[FFmpeg-devel] [PATCH] Handling special characters in a URL.

[Senthilnathan Maadasamy]

On Thu, Feb 28, 2013 at 6:09 AM, Michael Niedermayer <michaelni at gmx.at>wrote:

>
> > +    while (c = *src) {
>
> null pointer dereference
>
Added a check to fix this.

>
>
> > +        if (isalnum(c) || strchr("-._~%", c)
> > +            || (allowed && strchr(allowed, c))) {
> > +            if (enc_len+1 < MAX_URL_SIZE) enc[enc_len] = c;
> > +            else break;
> > +            enc_len++;
> > +        } else {
> > +            if (enc_len+3 < MAX_URL_SIZE) snprintf(&enc[enc_len], 4,
> "%%%02x", c);
> > +            else break;
> > +            enc_len += 3;
> > +        }
> > +        src++;
> > +    }
> > +
>
> > +    enc[enc_len++] = '\0';
>
> i suspect this can write outside of the array
>
No.  The previous two comparisons of enc_len with MAX_URL_SIZE make sure
that there is always place for the trailing NULL character.

>
>
> > +    if (enc_len <= component_size) {
>
> > +        av_strlcpy(component, enc, component_size);
>
> this encodes things like
> A.B.C.D?ttl=123
> which thebn fail apparently
>
I have added '=' to the list of character which must not be encoded.
I have tried my best to test different cases.  Please let me know if it
needs further changes.

Thanks,
Senthil
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