From 54a6e6bbf3bef25c8eb65619edde70af49bd3db0 Mon Sep 17 00:00:00 2001 From: Tahera Fahimi Date: Fri, 6 Sep 2024 15:30:03 -0600 Subject: landlock: Add signal scoping MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün Signed-off-by: Mickaël Salaün --- tools/testing/selftests/landlock/scoped_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/landlock/scoped_test.c b/tools/testing/selftests/landlock/scoped_test.c index 2d15f09d63e2..b90f76ed0d9c 100644 --- a/tools/testing/selftests/landlock/scoped_test.c +++ b/tools/testing/selftests/landlock/scoped_test.c @@ -12,7 +12,7 @@ #include "common.h" -#define ACCESS_LAST LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET +#define ACCESS_LAST LANDLOCK_SCOPE_SIGNAL TEST(ruleset_with_unknown_scope) { -- cgit