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authorChristian Seiler <christian@iwakd.de>2015-01-27 18:58:40 +0100
committerLennart Poettering <lennart@poettering.net>2015-01-27 18:58:40 +0100
commit11c6476a08af7a8a9ae6a2d0f8370587f7b31663 (patch)
tree141141196d3c4670d6c05bed548800ab5919df22
parent4d858e7d9f39038713f760d7acc64acf7bba2aa7 (diff)
logind: chown+chmod /run/user/$UID if mount(tmpfs) fails with EPERM
In containers without CAP_SYS_ADMIN, it is not possible to mount tmpfs (or any filesystem for that matter) on top of /run/user/$UID. Previously, logind just failed in such a situation. Now, logind will resort to chown+chmod of the directory instead. This allows logind still to work in those environments, although without the guarantees it provides (i.e. users not being able to DOS /run or other users' /run/user/$UID space) when CAP_SYS_ADMIN is available.
-rw-r--r--src/login/logind-user.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index d1f91d6a29..928afd35e2 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -335,8 +335,20 @@ static int user_mkdir_runtime_path(User *u) {
r = mount("tmpfs", p, "tmpfs", MS_NODEV|MS_NOSUID, t);
if (r < 0) {
- r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", p);
- goto fail;
+ if (errno != EPERM) {
+ r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", p);
+ goto fail;
+ }
+
+ /* Lacking permissions, maybe
+ * CAP_SYS_ADMIN-less container? In this case,
+ * just use a normal directory. */
+
+ r = chmod_and_chown(p, 0700, u->uid, u->gid);
+ if (r < 0) {
+ log_error_errno(r, "Failed to change runtime directory ownership and mode: %m");
+ goto fail;
+ }
}
}
@@ -514,7 +526,11 @@ static int user_remove_runtime_path(User *u) {
if (r < 0)
log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
- if (umount2(u->runtime_path, MNT_DETACH) < 0)
+ /* Ignore cases where the directory isn't mounted, as that's
+ * quite possible, if we lacked the permissions to mount
+ * something */
+ r = umount2(u->runtime_path, MNT_DETACH);
+ if (r < 0 && errno != EINVAL && errno != ENOENT)
log_error_errno(errno, "Failed to unmount user runtime directory %s: %m", u->runtime_path);
r = rm_rf(u->runtime_path, false, true, false);