[PATCH 5.10 228/406] scsi: qedf: Do not touch __user pointer in qedf_dbg_fp_int_cmd_read() directly

Greg Kroah-Hartman
2023-09-17T19:33:46Z

From: Oleksandr Natalenko <oleksandr@redhat.com>

[ Upstream commit 25dbc20deab5165f847b4eb42f376f725a986ee8 ]

The qedf_dbg_fp_int_cmd_read() function invokes sprintf() directly on a
__user pointer, which may crash the kernel.

Avoid doing that by vmalloc()'ating a 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 <skashyap@marvell.com>
Cc: Rob Evers <revers@redhat.com>
Cc: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Jozef Bacik <jobacik@redhat.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: GR-QLogic-Storage-Upstream@marvell.com
Cc: linux-scsi@vger.kernel.org
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com>
Link: https://lore.kernel.org/r/20230731084034.37021-4-oleksandr@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/qedf/qedf_dbg.h | 2 ++
drivers/scsi/qedf/qedf_debugfs.c | 21 +++++++++++++++------
2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/qedf/qedf_dbg.h b/drivers/scsi/qedf/qedf_dbg.h
index 2386bfb73c461..4a536c8377081 100644
--- a/drivers/scsi/qedf/qedf_dbg.h
+++ b/drivers/scsi/qedf/qedf_dbg.h
@@ -60,6 +60,8 @@ extern uint qedf_debug;
#define QEDF_LOG_NOTICE 0x40000000 /* Notice logs */
#define QEDF_LOG_WARN 0x80000000 /* Warning logs */

+#define QEDF_DEBUGFS_LOG_LEN (2 * PAGE_SIZE)
+
/* Debug context structure */
struct qedf_dbg_ctx {
unsigned int host_no;
diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c
index 1c5716540e465..451fd236bfd05 100644
--- a/drivers/scsi/qedf/qedf_debugfs.c
+++ b/drivers/scsi/qedf/qedf_debugfs.c
@@ -8,6 +8,7 @@
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <linux/module.h>
+#include <linux/vmalloc.h>

#include "qedf.h"
#include "qedf_dbg.h"
@@ -98,7 +99,9 @@ static ssize_t
qedf_dbg_fp_int_cmd_read(struct file *filp, char __user *buffer, size_t count,
loff_t *ppos)
{
+ ssize_t ret;
size_t cnt = 0;
+ char *cbuf;
int id;
struct qedf_fastpath *fp = NULL;
struct qedf_dbg_ctx *qedf_dbg =
@@ -108,19 +111,25 @@ qedf_dbg_fp_int_cmd_read(struct file *filp, char __user *buffer, size_t count,

QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "entered\n");

- cnt = sprintf(buffer, "\nFastpath I/O completions\n\n");
+ cbuf = vmalloc(QEDF_DEBUGFS_LOG_LEN);
+ if (!cbuf)
+ return 0;
+
+ cnt += scnprintf(cbuf + cnt, QEDF_DEBUGFS_LOG_LEN - cnt, "\nFastpath I/O completions\n\n");

for (id = 0; id < qedf->num_queues; id++) {
fp = &(qedf->fp_array[id]);
if (fp->sb_id == QEDF_SB_ID_NULL)
continue;
- cnt += sprintf((buffer + cnt), "#%d: %lu\n", id,
- fp->completions);
+ cnt += scnprintf(cbuf + cnt, QEDF_DEBUGFS_LOG_LEN - cnt,
+ "#%d: %lu\n", id, fp->completions);
}

- cnt = min_t(int, count, cnt - *ppos);
- *ppos += cnt;
- return cnt;
+ ret = simple_read_from_buffer(buffer, count, ppos, cbuf, cnt);
+
+ vfree(cbuf);
+
+ return ret;
}

static ssize_t
--
2.40.1