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 997CD2F0C70; Wed, 28 Jan 2026 15:40:37 +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=1769614837; cv=none; b=uJY/HEoPqoYKS13VDfoRobVjHZKRlZtxVRjKEia2vq2AEY3KMlHHBu63ZNMC2ZKJGw6o6at8ARH3v+odGGJhN1k2siJIfe64g9h5lXfR/VuO7TQdaK2d8mUwcSwWfjxFdU/WYTStS/gLI27FdUJgtopoQ1+YPBj1lHdFB/UjyOY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769614837; c=relaxed/simple; bh=EXOVJcZYoJjOsIF/2kYmLlC/PvMNrNyFJKdc818a9Zk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mKWF5cOI+KMUiKYMrrwKpEw+kNggAox6bAOqxhdh/qTU3+YITcQyNrUZLcvqsnY2WLXMtH0KfH+z3XkRCowrrjQkG/qpk+Zk/6S5q2K+CjYPUsOF8GXj3vtsQsJbrb1eyeaADZKdxqqFBauNNy/CrF0XDGpI2XbViMX2hMvhtQg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=J4GvEN6g; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="J4GvEN6g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 859BEC4CEF7; Wed, 28 Jan 2026 15:40:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769614837; bh=EXOVJcZYoJjOsIF/2kYmLlC/PvMNrNyFJKdc818a9Zk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J4GvEN6gOVA1RNdbKtiugZaFO3UIZb42PbfTa30PWta/YxVrZBh/zId53F3T13g2W BW6KHLSiMB2+MWwyw7Gqq7ZpOLQyZkYkt90G055Oaq8UFfTnlq8g2XLzFNflAYYXe9 GxX/PrAtQaaXhMaM4To/XwR2hevot8cn/Z8RwUgU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Norbert Szetei , Namjae Jeon , Steve French , Li hongliang <1468888505@139.com> Subject: [PATCH 6.6 247/254] ksmbd: fix use-after-free in ksmbd_session_rpc_open Date: Wed, 28 Jan 2026 16:23:43 +0100 Message-ID: <20260128145353.686626088@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260128145344.698118637@linuxfoundation.org> References: <20260128145344.698118637@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Namjae Jeon [ Upstream commit a1f46c99d9ea411f9bf30025b912d881d36fc709 ] A UAF issue can occur due to a race condition between ksmbd_session_rpc_open() and __session_rpc_close(). Add rpc_lock to the session to protect it. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei Tested-by: Norbert Szetei Signed-off-by: Namjae Jeon Signed-off-by: Steve French [ KSMBD_DEFAULT_GFP is introduced by commit 0066f623bce8 ("ksmbd: use __GFP_RETRY_MAYFAIL") after linux-6.13. Here we still use GFP_KERNEL. ] Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/mgmt/user_session.c | 20 ++++++++++++++------ fs/smb/server/mgmt/user_session.h | 1 + 2 files changed, 15 insertions(+), 6 deletions(-) --- a/fs/smb/server/mgmt/user_session.c +++ b/fs/smb/server/mgmt/user_session.c @@ -59,10 +59,12 @@ static void ksmbd_session_rpc_clear_list struct ksmbd_session_rpc *entry; long index; + down_write(&sess->rpc_lock); xa_for_each(&sess->rpc_handle_list, index, entry) { xa_erase(&sess->rpc_handle_list, index); __session_rpc_close(sess, entry); } + up_write(&sess->rpc_lock); xa_destroy(&sess->rpc_handle_list); } @@ -92,7 +94,7 @@ int ksmbd_session_rpc_open(struct ksmbd_ { struct ksmbd_session_rpc *entry, *old; struct ksmbd_rpc_command *resp; - int method; + int method, id; method = __rpc_method(rpc_name); if (!method) @@ -102,26 +104,29 @@ int ksmbd_session_rpc_open(struct ksmbd_ if (!entry) return -ENOMEM; + down_read(&sess->rpc_lock); entry->method = method; - entry->id = ksmbd_ipc_id_alloc(); - if (entry->id < 0) + entry->id = id = ksmbd_ipc_id_alloc(); + if (id < 0) goto free_entry; - old = xa_store(&sess->rpc_handle_list, entry->id, entry, GFP_KERNEL); + old = xa_store(&sess->rpc_handle_list, id, entry, GFP_KERNEL); if (xa_is_err(old)) goto free_id; - resp = ksmbd_rpc_open(sess, entry->id); + resp = ksmbd_rpc_open(sess, id); if (!resp) goto erase_xa; + up_read(&sess->rpc_lock); kvfree(resp); - return entry->id; + return id; erase_xa: xa_erase(&sess->rpc_handle_list, entry->id); free_id: ksmbd_rpc_id_free(entry->id); free_entry: kfree(entry); + up_read(&sess->rpc_lock); return -EINVAL; } @@ -129,9 +134,11 @@ void ksmbd_session_rpc_close(struct ksmb { struct ksmbd_session_rpc *entry; + down_write(&sess->rpc_lock); entry = xa_erase(&sess->rpc_handle_list, id); if (entry) __session_rpc_close(sess, entry); + up_write(&sess->rpc_lock); } int ksmbd_session_rpc_method(struct ksmbd_session *sess, int id) @@ -438,6 +445,7 @@ static struct ksmbd_session *__session_c sess->sequence_number = 1; rwlock_init(&sess->tree_conns_lock); atomic_set(&sess->refcnt, 2); + init_rwsem(&sess->rpc_lock); ret = __init_smb2_session(sess); if (ret) --- a/fs/smb/server/mgmt/user_session.h +++ b/fs/smb/server/mgmt/user_session.h @@ -63,6 +63,7 @@ struct ksmbd_session { rwlock_t tree_conns_lock; atomic_t refcnt; + struct rw_semaphore rpc_lock; }; static inline int test_session_flag(struct ksmbd_session *sess, int bit)