ASoC: Check list debugfs files for PAGE_SIZE overflow

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 225b5bd..6cee97e 100644 (file)
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -274,15 +274,22 @@ static ssize_t codec_list_read_file(struct file *file, char __user *user_buf,
                                    size_t count, loff_t *ppos)
 {
        char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-       ssize_t ret = 0;
+       ssize_t len, ret = 0;
        struct snd_soc_codec *codec;
 
        if (!buf)
                return -ENOMEM;
 
-       list_for_each_entry(codec, &codec_list, list)
-               ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
-                               codec->name);
+       list_for_each_entry(codec, &codec_list, list) {
+               len = snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
+                              codec->name);
+               if (len >= 0)
+                       ret += len;
+               if (ret > PAGE_SIZE) {
+                       ret = PAGE_SIZE;
+                       break;
+               }
+       }
 
        if (ret >= 0)
                ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
@@ -301,17 +308,23 @@ static ssize_t dai_list_read_file(struct file *file, char __user *user_buf,
                                  size_t count, loff_t *ppos)
 {
        char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-       ssize_t ret = 0;
+       ssize_t len, ret = 0;
        struct snd_soc_dai *dai;
 
        if (!buf)
                return -ENOMEM;
 
-       list_for_each_entry(dai, &dai_list, list)
-               ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s\n", dai->name);
+       list_for_each_entry(dai, &dai_list, list) {
+               len = snprintf(buf + ret, PAGE_SIZE - ret, "%s\n", dai->name);
+               if (len >= 0)
+                       ret += len;
+               if (ret > PAGE_SIZE) {
+                       ret = PAGE_SIZE;
+                       break;
+               }
+       }
 
-       if (ret >= 0)
-               ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
+       ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
 
        kfree(buf);
 
@@ -328,18 +341,24 @@ static ssize_t platform_list_read_file(struct file *file,
                                       size_t count, loff_t *ppos)
 {
        char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-       ssize_t ret = 0;
+       ssize_t len, ret = 0;
        struct snd_soc_platform *platform;
 
        if (!buf)
                return -ENOMEM;
 
-       list_for_each_entry(platform, &platform_list, list)
-               ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
-                               platform->name);
+       list_for_each_entry(platform, &platform_list, list) {
+               len = snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
+                              platform->name);
+               if (len >= 0)
+                       ret += len;
+               if (ret > PAGE_SIZE) {
+                       ret = PAGE_SIZE;
+                       break;
+               }
+       }
 
-       if (ret >= 0)
-               ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
+       ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
 
        kfree(buf);