avformat/avio: Limit url option parsing to the documented cases

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 984d58a344)

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2016-01-20 09:43:54 +01:00
parent 7ee0b1937a
commit 30463a0c99

View File

@ -155,8 +155,15 @@ 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;
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);
@ -222,7 +229,7 @@ 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