From a17c60e533f5cd832e77e0d194e2e0bb663371b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <mic@digikod.net>
Date: Thu, 7 Mar 2024 15:38:49 +0100
Subject: [PATCH] samples/landlock: Don't error out if a file path cannot be
opened
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Instead of creating a hard error and aborting the sandbox creation,
accept file path not usable in the LL_FS_RO and LL_FS_RW environment
variables but only print a warning. This makes it easier to test, for
instance with LL_FS_RO="${PATH}:/usr/lib:/lib"
Print that we are going to execute the command in the sandbox before
doing so.
Rename "launch" to "execute", and improve header description.
Reviewed-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240307143849.1517218-1-mic@digikod.net
[mic: Improve header description as suggested by Günther]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
---
samples/landlock/sandboxer.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 08596c0ef0707..32e930c853bba 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: BSD-3-Clause
/*
- * Simple Landlock sandbox manager able to launch a process restricted by a
- * user-defined filesystem access control policy.
+ * Simple Landlock sandbox manager able to execute a process restricted by
+ * user-defined file system and network access control policies.
*
* Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
* Copyright © 2020 ANSSI
@@ -120,9 +120,11 @@ static int populate_ruleset_fs(const char *const env_var, const int ruleset_fd,
if (path_beneath.parent_fd < 0) {
fprintf(stderr, "Failed to open \"%s\": %s\n",
path_list[i], strerror(errno));
- goto out_free_name;
+ continue;
}
if (fstat(path_beneath.parent_fd, &statbuf)) {
+ fprintf(stderr, "Failed to stat \"%s\": %s\n",
+ path_list[i], strerror(errno));
close(path_beneath.parent_fd);
goto out_free_name;
}
@@ -227,7 +229,7 @@ int main(const int argc, char *const argv[], char *const *const envp)
ENV_FS_RO_NAME, ENV_FS_RW_NAME, ENV_TCP_BIND_NAME,
ENV_TCP_CONNECT_NAME, argv[0]);
fprintf(stderr,
- "Launch a command in a restricted environment.\n\n");
+ "Execute a command in a restricted environment.\n\n");
fprintf(stderr,
"Environment variables containing paths and ports "
"each separated by a colon:\n");
@@ -248,7 +250,7 @@ int main(const int argc, char *const argv[], char *const *const envp)
ENV_TCP_CONNECT_NAME);
fprintf(stderr,
"\nexample:\n"
- "%s=\"/bin:/lib:/usr:/proc:/etc:/dev/urandom\" "
+ "%s=\"${PATH}:/lib:/usr:/proc:/etc:/dev/urandom\" "
"%s=\"/dev/null:/dev/full:/dev/zero:/dev/pts:/tmp\" "
"%s=\"9418\" "
"%s=\"80:443\" "
@@ -383,6 +385,7 @@ int main(const int argc, char *const argv[], char *const *const envp)
cmd_path = argv[1];
cmd_argv = argv + 1;
+ fprintf(stderr, "Executing the sandboxed command...\n");
execvpe(cmd_path, cmd_argv, envp);
fprintf(stderr, "Failed to execute \"%s\": %s\n", cmd_path,
strerror(errno));
--
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