From 43908f4c1d8489ca284c47fb835ec3fa348016b0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= Date: Sat, 5 Jun 2021 16:45:10 +0200 Subject: [PATCH] buildFhsUserenv: don't leak mounts to other processes If run as root we were leaking mounts to the parent namespace, which lead to an error when removing the temporary mountroot. To fix this we remount the whole tree as private as soon as we created the new mountenamespace. --- pkgs/build-support/build-fhs-userenv/chrootenv/chrootenv.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/pkgs/build-support/build-fhs-userenv/chrootenv/chrootenv.c b/pkgs/build-support/build-fhs-userenv/chrootenv/chrootenv.c index a438b80e182..27e70e3fe5c 100644 --- a/pkgs/build-support/build-fhs-userenv/chrootenv/chrootenv.c +++ b/pkgs/build-support/build-fhs-userenv/chrootenv/chrootenv.c @@ -43,7 +43,6 @@ const gchar *create_tmpdir() { void pivot_host(const gchar *guest) { g_autofree gchar *point = g_build_filename(guest, "host", NULL); fail_if(g_mkdir(point, 0755)); - fail_if(mount(0, "/", 0, MS_PRIVATE | MS_REC, 0)); fail_if(pivot_root(guest, point)); } @@ -122,6 +121,9 @@ int main(gint argc, gchar **argv) { fail("unshare", unshare_errno); } + // hide all mounts we do from the parent + fail_if(mount(0, "/", 0, MS_PRIVATE | MS_REC, 0)); + if (uid != 0) { spit("/proc/self/setgroups", "deny"); spit("/proc/self/uid_map", "%d %d 1", uid, uid);