[PATCH] media: siano: be sure to not override devpath size

[Mauro Carvalho Chehab]

Right now, at siano driver, all places where devpath is
defined has sizeof(devpath) == 32. So, there's no practical
risc of going past devpath array anywhere.

Still, code changes might cause troubles. It also confuses
Coverity:
        CID 139059 (#1 of 1): Copy into fixed size buffer (STRING_OVERFLOW)
        9. fixed_size_dest: You might overrun the 32-character
           fixed-size string entry->devpath by copying devpath
           without checking the length.
        10. parameter_as_source: Note: This defect has an
            elevated risk because the source argument
            is a parameter of the current function.

So, explicitly limit strcmp() and strcpy() to ensure that the
devpath size (32) will be respected.

Signed-off-by: Mauro Carvalho Chehab <mche...@s-opensource.com>
---
 drivers/media/common/siano/smscoreapi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/media/common/siano/smscoreapi.c 
b/drivers/media/common/siano/smscoreapi.c
index b5dcc6d1fe90..1c93258a2d47 100644
--- a/drivers/media/common/siano/smscoreapi.c
+++ b/drivers/media/common/siano/smscoreapi.c
@@ -415,8 +415,8 @@ EXPORT_SYMBOL_GPL(smscore_get_board_id);
 
 struct smscore_registry_entry_t {
        struct list_head entry;
-       char                    devpath[32];
-       int                             mode;
+       char devpath[32];
+       int mode;
        enum sms_device_type_st type;
 };
 
@@ -442,7 +442,7 @@ static struct smscore_registry_entry_t 
*smscore_find_registry(char *devpath)
             next != &g_smscore_registry;
             next = next->next) {
                entry = (struct smscore_registry_entry_t *) next;
-               if (!strcmp(entry->devpath, devpath)) {
+               if (!strncmp(entry->devpath, devpath, sizeof(entry->devpath))) {
                        kmutex_unlock(&g_smscore_registrylock);
                        return entry;
                }
@@ -450,7 +450,7 @@ static struct smscore_registry_entry_t 
*smscore_find_registry(char *devpath)
        entry = kmalloc(sizeof(*entry), GFP_KERNEL);
        if (entry) {
                entry->mode = default_mode;
-               strcpy(entry->devpath, devpath);
+               strlcpy(entry->devpath, devpath, sizeof(entry->devpath));
                list_add(&entry->entry, &g_smscore_registry);
        } else
                pr_err("failed to create smscore_registry.\n");
@@ -733,7 +733,7 @@ int smscore_register_device(struct smsdevice_params_t 
*params,
        dev->postload_handler = params->postload_handler;
 
        dev->device_flags = params->flags;
-       strcpy(dev->devpath, params->devpath);
+       strlcpy(dev->devpath, params->devpath, sizeof(dev->devpath));
 
        smscore_registry_settype(dev->devpath, params->device_type);
 
-- 
2.14.3