kernel/linux.git/fs/smb/server/oplock.c, branch linux-7.0.y

ksmbd: validate owner of durable handle on reconnect

2026-04-27T13:30:16+00:00

[ Upstream commit 49110a8ce654bbe56bef7c5e44cce31f4b102b8a ] Currently, ksmbd does not verify if the user attempting to reconnect to a durable handle is the same user who originally opened the file. This allows any authenticated user to hijack an orphaned durable handle by predicting or brute-forcing the persistent ID. According to MS-SMB2, the server MUST verify that the SecurityContext of the reconnect request matches the SecurityContext associated with the existing open. Add a durable_owner structure to ksmbd_file to store the original opener's UID, GID, and account name. and catpure the owner information when a file handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner() to validate the identity of the requester during SMB2_CREATE (DHnC). Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2") Reported-by: Davide Ornaghi Reported-by: Navaneeth K Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ksmbd: fix use-after-free and NULL deref in smb_grant_oplock()

2026-03-22T22:15:00+00:00

smb_grant_oplock() has two issues in the oplock publication sequence: 1) opinfo is linked into ci->m_op_list (via opinfo_add) before add_lease_global_list() is called. If add_lease_global_list() fails (kmalloc returns NULL), the error path frees the opinfo via __free_opinfo() while it is still linked in ci->m_op_list. Concurrent m_op_list readers (opinfo_get_list, or direct iteration in smb_break_all_levII_oplock) dereference the freed node. 2) opinfo->o_fp is assigned after add_lease_global_list() publishes the opinfo on the global lease list. A concurrent find_same_lease_key() can walk the lease list and dereference opinfo->o_fp->f_ci while o_fp is still NULL. Fix by restructuring the publication sequence to eliminate post-publish failure: - Set opinfo->o_fp before any list publication (fixes NULL deref). - Preallocate lease_table via alloc_lease_table() before opinfo_add() so add_lease_global_list() becomes infallible after publication. - Keep the original m_op_list publication order (opinfo_add before lease list) so concurrent opens via same_client_has_lease() and opinfo_get_list() still see the in-flight grant. - Use opinfo_put() instead of __free_opinfo() on err_out so that the RCU-deferred free path is used. This also requires splitting add_lease_global_list() to take a preallocated lease_table and changing its return type from int to void, since it can no longer fail. Fixes: 1dfd062caa16 ("ksmbd: fix use-after-free by using call_rcu() for oplock_info") Cc: stable@vger.kernel.org Signed-off-by: Werner Kasselman Reviewed-by: ChenXiaoSong Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close()

2026-03-09T02:28:39+00:00

opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is being accessed after rcu_read_unlock() has been called. This creates a race condition where the memory could be freed by a concurrent writer between the unlock and the subsequent pointer dereferences (opinfo->is_lease, etc.), leading to a use-after-free. Fixes: 5fb282ba4fef ("ksmbd: fix possible null-deref in smb_lazy_parent_lease_break_close") Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix use-after-free by using call_rcu() for oplock_info

2026-03-09T02:28:39+00:00

ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfo_get() and proc_show_files(). Since there is no RCU grace period delay between nullifying the pointer and freeing the memory, a reader can still access oplock_info structure after it has been freed. This can leads to a use-after-free especially in opinfo_get() where atomic_inc_not_zero() is called on already freed memory. Fix this by switching to deferred freeing using call_rcu(). Fixes: 18b4fac5ef17 ("ksmbd: fix use-after-free in smb_break_all_levII_oplock()") Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon Signed-off-by: Steve French

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ksmbd: rename smb2_get_msg to smb_get_msg

2025-12-22T01:20:46+00:00

With the removal of the RFC1002 length field from the SMB header, smb2_get_msg is now used to get the smb1 request from the request buffer. Since this function is no longer exclusive to smb2 and now supports smb1 as well, This patch rename it to smb_get_msg to better reflect its usage. Signed-off-by: Namjae Jeon Signed-off-by: Steve French

smb: move create_durable_rsp_v2 to common/smb2pdu.h

2025-12-01T03:11:44+00:00

Modify the following places: - some fields in "struct create_durable_v2_rsp" -> struct durable_context_v2_rsp - durable_reconnect_context_v2_rsp -> durable_context_v2_rsp - create_durable_v2_rsp -> create_durable_rsp_v2 Then move them to common header file. Signed-off-by: ChenXiaoSong Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix refcount leak causing resource not released

2025-08-18T00:33:29+00:00

When ksmbd_conn_releasing(opinfo->conn) returns true,the refcount was not decremented properly, causing a refcount leak that prevents the count from reaching zero and the memory from being released. Cc: stable@vger.kernel.org Signed-off-by: Ziyan Xu Signed-off-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: use list_first_entry_or_null for opinfo_get_list()

2025-05-22T03:30:39+00:00

The list_first_entry() macro never returns NULL. If the list is empty then it returns an invalid pointer. Use list_first_entry_or_null() to check if the list is empty. Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202505080231.7OXwq4Te-lkp@intel.com/ Signed-off-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix memory leak in parse_lease_state()

2025-05-01T23:58:48+00:00

The previous patch that added bounds check for create lease context introduced a memory leak. When the bounds check fails, the function returns NULL without freeing the previously allocated lease_ctx_info structure. This patch fixes the issue by adding kfree(lreq) before returning NULL in both boundary check cases. Fixes: bab703ed8472 ("ksmbd: add bounds check for create lease context") Signed-off-by: Wang Zhaolong Acked-by: Namjae Jeon Signed-off-by: Steve French