From c091a57ece33a8fd36161c319f2fa78546467b7f Mon Sep 17 00:00:00 2001
From: Helmut Grohne <helmut@subdivi.de>
Date: Fri, 1 Mar 2024 18:49:24 +0100
Subject: fix read-only bind_mount
As we learn from util-linux, MS_RDONLY is ignored on MS_BIND. Rather
than remount, just use the new mount API as it doesn't suffer this
limitation.
---
linuxnamespaces/__init__.py | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/linuxnamespaces/__init__.py b/linuxnamespaces/__init__.py
index ce6d44f..625f6c6 100644
--- a/linuxnamespaces/__init__.py
+++ b/linuxnamespaces/__init__.py
@@ -246,6 +246,10 @@ def bind_mount(
source = AtLocation(source)
target = AtLocation(target)
try:
+ if readonly:
+ # We would have to remount to apply the readonly flag, see
+ # https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=9ac77b8a78452eab0612523d27fee52159f5016a
+ raise ValueError()
srcloc = os.fspath(source)
tgtloc = os.fspath(target)
except ValueError:
@@ -255,14 +259,12 @@ def bind_mount(
with open_tree(source, otflags) as srcfd:
if readonly:
mount_setattr(srcfd, recursive, MountAttrFlags.RDONLY)
- return move_mount(srcfd, target)
+ move_mount(srcfd, target)
else:
mflags = MountFlags.BIND
if recursive:
mflags |= MountFlags.REC
- if readonly:
- mflags |= MountFlags.RDONLY
- return mount(srcloc, tgtloc, None, mflags)
+ mount(srcloc, tgtloc, None, mflags)
_P = typing.ParamSpec("_P")
--
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