From: Alistair Delva <adelva@xxxxxxxxxx> commit f89672cc3681952f2d06314981a6b45f8b0045d1 upstream. Check count for 0, to avoid a potential underflow. Make the check the same as the one in rproc_recovery_write(). Fixes: 3afdc59e4390 ("remoteproc: Add coredump debugfs entry") Signed-off-by: Alistair Delva <adelva@xxxxxxxxxx> Cc: Rishabh Bhatnagar <rishabhb@xxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Cc: Ohad Ben-Cohen <ohad@xxxxxxxxxx> Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Cc: Sibi Sankar <sibis@xxxxxxxxxxxxxx> Cc: linux-remoteproc@xxxxxxxxxxxxxxx Cc: kernel-team@xxxxxxxxxxx Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220119232139.1125908-1-adelva@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/remoteproc/remoteproc_debugfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/remoteproc/remoteproc_debugfs.c +++ b/drivers/remoteproc/remoteproc_debugfs.c @@ -76,7 +76,7 @@ static ssize_t rproc_coredump_write(stru int ret, err = 0; char buf[20]; - if (count > sizeof(buf)) + if (count < 1 || count > sizeof(buf)) return -EINVAL; ret = copy_from_user(buf, user_buf, count);