From 472f2497a4c8aa27220e276ff77d618bef482b2a Mon Sep 17 00:00:00 2001 From: Oleksandr Natalenko Date: Mon, 31 Jul 2023 10:40:32 +0200 Subject: [PATCH] scsi: qedf: Do not touch __user pointer in qedf_dbg_stop_io_on_error_cmd_read() directly [ Upstream commit 7d3d20dee4f648ec44e9717d5f647d594d184433 ] The qedf_dbg_stop_io_on_error_cmd_read() function invokes sprintf() directly on a __user pointer, which may crash the kernel. Avoid doing that by using a small on-stack buffer for scnprintf() and then calling simple_read_from_buffer() which does a proper copy_to_user() call. Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.") Link: https://lore.kernel.org/lkml/20230724120241.40495-1-oleksandr@redhat.com/ Link: https://lore.kernel.org/linux-scsi/20230726101236.11922-1-skashyap@marvell.com/ Cc: Saurav Kashyap Cc: Rob Evers Cc: Johannes Thumshirn Cc: David Laight Cc: Jozef Bacik Cc: Laurence Oberman Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Cc: GR-QLogic-Storage-Upstream@marvell.com Cc: linux-scsi@vger.kernel.org Reviewed-by: Laurence Oberman Reviewed-by: Johannes Thumshirn Tested-by: Laurence Oberman Acked-by: Saurav Kashyap Signed-off-by: Oleksandr Natalenko Link: https://lore.kernel.org/r/20230731084034.37021-2-oleksandr@redhat.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/qedf/qedf_debugfs.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c index a3ed681c8ce3f..3eb4334ac6a32 100644 --- a/drivers/scsi/qedf/qedf_debugfs.c +++ b/drivers/scsi/qedf/qedf_debugfs.c @@ -185,18 +185,17 @@ qedf_dbg_stop_io_on_error_cmd_read(struct file *filp, char __user *buffer, size_t count, loff_t *ppos) { int cnt; + char cbuf[7]; struct qedf_dbg_ctx *qedf_dbg = (struct qedf_dbg_ctx *)filp->private_data; struct qedf_ctx *qedf = container_of(qedf_dbg, struct qedf_ctx, dbg_ctx); QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "entered\n"); - cnt = sprintf(buffer, "%s\n", + cnt = scnprintf(cbuf, sizeof(cbuf), "%s\n", qedf->stop_io_on_error ? "true" : "false"); - cnt = min_t(int, count, cnt - *ppos); - *ppos += cnt; - return cnt; + return simple_read_from_buffer(buffer, count, ppos, cbuf, cnt); } static ssize_t