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