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Date:   Wed, 19 Jan 2022 23:21:39 +0000
Message-Id: <20220119232139.1125908-1-adelva@google.com>
Mime-Version: 1.0
Subject: [PATCH] remoteproc: Fix count check in rproc_coredump_write()
From:   Alistair Delva <adelva@google.com>
To:     linux-kernel@vger.kernel.org
Cc:     Rishabh Bhatnagar <rishabhb@codeaurora.org>,
        stable@vger.kernel.org, Ohad Ben-Cohen <ohad@wizery.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Sibi Sankar <sibis@codeaurora.org>,
        linux-remoteproc@vger.kernel.org, kernel-team@android.com
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Precedence: bulk

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
---
 drivers/remoteproc/remoteproc_debugfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
index b5a1e3b697d9..581930483ef8 100644
--- 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);
-- 
2.30.2