diff mbox series

[bug#75810,v3,03/11] daemon: Remount inputs as read-only.

Message ID e62cb42e65d821ec41f8394a49c28da693d78d77.1740142328.git.ludo@gnu.org
State New
Headers
Series Rootless guix-daemon |

Commit Message

Ludovic Courtès Feb. 21, 2025, 1:05 p.m. UTC 
  * nix/libstore/build.cc (DerivationGoal::runChild): Remount ‘target’ as
read-only.

Reported-by: Reepca Russelstein <reepca@russelstein.xyz>
Change-Id: Ib7201bcf4363be566f205d23d17fe2f55d3ad666
---
 nix/libstore/build.cc | 7 +++++++
 1 file changed, 7 insertions(+)
diff mbox series

Patch

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index f4cd2131c84..6244c99e751 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -2094,8 +2094,15 @@  void DerivationGoal::runChild()
                     createDirs(dirOf(target));
                     writeFile(target, "");
                 }
+
+		/* Extra flags passed with MS_BIND are ignored, hence the
+		   extra MS_REMOUNT.  */
                 if (mount(source.c_str(), target.c_str(), "", MS_BIND, 0) == -1)
                     throw SysError(format("bind mount from `%1%' to `%2%' failed") % source % target);
+		if (source.compare(0, settings.nixStore.length(), settings.nixStore) == 0) {
+		     if (mount(source.c_str(), target.c_str(), "", MS_BIND | MS_REMOUNT | MS_RDONLY, 0) == -1)
+			  throw SysError(format("read-only remount of `%1%' failed") % target);
+		}
             }
 
             /* Bind a new instance of procfs on /proc to reflect our