avformat/avio: Limit url option parsing to the documented cases
authorMichael Niedermayer <michael@niedermayer.cc>
Wed, 20 Jan 2016 08:43:54 +0000 (09:43 +0100)
committerMichael Niedermayer <michael@niedermayer.cc>
Sat, 30 Jan 2016 23:23:45 +0000 (00:23 +0100)
This feature is not know much or used much AFAIK, and it might be helpfull in
exploits.
No specific case is known where it can be used in an exploit though
subsequent commits depend on this commit though

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 984d58a3440d513f66344b5332f6b589c0a6bbc6)

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavformat/avio.c

index 261ff2a..822f87c 100644 (file)
@@ -156,9 +156,16 @@ static int url_alloc_for_protocol(URLContext **puc, struct URLProtocol *up,
                 char sep= *++p;
                 char *key, *val;
                 p++;
+
+                if (strcmp(up->name, "subfile"))
+                    ret = AVERROR(EINVAL);
+
                 while(ret >= 0 && (key= strchr(p, sep)) && p<key && (val = strchr(key+1, sep))){
                     *val= *key= 0;
-                    ret= av_opt_set(uc->priv_data, p, key+1, 0);
+                    if (strcmp(p, "start") && strcmp(p, "end")) {
+                        ret = AVERROR_OPTION_NOT_FOUND;
+                    } else
+                        ret= av_opt_set(uc->priv_data, p, key+1, 0);
                     if (ret == AVERROR_OPTION_NOT_FOUND)
                         av_log(uc, AV_LOG_ERROR, "Key '%s' not found.\n", p);
                     *val= *key= sep;
@@ -223,7 +230,7 @@ static struct URLProtocol *url_find_protocol(const char *filename)
     size_t proto_len = strspn(filename, URL_SCHEME_CHARS);
 
     if (filename[proto_len] != ':' &&
-        (filename[proto_len] != ',' || !strchr(filename + proto_len + 1, ':')) ||
+        (strncmp(filename, "subfile,", 8) || !strchr(filename + proto_len + 1, ':')) ||
         is_dos_path(filename))
         strcpy(proto_str, "file");
     else