param: lock if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes.

Since it can be changed via sysfs, we need to make a copy.  This most
generic way of doing this is to keep a flag so we know when to free it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Cc: Dan Williams <dcbw@redhat.com>
Cc: John W. Linville <linville@tuxdriver.com>
Cc: libertas-dev@lists.infradead.org
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org

1 files changed, 30 insertions, 2 deletions

diff --git a/drivers/net/wireless/libertas/if_sdio.c b/drivers/net/wireless/libertas/if_sdio.c
index 6e71346a7550..ba854c70ab94 100644
--- a/drivers/net/wireless/libertas/if_sdio.c
+++ b/drivers/net/wireless/libertas/if_sdio.c
@@ -125,6 +125,8 @@ struct if_sdio_card {
 
         const char              *helper;
         const char              *firmware;
+        bool                    helper_allocated;
+        bool                    firmware_allocated;
 
         u8                      buffer[65536];
 
@@ -984,16 +986,34 @@ static int if_sdio_probe(struct sdio_func *func,
         card->helper = if_sdio_models[i].helper;
         card->firmware = if_sdio_models[i].firmware;
 
+        kparam_block_sysfs_write(helper_name);
         if (lbs_helper_name) {
+                char *helper = kstrdup(lbs_helper_name, GFP_KERNEL);
+                if (!helper) {
+                        kparam_unblock_sysfs_write(helper_name);
+                        ret = -ENOMEM;
+                        goto free;
+                }
                 lbs_deb_sdio("overriding helper firmware: %s\n",
                         lbs_helper_name);
-                card->helper = lbs_helper_name;
+                card->helper = helper;
+                card->helper_allocated = true;
         }
+        kparam_unblock_sysfs_write(helper_name);
 
+        kparam_block_sysfs_write(fw_name);
         if (lbs_fw_name) {
+                char *fw_name = kstrdup(lbs_fw_name, GFP_KERNEL);
+                if (!fw_name) {
+                        kparam_unblock_sysfs_write(fw_name);
+                        ret = -ENOMEM;
+                        goto free;
+                }
                 lbs_deb_sdio("overriding firmware: %s\n", lbs_fw_name);
-                card->firmware = lbs_fw_name;
+                card->firmware = fw_name;
+                card->firmware_allocated = true;
         }
+        kparam_unblock_sysfs_write(fw_name);
 
         sdio_claim_host(func);
 
@@ -1127,6 +1147,10 @@ free:
                 kfree(packet);
         }
 
+        if (card->helper_allocated)
+                kfree(card->helper);
+        if (card->firmware_allocated)
+                kfree(card->firmware);
         kfree(card);
 
         goto out;
@@ -1177,6 +1201,10 @@ static void if_sdio_remove(struct sdio_func *func)
                 kfree(packet);
         }
 
+        if (card->helper_allocated)
+                kfree(card->helper);
+        if (card->firmware_allocated)
+                kfree(card->firmware);
         kfree(card);
 
         lbs_deb_leave(LBS_DEB_SDIO);