From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9059A2ECE9B; Sun, 1 Mar 2026 01:55:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772330102; cv=none; b=GrTayLysHLeY8Q0XpotyzF+657zHD0g1MINtYX4pvmb9GpJX50u056CYuHtPaMGnAtKx68BsIOffIkMWAyzHl1gQj+4uF9pY5DHsjAMJBvJ2e5/xOWomkI/zzl7LZgz960jzHeQPPXmYvYZYeWa0MmeNuQRU0MsZYa6rKlwMTuM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772330102; c=relaxed/simple; bh=43rUhhdiEu3agoNzq1KcTZeUApgjgvOc6iYVwOYpF48=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IsQOKS2lw90bNbYxRSrBv6nk5d3lg0GRbpBO/tbN3gXUs+6u+1yMNCd35QQ0ekUSf5G6y8e7t9WEAN2WwbmMgo0jxazmWN59M0E6rjvWZKHP37mZRUifZKwBLr0ZlLWPNEgOnJ/wRBrZ1Y+d4pAa/6cja6R6d8gg9U0I2j7/I/k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KeIYTuUC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KeIYTuUC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B44FC19421; Sun, 1 Mar 2026 01:55:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772330102; bh=43rUhhdiEu3agoNzq1KcTZeUApgjgvOc6iYVwOYpF48=; h=From:To:Cc:Subject:Date:From; b=KeIYTuUCaw0CoWydIm45t49U1OqP87hPQdapdIYHsGZaIhy4Kno9B4EbjwZ1QCAU4 EyOMty8vGK24BNPxqmUoXOBtBkqc9ZbCf4zPsZtAShYweS/ClFdsYuL/+vfOd1VTSR fhBLkpEEZBcPAqPate7L1fEf4CKor2OE0HDZ2LSV+cgfgUKNNF4K8Y5NWtJJS0+Vsm AFjr1Wx6+bB5gd1BLdSLOOEXikxO6P/9A7ZBFfgqrtZClFGPB03NAhnn5AAg3opoaX F8o/2Wv+bNTDx0AoseEfBcCtZIYZ/jR8I2nF4WY79Nmq19RC8+hf4DB+hczBHv7wUL WllTo9zDW8Wjg== From: Sasha Levin To: stable@vger.kernel.org, linkinjeon@kernel.org Cc: Igor Stepansky , Steve French , linux-cifs@vger.kernel.org Subject: FAILED: Patch "ksmbd: add chann_lock to protect ksmbd_chann_list xarray" failed to apply to 5.15-stable tree Date: Sat, 28 Feb 2026 20:54:59 -0500 Message-ID: <20260301015500.1722104-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 4f3a06cc57976cafa8c6f716646be6c79a99e485 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Mon, 9 Feb 2026 10:43:19 +0900 Subject: [PATCH] ksmbd: add chann_lock to protect ksmbd_chann_list xarray ksmbd_chann_list xarray lacks synchronization, allowing use-after-free in multi-channel sessions (between lookup_chann_list() and ksmbd_chann_del). Adds rw_semaphore chann_lock to struct ksmbd_session and protects all xa_load/xa_store/xa_erase accesses. Cc: stable@vger.kernel.org Reported-by: Igor Stepansky Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/mgmt/user_session.c | 5 +++++ fs/smb/server/mgmt/user_session.h | 1 + fs/smb/server/smb2pdu.c | 12 +++++++++++- 3 files changed, 17 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_session.c index 68b3e0cb54d38..8c2b14ea7b0ec 100644 --- a/fs/smb/server/mgmt/user_session.c +++ b/fs/smb/server/mgmt/user_session.c @@ -244,12 +244,14 @@ static void free_channel_list(struct ksmbd_session *sess) struct channel *chann; unsigned long index; + down_write(&sess->chann_lock); xa_for_each(&sess->ksmbd_chann_list, index, chann) { xa_erase(&sess->ksmbd_chann_list, index); kfree(chann); } xa_destroy(&sess->ksmbd_chann_list); + up_write(&sess->chann_lock); } static void __session_rpc_close(struct ksmbd_session *sess, @@ -434,7 +436,9 @@ static int ksmbd_chann_del(struct ksmbd_conn *conn, struct ksmbd_session *sess) { struct channel *chann; + down_write(&sess->chann_lock); chann = xa_erase(&sess->ksmbd_chann_list, (long)conn); + up_write(&sess->chann_lock); if (!chann) return -ENOENT; @@ -668,6 +672,7 @@ static struct ksmbd_session *__session_create(int protocol) rwlock_init(&sess->tree_conns_lock); atomic_set(&sess->refcnt, 2); init_rwsem(&sess->rpc_lock); + init_rwsem(&sess->chann_lock); ret = __init_smb2_session(sess); if (ret) diff --git a/fs/smb/server/mgmt/user_session.h b/fs/smb/server/mgmt/user_session.h index 176d800c24906..d94f5e128a9b4 100644 --- a/fs/smb/server/mgmt/user_session.h +++ b/fs/smb/server/mgmt/user_session.h @@ -48,6 +48,7 @@ struct ksmbd_session { char sess_key[CIFS_KEY_SIZE]; struct hlist_node hlist; + struct rw_semaphore chann_lock; struct xarray ksmbd_chann_list; struct xarray tree_conns; struct ida tree_conn_ida; diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 4d3154cc493ea..3efcc7da1b9f6 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -80,7 +80,13 @@ static inline bool check_session_id(struct ksmbd_conn *conn, u64 id) struct channel *lookup_chann_list(struct ksmbd_session *sess, struct ksmbd_conn *conn) { - return xa_load(&sess->ksmbd_chann_list, (long)conn); + struct channel *chann; + + down_read(&sess->chann_lock); + chann = xa_load(&sess->ksmbd_chann_list, (long)conn); + up_read(&sess->chann_lock); + + return chann; } /** @@ -1559,8 +1565,10 @@ static int ntlm_authenticate(struct ksmbd_work *work, return -ENOMEM; chann->conn = conn; + down_write(&sess->chann_lock); old = xa_store(&sess->ksmbd_chann_list, (long)conn, chann, KSMBD_DEFAULT_GFP); + up_write(&sess->chann_lock); if (xa_is_err(old)) { kfree(chann); return xa_err(old); @@ -1652,8 +1660,10 @@ static int krb5_authenticate(struct ksmbd_work *work, return -ENOMEM; chann->conn = conn; + down_write(&sess->chann_lock); old = xa_store(&sess->ksmbd_chann_list, (long)conn, chann, KSMBD_DEFAULT_GFP); + up_write(&sess->chann_lock); if (xa_is_err(old)) { kfree(chann); return xa_err(old); -- 2.51.0