Re: ASAN and dhcpcd with privilege separation

[Roy Marples <roy%marples.name@localhost>]

On 31/01/2021 11:15, RVP wrote:
> On Sun, 31 Jan 2021, Roy Marples wrote:
>
> > Why does this not work for dhcpcd privilege separation?
>
> I suspect this is what's happening:
>
> $ cat t.c
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
>
> int main(int argc, char* argv[]) {
>          char* s;
>          printf("dropping privs\n");
>          setgid(getgid());
>          setuid(getuid());
>          s = malloc(BUFSIZ);
>          return 0;
> }

I sent this patch as well to disable that:
diff -r 7ea0253a7567 external/bsd/dhcpcd/dist/src/privsep.c
--- a/external/bsd/dhcpcd/dist/src/privsep.c    Fri Jan 29 07:58:57 2021 +0000
+++ b/external/bsd/dhcpcd/dist/src/privsep.c    Sun Jan 31 02:50:23 2021 +0000
@@ -114,6 +114,8 @@
 static int
 ps_dropprivs(struct dhcpcd_ctx *ctx)
 {
+return 0;
+
        struct passwd *pw = ctx->ps_user;

        if (ctx->options & DHCPCD_LAUNCHER)


So all it's doing is forking and running as root.
I'm just surprised that it's not working is all.

What I want to end up with is some #ifdef SANITIZE foo so that enough is 
disabled to make it work.

Roy