From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96C9B446840 for ; Thu, 16 Jul 2026 18:22:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784226139; cv=none; b=pokE9QX1s6Unfz0o1KPA+HcUbPhazP/aCzdKDxE0AjXUw5DBB93AODUiBskRICiQKhMhKbk3KQ+P+MASuZUj+sw3stOO6kx4Vxq7+H2PO4q4s4AydcfVCDSNhVgXRwgEb3wOGd60ot33P4ITBYryFztz2ziufW1CrKjOqpO7ybw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784226139; c=relaxed/simple; bh=JW5lV6QzR/gz/VxJKF/ysWJ2BV0tccL2n6Wk/Jj8wFk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Mac4sMlFcgMEqk8GqaoN1SdBTAKS/Lgz9WWf2kfEGQCdSUMdIMWUd9HG1YrUSzlVuSJ7TVQgqmRMaruQakhGM1qYU7UDaZt73X5b5a3UCOFSCy1G4o/W+0tuPhwM59urr8f2ZWbbh/UTEUq4HTPGENDc/JQZG0XnS+ORjuWCX+g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=klJj4ey1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="klJj4ey1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E69981F00ACA; Thu, 16 Jul 2026 18:22:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784226129; bh=1yowg+baIjA+VCzswIiTxD4UxnRCeeyBiXXIKQbzYHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=klJj4ey1hOxkcw4zdRJvn0152YD7tpF8wDS5QYk8ZWZtXK8q1Mp+J5X5L8eoXs9hv Ymo4rjVL2TV3EIuU6+iuFxdsyXIBhWL/EzdwZ/j5L5DwoqFKpDJyiqMsRaPTRg+pkf w/dxGAc0F6CXFRQwtxZFZx4rIddiVTESs5L9gGWIJT3KaA2iTAzmuCYZUm4uyAzJc5 xUNGPwFOuP5lJznw5YFcGtFFHSHtFuqlnPjFBuaPRJIDeXKWvYjoXaIuhfzJGDSbJ5 W1NxGHFU+9bmlMRznwOLOm52X7Cv9480VUW+xjct5GOeiy24vcRRDkmQ7K0JC0lpBD LeaZikHrv9J8w== From: Sasha Levin To: stable@vger.kernel.org Cc: Namjae Jeon , munan Huang , ChenXiaoSong , Steve French , Sasha Levin Subject: [PATCH 5.15.y 3/7] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger Date: Thu, 16 Jul 2026 14:22:01 -0400 Message-ID: <20260716182205.921233-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260716182205.921233-1-sashal@kernel.org> References: <2026071415-rambling-chooser-b760@gregkh> <20260716182205.921233-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Namjae Jeon [ Upstream commit 235e32320a470fcd3998fb3774f2290a0eb302a1 ] When a durable file handle survives session disconnect (TCP close without SMB2_LOGOFF), session_fd_check() sets fp->conn = NULL to preserve the handle for later reconnection. However, it did not clean up the byte-range locks on fp->lock_list. Later, when the durable scavenger thread times out and calls __ksmbd_close_fd(NULL, fp), the lock cleanup loop did: spin_lock(&fp->conn->llist_lock); This caused a slab use-after-free because fp->conn was NULL and the original connection object had already been freed by ksmbd_tcp_disconnect(). The root cause is asymmetric cleanup: lock entries (smb_lock->clist) were left dangling on the freed conn->lock_list while fp->conn was nulled out. To fix this issue properly, we need to handle the lifetime of smb_lock->clist across three paths: - Safely skip clist deletion when list is empty and fp->conn is NULL. - Remove the lock from the old connection's lock_list in session_fd_check() - Re-add the lock to the new connection's lock_list in ksmbd_reopen_durable_fd(). Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2") Co-developed-by: munan Huang Signed-off-by: munan Huang Reviewed-by: ChenXiaoSong Signed-off-by: Namjae Jeon Signed-off-by: Steve French Stable-dep-of: c1016dd1d8b2 ("ksmbd: track the connection owning a byte-range lock") Signed-off-by: Sasha Levin --- fs/ksmbd/vfs_cache.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c index 2528ce8aeebbef..65dd85668cee24 100644 --- a/fs/ksmbd/vfs_cache.c +++ b/fs/ksmbd/vfs_cache.c @@ -317,9 +317,11 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp) * there are not accesses to fp->lock_list. */ list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) { - spin_lock(&fp->conn->llist_lock); - list_del(&smb_lock->clist); - spin_unlock(&fp->conn->llist_lock); + if (!list_empty(&smb_lock->clist) && fp->conn) { + spin_lock(&fp->conn->llist_lock); + list_del(&smb_lock->clist); + spin_unlock(&fp->conn->llist_lock); + } list_del(&smb_lock->flist); locks_free_lock(smb_lock->fl); -- 2.53.0