smb: client: Avoid race in open_cached_dir with lease breaks

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: Avoid race in open_cached_dir with lease breaks A pre-existing valid cfid returned from find_or_create_cached_dir might race with a lease break, meaning open_cached_dir doesn't consider it valid, and thinks it's newly-constructed. This leaks a dentry reference if the allocation occurs before the queued lease break work runs. Avoid the race by extending holding the cfid_list_lock across find_or_create_cached_dir and when the result is checked.

References

• https://git.kernel.org/stable/c/2ed98e89ebc2e1bc73534dc3c18cb7843a889ff9
• https://git.kernel.org/stable/c/571dcf3d27b24800c171aea7b5e04ff06d10e2e9
• https://git.kernel.org/stable/c/2407265dc32bc8cc45b62a612c2a214ba9038e8b
• https://git.kernel.org/stable/c/3ca02e63edccb78ef3659bebc68579c7224a6ca2