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.
Signed-off-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxx>
---
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 f4d81127239eb..5ec2b817c694a 100644
--- a/drivers/scsi/qedf/qedf_dbg.h
+++ b/drivers/scsi/qedf/qedf_dbg.h
@@ -59,6 +59,8 @@ 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 f910af0029a2c..6db996b73fe39 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
--
2.41.0
