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

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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: 5fb282ba4f ("ksmbd: fix possible null-deref in smb_lazy_parent_lease_break_close")
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Namjae Jeon
2026-03-02 12:55:02 +09:00
committed by Steve French
parent 1dfd062caa
commit eac3361e3d
1 changed files with 4 additions and 2 deletions
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6
fs/smb/server/oplock.c
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@@ -1135,10 +1135,12 @@ void smb_lazy_parent_lease_break_close(struct ksmbd_file *fp)
rcu_read_lock(); rcu_read_lock();
opinfo = rcu_dereference(fp->f_opinfo); opinfo = rcu_dereference(fp->f_opinfo);
rcu_read_unlock();
if (!opinfo || !opinfo->is_lease || opinfo->o_lease->version != 2) if (!opinfo || !opinfo->is_lease || opinfo->o_lease->version != 2) {
rcu_read_unlock();
return; return;
}
rcu_read_unlock();
p_ci = ksmbd_inode_lookup_lock(fp->filp->f_path.dentry->d_parent); p_ci = ksmbd_inode_lookup_lock(fp->filp->f_path.dentry->d_parent);
if (!p_ci) if (!p_ci)