Re: segfault and uid problem

On Sun, Feb 15, 2004 at 03:14:43PM -0500, Hendrik Scholz wrote:
> Reading the make output and the strncpy/strerror manpages it becomes 
> pretty
> much evident that string.h has to be included:
> 
> --- screen.c.orig       Sun Feb 15 14:49:28 2004
> +++ screen.c    Sun Feb 15 14:50:16 2004
> @@ -35,6 +35,10 @@
> 
>   #include <fcntl.h>
> 
> +#ifdef __FreeBSD__
> +#include <string.h>
> +#endif
> +

This should be done in os.h. I guess SVR4 is not defined in config.h,
is it ok to include both "strings.h" and "string.h" on FreeBSD?

> @@ -1906,7 +1910,7 @@
>         p += strlen(p);
>         *p++ = ':';
>         *p++ = ' ';
> -      strncpy(p, strerror(err), buf + sizeof(buf) - p - 1);
> +      strncpy(p, (char *)strerror(err), buf + sizeof(buf) - p - 1);
>         buf[sizeof(buf) - 1] = 0;
>       }
>     debug2("Msg('%s') (%#x);\n", buf, (unsigned int)display);
> @@ -1960,7 +1964,7 @@
>         p += strlen(p);
>         *p++ = ':';
>         *p++ = ' ';
> -      strncpy(p, strerror(err), buf + sizeof(buf) - p - 1);
> +      strncpy(p, (char *)strerror(err), buf + sizeof(buf) - p - 1);
>         buf[sizeof(buf) - 1] = 0;
>       }
>     debug3("Panic('%s'); display=%x displays=%x\n", buf, display, 
> displays);

These casts don't make sense, they are not needed if strerror() is
declared to return (char *) and don't help if the compiler thinks
strerror() returns an int.

> Once correctly patched screen doesn't core dump but prints:
> [0.20] root@slurmcan:~ > screen
> /tmp/screens/S-root/89382.ttyp3.slurmcan: No such file or directory
> [0.20] root@slurmcan:~ >

Yes, that's normal. You have to use "screen -m" in that case, because
otherwise screen tries to create a new window in the running screen
and fails to connect to the socket/pipe. We could check the socketname
for an uid mismatch, though...

Cheers,
  Michael.

-- 
Michael Schroeder           [email protected]
main(_){while(_=~getchar())putchar(~_-1/(~(_|32)/13*2-11)*13);}


 
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