[PATCH 0/1] Make urandom-seed service behavior less surprising

[PATCH 0/1] Make urandom-seed service behavior less surprising

[Leo Famulari]

I noticed that if you delete the random seed file, and then recreate it
with `herd stop urandom-seed`, it will have incorrect permissions of
-rw-r--r-- when they should be -rw-------.

Well, don't do that ;)

But if you do, the system should make sure the right thing happens. This
patch does so by setting the umask at what I think is the right point.

Any objections?

Leo Famulari (1):
  services: urandom-seed: Set umask to 077 while shutting down.

 gnu/services/base.scm | 1 +
 1 file changed, 1 insertion(+)

-- 
2.8.3

[PATCH 1/1] services: urandom-seed: Set umask to 077 while shutting down.

[Leo Famulari]

* gnu/services/base.scm (urandom-seed-shepherd-service): Call 'umask'.
---
 gnu/services/base.scm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index a45f219..8ed40a4 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -461,6 +461,7 @@ stopped before 'kill' is called."
                      (call-with-input-file "/dev/urandom"
                        (lambda (urandom)
                          (get-bytevector-n! urandom buf 0 512)
+                         (umask #o077)
                          (call-with-output-file #$%random-seed-file
                            (lambda (seed)
                              (put-bytevector seed buf)))
-- 
2.8.3

Re: [PATCH 1/1] services: urandom-seed: Set umask to 077 while shutting down.

[Ludovic Courtès]

Leo Famulari <leo@famulari.name> skribis:

> * gnu/services/base.scm (urandom-seed-shepherd-service): Call 'umask'.
> ---
>  gnu/services/base.scm | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/gnu/services/base.scm b/gnu/services/base.scm
> index a45f219..8ed40a4 100644
> --- a/gnu/services/base.scm
> +++ b/gnu/services/base.scm
> @@ -461,6 +461,7 @@ stopped before 'kill' is called."
>                       (call-with-input-file "/dev/urandom"
>                         (lambda (urandom)
>                           (get-bytevector-n! urandom buf 0 512)
> +                         (umask #o077)
>                           (call-with-output-file #$%random-seed-file

I think it’s safer to restore the umask afterwards, like:

  (let ((previous-umask (umask #o077)))
    …
    (umask previous-umask))

Otherwise LGTM, thanks!

Ludo’.