From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
The current sk storage test ensures the memory free works when
the local_storage->smap is NULL.
This patch adds a task storage test to ensure the memory free
code path works when local_storage->smap is NULL.
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
---
.../bpf/prog_tests/test_local_storage.c | 7 ++-
.../selftests/bpf/progs/local_storage.c | 56 ++++++++++++++-----
2 files changed, 46 insertions(+), 17 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
index 563a9c746b7b..bcf2e1905ed7 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
@@ -23,7 +23,7 @@ struct storage {
/* Fork and exec the provided rm binary and return the exit code of the
* forked process and its pid.
*/
-static int run_self_unlink(int *monitored_pid, const char *rm_path)
+static int run_self_unlink(struct local_storage *skel, const char *rm_path)
{
int child_pid, child_status, ret;
int null_fd;
@@ -35,7 +35,7 @@ static int run_self_unlink(int *monitored_pid, const char *rm_path)
dup2(null_fd, STDERR_FILENO);
close(null_fd);
- *monitored_pid = getpid();
+ skel->bss->monitored_pid = getpid();
/* Use the copied /usr/bin/rm to delete itself
* /tmp/copy_of_rm /tmp/copy_of_rm.
*/
@@ -44,6 +44,7 @@ static int run_self_unlink(int *monitored_pid, const char *rm_path)
exit(errno);
} else if (child_pid > 0) {
waitpid(child_pid, &child_status, 0);
+ ASSERT_EQ(skel->data->task_storage_result, 0, "task_storage_result");
return WEXITSTATUS(child_status);
}
@@ -133,7 +134,7 @@ void test_test_local_storage(void)
* unlink its executable. This operation should be denied by the loaded
* LSM program.
*/
- err = run_self_unlink(&skel->bss->monitored_pid, tmp_exec_path);
+ err = run_self_unlink(skel, tmp_exec_path);
if (!ASSERT_EQ(err, EPERM, "run_self_unlink"))
goto close_prog_rmdir;
diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c
index c8ba7207f5a5..bc8ea56671a1 100644
--- a/tools/testing/selftests/bpf/progs/local_storage.c
+++ b/tools/testing/selftests/bpf/progs/local_storage.c
@@ -16,6 +16,7 @@ char _license[] SEC("license") = "GPL";
int monitored_pid = 0;
int inode_storage_result = -1;
int sk_storage_result = -1;
+int task_storage_result = -1;
struct local_storage {
struct inode *exec_inode;
@@ -50,26 +51,57 @@ struct {
__type(value, struct local_storage);
} task_storage_map SEC(".maps");
+struct {
+ __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
+ __uint(map_flags, BPF_F_NO_PREALLOC);
+ __type(key, int);
+ __type(value, struct local_storage);
+} task_storage_map2 SEC(".maps");
+
SEC("lsm/inode_unlink")
int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim)
{
__u32 pid = bpf_get_current_pid_tgid() >> 32;
+ struct bpf_local_storage *local_storage;
struct local_storage *storage;
+ struct task_struct *task;
bool is_self_unlink;
if (pid != monitored_pid)
return 0;
- storage = bpf_task_storage_get(&task_storage_map,
- bpf_get_current_task_btf(), 0, 0);
- if (storage) {
- /* Don't let an executable delete itself */
- is_self_unlink = storage->exec_inode == victim->d_inode;
- if (is_self_unlink)
- return -EPERM;
- }
+ task = bpf_get_current_task_btf();
+ if (!task)
+ return 0;
- return 0;
+ task_storage_result = -1;
+
+ storage = bpf_task_storage_get(&task_storage_map, task, 0, 0);
+ if (!storage)
+ return 0;
+
+ /* Don't let an executable delete itself */
+ is_self_unlink = storage->exec_inode == victim->d_inode;
+
+ storage = bpf_task_storage_get(&task_storage_map2, task, 0,
+ BPF_LOCAL_STORAGE_GET_F_CREATE);
+ if (!storage || storage->value)
+ return 0;
+
+ if (bpf_task_storage_delete(&task_storage_map, task))
+ return 0;
+
+ /* Ensure that the task_storage_map is disconnected from the storage.
+ * The storage memory should not be freed back to the
+ * bpf_mem_alloc.
+ */
+ local_storage = task->bpf_storage;
+ if (!local_storage || local_storage->smap)
+ return 0;
+
+ task_storage_result = 0;
+
+ return is_self_unlink ? -EPERM : 0;
}
SEC("lsm.s/inode_rename")
@@ -139,11 +171,7 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address,
if (bpf_sk_storage_delete(&sk_storage_map, sock->sk))
return 0;
- /* Ensure that the sk_storage_map is disconnected from the storage.
- * The storage memory should not be freed back to the
- * bpf_mem_alloc of the sk_bpf_storage_map because
- * sk_bpf_storage_map may have been gone.
- */
+ /* Ensure that the sk_storage_map is disconnected from the storage. */
if (!sock->sk->sk_bpf_storage || sock->sk->sk_bpf_storage->smap)
return 0;
--
2.34.1
