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 BF7B321D596; Wed, 25 Feb 2026 01:27:50 +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=1771982870; cv=none; b=JxL6/7/iETOoZoxhcy8Uc/niOqJctfsJc5iJavCszbwahDskBd8bFF4sXV0FHJWuBkzI+1lkZwOOVwOhjq4EALZD5CxMuVjlXF+wuSfV2VqzlST3dHWhdNa0qv9VNjhyJ0Vy0sQUL0LUhqJ1IbQJLy2o4YeQK35O2H7draYhEJc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771982870; c=relaxed/simple; bh=6tG94616Mie+Y9od8ss6cVVbzD5eOOkkkP5Do/+O/PU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dODKy9/OCflhL9pQLI7ZuR6bfInuFA45bEr0F89WEEJFiDAYkchhhnEMRi7dUWsKBv+BY5uqMsnXT3az1eoki9vus3OGje4sa1r31h5xl1YKhcJlcrd8CLT0fzxEv6qIABilETXeiMl5LyB5PbZz+NAPpJlYf/XQ9ZwfXeKoUT0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JBjlU72m; 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="JBjlU72m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46240C116D0; Wed, 25 Feb 2026 01:27:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1771982870; bh=6tG94616Mie+Y9od8ss6cVVbzD5eOOkkkP5Do/+O/PU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JBjlU72m07SQ6Qh8p0QO4FblaDjjjzuA/pyLIp5C689ZBGFq5BYw01QKlLuO/Vslj uob9Nd/ZSk7rIGPotEj1wyFGgWRr57dbtRP1Ezv75syfvCaQswdT4+DM+y/fCJ3b6Z bfFoI6CLMNeUg+AXGlRqoa1yty1vTTpRxc4ooFsw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Caleb Sander Mateos , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 6.19 056/781] ublk: use READ_ONCE() to read struct ublksrv_ctrl_cmd Date: Tue, 24 Feb 2026 17:12:45 -0800 Message-ID: <20260225012401.080776686@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012359.695468795@linuxfoundation.org> References: <20260225012359.695468795@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 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Caleb Sander Mateos [ Upstream commit ed9f54cc1e335096733aed03c2a46de3d58922ed ] struct ublksrv_ctrl_cmd is part of the io_uring_sqe, which may lie in userspace-mapped memory. It's racy to access its fields with normal loads, as userspace may write to them concurrently. Use READ_ONCE() to copy the ublksrv_ctrl_cmd from the io_uring_sqe to the stack. Use the local copy in place of the one in the io_uring_sqe. Fixes: 87213b0d847c ("ublk: allow non-blocking ctrl cmds in IO_URING_F_NONBLOCK issue") Signed-off-by: Caleb Sander Mateos Reviewed-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/ublk_drv.c | 56 ++++++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 25 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 0ce0e537fb850..06e0790150d1d 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -3311,12 +3311,11 @@ static int ublk_ctrl_del_dev(struct ublk_device **p_ub, bool wait) return 0; } -static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd) +static inline void ublk_ctrl_cmd_dump(u32 cmd_op, + const struct ublksrv_ctrl_cmd *header) { - const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe); - pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n", - __func__, cmd->cmd_op, header->dev_id, header->queue_id, + __func__, cmd_op, header->dev_id, header->queue_id, header->data[0], header->addr, header->len); } @@ -3685,9 +3684,8 @@ static int ublk_char_dev_permission(struct ublk_device *ub, } static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub, - struct io_uring_cmd *cmd) + u32 cmd_op, struct ublksrv_ctrl_cmd *header) { - struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)io_uring_sqe_cmd(cmd->sqe); bool unprivileged = ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV; void __user *argp = (void __user *)(unsigned long)header->addr; char *dev_path = NULL; @@ -3703,7 +3701,7 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub, * know if the specified device is created as unprivileged * mode. */ - if (_IOC_NR(cmd->cmd_op) != UBLK_CMD_GET_DEV_INFO2) + if (_IOC_NR(cmd_op) != UBLK_CMD_GET_DEV_INFO2) return 0; } @@ -3724,7 +3722,7 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub, return PTR_ERR(dev_path); ret = -EINVAL; - switch (_IOC_NR(cmd->cmd_op)) { + switch (_IOC_NR(cmd_op)) { case UBLK_CMD_GET_DEV_INFO: case UBLK_CMD_GET_DEV_INFO2: case UBLK_CMD_GET_QUEUE_AFFINITY: @@ -3753,7 +3751,7 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub, header->addr += header->dev_path_len; } pr_devel("%s: dev id %d cmd_op %x uid %d gid %d path %s ret %d\n", - __func__, ub->ub_number, cmd->cmd_op, + __func__, ub->ub_number, cmd_op, ub->dev_info.owner_uid, ub->dev_info.owner_gid, dev_path, ret); exit: @@ -3777,7 +3775,9 @@ static bool ublk_ctrl_uring_cmd_may_sleep(u32 cmd_op) static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) { - const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe); + /* May point to userspace-mapped memory */ + const struct ublksrv_ctrl_cmd *ub_src = io_uring_sqe_cmd(cmd->sqe); + struct ublksrv_ctrl_cmd header; struct ublk_device *ub = NULL; u32 cmd_op = cmd->cmd_op; int ret = -EINVAL; @@ -3789,41 +3789,47 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, if (!(issue_flags & IO_URING_F_SQE128)) return -EINVAL; - ublk_ctrl_cmd_dump(cmd); + header.dev_id = READ_ONCE(ub_src->dev_id); + header.queue_id = READ_ONCE(ub_src->queue_id); + header.len = READ_ONCE(ub_src->len); + header.addr = READ_ONCE(ub_src->addr); + header.data[0] = READ_ONCE(ub_src->data[0]); + header.dev_path_len = READ_ONCE(ub_src->dev_path_len); + ublk_ctrl_cmd_dump(cmd_op, &header); ret = ublk_check_cmd_op(cmd_op); if (ret) goto out; if (cmd_op == UBLK_U_CMD_GET_FEATURES) { - ret = ublk_ctrl_get_features(header); + ret = ublk_ctrl_get_features(&header); goto out; } if (_IOC_NR(cmd_op) != UBLK_CMD_ADD_DEV) { ret = -ENODEV; - ub = ublk_get_device_from_id(header->dev_id); + ub = ublk_get_device_from_id(header.dev_id); if (!ub) goto out; - ret = ublk_ctrl_uring_cmd_permission(ub, cmd); + ret = ublk_ctrl_uring_cmd_permission(ub, cmd_op, &header); if (ret) goto put_dev; } switch (_IOC_NR(cmd_op)) { case UBLK_CMD_START_DEV: - ret = ublk_ctrl_start_dev(ub, header); + ret = ublk_ctrl_start_dev(ub, &header); break; case UBLK_CMD_STOP_DEV: ret = ublk_ctrl_stop_dev(ub); break; case UBLK_CMD_GET_DEV_INFO: case UBLK_CMD_GET_DEV_INFO2: - ret = ublk_ctrl_get_dev_info(ub, header); + ret = ublk_ctrl_get_dev_info(ub, &header); break; case UBLK_CMD_ADD_DEV: - ret = ublk_ctrl_add_dev(header); + ret = ublk_ctrl_add_dev(&header); break; case UBLK_CMD_DEL_DEV: ret = ublk_ctrl_del_dev(&ub, true); @@ -3832,26 +3838,26 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, ret = ublk_ctrl_del_dev(&ub, false); break; case UBLK_CMD_GET_QUEUE_AFFINITY: - ret = ublk_ctrl_get_queue_affinity(ub, header); + ret = ublk_ctrl_get_queue_affinity(ub, &header); break; case UBLK_CMD_GET_PARAMS: - ret = ublk_ctrl_get_params(ub, header); + ret = ublk_ctrl_get_params(ub, &header); break; case UBLK_CMD_SET_PARAMS: - ret = ublk_ctrl_set_params(ub, header); + ret = ublk_ctrl_set_params(ub, &header); break; case UBLK_CMD_START_USER_RECOVERY: - ret = ublk_ctrl_start_recovery(ub, header); + ret = ublk_ctrl_start_recovery(ub, &header); break; case UBLK_CMD_END_USER_RECOVERY: - ret = ublk_ctrl_end_recovery(ub, header); + ret = ublk_ctrl_end_recovery(ub, &header); break; case UBLK_CMD_UPDATE_SIZE: - ublk_ctrl_set_size(ub, header); + ublk_ctrl_set_size(ub, &header); ret = 0; break; case UBLK_CMD_QUIESCE_DEV: - ret = ublk_ctrl_quiesce_dev(ub, header); + ret = ublk_ctrl_quiesce_dev(ub, &header); break; default: ret = -EOPNOTSUPP; @@ -3863,7 +3869,7 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, ublk_put_device(ub); out: pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n", - __func__, ret, cmd->cmd_op, header->dev_id, header->queue_id); + __func__, ret, cmd_op, header.dev_id, header.queue_id); return ret; } -- 2.51.0