[PATCH AUTOSEL 4.19 125/209] remoteproc: Check for NULL firmwares in sysfs interface

[Sasha Levin]

From: Suman Anna <s-anna@xxxxxx>

[ Upstream commit faeadbb64094757150a8c2a3175ca418dbdd472c ]

The remoteproc framework provides a sysfs file 'firmware'
for modifying the firmware image name from userspace. Add
an additional check to ensure NULL firmwares are errored
out right away, rather than getting a delayed error while
requesting a firmware during the start of a remoteproc
later on.

Tested-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>
Signed-off-by: Suman Anna <s-anna@xxxxxx>
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/remoteproc/remoteproc_sysfs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index 47be411400e56..3a4c3d7cafca3 100644
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -48,6 +48,11 @@ static ssize_t firmware_store(struct device *dev,
 	}
 
 	len = strcspn(buf, "\n");
+	if (!len) {
+		dev_err(dev, "can't provide a NULL firmware\n");
+		err = -EINVAL;
+		goto out;
+	}
 
 	p = kstrndup(buf, len, GFP_KERNEL);
 	if (!p) {
-- 
2.20.1