[sudo-workers] execve() failure & closefrom() in fork_cmnd()

[Todd C. Miller]

On Tue, 29 Nov 2011 17:47:46 +0100, Daniel Kopecek wrote:

> It seems that the usage of closefrom() in the fork_cmnd() function 
> (http://www.sudo.ws/repos/sudo/file/ec0f2beaad36/src/exec.c#l140) should 
> take into consideration that the execve() call might fail and ensure 
> that the sv[1] descriptor used for sending the cstat structure back to 
> the parent process stays open. In the current state and with 
> def_closefrom not set to some higher number than sv[1], the descriptor 
> gets closed and sudo doesn't report an error.

Good catch.  I've just committed a fix that uses dup2() + FD_CLOEXEC
to avoid closing sv[1] in the closefrom() call.

 - todd