fields to store the original user-specified values separately from the negotiated values 2. Uses got_rsize/got_wsize flags to determine if values were user-specified rather than checking for non-zero values, which is more reliable 3. Adds a prevent_zero_iosize() helper function to ensure IO sizes are never negotiated down to zero, which could happen in edge cases like when server->max_read/write is zero The changes make the CIFS client more resilient to unusual server responses and reconnection scenarios, preventing potential failures when IO sizes are calculated to be zero. Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31smb:client: smb: client: Add reverse mapping from tcon to superblocksWang Zhaolong
Currently, when a SMB connection is reset and renegotiated with the server, there's no way to update all related mount points with new negotiated sizes. This is because while superblocks (cifs_sb_info) maintain references to tree connections (tcon) through tcon_link structures, there is no reverse mapping from a tcon back to all the superblocks using it. This patch adds a bidirectional relationship between tcon and cifs_sb_info structures by: 1. Adding a cifs_sb_list to tcon structure with appropriate locking 2. Adding tcon_sb_link to cifs_sb_info to join the list 3. Managing the list entries during mount and umount operations The bidirectional relationship enables future functionality to locate and update all superblocks connected to a specific tree connection, such as: - Updating negotiated parameters after reconnection - Efficiently notifying all affected mounts of capability changes This is the first part of a series to improve connection resilience by keeping all mount parameters in sync with server capabilities after reconnection. Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31cifs: remove unreachable code in cifs_get_tcp_session()Roman Smirnov
echo_interval is checked at mount time, the code has become unreachable. Signed-off-by: Roman Smirnov <r.smirnov@omp.ru> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31cifs: fix integer overflow in match_server()Roman Smirnov
The echo_interval is not limited in any way during mounting, which makes it possible to write a large number to it. This can cause an overflow when multiplying ctx->echo_interval by HZ in match_server(). Add constraints for echo_interval to smb3_fs_context_parse_param(). Found by Linux Verification Center (linuxtesting.org) with Svace. Fixes: adfeb3e00e8e1 ("cifs: Make echo interval tunable") Cc: stable@vger.kernel.org Signed-off-by: Roman Smirnov <r.smirnov@omp.ru> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31Merge tag 'v6.15rc-part1-ksmbd-server-fixes' of git://git.samba.org/ksmbdLinus Torvalds
Pull smb server updates from Steve French: - Two fixes for bounds checks of open contexts - Two multichannel fixes, including one for important UAF - Oplock/lease break fix for potential ksmbd connection refcount leak - Security fix to free crypto data more securely - Fix to enable allowing Kerberos authentication by default - Two RDMA/smbdirect fixes - Minor cleanup * tag 'v6.15rc-part1-ksmbd-server-fixes' of git://git.samba.org/ksmbd: ksmbd: fix r_count dec/increment mismatch ksmbd: fix multichannel connection failure ksmbd: fix use-after-free in ksmbd_sessions_deregister() ksmbd: use ib_device_get_netdev() instead of calling ops.get_netdev ksmbd: use aead_request_free to match aead_request_alloc Revert "ksmbd: fix missing RDMA-capable flag for IPoIB device in ksmbd_rdma_capable_netdev()" ksmbd: add bounds check for create lease context ksmbd: add bounds check for durable handle context ksmbd: make SMB_SERVER_KERBEROS5 enable by default ksmbd: Use str_read_write() and str_true_false() helpers
2025-03-31Merge tag '6.15-rc-part1-smb3-client-fixes' of ↵Linus Torvalds
git://git.samba.org/sfrench/cifs-2.6 Pull smb client updates from Steve French: - Fix for network namespace refcount leak - Multichannel fix and minor multichannel debug message cleanup - Fix potential null ptr reference in SMB3 close - Fix for special file handling when reparse points not supported by server - Two ACL fixes one for stricter ACE validation, one for incorrect perms requested - Three RFC1001 fixes: one for SMB3 mounts on port 139, one for better default hostname, and one for better session response processing - Minor update to email address for MAINTAINERS file - Allow disabling Unicode for access to old SMB1 servers - Three minor cleanups * tag '6.15-rc-part1-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: Add new mount option -o nounicode to disable SMB1 UNICODE mode cifs: Set default Netbios RFC1001 server name to hostname in UNC smb: client: Fix netns refcount imbalance causing leaks and use-after-free cifs: add validation check for the fields in smb_aces CIFS: Propagate min offload along with other parameters from primary to secondary channels. cifs: Improve establishing SMB connection with NetBIOS session cifs: Fix establishing NetBIOS session for SMB2+ connection cifs: Fix getting DACL-only xattr system.cifs_acl and system.smb3_acl cifs: Check if server supports reparse points before using them MAINTAINERS: reorder preferred email for Steve French cifs: avoid NULL pointer dereference in dbg call smb: client: Remove redundant check in smb2_is_path_accessible() smb: client: Remove redundant check in cifs_oplock_break() smb: mark the new channel addition log as informational log with cifs_info smb: minor cleanup to remove unused function declaration
2025-03-27ksmbd: fix r_count dec/increment mismatchNamjae Jeon
r_count is only increased when there is an oplock break wait, so r_count inc/decrement are not paired. This can cause r_count to become negative, which can lead to a problem where the ksmbd thread does not terminate. Fixes: 3aa660c05924 ("ksmbd: prevent connection release during oplock break notification") Reported-by: Norbert Szetei <norbert@doyensec.com> Tested-by: Norbert Szetei <norbert@doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-27ksmbd: fix multichannel connection failureNamjae Jeon
ksmbd check that the session of second channel is in the session list of first connection. If it is in session list, multichannel connection should not be allowed. Fixes: b95629435b84 ("ksmbd: fix racy issue from session lookup and expire") Reported-by: Sean Heelan <seanheelan@gmail.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-27ksmbd: fix use-after-free in ksmbd_sessions_deregister()Namjae Jeon
In multichannel mode, UAF issue can occur in session_deregister when the second channel sets up a session through the connection of the first channel. session that is freed through the global session table can be accessed again through ->sessions of connection. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei <norbert@doyensec.com> Tested-by: Norbert Szetei <norbert@doyensec.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>