remoteproc: Fix count check in rproc_coredump_write()

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@google.com>
Cc: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Cc: stable@vger.kernel.org
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Sibi Sankar <sibis@codeaurora.org>
Cc: linux-remoteproc@vger.kernel.org
Cc: kernel-team@android.com
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220119232139.1125908-1-adelva@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
index b5a1e3b..5819304 100644 (file)
--- a/drivers/remoteproc/remoteproc_debugfs.c
+++ b/drivers/remoteproc/remoteproc_debugfs.c
@@ -76,7 +76,7 @@ static ssize_t rproc_coredump_write(struct file *filp,
        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);