From nobody Sun Feb 8 19:44:07 2026 Received: from n169-114.mail.139.com (n169-114.mail.139.com [120.232.169.114]) (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 2D4B52BCF4A; Tue, 27 Jan 2026 08:32:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=120.232.169.114 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769502731; cv=none; b=gjYX8nh6F1hH5Ry0I5OLyDYsZuvy+bbZQZ4pW2OuoF4OS234VsCjHaTDk6axi9vaUMa7gJQ5yFXGw3sZsaBd0VOHjFnYfrrRh9ITHDrrMJZkOZVVWqHJQI9rRl5kgVRa9z2fIqkOXKa9fXtERuVt8LpdPWotx/MpTaWah4SGqoQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769502731; c=relaxed/simple; bh=7R/0y3r+kLaNah1uVZ+xLzGFJEfXNObb51z6mKttBuY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=rXaiKRomi8GXb2t+cxhC1cnlApnMDEShXy4JT3jI+h0jumeCdUIzFbH6+VjhSjH2ZHd1q3e+/kTAtqkt6G7RqSn+9Xm1NSJQHYQyOLpq64Ap8dKopsG8ZjSzwPgfungYId/22h/LYHH5gaDksIngZ8ot58ZQfORROwdIhT9IPoA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=139.com; spf=pass smtp.mailfrom=139.com; dkim=pass (1024-bit key) header.d=139.com header.i=@139.com header.b=n9XI7u0V; arc=none smtp.client-ip=120.232.169.114 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=139.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=139.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=139.com header.i=@139.com header.b="n9XI7u0V" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=139.com; s=dkim; l=0; h=from:subject:message-id:to:cc:mime-version; bh=47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=; b=n9XI7u0V4MPYME59knGIekq7ypZg6um6ycLKJ1g+yZ/irZ+9pYxcjq0gp37RLqGMq9cPuuMANJRZ3 rVep8bkee4QpDza2bdGvrC0jDz4jBPEZ5+HPYZRnlk7yXJNdVEBO+tO8O6ITcUw42sMyf2yfZ9huKW vRQA6ZP7H5FIWmGk= X-RM-TagInfo: emlType=0 X-RM-SPAM: X-RM-SPAM-FLAG: 00000000 Received: from NTT-kernel-dev (unknown[60.247.85.88]) by rmsmtp-lg-appmail-43-12057 (RichMail) with SMTP id 2f19697877f71d1-011ea; Tue, 27 Jan 2026 16:31:53 +0800 (CST) X-RM-TRANSID: 2f19697877f71d1-011ea From: Li hongliang <1468888505@139.com> To: gregkh@linuxfoundation.org, stable@vger.kernel.org, linkinjeon@kernel.org Cc: patches@lists.linux.dev, linux-kernel@vger.kernel.org, sfrench@samba.org, senozhatsky@chromium.org, tom@talpey.com, sujana.subramaniam@sap.com, sashal@kernel.org, linux-cifs@vger.kernel.org, norbert@doyensec.com, stfrench@microsoft.com Subject: [PATCH 6.6.y] ksmbd: fix use-after-free in ksmbd_session_rpc_open Date: Tue, 27 Jan 2026 16:31:49 +0800 Message-Id: <20260127083149.3344689-1-1468888505@139.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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> --- fs/smb/server/mgmt/user_session.c | 20 ++++++++++++++------ fs/smb/server/mgmt/user_session.h | 1 + 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_se= ssion.c index 0ca788009c93..450a9f8ca7c7 100644 --- 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_s= ession *sess) struct ksmbd_session_rpc *entry; long index; =20 + 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); =20 xa_destroy(&sess->rpc_handle_list); } @@ -92,7 +94,7 @@ int ksmbd_session_rpc_open(struct ksmbd_session *sess, ch= ar *rpc_name) { struct ksmbd_session_rpc *entry, *old; struct ksmbd_rpc_command *resp; - int method; + int method, id; =20 method =3D __rpc_method(rpc_name); if (!method) @@ -102,26 +104,29 @@ int ksmbd_session_rpc_open(struct ksmbd_session *sess= , char *rpc_name) if (!entry) return -ENOMEM; =20 + down_read(&sess->rpc_lock); entry->method =3D method; - entry->id =3D ksmbd_ipc_id_alloc(); - if (entry->id < 0) + entry->id =3D id =3D ksmbd_ipc_id_alloc(); + if (id < 0) goto free_entry; - old =3D xa_store(&sess->rpc_handle_list, entry->id, entry, GFP_KERNEL); + old =3D xa_store(&sess->rpc_handle_list, id, entry, GFP_KERNEL); if (xa_is_err(old)) goto free_id; =20 - resp =3D ksmbd_rpc_open(sess, entry->id); + resp =3D ksmbd_rpc_open(sess, id); if (!resp) goto erase_xa; =20 + 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; } =20 @@ -129,9 +134,11 @@ void ksmbd_session_rpc_close(struct ksmbd_session *ses= s, int id) { struct ksmbd_session_rpc *entry; =20 + down_write(&sess->rpc_lock); entry =3D xa_erase(&sess->rpc_handle_list, id); if (entry) __session_rpc_close(sess, entry); + up_write(&sess->rpc_lock); } =20 int ksmbd_session_rpc_method(struct ksmbd_session *sess, int id) @@ -438,6 +445,7 @@ static struct ksmbd_session *__session_create(int proto= col) sess->sequence_number =3D 1; rwlock_init(&sess->tree_conns_lock); atomic_set(&sess->refcnt, 2); + init_rwsem(&sess->rpc_lock); =20 ret =3D __init_smb2_session(sess); if (ret) diff --git a/fs/smb/server/mgmt/user_session.h b/fs/smb/server/mgmt/user_se= ssion.h index f21348381d59..c5749d6ec715 100644 --- 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; =20 atomic_t refcnt; + struct rw_semaphore rpc_lock; }; =20 static inline int test_session_flag(struct ksmbd_session *sess, int bit) --=20 2.34.1