Bugtraq: Re: GnuPG 1.2.3, 1.3.3 external HKP interface format string issue

[David Shaw <dshaw () jabberwocky com>]

On Wed, Dec 03, 2003 at 04:30:38PM +0300, S-Quadra Security Research wrote:
>      if(gotit)
>        {
>          // S-Quadra: here is where format string bug lives
>          fprintf(output,line);
>          if(strcmp(line,"-----END PGP PUBLIC KEY BLOCK-----\n")==0)
>        break;
>        }
This one is indeed a problem.

>        if(strcmp(line,"-----BEGIN PGP PUBLIC KEY BLOCK-----\n")==0)
>          {
>            // S-Quadra: here is where format string bug lives
>        fprintf(output,line);
>        gotit=1;
>          }
But this one is not.  You can't get to the dangerous fprintf without
"line" being verified as safe.

David