[PATCH][media-next][V2] media: davinci_vpfe: fix memory leaks of params

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

There are memory leaks of params; when copy_to_user fails and also
the exit via the label 'error'. Also, there is a bogos memory allocation
check on pointer 'to' when memory allocation fails on params.

Fix this by kfree'ing params in error exit path and jumping to this on
the copy_to_user failure path.  Also check the to see if the allocation
of params fails and remove the bogus null pointer checks on pointer 'to'.

Also explicitly return 0 on success rather than rval.

Detected by CoverityScan, CID#1467966 ("Resource leak")

Fixes: da43b6ccadcf ("[media] davinci: vpfe: dm365: add IPIPE support for media controller driver")
Signed-off-by: Colin Ian King <colin.king at canonical.com>
---

V2: Add checks on allocation of params.  Remove bogus checks on
    pointer 'to'. Explicitly return 0 on success. Thanks to
    Dan Carpenter for the suggested improvements.

---
 drivers/staging/media/davinci_vpfe/dm365_ipipe.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/media/davinci_vpfe/dm365_ipipe.c b/drivers/staging/media/davinci_vpfe/dm365_ipipe.c
index 95942768639c..b135e38a18b3 100644
--- a/drivers/staging/media/davinci_vpfe/dm365_ipipe.c
+++ b/drivers/staging/media/davinci_vpfe/dm365_ipipe.c
@@ -1252,12 +1252,12 @@ static const struct ipipe_module_if ipipe_modules[VPFE_IPIPE_MAX_MODULES] = {
 static int ipipe_s_config(struct v4l2_subdev *sd, struct vpfe_ipipe_config *cfg)
 {
 	struct vpfe_ipipe_device *ipipe = v4l2_get_subdevdata(sd);
+	struct ipipe_module_params *params;
 	unsigned int i;
 	int rval = 0;
 
 	for (i = 0; i < ARRAY_SIZE(ipipe_modules); i++) {
 		const struct ipipe_module_if *module_if;
-		struct ipipe_module_params *params;
 		void *from, *to;
 		size_t size;
 
@@ -1269,25 +1269,31 @@ static int ipipe_s_config(struct v4l2_subdev *sd, struct vpfe_ipipe_config *cfg)
 
 		params = kmalloc(sizeof(struct ipipe_module_params),
 				 GFP_KERNEL);
+		if (!params) {
+			rval = -ENOMEM;
+			goto error;
+		}
 		to = (void *)params + module_if->param_offset;
 		size = module_if->param_size;
 
-		if (to && from && size) {
+		if (from && size) {
 			if (copy_from_user(to, (void __user *)from, size)) {
 				rval = -EFAULT;
-				break;
+				goto error;
 			}
 			rval = module_if->set(ipipe, to);
 			if (rval)
 				goto error;
-		} else if (to && !from && size) {
+		} else if (!from && size) {
 			rval = module_if->set(ipipe, NULL);
 			if (rval)
 				goto error;
 		}
 		kfree(params);
 	}
+	return 0;
 error:
+	kfree(params);
 	return rval;
 }
 
-- 
2.17.0