Re: [PATCH v6 17/17] samples/landlock: adds network demo

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7/27/2022 11:26 PM, Mickaël Salaün пишет:

On 21/06/2022 10:23, Konstantin Meskhidze wrote:
This commit adds network demo. It's possible to
allow a sandoxer to bind/connect to a list of
particular ports restricting networks actions to
the rest of ports.

Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---

Changes since v5:
* Makes network ports sandboxing optional.
* Fixes some logic errors.
* Formats code with clang-format-14.

Changes since v4:
* Adds ENV_TCP_BIND_NAME "LL_TCP_BIND" and
ENV_TCP_CONNECT_NAME "LL_TCP_CONNECT" variables
to insert TCP ports.
* Renames populate_ruleset() to populate_ruleset_fs().
* Adds populate_ruleset_net() and parse_port_num() helpers.
* Refactors main() to support network sandboxing.

---
  samples/landlock/sandboxer.c | 118 +++++++++++++++++++++++++++++++----
  1 file changed, 107 insertions(+), 11 deletions(-)

diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 3e404e51ec64..0606c676fded 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c


[...]

@@ -232,16 +308,36 @@ int main(const int argc, char *const argv[], char *const *const envp)
  		access_fs_rw &= ~ACCESS_ABI_2;

We need to check the ABI to make this sample work without a kernel
supporting Landlock network access rights, and error out if the user
explicitely asked for it anyway (with the environement variable).

  Good point. Thanks for that.
  I will check it.

  	}

+	/* Adds optionally network bind() support. */
+	env_port_name = getenv(ENV_TCP_BIND_NAME);
+	if (env_port_name) {
+		access_net_tcp |= LANDLOCK_ACCESS_NET_BIND_TCP;
+	}
+	/* Adds optionally network connect() support. */
+	env_port_name = getenv(ENV_TCP_CONNECT_NAME);
+	if (env_port_name) {
+		access_net_tcp |= LANDLOCK_ACCESS_NET_CONNECT_TCP;
+	}
+	ruleset_attr.handled_access_net = access_net_tcp;
+
  	ruleset_fd =
  		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
  	if (ruleset_fd < 0) {
  		perror("Failed to create a ruleset");
  		return 1;
  	}
-	if (populate_ruleset(ENV_FS_RO_NAME, ruleset_fd, access_fs_ro)) {
+	if (populate_ruleset_fs(ENV_FS_RO_NAME, ruleset_fd, access_fs_ro)) {
+		goto err_close_ruleset;
+	}
+	if (populate_ruleset_fs(ENV_FS_RW_NAME, ruleset_fd, access_fs_rw)) {
+		goto err_close_ruleset;
+	}
+	if (populate_ruleset_net(ENV_TCP_BIND_NAME, ruleset_fd,
+				 LANDLOCK_ACCESS_NET_BIND_TCP)) {
  		goto err_close_ruleset;
  	}
-	if (populate_ruleset(ENV_FS_RW_NAME, ruleset_fd, access_fs_rw)) {
+	if (populate_ruleset_net(ENV_TCP_CONNECT_NAME, ruleset_fd,
+				 LANDLOCK_ACCESS_NET_CONNECT_TCP)) {
  		goto err_close_ruleset;
  	}
  	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
--
2.25.1

.



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