Hi,
i found that some software sends empty fmtp media attribute.
like: "a=ftmp:0\r\n" ("\r\n" immediatly follows after payload id)
in this case sdp parser throws exception and this exception destroys
AmSession leg
point of failure is here:
<pre>
core/AmSdp.cpp:
966 static void parse_sdp_attr(AmSdp* sdp_msg, char* s)
{
...
1102 case FORMAT_PARAM:
1103 {
1104 line_end--;
1105 while (is_wsp(*line_end))
1106 line_end--;
1107
1108 params = string(attr_line, line_end-attr_line+1); // <--
(line_end-attr_line+1) will be -1 for the "a=ftmp:0\r\n" as source data
1109 parsing = 0;
1110 }
1111 break;
...
}
</pre>
thus this code will throw exception in string() constructor
i simply patched code for this certain case:
<pre>
- params = string(attr_line, line_end-attr_line+1);
+ if(attr_line >= line_end){
+ DBG("empty param for fmtp. ignore it");
+ } else {
+ params = string(attr_line, line_end-attr_line+1);
+ }
</pre>
but it's seems wrong to destroy entire leg due to sdp parsing error.
should be added checks for other params and/or catch for parsing
exceptions to respond with smth like 488 instead of 481
--
Best Regards
Michael Furmur
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