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 B8D1130EF9A; Tue, 21 Jul 2026 22:27:39 +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=1784672861; cv=none; b=AIv2EPoQLSEh/Om2oEpbKJd3GPDsReqWLKm3dvDh2RLaAK7lIIo8GG/Jbd8PoUGKEpvSZnflqZwVF/dlzbbyuGVnLYXRMnEZBcDoP0rxSuJWH2Eo2gsDr/XlGSqFCDI30CTrZIywO3O1wCMWsRo9KGbj7SzoSfOaB6NS8APkBuE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784672861; c=relaxed/simple; bh=I8OlI5FyyvoNXT8ncOSbBsVisKjB8r4aIbtTPe4coSU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HKqInL1d/ryHrjTofz3t6QipBNQXMwzWdNrcpCfMXFonx+BhbWjSY529jStKublOW/YK8lK7FTIWSaxlQ+QY9JhIk+kC2JLSoCbGa0EHvah99Q0FYzhVPuDVGAK/EkfcknalwPIvxJJsgmfPF+Vp43ZUsPQO7EiN9hsT9eUGD8g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kvk1H9Vj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kvk1H9Vj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 222021F000E9; Tue, 21 Jul 2026 22:27:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784672859; bh=Q9XuaFndJPH+Qo0zwxolU9QVhx9Vt/JxYUFF9KEcFz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kvk1H9Vj+DVmKpfS2Jrxx5sS/f+RUpyui252g8m9IpiG2LosRgxZHeoIowwLuj+D5 5z2N/SVQzC/IrbQPRD3R5xf9pT9V/uq3HhH07oCjv6H32LEO0KQGkMLl4d3MlJvg0r HbALyfjHnEmojkT6sx4wLM3LWNzV9j5VQBRhVgyU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, munan Huang , ChenXiaoSong , Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 5.15 785/843] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger Date: Tue, 21 Jul 2026 17:27:00 +0200 Message-ID: <20260721152423.721419064@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- fs/ksmbd/vfs_cache.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/fs/ksmbd/vfs_cache.c +++ b/fs/ksmbd/vfs_cache.c @@ -317,9 +317,11 @@ static void __ksmbd_close_fd(struct ksmb * 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);