blobmsg: drop old comment about json formatting functions

[oweals/libubox.git] / blob.c

diff --git a/blob.c b/blob.c
index ee93894b9e6fd36503c870cf3795a0d18774afda..433becb904f54d4e0b3fb186756f62c71beb0ba5 100644 (file)
--- a/blob.c
+++ b/blob.c
@@ -218,20 +218,33 @@ blob_check_type(const void *ptr, unsigned int len, int type)
 }
 
 static int
-blob_parse_attr(struct blob_attr *attr, struct blob_attr **data, const struct blob_attr_info *info, int max)
+blob_parse_attr(struct blob_attr *attr, size_t attr_len, struct blob_attr **data, const struct blob_attr_info *info, int max)
 {
+       int id;
+       size_t len;
        int found = 0;
-       int id = blob_id(attr);
-       size_t len = blob_len(attr);
+       size_t data_len;
 
+       if (!attr || attr_len < sizeof(struct blob_attr))
+               return 0;
+
+       id = blob_id(attr);
        if (id >= max)
                return 0;
 
+       len = blob_raw_len(attr);
+       if (len > attr_len || len < sizeof(struct blob_attr))
+               return 0;
+
+       data_len = blob_len(attr);
+       if (data_len > len)
+               return 0;
+
        if (info) {
                int type = info[id].type;
 
                if (type < BLOB_ATTR_LAST) {
-                       if (!blob_check_type(blob_data(attr), len, type))
+                       if (!blob_check_type(blob_data(attr), data_len, type))
                                return 0;
                }
 
@@ -252,6 +265,30 @@ blob_parse_attr(struct blob_attr *attr, struct blob_attr **data, const struct bl
        return found;
 }
 
+int
+blob_parse_untrusted(struct blob_attr *attr, size_t attr_len, struct blob_attr **data, const struct blob_attr_info *info, int max)
+{
+       struct blob_attr *pos;
+       size_t len = 0;
+       int found = 0;
+       size_t rem;
+
+       if (!attr || attr_len < sizeof(struct blob_attr))
+               return 0;
+
+       len = blob_raw_len(attr);
+       if (attr_len < len)
+               return 0;
+
+       memset(data, 0, sizeof(struct blob_attr *) * max);
+       blob_for_each_attr_len(pos, attr, len, rem) {
+               found += blob_parse_attr(pos, rem, data, info, max);
+       }
+
+       return found;
+}
+
+/* use only on trusted input, otherwise consider blob_parse_untrusted */
 int
 blob_parse(struct blob_attr *attr, struct blob_attr **data, const struct blob_attr_info *info, int max)
 {
@@ -261,7 +298,7 @@ blob_parse(struct blob_attr *attr, struct blob_attr **data, const struct blob_at
 
        memset(data, 0, sizeof(struct blob_attr *) * max);
        blob_for_each_attr(pos, attr, rem) {
-               found += blob_parse_attr(pos, data, info, max);
+               found += blob_parse_attr(pos, rem, data, info, max);
        }
 
        return found;