diff options
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/landlock/sandboxer.c | 73 |
1 files changed, 69 insertions, 4 deletions
diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c index e8223c3e781a..f847e832ba14 100644 --- a/samples/landlock/sandboxer.c +++ b/samples/landlock/sandboxer.c @@ -14,6 +14,7 @@ #include <fcntl.h> #include <linux/landlock.h> #include <linux/prctl.h> +#include <linux/socket.h> #include <stddef.h> #include <stdio.h> #include <stdlib.h> @@ -22,6 +23,7 @@ #include <sys/stat.h> #include <sys/syscall.h> #include <unistd.h> +#include <stdbool.h> #ifndef landlock_create_ruleset static inline int @@ -55,6 +57,7 @@ static inline int landlock_restrict_self(const int ruleset_fd, #define ENV_FS_RW_NAME "LL_FS_RW" #define ENV_TCP_BIND_NAME "LL_TCP_BIND" #define ENV_TCP_CONNECT_NAME "LL_TCP_CONNECT" +#define ENV_SCOPED_NAME "LL_SCOPED" #define ENV_DELIMITER ":" static int parse_path(char *env_path, const char ***const path_list) @@ -184,6 +187,55 @@ out_free_name: return ret; } +/* Returns true on error, false otherwise. */ +static bool check_ruleset_scope(const char *const env_var, + struct landlock_ruleset_attr *ruleset_attr) +{ + char *env_type_scope, *env_type_scope_next, *ipc_scoping_name; + bool error = false; + bool abstract_scoping = false; + bool signal_scoping = false; + + /* Scoping is not supported by Landlock ABI */ + if (!(ruleset_attr->scoped & + (LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | LANDLOCK_SCOPE_SIGNAL))) + goto out_unset; + + env_type_scope = getenv(env_var); + /* Scoping is not supported by the user */ + if (!env_type_scope || strcmp("", env_type_scope) == 0) + goto out_unset; + + env_type_scope = strdup(env_type_scope); + env_type_scope_next = env_type_scope; + while ((ipc_scoping_name = + strsep(&env_type_scope_next, ENV_DELIMITER))) { + if (strcmp("a", ipc_scoping_name) == 0 && !abstract_scoping) { + abstract_scoping = true; + } else if (strcmp("s", ipc_scoping_name) == 0 && + !signal_scoping) { + signal_scoping = true; + } else { + fprintf(stderr, "Unknown or duplicate scope \"%s\"\n", + ipc_scoping_name); + error = true; + goto out_free_name; + } + } + +out_free_name: + free(env_type_scope); + +out_unset: + if (!abstract_scoping) + ruleset_attr->scoped &= ~LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET; + if (!signal_scoping) + ruleset_attr->scoped &= ~LANDLOCK_SCOPE_SIGNAL; + + unsetenv(env_var); + return error; +} + /* clang-format off */ #define ACCESS_FS_ROUGHLY_READ ( \ @@ -208,7 +260,7 @@ out_free_name: /* clang-format on */ -#define LANDLOCK_ABI_LAST 5 +#define LANDLOCK_ABI_LAST 6 int main(const int argc, char *const argv[], char *const *const envp) { @@ -223,14 +275,16 @@ int main(const int argc, char *const argv[], char *const *const envp) .handled_access_fs = access_fs_rw, .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | LANDLOCK_ACCESS_NET_CONNECT_TCP, + .scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | + LANDLOCK_SCOPE_SIGNAL, }; if (argc < 2) { fprintf(stderr, - "usage: %s=\"...\" %s=\"...\" %s=\"...\" %s=\"...\"%s " + "usage: %s=\"...\" %s=\"...\" %s=\"...\" %s=\"...\" %s=\"...\" %s " "<cmd> [args]...\n\n", ENV_FS_RO_NAME, ENV_FS_RW_NAME, ENV_TCP_BIND_NAME, - ENV_TCP_CONNECT_NAME, argv[0]); + ENV_TCP_CONNECT_NAME, ENV_SCOPED_NAME, argv[0]); fprintf(stderr, "Execute a command in a restricted environment.\n\n"); fprintf(stderr, @@ -251,15 +305,18 @@ int main(const int argc, char *const argv[], char *const *const envp) fprintf(stderr, "* %s: list of ports allowed to connect (client).\n", ENV_TCP_CONNECT_NAME); + fprintf(stderr, "* %s: list of scoped IPCs.\n", + ENV_SCOPED_NAME); fprintf(stderr, "\nexample:\n" "%s=\"${PATH}:/lib:/usr:/proc:/etc:/dev/urandom\" " "%s=\"/dev/null:/dev/full:/dev/zero:/dev/pts:/tmp\" " "%s=\"9418\" " "%s=\"80:443\" " + "%s=\"a:s\" " "%s bash -i\n\n", ENV_FS_RO_NAME, ENV_FS_RW_NAME, ENV_TCP_BIND_NAME, - ENV_TCP_CONNECT_NAME, argv[0]); + ENV_TCP_CONNECT_NAME, ENV_SCOPED_NAME, argv[0]); fprintf(stderr, "This sandboxer can use Landlock features " "up to ABI version %d.\n", @@ -327,6 +384,11 @@ int main(const int argc, char *const argv[], char *const *const envp) /* Removes LANDLOCK_ACCESS_FS_IOCTL_DEV for ABI < 5 */ ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_IOCTL_DEV; + __attribute__((fallthrough)); + case 5: + /* Removes LANDLOCK_SCOPE_* for ABI < 6 */ + ruleset_attr.scoped &= ~(LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | + LANDLOCK_SCOPE_SIGNAL); fprintf(stderr, "Hint: You should update the running kernel " "to leverage Landlock features " @@ -358,6 +420,9 @@ int main(const int argc, char *const argv[], char *const *const envp) ~LANDLOCK_ACCESS_NET_CONNECT_TCP; } + if (check_ruleset_scope(ENV_SCOPED_NAME, &ruleset_attr)) + return 1; + ruleset_fd = landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); if (ruleset_fd < 0) { |