From a552ed625bdd1cb7336606e8cbf7bd6ebc6442e2 Mon Sep 17 00:00:00 2001
From: Colin <colin@uninsane.org>
Date: Fri, 16 Aug 2024 02:15:46 +0000
Subject: [PATCH] make-sandboxed: fix several edge-cases for e.g. brave,
 firefox, especially around handling of wrapped binaries

---
 modules/programs/make-sandboxed.nix | 56 ++++++++++-------------------
 1 file changed, 19 insertions(+), 37 deletions(-)

diff --git a/modules/programs/make-sandboxed.nix b/modules/programs/make-sandboxed.nix
index 891e0386f..157fa8b5b 100644
--- a/modules/programs/make-sandboxed.nix
+++ b/modules/programs/make-sandboxed.nix
@@ -156,7 +156,9 @@ let
         for item in "''${items[@]}"; do
           if [ "$item" != . ] && [ "$item" != .. ]; then
             local target="$_dir/$item"
-            if [ -x "$target" ] && ! [ -d "$target" ]; then
+            if [ -d "$target" ]; then
+              crawlAndWrap "$output" "$target"
+            elif [ -x "$target" ] && [[ "$item" != .* ]]; then
               # in the case of symlinks, deref until we find the real file, or the symlink points outside the package
               target=$(derefWhileInSameOutput "$output" "$target")
               target=$(findUnwrapped "$target")
@@ -165,10 +167,8 @@ let
                 local bin=$(basename "$target")
                 sandboxWrap "$parent" "$bin"
               fi
-            elif [ -d "$target" ]; then
-              crawlAndWrap "$output" "$target"
             fi
-            # ignore all non-binaries
+            # ignore all non-binaries or "hidden" binaries (to avoid double-wrapping)
           fi
         done
       }
@@ -196,15 +196,14 @@ let
   ;
 
   # helper used for `wrapperType == "wrappedDerivation"` which simply symlinks all a package's binaries into a new derivation
-  symlinkBinaries = pkgName: package: (runCommandLocal "${pkgName}-bin-only" {
+  symlinkDirs = suffix: symlinkRoots: pkgName: package: (runCommandLocal "${pkgName}-${suffix}" {
+    env.symlinkRoots = lib.concatStringsSep " " symlinkRoots;
     nativeBuildInputs = [ gnused ];
   } ''
     set -e
     symlinkPath() {
       if [ -e "$out/$1" ]; then
         :  # already linked. may happen when e.g. the package has bin/foo, and sbin -> bin.
-      elif ! [ -x "${package}/$1" ]; then
-        :  # not a binary, nor a directory (-x) which could contain binaries
       elif [ -L "${package}/$1" ]; then
         local target=$(readlink "${package}/$1")
         if [[ "$target" =~ ^${package}/ ]]; then
@@ -235,7 +234,7 @@ let
         mkdir -p "$out/$1"
         items=($(ls -a "${package}/$1"))
         for item in "''${items[@]}"; do
-          if [ "$item" != . ] && [ "$item" != .. ]; then
+          if [ "$item" != . ] && [ "$item" != .. ] && [[ "$item" != .* ]]; then
             symlinkPath "$1/$item"
           fi
         done
@@ -244,16 +243,22 @@ let
         ln -s "${package}/$1" "$out/$1"
       fi
     }
-    symlinkPath bin
-    symlinkPath sbin
-    symlinkPath libexec
-    # allow downstream wrapping to hook this (and thereby actually wrap the binaries)
+    mkdir -p "$out"
+    _symlinkRoots=($symlinkRoots)
+    for root in "''${_symlinkRoots[@]}"; do
+      echo "crawling top-level directory for symlinking: $root"
+      symlinkPath "$root"
+    done
+    # allow downstream wrapping to hook this (and thereby actually wrap binaries, etc)
+    runHook postInstall
     runHook postFixup
   '').overrideAttrs (_: {
     # specifically, preserve meta.priority
     meta = extractMeta package;
   });
 
+  symlinkBinaries = symlinkDirs "bin-only" [ "bin" "sbin" "libexec" ];
+
   # helper used for `wrapperType == "wrappedDerivation"` which ensures that any copied/symlinked share/ files (like .desktop) files
   # don't point to the unwrapped binaries.
   # other important files it preserves:
@@ -281,12 +286,9 @@ let
       }
 
       # remove any files which exist in sandoxedBin (makes it possible to sandbox /opt-style packages)
-      # also remove any files which would be "hidden". mostly useful for /opt-style packages which contain nix-wrapped binaries.
       removeUnwanted() {
         local file_=$(basename "$1")
-        if [[ "$file_" == .* ]]; then
-          rm -r "$out/$1"
-        elif [ -f "$out/$1" ] || [ -L "$out/$1" ]; then
+        if [ -f "$out/$1" ] || [ -L "$out/$1" ]; then
           if [ -e "${sandboxedBin}/$1" ]; then
             rm "$out/$1"
           fi
@@ -320,8 +322,6 @@ let
     passthru = (prevAttrs.passthru or {}) // {
       # check that sandboxedNonBin references only sandboxed binaries, and never the original unsandboxed binaries.
       # do this by dereferencing all sandboxedNonBin symlinks, and making `unsandboxed` a disallowedReference.
-      # further, since the sandboxed binaries intentionally reference the unsandboxed binaries,
-      # we have to patch those out as a way to whitelist them.
       checkSandboxed = let
         sandboxedNonBin = fixHardcodedRefs unsandboxed sandboxedBin unsandboxedNonBin;
       in runCommandLocal "${sandboxedNonBin.name}-check-sandboxed"
@@ -342,25 +342,7 @@ let
   # patch them to use the sandboxed binaries,
   # and add some passthru metadata to enforce no lingering references to the unsandboxed binaries.
   sandboxNonBinaries = pkgName: unsandboxed: sandboxedBin: let
-    sandboxedWithoutFixedRefs = (runCommandLocal "${pkgName}-sandboxed-non-binary" {
-      nativeBuildInputs = [ xorg.lndir ];
-    } ''
-      set -e
-      mkdir "$out"
-      # link in a limited subset of the directories.
-      # lib/ is the primary one to avoid, because of shared objects that would be unsandboxed if dlopen'd.
-      # all other directories are safe-ish, because they won't end up on PATH or LDPATH.
-      for dir in etc share; do
-        if [ -e "${unsandboxed}/$dir" ]; then
-          mkdir "$out/$dir"
-          lndir "${unsandboxed}/$dir" "$out/$dir"
-        fi
-      done
-      runHook postInstall
-    '').overrideAttrs (_: {
-      # specifically for meta.priority, though it shouldn't actually matter here.
-      meta = extractMeta unsandboxed;
-    });
+    sandboxedWithoutFixedRefs = symlinkDirs "non-bin" [ "etc" "share" ] pkgName unsandboxed;
   in fixHardcodedRefs unsandboxed sandboxedBin sandboxedWithoutFixedRefs;
 
   # take the nearly-final sandboxed package, with binaries and all else, and