[bug#30254] [PATCH 0/3] guix environment --user, --link-profile, --no-cwd

[bug#30254] [PATCH 0/3] guix environment --user, --link-profile, --no-cwd

[Mike Gerwitz]

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On help-guix I initiated a conversation on using IceCat within a container
(<87vag2wopo.fsf@gnu.org>).  This covers some of the lower-level concepts I
was thinking off.  Specifically:

0. The ability to hide the user (and home directory) from procsses within the
   container.  This includes rewritting mapped paths;
1. Suppressing the behavior of automatically sharing cwd; and
2. Linking $GUIX_ENVIRONMENT to ~/.guix-profile.

The first two are for privacy (#1 is for conveinence, since creating an empty
dir just to cd into it is a bit klugy as a workaround).  #2 was motivated by
my needs with font-config, but I can imaging that it'd be useful elsewhere
as well.  It only really makes sense if you're not sharing your home
directory.

Mike Gerwitz (3):
  scripts: environment: Add --link-profile.
  scripts: environment: Add --user.
  scripts: environment: Add --no-cwd.

 doc/guix.texi                |  59 +++++++++++++-
 guix/scripts/environment.scm | 178 +++++++++++++++++++++++++++++++++++--------
 tests/guix-environment.sh    |  30 ++++++++
 3 files changed, 233 insertions(+), 34 deletions(-)

-- 
2.15.1


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[bug#30255] [PATCH 1/3] scripts: environment: Add --link-profile.

[Mike Gerwitz]

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This change is motivated by attempts to run programs (like GNU IceCat) within
containers.  The 'fontconfig' program, for example, is configured explicitly
to check ~/.guix-profile for additional fonts.

There were no existing container tests in 'tests/guix-environment.sh', but I
added one anyway for this change.

* doc/guix.texi (Invoking guix environment): Add '--link-profile'.
* guix/scripts/environment.scm (show-help): Add '--link-profile'.
(%options): Add 'link-profile' as '#\P', assigned to 'link-profile?'.
(lnk-environment): New procedure.
(launch-environment/container): Use it when 'link-profile?'.
[link-profile?]: New parameter.
(guix-environment): Leave when '--link-prof' but not '--container'.  Add
'#:link-profile?' argument to 'launch-environment/container' application.
* tests/guix-environment.sh: New '--link-profile' test.
---
 doc/guix.texi                | 17 +++++++++++++++++
 guix/scripts/environment.scm | 43 +++++++++++++++++++++++++++++++++++++------
 tests/guix-environment.sh    | 12 ++++++++++++
 3 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 1ecdcd218..3b6ae1ab9 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -46,6 +46,7 @@ Copyright @copyright{} 2017 Andy Wingo@*
 Copyright @copyright{} 2017 Arun Isaac@*
 Copyright @copyright{} 2017 nee@*
 Copyright @copyright{} 2018 Rutger Helling
+Copyright @copyright{} 2018 Mike Gerwitz
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -7166,6 +7167,22 @@ For containers, share the network namespace with the host system.
 Containers created without this flag only have access to the loopback
 device.
 
+@item --link-profile
+@itemx -P
+For containers, link the environment profile to
+@file{~/.guix-profile} within the container.  This is equivalent to
+running the command @command{ln -s $GUIX_ENVIRONMENT ~/.guix-profile}
+within the container.  Linking will fail and abort the environment if
+the directory already exists, which will certainly be the case if
+@command{guix environment} was invoked in the user's home directory.
+
+Certain packages are configured to look in
+@code{~/.guix-profile} for configuration files and data;@footnote{For
+example, the @code{fontconfig} package inspects
+@file{~/.guix-profile/share/fonts} for additional fonts.}
+@code{--link-profile} allows these programs to behave as expected within
+the environment.
+
 @item --expose=@var{source}[=@var{target}]
 For containers, expose the file system @var{source} from the host system
 as the read-only file system @var{target} within the container.  If
diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index d2568e6a7..771574c15 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014, 2015 David Thompson <davet@gnu.org>
 ;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2018 Mike Gerwitz <mtg@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -157,6 +158,9 @@ COMMAND or an interactive shell in that environment.\n"))
   -C, --container        run command within an isolated container"))
   (display (G_ "
   -N, --network          allow containers to access the network"))
+  (display (G_ "
+  -P, --link-profile     link environment profile to ~/.guix-profile within
+                         an isolated container"))
   (display (G_ "
       --share=SPEC       for containers, share writable host file system
                          according to SPEC"))
@@ -236,6 +240,9 @@ COMMAND or an interactive shell in that environment.\n"))
          (option '(#\N "network") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'network? #t result)))
+         (option '(#\P "link-profile") #f #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'link-profile? #t result)))
          (option '("share") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'file-system-mapping
@@ -384,18 +391,20 @@ environment variables are cleared before setting the new ones."
            ((_ . status) status)))))
 
 (define* (launch-environment/container #:key command bash user-mappings
-                                       profile paths network?)
+                                       profile paths link-profile? network?)
   "Run COMMAND within a container that features the software in PROFILE.
 Environment variables are set according to PATHS, a list of native search
 paths.  The global shell is BASH, a file name for a GNU Bash binary in the
 store.  When NETWORK?, access to the host system network is permitted.
 USER-MAPPINGS, a list of file system mappings, contains the user-specified
-host file systems to mount inside the container."
+host file systems to mount inside the container.  LINK-PROFILE? creates a
+symbolic link from ~/.guix-profile to the environment profile."
   (mlet %store-monad ((reqs (inputs->requisites
                              (list (direct-store-path bash) profile))))
     (return
-     (let* ((cwd (getcwd))
-            (passwd (getpwuid (getuid)))
+     (let* ((cwd      (getcwd))
+            (passwd   (getpwuid (getuid)))
+            (home-dir (passwd:dir passwd))
             ;; Bind-mount all requisite store items, user-specified mappings,
             ;; /bin/sh, the current working directory, and possibly networking
             ;; configuration files within the container.
@@ -440,8 +449,13 @@ host file systems to mount inside the container."
 
             ;; Create a dummy home directory under the same name as on the
             ;; host.
-            (mkdir-p (passwd:dir passwd))
-            (setenv "HOME" (passwd:dir passwd))
+            (mkdir-p home-dir)
+            (setenv "HOME" home-dir)
+
+            ;; If requested, link $GUIX_ENVIRONMENT to $HOME/.guix-profile;
+            ;; this allows programs expecting that path to continue working as
+            ;; expected within a container.
+            (when link-profile? (link-environment profile home-dir))
 
             ;; Create a dummy /etc/passwd to satisfy applications that demand
             ;; to read it, such as 'git clone' over SSH, a valid use-case when
@@ -471,6 +485,18 @@ host file systems to mount inside the container."
                            (delq 'net %namespaces) ; share host network
                            %namespaces)))))))
 
+(define (link-environment profile home-dir)
+  "Create a symbolic link from HOME-DIR/.guix-profile to PROFILE."
+  (let ((profile-dir (string-append home-dir "/.guix-profile")))
+    (catch 'system-error
+      (lambda ()
+        (symlink profile profile-dir))
+      (lambda args
+        (if (= EEXIST (system-error-errno args))
+            (leave (G_ "cannot link profile: path '~a' already exists within container~%")
+                   profile-dir)
+            (apply throw args))))))
+
 (define (environment-bash container? bootstrap? system)
   "Return a monadic value in the store monad for the version of GNU Bash
 needed in the environment for SYSTEM, if any.  If CONTAINER? is #f, return #f.
@@ -544,6 +570,7 @@ message if any test fails."
     (let* ((opts       (parse-args args))
            (pure?      (assoc-ref opts 'pure))
            (container? (assoc-ref opts 'container?))
+           (link-prof? (assoc-ref opts 'link-profile?))
            (network?   (assoc-ref opts 'network?))
            (bootstrap? (assoc-ref opts 'bootstrap?))
            (system     (assoc-ref opts 'system))
@@ -577,6 +604,9 @@ message if any test fails."
 
       (when container? (assert-container-features))
 
+      (when (and (not container?) link-prof?)
+        (leave (G_ "--link-prof cannot be used without --container~%")))
+
       (with-store store
         (set-build-options-from-command-line store opts)
 
@@ -626,6 +656,7 @@ message if any test fails."
                                                   #:user-mappings mappings
                                                   #:profile profile
                                                   #:paths paths
+                                                  #:link-profile? link-prof?
                                                   #:network? network?)))
                  (else
                   (return
diff --git a/tests/guix-environment.sh b/tests/guix-environment.sh
index bf5ca17fa..e995636df 100644
--- a/tests/guix-environment.sh
+++ b/tests/guix-environment.sh
@@ -62,6 +62,18 @@ fi
 guix environment --bootstrap --ad-hoc guile-bootstrap --pure \
      -- "$SHELL" -c 'test -f "$GUIX_ENVIRONMENT/bin/guile"'
 
+# Make sure 'GUIX_ENVIRONMENT' is linked to '~/.guix-profile' when requested
+# within a container
+(
+  linktest='(exit (string=? (getenv "GUIX_ENVIRONMENT")
+(readlink (string-append (getenv "HOME") "/.guix-profile"))))'
+
+  cd "$tmpdir" \
+     && guix environment --bootstrap --container --link-profile \
+             --ad-hoc guile-bootstrap --pure \
+             -- guile -c "$linktest"
+)
+
 # Make sure '-r' works as expected.
 rm -f "$gcroot"
 expected="`guix environment --bootstrap --ad-hoc guile-bootstrap \
-- 
2.15.1


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bug#30255: [PATCH 1/3] scripts: environment: Add --link-profile.

[Ludovic Courtès]

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Hi Mike,

Mike Gerwitz <mtg@gnu.org> skribis:

> This change is motivated by attempts to run programs (like GNU IceCat) within
> containers.  The 'fontconfig' program, for example, is configured explicitly
> to check ~/.guix-profile for additional fonts.
>
> There were no existing container tests in 'tests/guix-environment.sh', but I
> added one anyway for this change.
>
> * doc/guix.texi (Invoking guix environment): Add '--link-profile'.
> * guix/scripts/environment.scm (show-help): Add '--link-profile'.
> (%options): Add 'link-profile' as '#\P', assigned to 'link-profile?'.
> (lnk-environment): New procedure.
> (launch-environment/container): Use it when 'link-profile?'.
> [link-profile?]: New parameter.
> (guix-environment): Leave when '--link-prof' but not '--container'.  Add
> '#:link-profile?' argument to 'launch-environment/container' application.
> * tests/guix-environment.sh: New '--link-profile' test.

Sorry for forgetting about this patch series.  It’s perfect, and
very useful!

I applied this one with the changes below.  The main change is moving
the test to guix-environment-container.sh, which is skipped when user
namespaces are not supported.

Thank you!

Ludo’.


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diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index d86d30308..5c7d83881 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -513,7 +513,7 @@ symbolic link from ~/.guix-profile to the environment profile."
         (symlink profile profile-dir))
       (lambda args
         (if (= EEXIST (system-error-errno args))
-            (leave (G_ "cannot link profile: path '~a' already exists within container~%")
+            (leave (G_ "cannot link profile: '~a' already exists within container~%")
                    profile-dir)
             (apply throw args))))))
 
@@ -625,7 +625,7 @@ message if any test fails."
       (when container? (assert-container-features))
 
       (when (and (not container?) link-prof?)
-        (leave (G_ "--link-prof cannot be used without --container~%")))
+        (leave (G_ "'--link-profile' cannot be used without '--container'~%")))
 
       (with-store store
         (set-build-options-from-command-line store opts)
diff --git a/tests/guix-environment-container.sh b/tests/guix-environment-container.sh
index d7c1b7057..df40ce03e 100644
--- a/tests/guix-environment-container.sh
+++ b/tests/guix-environment-container.sh
@@ -97,6 +97,20 @@ grep -e "$NIX_STORE_DIR/.*-bash" $tmpdir/mounts # bootstrap bash
 
 rm $tmpdir/mounts
 
+# Make sure 'GUIX_ENVIRONMENT' is linked to '~/.guix-profile' when requested
+# within a container.
+(
+  linktest='(exit (string=? (getenv "GUIX_ENVIRONMENT")
+(readlink (string-append (getenv "HOME") "/.guix-profile"))))'
+
+  cd "$tmpdir" \
+     && guix environment --bootstrap --container --link-profile \
+             --ad-hoc guile-bootstrap --pure \
+             -- guile -c "$linktest"
+)
+
+# Check the exit code.
+
 abnormal_exit_code="
 (use-modules (system foreign))
 ;; Purposely make Guile crash with a segfault. :)
diff --git a/tests/guix-environment.sh b/tests/guix-environment.sh
index ba686816f..b44aca099 100644
--- a/tests/guix-environment.sh
+++ b/tests/guix-environment.sh
@@ -71,18 +71,6 @@ echo "(use-modules (guix profiles) (gnu packages bootstrap))
 guix environment --bootstrap --manifest=$tmpdir/manifest.scm --pure \
      -- "$SHELL" -c 'test -f "$GUIX_ENVIRONMENT/bin/guile"'
 
-# Make sure 'GUIX_ENVIRONMENT' is linked to '~/.guix-profile' when requested
-# within a container
-(
-  linktest='(exit (string=? (getenv "GUIX_ENVIRONMENT")
-(readlink (string-append (getenv "HOME") "/.guix-profile"))))'
-
-  cd "$tmpdir" \
-     && guix environment --bootstrap --container --link-profile \
-             --ad-hoc guile-bootstrap --pure \
-             -- guile -c "$linktest"
-)
-
 # Make sure '-r' works as expected.
 rm -f "$gcroot"
 expected="`guix environment --bootstrap --ad-hoc guile-bootstrap \

[bug#30257] [PATCH 2/3] scripts: environment: Add --user.

[Mike Gerwitz]

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This change allows overriding the home directory of all filesystem mappings to
help hide the identity of the calling user in a container.

* doc/guix.texi (Invoking guix environment)[--container]: Mention --user.
[--user]: Add item.
* guix/scripts/environment.scm (show-help): Add --user.
(%options): Add --user.
(launch-environment/container) Add 'user' parameter.  Update doc.  Override
'user-mappings' using 'override-user-mappings'.  Consider override for chdir.
(mock-passwd, user-override-home, overrid-euser-dir): New procedures.
(guix-environment): Disallow --user without --container.  Provide user to
'launch-environment/container'.
* tests/guix-environment.sh: Add user test.
---
 doc/guix.texi                |  34 ++++++++++--
 guix/scripts/environment.scm | 122 ++++++++++++++++++++++++++++++++++---------
 tests/guix-environment.sh    |  10 ++++
 3 files changed, 137 insertions(+), 29 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 3b6ae1ab9..8218c6637 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -7156,10 +7156,11 @@ Attempt to build for @var{system}---e.g., @code{i686-linux}.
 @cindex container
 Run @var{command} within an isolated container.  The current working
 directory outside the container is mapped inside the container.
-Additionally, a dummy home directory is created that matches the current
-user's home directory, and @file{/etc/passwd} is configured accordingly.
-The spawned process runs as the current user outside the container, but
-has root privileges in the context of the container.
+Additionally, unless overridden with @code{--user}, a dummy home
+directory is created that matches the current user's home directory, and
+@file{/etc/passwd} is configured accordingly.  The spawned process runs
+as the current user outside the container, but has root privileges in
+the context of the container.
 
 @item --network
 @itemx -N
@@ -7183,6 +7184,31 @@ example, the @code{fontconfig} package inspects
 @code{--link-profile} allows these programs to behave as expected within
 the environment.
 
+@item --user=@var{user}
+@itemx -u @var{user}
+For containers, use the username @var{user} in place of the current
+user.  The generated @file{/etc/passwd} entry within the container will
+contain the name @var{user}; the home directory will be
+@file{/home/USER}; and no user GECOS data will be copied.  @var{user}
+need not exist on the system.
+
+Additionally, any shared or exposed path (see @code{--share} and
+@code{--expose} respectively) whose target is within the current user's
+home directory will be remapped relative to @file{/home/USER}; this
+includes the automatic mapping of the current working directory.
+
+@example
+# will expose paths as /home/foo/wd, /home/foo/test, and /home/foo/target
+cd $HOME/wd
+guix environment --container --user=foo \
+     --expose=$HOME/test \
+     --expose=/tmp/target=$HOME/target
+@end example
+
+While this will limit the leaking of user identity through home paths
+and each of the user fields, this is only one useful component of a
+broader privacy/anonymity solution---not one in and of itself.
+
 @item --expose=@var{source}[=@var{target}]
 For containers, expose the file system @var{source} from the host system
 as the read-only file system @var{target} within the container.  If
diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index 771574c15..f50018faf 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -161,6 +161,10 @@ COMMAND or an interactive shell in that environment.\n"))
   (display (G_ "
   -P, --link-profile     link environment profile to ~/.guix-profile within
                          an isolated container"))
+  (display (G_ "
+  -u, --user=USER        instead of copying the name and home of the current
+                         user into an isolated container, use the name USER
+                         with home directory /home/USER"))
   (display (G_ "
       --share=SPEC       for containers, share writable host file system
                          according to SPEC"))
@@ -243,6 +247,10 @@ COMMAND or an interactive shell in that environment.\n"))
          (option '(#\P "link-profile") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'link-profile? #t result)))
+         (option '(#\u "user") #t #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'user arg
+                               (alist-delete 'user result eq?))))
          (option '("share") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'file-system-mapping
@@ -390,43 +398,50 @@ environment variables are cleared before setting the new ones."
     (pid (match (waitpid pid)
            ((_ . status) status)))))
 
-(define* (launch-environment/container #:key command bash user-mappings
+(define* (launch-environment/container #:key command bash user user-mappings
                                        profile paths link-profile? network?)
   "Run COMMAND within a container that features the software in PROFILE.
 Environment variables are set according to PATHS, a list of native search
 paths.  The global shell is BASH, a file name for a GNU Bash binary in the
 store.  When NETWORK?, access to the host system network is permitted.
 USER-MAPPINGS, a list of file system mappings, contains the user-specified
-host file systems to mount inside the container.  LINK-PROFILE? creates a
-symbolic link from ~/.guix-profile to the environment profile."
+host file systems to mount inside the container.  If USER is not #f, each
+target of USER-MAPPINGS will be re-written relative to '/home/USER', and USER
+will be used for the passwd entry.  LINK-PROFILE? creates a symbolic link from
+~/.guix-profile to the environment profile."
   (mlet %store-monad ((reqs (inputs->requisites
                              (list (direct-store-path bash) profile))))
     (return
      (let* ((cwd      (getcwd))
-            (passwd   (getpwuid (getuid)))
+            (home     (getenv "HOME"))
+            (passwd   (mock-passwd (getpwuid (getuid))
+                                   user
+                                   bash))
             (home-dir (passwd:dir passwd))
             ;; Bind-mount all requisite store items, user-specified mappings,
             ;; /bin/sh, the current working directory, and possibly networking
             ;; configuration files within the container.
             (mappings
-             (append user-mappings
-                     ;; Current working directory.
-                     (list (file-system-mapping
-                            (source cwd)
-                            (target cwd)
-                            (writable? #t)))
-                     ;; When in Rome, do as Nix build.cc does: Automagically
-                     ;; map common network configuration files.
-                     (if network?
-                         %network-file-mappings
-                         '())
-                     ;; Mappings for the union closure of all inputs.
-                     (map (lambda (dir)
-                            (file-system-mapping
-                             (source dir)
-                             (target dir)
-                             (writable? #f)))
-                          reqs)))
+             (override-user-mappings
+              user home
+              (append user-mappings
+                      ;; Current working directory.
+                      (list (file-system-mapping
+                             (source cwd)
+                             (target cwd)
+                             (writable? #t)))
+                      ;; When in Rome, do as Nix build.cc does: Automagically
+                      ;; map common network configuration files.
+                      (if network?
+                          %network-file-mappings
+                          '())
+                      ;; Mappings for the union closure of all inputs.
+                      (map (lambda (dir)
+                             (file-system-mapping
+                              (source dir)
+                              (target dir)
+                              (writable? #f)))
+                           reqs))))
             (file-systems (append %container-file-systems
                                   (map file-system-mapping->bind-mount
                                        mappings))))
@@ -447,8 +462,7 @@ symbolic link from ~/.guix-profile to the environment profile."
                       ;; The same variables as in Nix's 'build.cc'.
                       '("TMPDIR" "TEMPDIR" "TMP" "TEMP"))
 
-            ;; Create a dummy home directory under the same name as on the
-            ;; host.
+            ;; Create a dummy home directory.
             (mkdir-p home-dir)
             (setenv "HOME" home-dir)
 
@@ -475,7 +489,7 @@ symbolic link from ~/.guix-profile to the environment profile."
 
             ;; For convenience, start in the user's current working
             ;; directory rather than the root directory.
-            (chdir cwd)
+            (chdir (override-user-dir user home cwd))
 
             (primitive-exit/status
              ;; A container's environment is already purified, so no need to
@@ -485,6 +499,60 @@ symbolic link from ~/.guix-profile to the environment profile."
                            (delq 'net %namespaces) ; share host network
                            %namespaces)))))))
 
+(define (mock-passwd passwd user-override shell)
+  "Generate mock information for '/etc/passwd'.  If USER-OVERRIDE is not '#f',
+it is expected to be a string representing the mock username; it will produce
+a user of that name, with a home directory of '/home/USER-OVERRIDE', and no
+GECOS field.  If USER-OVERRIDE is '#f', data will be inherited from PASSWD.
+In either case, the shadow password and UID/GID are cleared, since the user
+runs as root within the container.  SHELL will always be used in place of the
+shell in PASSWD.
+
+The resulting vector is suitable for use with Guile's POSIX user procedures.
+
+See passwd(5) for more information each of the fields."
+  (if user-override
+      (vector
+       user-override
+        "x" "0" "0"  ;; no shadow, user is now root
+        ""           ;; no personal information
+        (user-override-home user-override)
+        shell)
+      (vector
+       (passwd:name passwd)
+        "x" "0" "0"  ;; no shadow, user is now root
+        (passwd:gecos passwd)
+        (passwd:dir passwd)
+        shell)))
+
+(define (user-override-home user)
+  "Return home directory for override user USER."
+  (string-append "/home/" user))
+
+(define (override-user-mappings user home mappings)
+  "If a username USER is provided, rewrite each HOME prefix in file system
+mappings MAPPINGS to a home directory determined by 'override-user-dir';
+otherwise, return MAPPINGS."
+  (if (not user)
+      mappings
+      (map (lambda (mapping)
+             (let ((target (file-system-mapping-target mapping)))
+               (if (string-prefix? home target)
+                   (file-system-mapping
+                    (source    (file-system-mapping-source mapping))
+                    (target    (override-user-dir user home target))
+                    (writable? (file-system-mapping-writable? mapping)))
+                   mapping)))
+           mappings)))
+
+(define (override-user-dir user home dir)
+  "If username USER is provided, overwrite string prefix HOME in DIR with a
+directory determined by 'user-override-home'; otherwise, return DIR."
+  (if (and user (string-prefix? home dir))
+      (string-append (user-override-home user)
+                     (substring dir (string-length home)))
+      dir))
+
 (define (link-environment profile home-dir)
   "Create a symbolic link from HOME-DIR/.guix-profile to PROFILE."
   (let ((profile-dir (string-append home-dir "/.guix-profile")))
@@ -572,6 +640,7 @@ message if any test fails."
            (container? (assoc-ref opts 'container?))
            (link-prof? (assoc-ref opts 'link-profile?))
            (network?   (assoc-ref opts 'network?))
+           (user       (assoc-ref opts 'user))
            (bootstrap? (assoc-ref opts 'bootstrap?))
            (system     (assoc-ref opts 'system))
            (command    (or (assoc-ref opts 'exec)
@@ -606,6 +675,8 @@ message if any test fails."
 
       (when (and (not container?) link-prof?)
         (leave (G_ "--link-prof cannot be used without --container~%")))
+      (when (and (not container?) user)
+        (leave (G_ "--user cannot be used without --container~%")))
 
       (with-store store
         (set-build-options-from-command-line store opts)
@@ -653,6 +724,7 @@ message if any test fails."
                                             "/bin/sh"))))
                     (launch-environment/container #:command command
                                                   #:bash bash-binary
+                                                  #:user user
                                                   #:user-mappings mappings
                                                   #:profile profile
                                                   #:paths paths
diff --git a/tests/guix-environment.sh b/tests/guix-environment.sh
index e995636df..a1ce96579 100644
--- a/tests/guix-environment.sh
+++ b/tests/guix-environment.sh
@@ -74,6 +74,16 @@ guix environment --bootstrap --ad-hoc guile-bootstrap --pure \
              -- guile -c "$linktest"
 )
 
+# Test that user can be mocked.
+usertest='(exit (and (string=? (getenv "HOME") "/home/foognu")
+                     (string=? (passwd:name (getpwuid 0)) "foognu")
+                     (file-exists? "/home/foognu/umock")))'
+touch "$tmpdir/umock"
+HOME="$tmpdir" guix environment --bootstrap --container --user=foognu \
+     --ad-hoc guile-bootstrap --pure \
+     --share="$tmpdir/umock" \
+     -- guile -c "$usertest"
+
 # Make sure '-r' works as expected.
 rm -f "$gcroot"
 expected="`guix environment --bootstrap --ad-hoc guile-bootstrap \
-- 
2.15.1


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[bug#30257] [PATCH 2/3] scripts: environment: Add --user.

[Ludovic Courtès]

Mike Gerwitz <mtg@gnu.org> skribis:

> This change allows overriding the home directory of all filesystem mappings to
> help hide the identity of the calling user in a container.
>
> * doc/guix.texi (Invoking guix environment)[--container]: Mention --user.
> [--user]: Add item.
> * guix/scripts/environment.scm (show-help): Add --user.
> (%options): Add --user.
> (launch-environment/container) Add 'user' parameter.  Update doc.  Override
> 'user-mappings' using 'override-user-mappings'.  Consider override for chdir.
> (mock-passwd, user-override-home, overrid-euser-dir): New procedures.
> (guix-environment): Disallow --user without --container.  Provide user to
> 'launch-environment/container'.
> * tests/guix-environment.sh: Add user test.

Awesome, I moved the test to guix-environment-container.sh and applied.

Ludo’.

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

[-- Attachment #1: Type: text/plain, Size: 7358 bytes --]

* doc/guix.texi (Invoking guix environment): Add --no-cwd.
* guix/scripts/environment.scm (show-help, %options): Add --no-cwd.
(launch-environment/container): Add 'map-cwd?' param; only add mapping for cwd
if #t.  Only change to cwd within container if #t, otherwise home.
(guix-environment): Error if --no-cwd without --container.  Provide '(not
no-cwd?)' to launch-environment/container as 'map-cwd?'.
* tests/guix-environment.sh: Add test for no-cwd.
---
 doc/guix.texi                |  8 ++++++++
 guix/scripts/environment.scm | 33 ++++++++++++++++++++++++---------
 tests/guix-environment.sh    |  8 ++++++++
 3 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 8218c6637..ce4545038 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -7209,6 +7209,14 @@ While this will limit the leaking of user identity through home paths
 and each of the user fields, this is only one useful component of a
 broader privacy/anonymity solution---not one in and of itself.
 
+@item --no-cwd
+For containers, the default behavior is to share the current working
+directory with the isolated container and immediately change to that
+directory within the container.  If this is undesirable, @code{--no-cwd}
+will cause the current working directory to @emph{not} be automatically
+shared and will change to the user's home directory within the container
+instead.  See also @code{--user}.
+
 @item --expose=@var{source}[=@var{target}]
 For containers, expose the file system @var{source} from the host system
 as the read-only file system @var{target} within the container.  If
diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index f50018faf..6be263a64 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -165,6 +165,9 @@ COMMAND or an interactive shell in that environment.\n"))
   -u, --user=USER        instead of copying the name and home of the current
                          user into an isolated container, use the name USER
                          with home directory /home/USER"))
+  (display (G_ "
+      --no-cwd           do not share current working directory with an
+                         isolated container"))
   (display (G_ "
       --share=SPEC       for containers, share writable host file system
                          according to SPEC"))
@@ -251,6 +254,9 @@ COMMAND or an interactive shell in that environment.\n"))
                  (lambda (opt name arg result)
                    (alist-cons 'user arg
                                (alist-delete 'user result eq?))))
+         (option '("no-cwd") #f #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'no-cwd? #t result)))
          (option '("share") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'file-system-mapping
@@ -399,7 +405,8 @@ environment variables are cleared before setting the new ones."
            ((_ . status) status)))))
 
 (define* (launch-environment/container #:key command bash user user-mappings
-                                       profile paths link-profile? network?)
+                                       profile paths link-profile? network?
+                                       map-cwd?)
   "Run COMMAND within a container that features the software in PROFILE.
 Environment variables are set according to PATHS, a list of native search
 paths.  The global shell is BASH, a file name for a GNU Bash binary in the
@@ -425,11 +432,13 @@ will be used for the passwd entry.  LINK-PROFILE? creates a symbolic link from
              (override-user-mappings
               user home
               (append user-mappings
-                      ;; Current working directory.
-                      (list (file-system-mapping
-                             (source cwd)
-                             (target cwd)
-                             (writable? #t)))
+                      ;; Share current working directory, unless asked not to.
+                      (if map-cwd?
+                          (list (file-system-mapping
+                                 (source cwd)
+                                 (target cwd)
+                                 (writable? #t)))
+                          '())
                       ;; When in Rome, do as Nix build.cc does: Automagically
                       ;; map common network configuration files.
                       (if network?
@@ -488,8 +497,10 @@ will be used for the passwd entry.  LINK-PROFILE? creates a symbolic link from
                 (newline port)))
 
             ;; For convenience, start in the user's current working
-            ;; directory rather than the root directory.
-            (chdir (override-user-dir user home cwd))
+            ;; directory or, if unmapped, the home directory.
+            (chdir (if map-cwd?
+                       (override-user-dir user home cwd)
+                       home-dir))
 
             (primitive-exit/status
              ;; A container's environment is already purified, so no need to
@@ -640,6 +651,7 @@ message if any test fails."
            (container? (assoc-ref opts 'container?))
            (link-prof? (assoc-ref opts 'link-profile?))
            (network?   (assoc-ref opts 'network?))
+           (no-cwd?    (assoc-ref opts 'no-cwd?))
            (user       (assoc-ref opts 'user))
            (bootstrap? (assoc-ref opts 'bootstrap?))
            (system     (assoc-ref opts 'system))
@@ -677,6 +689,8 @@ message if any test fails."
         (leave (G_ "--link-prof cannot be used without --container~%")))
       (when (and (not container?) user)
         (leave (G_ "--user cannot be used without --container~%")))
+      (when (and (not container?) no-cwd?)
+        (leave (G_ "--no-cwd cannot be used without --container~%")))
 
       (with-store store
         (set-build-options-from-command-line store opts)
@@ -729,7 +743,8 @@ message if any test fails."
                                                   #:profile profile
                                                   #:paths paths
                                                   #:link-profile? link-prof?
-                                                  #:network? network?)))
+                                                  #:network? network?
+                                                  #:map-cwd? (not no-cwd?))))
                  (else
                   (return
                    (exit/status
diff --git a/tests/guix-environment.sh b/tests/guix-environment.sh
index a1ce96579..abb019794 100644
--- a/tests/guix-environment.sh
+++ b/tests/guix-environment.sh
@@ -84,6 +84,14 @@ HOME="$tmpdir" guix environment --bootstrap --container --user=foognu \
      --share="$tmpdir/umock" \
      -- guile -c "$usertest"
 
+# if not sharing CWD, chdir home
+(
+  cd "$tmpdir" \
+    && guix environment --bootstrap --container --no-cwd --user=foo  \
+            --ad-hoc guile-bootstrap --pure \
+            -- /bin/sh -c 'test $(pwd) == "/home/foo" -a ! -d '"$tmpdir"
+)
+
 # Make sure '-r' works as expected.
 rm -f "$gcroot"
 expected="`guix environment --bootstrap --ad-hoc guile-bootstrap \
-- 
2.15.1


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[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

Mike Gerwitz <mtg@gnu.org> skribis:

> * doc/guix.texi (Invoking guix environment): Add --no-cwd.
> * guix/scripts/environment.scm (show-help, %options): Add --no-cwd.
> (launch-environment/container): Add 'map-cwd?' param; only add mapping for cwd
> if #t.  Only change to cwd within container if #t, otherwise home.
> (guix-environment): Error if --no-cwd without --container.  Provide '(not
> no-cwd?)' to launch-environment/container as 'map-cwd?'.
> * tests/guix-environment.sh: Add test for no-cwd.

This one LGTM as well (with the test moved to
guix-environment-container.sh).  There’s just a minor issue:

> --- a/tests/guix-environment.sh
> +++ b/tests/guix-environment.sh
> @@ -84,6 +84,14 @@ HOME="$tmpdir" guix environment --bootstrap --container --user=foognu \
>       --share="$tmpdir/umock" \
>       -- guile -c "$usertest"
>  
> +# if not sharing CWD, chdir home
> +(
> +  cd "$tmpdir" \
> +    && guix environment --bootstrap --container --no-cwd --user=foo  \
> +            --ad-hoc guile-bootstrap --pure \
> +            -- /bin/sh -c 'test $(pwd) == "/home/foo" -a ! -d '"$tmpdir"
> +)
> +

This test would fail for me because my test store is at
~ludo/src/guix/test-tmp/store and my CWD is ~/src/guix.  So when using
both --user and --no-cwd, the effect is that
~ludo/src/guix/test-tmp/store is not available at all within the
container, and thus execve("/bin/sh") fails with ENOENT:

--8<---------------cut here---------------start------------->8---
$ ./test-env guix environment --bootstrap --container --no-cwd --user=foo --ad-hoc guile-bootstrap
accepted connection from pid 29684, user ludo
accepted connection from pid 29695, user ludo
./test-env: line 1: 29683 Terminated              "/home/ludo/src/guix/pre-inst-env" "/home/ludo/src/guix/guix-daemon" --disable-chroot --substitute-urls="$GUIX_BINARY_SUBSTITUTE_URL"
$ echo $?
1
--8<---------------cut here---------------end--------------->8---

Thoughts?

TIA,
Ludo’.

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

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Hey, Ludo!

Sorry I've been silent on the script you provided to me---between my GNU
volunteer work and preparing for my LP2018 talk, I've had no free time,
so I haven't even looked at it yet.  After the conference I'll have the
time to collaborate a bit more.

Also---I thought the decision was that this patchset was inappropriate
for `guix environment`; did I misinterpret?

On Fri, Mar 02, 2018 at 11:54:30 +0100, Ludovic Courtès wrote:
>> --- a/tests/guix-environment.sh
>> +++ b/tests/guix-environment.sh
>> @@ -84,6 +84,14 @@ HOME="$tmpdir" guix environment --bootstrap --container --user=foognu \
>>       --share="$tmpdir/umock" \
>>       -- guile -c "$usertest"
>>  
>> +# if not sharing CWD, chdir home
>> +(
>> +  cd "$tmpdir" \
>> +    && guix environment --bootstrap --container --no-cwd --user=foo  \
>> +            --ad-hoc guile-bootstrap --pure \
>> +            -- /bin/sh -c 'test $(pwd) == "/home/foo" -a ! -d '"$tmpdir"
>> +)
>> +
>
> This test would fail for me because my test store is at
> ~ludo/src/guix/test-tmp/store and my CWD is ~/src/guix.  So when using
> both --user and --no-cwd, the effect is that
> ~ludo/src/guix/test-tmp/store is not available at all within the
> container, and thus execve("/bin/sh") fails with ENOENT:
>
> $ ./test-env guix environment --bootstrap --container --no-cwd --user=foo --ad-hoc guile-bootstrap
> accepted connection from pid 29684, user ludo
> accepted connection from pid 29695, user ludo
> ./test-env: line 1: 29683 Terminated              "/home/ludo/src/guix/pre-inst-env" "/home/ludo/src/guix/guix-daemon" --disable-chroot --substitute-urls="$GUIX_BINARY_SUBSTITUTE_URL"
> $ echo $?
> 1
>
> Thoughts?

I admit that I forgot some of the implementation details of my own
patch; I'd have to look at it in more detail.  I'll consider it tonight
or this weekend.

Thanks for taking a look at and applying these.  If there are better
solutions, I'm fine with that---I just wanted a proof-of-concept to
start the discussion.  Though, starting the discussion and then ducking
out for other obligations wasn't quite what I had in mind...

-- 
Mike Gerwitz
Free Software Hacker+Activist | GNU Maintainer & Volunteer
GPG: D6E9 B930 028A 6C38 F43B  2388 FEF6 3574 5E6F 6D05
https://mikegerwitz.com

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[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

Hi Mike,

Mike Gerwitz <mtg@gnu.org> skribis:

> Sorry I've been silent on the script you provided to me---between my GNU
> volunteer work and preparing for my LP2018 talk, I've had no free time,
> so I haven't even looked at it yet.  After the conference I'll have the
> time to collaborate a bit more.

Sure, understood!

> Also---I thought the decision was that this patchset was inappropriate
> for `guix environment`; did I misinterpret?

My initial reaction was that we shouldn’t stretch ‘guix environment’ to
do something that’s unrelated to environment management.

However as I looked at your patches, I found that the additions you made
are useful per se (for instance I’ve been wanting ‘--link-profile’ on a
couple of occasions for reasons like the one you gave, Fontconfig,
etc.).  And the patches had tests, documentation, and everything, so it
seemed more beneficial to include them.  :-)

> I admit that I forgot some of the implementation details of my own
> patch; I'd have to look at it in more detail.  I'll consider it tonight
> or this weekend.

OK!

> Thanks for taking a look at and applying these.  If there are better
> solutions, I'm fine with that---I just wanted a proof-of-concept to
> start the discussion.  Though, starting the discussion and then ducking
> out for other obligations wasn't quite what I had in mind...

Sure.  I think the issue of least-authority execution of programs
remains open anway.  Do we want a ‘guix run’-like command?  Something in
the shell, but which shell(s) then?  Automatically-generated wrappers so
we don’t depend on specific shells?

Thanks,
Ludo’.

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

[-- Attachment #1: Type: text/plain, Size: 2258 bytes --]

On Sat, Mar 03, 2018 at 15:44:43 +0100, Ludovic Courtès wrote:
>> Also---I thought the decision was that this patchset was inappropriate
>> for `guix environment`; did I misinterpret?
>
> My initial reaction was that we shouldn’t stretch ‘guix environment’ to
> do something that’s unrelated to environment management.
>
> However as I looked at your patches, I found that the additions you made
> are useful per se (for instance I’ve been wanting ‘--link-profile’ on a
> couple of occasions for reasons like the one you gave, Fontconfig,
> etc.).  And the patches had tests, documentation, and everything, so it
> seemed more beneficial to include them.  :-)

Okay, sounds good.

>> Thanks for taking a look at and applying these.  If there are better
>> solutions, I'm fine with that---I just wanted a proof-of-concept to
>> start the discussion.  Though, starting the discussion and then ducking
>> out for other obligations wasn't quite what I had in mind...
>
> Sure.  I think the issue of least-authority execution of programs
> remains open anway.  Do we want a ‘guix run’-like command?  Something in
> the shell, but which shell(s) then?  Automatically-generated wrappers so
> we don’t depend on specific shells?

One thing in particular about using `guix environment --ad-hoc' that is
particularly unfortunate with how I'm abusing it is that it will build
new derivations as necessary (as it is supposed to).  So "starting
icecat" in a container isn't just that.  I recently upgraded Guix, and
icecat isn't available on Hydra yet, so I'm unable to start icecat at
all until it compiles, which is hours on an X200 (though I'm assuming
that reverting ~/.config/guix/latest might allow me to work around it
temporarily with an old version).  This would not have been a problem
with a normal icecat installation in my profile.

Obviously the desirable behavior is to just containerize whatever is in
your profile, if possible.  Maybe the script you sent me does just
that.  I'm excited to play around with it, I just can't atm. :(

-- 
Mike Gerwitz
Free Software Hacker+Activist | GNU Maintainer & Volunteer
GPG: D6E9 B930 028A 6C38 F43B  2388 FEF6 3574 5E6F 6D05
https://mikegerwitz.com

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[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

Heya,

Mike Gerwitz <mtg@gnu.org> skribis:

> On Sat, Mar 03, 2018 at 15:44:43 +0100, Ludovic Courtès wrote:

[...]

>> Sure.  I think the issue of least-authority execution of programs
>> remains open anway.  Do we want a ‘guix run’-like command?  Something in
>> the shell, but which shell(s) then?  Automatically-generated wrappers so
>> we don’t depend on specific shells?
>
> One thing in particular about using `guix environment --ad-hoc' that is
> particularly unfortunate with how I'm abusing it is that it will build
> new derivations as necessary (as it is supposed to).  So "starting
> icecat" in a container isn't just that.  I recently upgraded Guix, and
> icecat isn't available on Hydra yet, so I'm unable to start icecat at
> all until it compiles, which is hours on an X200 (though I'm assuming
> that reverting ~/.config/guix/latest might allow me to work around it
> temporarily with an old version).  This would not have been a problem
> with a normal icecat installation in my profile.

Right.  The ‘guix run’ script I sent doesn’t try to build things; it
just takes whatever is in $PATH (which has to be in the store,
ultimately) and runs it.

> Obviously the desirable behavior is to just containerize whatever is in
> your profile, if possible.  Maybe the script you sent me does just
> that.  I'm excited to play around with it, I just can't atm. :(

You still have to explicitly run ‘guix run icecat’, which isn’t great:
if you’re using GNOME Shell and clicking on the icon, you don’t get to
run it in a containerized environment.

Ludo’.

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

[-- Attachment #1: Type: text/plain, Size: 2417 bytes --]

On Sun, Mar 04, 2018 at 23:24:27 +0100, Ludovic Courtès wrote:
> Right.  The ‘guix run’ script I sent doesn’t try to build things; it
> just takes whatever is in $PATH (which has to be in the store,
> ultimately) and runs it.

Oh, great!

>> Obviously the desirable behavior is to just containerize whatever is in
>> your profile, if possible.  Maybe the script you sent me does just
>> that.  I'm excited to play around with it, I just can't atm. :(
>
> You still have to explicitly run ‘guix run icecat’, which isn’t great:
> if you’re using GNOME Shell and clicking on the icon, you don’t get to
> run it in a containerized environment.

Well, I do everything from a shell, so that works for me personally. :)
But yes, what you are describing is important.

But, from a security perspective, I'd like for containerization to be
_guaranteed_, otherwise a malicious script could just subvert it
(e.g. open icecat with an argument to a malicious HTML file).  I used
`guix environment` not only because of its container support, but
because that ensured that icecat wasn't in my profile at all to be
invoked by something else.

Currently, I'd have to write a package definition to add a wrapper; that
wouldn't be done automatically for me.  But considering a functional
package manager, it'd be an interesting problem to try to get around
that.  And you don't want containerized versions of _every_
package---that's some serious bloat.  Unless maybe they're packages that
are generated from existing package definitions (in some
yet-to-be-defined manner), and maybe those packages have a special
containerized output (in addition to `out',
e.g. `icecat:container').  (I suppose short-term, such outputs can be
created manually for select packages.)

Just spewing thoughts.  I'm still not well-versed in Guix.  So maybe
`guix run` is a good starting point and can be used by a wrapper in the
future.  It also allows users to containerize something optionally---for
example, maybe a user doesn't want to containerize their PDF reader, but
if they are opening an untrusted PDF, they'll want to.  A GNOME context
menu option to say "Open in isolated container" (sorta like Qubes)
sounds attractive.

-- 
Mike Gerwitz
Free Software Hacker+Activist | GNU Maintainer & Volunteer
GPG: D6E9 B930 028A 6C38 F43B  2388 FEF6 3574 5E6F 6D05
https://mikegerwitz.com

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[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

Hello,

Mike Gerwitz <mtg@gnu.org> skribis:

> On Sun, Mar 04, 2018 at 23:24:27 +0100, Ludovic Courtès wrote:

[...]

>> You still have to explicitly run ‘guix run icecat’, which isn’t great:
>> if you’re using GNOME Shell and clicking on the icon, you don’t get to
>> run it in a containerized environment.
>
> Well, I do everything from a shell, so that works for me personally. :)
> But yes, what you are describing is important.
>
> But, from a security perspective, I'd like for containerization to be
> _guaranteed_, otherwise a malicious script could just subvert it
> (e.g. open icecat with an argument to a malicious HTML file).  I used
> `guix environment` not only because of its container support, but
> because that ensured that icecat wasn't in my profile at all to be
> invoked by something else.

Good point.

> Currently, I'd have to write a package definition to add a wrapper; that
> wouldn't be done automatically for me.  But considering a functional
> package manager, it'd be an interesting problem to try to get around
> that.  And you don't want containerized versions of _every_
> package---that's some serious bloat.  Unless maybe they're packages that
> are generated from existing package definitions (in some
> yet-to-be-defined manner), and maybe those packages have a special
> containerized output (in addition to `out',
> e.g. `icecat:container').  (I suppose short-term, such outputs can be
> created manually for select packages.)

I was thinking ‘guix package’ could create those wrappers automatically
based on a number of criteria: a package property could request
containerization, command-line options could disable that, and so on.

> Just spewing thoughts.  I'm still not well-versed in Guix.  So maybe
> `guix run` is a good starting point and can be used by a wrapper in the
> future.  It also allows users to containerize something optionally---for
> example, maybe a user doesn't want to containerize their PDF reader, but
> if they are opening an untrusted PDF, they'll want to.  A GNOME context
> menu option to say "Open in isolated container" (sorta like Qubes)
> sounds attractive.

Yeah, though I very much think least authority would be a better default
than ambient authority.  :-)

Ludo’.

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

[-- Attachment #1: Type: text/plain, Size: 2525 bytes --]

On Tue, Mar 06, 2018 at 11:20:23 +0100, Ludovic Courtès wrote:
> Mike Gerwitz <mtg@gnu.org> skribis:
>> Currently, I'd have to write a package definition to add a wrapper; that
>> wouldn't be done automatically for me.  But considering a functional
>> package manager, it'd be an interesting problem to try to get around
>> that.  And you don't want containerized versions of _every_
>> package---that's some serious bloat.  Unless maybe they're packages that
>> are generated from existing package definitions (in some
>> yet-to-be-defined manner), and maybe those packages have a special
>> containerized output (in addition to `out',
>> e.g. `icecat:container').  (I suppose short-term, such outputs can be
>> created manually for select packages.)
>
> I was thinking ‘guix package’ could create those wrappers automatically
> based on a number of criteria: a package property could request
> containerization, command-line options could disable that, and so on.

Yes, I'd much prefer that.  That package definition might not be able to
infer certain things, so we'd need to be able to specify e.g. paths to
include in the container.  Preferably overridable as well---for example,
I don't share ~/.cache/mozilla/icecat with the container (I want it to
be ephemeral), but other users may prefer to.

>> Just spewing thoughts.  I'm still not well-versed in Guix.  So maybe
>> `guix run` is a good starting point and can be used by a wrapper in the
>> future.  It also allows users to containerize something optionally---for
>> example, maybe a user doesn't want to containerize their PDF reader, but
>> if they are opening an untrusted PDF, they'll want to.  A GNOME context
>> menu option to say "Open in isolated container" (sorta like Qubes)
>> sounds attractive.
>
> Yeah, though I very much think least authority would be a better default
> than ambient authority.  :-)

I agree for my needs; I suppose we'd need to see what downsides exist
from containerization (if any) that might make the user think
otherwise.  If containerization by default is suitable, then there may
be no need to provide a non-container option, so long as the user can
choose paths to share with the container (and network access).  This is
sounding more like an AppArmor type of permission system.  (Without the
AppArmor, of course.)

-- 
Mike Gerwitz
Free Software Hacker+Activist | GNU Maintainer & Volunteer
GPG: D6E9 B930 028A 6C38 F43B  2388 FEF6 3574 5E6F 6D05
https://mikegerwitz.com

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[bug#30254] [bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

Hello Mike,

There’s this last patch from the series you submitted a while back
that’s ready modulo an issue with the test.  Could you take a look?

TIA,
Ludo’.

ludo@gnu.org (Ludovic Courtès) skribis:

> Mike Gerwitz <mtg@gnu.org> skribis:
>
>> * doc/guix.texi (Invoking guix environment): Add --no-cwd.
>> * guix/scripts/environment.scm (show-help, %options): Add --no-cwd.
>> (launch-environment/container): Add 'map-cwd?' param; only add mapping for cwd
>> if #t.  Only change to cwd within container if #t, otherwise home.
>> (guix-environment): Error if --no-cwd without --container.  Provide '(not
>> no-cwd?)' to launch-environment/container as 'map-cwd?'.
>> * tests/guix-environment.sh: Add test for no-cwd.
>
> This one LGTM as well (with the test moved to
> guix-environment-container.sh).  There’s just a minor issue:
>
>> --- a/tests/guix-environment.sh
>> +++ b/tests/guix-environment.sh
>> @@ -84,6 +84,14 @@ HOME="$tmpdir" guix environment --bootstrap --container --user=foognu \
>>       --share="$tmpdir/umock" \
>>       -- guile -c "$usertest"
>>  
>> +# if not sharing CWD, chdir home
>> +(
>> +  cd "$tmpdir" \
>> +    && guix environment --bootstrap --container --no-cwd --user=foo  \
>> +            --ad-hoc guile-bootstrap --pure \
>> +            -- /bin/sh -c 'test $(pwd) == "/home/foo" -a ! -d '"$tmpdir"
>> +)
>> +
>
> This test would fail for me because my test store is at
> ~ludo/src/guix/test-tmp/store and my CWD is ~/src/guix.  So when using
> both --user and --no-cwd, the effect is that
> ~ludo/src/guix/test-tmp/store is not available at all within the
> container, and thus execve("/bin/sh") fails with ENOENT:
>
> $ ./test-env guix environment --bootstrap --container --no-cwd --user=foo --ad-hoc guile-bootstrap
> accepted connection from pid 29684, user ludo
> accepted connection from pid 29695, user ludo
> ./test-env: line 1: 29683 Terminated              "/home/ludo/src/guix/pre-inst-env" "/home/ludo/src/guix/guix-daemon" --disable-chroot --substitute-urls="$GUIX_BINARY_SUBSTITUTE_URL"
> $ echo $?
> 1
>
> Thoughts?
>
> TIA,
> Ludo’.

[bug#30254] [bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

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Ludo:

On Wed, Oct 17, 2018 at 15:19:33 +0200, Ludovic Courtès wrote:
> There’s this last patch from the series you submitted a while back
> that’s ready modulo an issue with the test.  Could you take a look?

I'm not ignoring this; I'll have time to look over the next couple of
weeks.  I'll need to research the issue.

-- 
Mike Gerwitz

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[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Carl Dong]

Hi Mike and Ludo!

I believe I've found a solution to the problem that Ludo was encountering. The
reason why Ludo was having trouble was because when a user specifies `--user`,
we rewrite the targets of our filesystem mappings so that every instance of
`$HOME` (as seen ouside the container) becomes `/home/$USER`. Since this applied
to all filesystem mappings, it included our filesystem mappings for inputs too.
However, our symlinks were not updated.

My change makes it so that we _only_ update the mappings that are either
user-specified, or cwd (if applicable). This solves Ludo's problems.

Here's the patch, let me know if it looks good:
https://github.com/dongcarl/guix/compare/8e92d5465fc154fed5d06f7e4a64d7dcccded74d...2019-06-env-no-cwd-fix.patch

Cheers,
Carl Dong

[bug#30254] [bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

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Hi Carl,

Carl Dong <contact@carldong.me> skribis:

> I believe I've found a solution to the problem that Ludo was encountering. The
> reason why Ludo was having trouble was because when a user specifies `--user`,
> we rewrite the targets of our filesystem mappings so that every instance of
> `$HOME` (as seen ouside the container) becomes `/home/$USER`. Since this applied
> to all filesystem mappings, it included our filesystem mappings for inputs too.
> However, our symlinks were not updated.
>
> My change makes it so that we _only_ update the mappings that are either
> user-specified, or cwd (if applicable). This solves Ludo's problems.
>
> Here's the patch, let me know if it looks good:
> https://github.com/dongcarl/guix/compare/8e92d5465fc154fed5d06f7e4a64d7dcccded74d...2019-06-env-no-cwd-fix.patch

Good catch!  The patches LGTM.  (Note: you can use the ‘Co-authored-by’
tag for the second patch, I think it’s a more or less common
convention.)

Speaking of which, could you create an account on Savannah?  That way we
could grant you commit access to make it more convenient for you and so
you can review and apply other people’s patches in your areas of expertise.

Please let me know what your account is, and reply with a message signed
by the key you’ll use to sign commits.  Also please read the ‘HACKING’
file for info on the commit “rules”.

Thanks!

Ludo’.

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[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Carl Dong]

Hi Ludo!

> Good catch! The patches LGTM. (Note: you can use the ‘Co-authored-by’ tag for
> the second patch, I think it’s a more or less common convention.)

Done! Updated at the same link as last time:
https://github.com/dongcarl/guix/compare/8e92d5465fc154fed5d06f7e4a64d7dcccded74d...2019-06-env-no-cwd-fix.patch


> Speaking of which, could you create an account on Savannah? That way we could
> grant you commit access to make it more convenient for you and so you can
> review and apply other people’s patches in your areas of expertise.

That's super exciting! :-)

> Please let me know what your account is, and reply with a message signed by
> the key you’ll use to sign commits.

Here you go!

My fingerprint:

0401 7A2A 6D9A 0CCD C81D  8EC2 96AB 007F 1A7E D999

My signed account info:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

My Savannah account as of (Sun 07 Jul 2019 02:06:45 PM UTC) is carl.
-----BEGIN PGP SIGNATURE-----

iQIzBAEBCAAdFiEECc3SW1JEo3Z49u6oDMUhUxl5kaUFAl0h/I8ACgkQDMUhUxl5
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> Also please read the ‘HACKING’ file for info on the commit “rules”.

Done!

Cheers,
Carl Dong
contact@carldong.me
"I fight for the users"

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Ludovic Courtès]

Hello!

Carl Dong <contact@carldong.me> skribis:

>> Good catch! The patches LGTM. (Note: you can use the ‘Co-authored-by’ tag for
>> the second patch, I think it’s a more or less common convention.)
>
> Done! Updated at the same link as last time:
> https://github.com/dongcarl/guix/compare/8e92d5465fc154fed5d06f7e4a64d7dcccded74d...2019-06-env-no-cwd-fix.patch

Alright!

>> Speaking of which, could you create an account on Savannah? That way we could
>> grant you commit access to make it more convenient for you and so you can
>> review and apply other people’s patches in your areas of expertise.
>
> That's super exciting! :-)
>
>> Please let me know what your account is, and reply with a message signed by
>> the key you’ll use to sign commits.
>
> Here you go!
>
> My fingerprint:
>
> 0401 7A2A 6D9A 0CCD C81D  8EC2 96AB 007F 1A7E D999
>
> My signed account info:
>
> My Savannah account as of (Sun 07 Jul 2019 02:06:45 PM UTC) is carl.

Cool, I’ve added you to the Savannah group.  You can now push these two
patches to test it.

Thank you and welcome on board!  :-)

Ludo’.

[bug#30256] bug#30254: [PATCH 0/3] guix environment --user, --link-profile, --no-cwd

[Maxim Cournoyer]

Hello,

Ludovic Courtès <ludo@gnu.org> writes:

> Hello!
>
> Carl Dong <contact@carldong.me> skribis:
>
>>> Good catch! The patches LGTM. (Note: you can use the ‘Co-authored-by’ tag for
>>> the second patch, I think it’s a more or less common convention.)
>>
>> Done! Updated at the same link as last time:
>> https://github.com/dongcarl/guix/compare/8e92d5465fc154fed5d06f7e4a64d7dcccded74d...2019-06-env-no-cwd-fix.patch
>
> Alright!
>
>>> Speaking of which, could you create an account on Savannah? That way we could
>>> grant you commit access to make it more convenient for you and so you can
>>> review and apply other people’s patches in your areas of expertise.

[...]

> Cool, I’ve added you to the Savannah group.  You can now push these two
> patches to test it.

Seems the patches have indeed been pushed :-).

Closing.

Maxim

[bug#30256] [PATCH 3/3] scripts: environment: Add --no-cwd.

[Mike Gerwitz]

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On Sat, Jun 29, 2019 at 23:27:43 +0000, Carl Dong wrote:
> Hi Mike and Ludo!
>
> I believe I've found a solution to the problem that Ludo was encountering.

Thank you for picking this up, and sorry again that I wasn't able to
find the time.  I'm glad this patch is useful to someone else, and I'm
looking forward to seeing it applied.

-- 
Mike Gerwitz

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