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Fix file descriptor leak, clobbered route updates #652

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merged 3 commits into from
May 24, 2023
Merged

Fix file descriptor leak, clobbered route updates #652

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ec92a4d
Close file descriptor.
tomc797 May 7, 2023
0f4cbd7
Update file offset.
tomc797 May 7, 2023
2ed66c8
Verify write status
tomc797 May 7, 2023
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68 changes: 45 additions & 23 deletions programs/ziti-edge-tunnel/netif_driver/linux/tun.c
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Original file line number Diff line number Diff line change
Expand Up @@ -128,43 +128,65 @@ static void route_updates_done(uv_work_t *wr, int status) {

static void process_routes_updates(uv_work_t *wr) {
struct rt_process_cmd *cmd = wr->data;
int rc;

uv_fs_t tmp_req = {0};
uv_file routes_file = uv_fs_mkstemp(wr->loop, &tmp_req, "/tmp/ziti-tunnel-routes.XXXXXX", NULL);
if (routes_file < 0) {
ZITI_LOG(ERROR, "failed to create temp file for route updates %d/%s", routes_file, uv_strerror(routes_file));
uv_fs_req_cleanup(&tmp_req);
return;
}

char buf[1024];
uv_fs_t req;

// get route deletes first
model_map_iter it = model_map_iterator(cmd->updates);
while(it) {
if (model_map_it_value(it) == 0) { // delete route
size_t len = snprintf(buf, sizeof(buf), "route delete %s dev %s\n", model_map_it_key(it), cmd->tun->name);
uv_buf_t b = uv_buf_init(buf, len);
uv_fs_write(wr->loop, &req, routes_file, &b, 1, 0, NULL);
}
it = model_map_it_next(it);
}

it = model_map_iterator(cmd->updates);
while(it) {
if ((uintptr_t)model_map_it_value(it) == 1) {
size_t len = snprintf(buf, sizeof(buf), "route add %s dev %s\n", model_map_it_key(it), cmd->tun->name);
uv_buf_t b = uv_buf_init(buf, len);
uv_fs_write(wr->loop, &req, routes_file, &b, 1, -1, NULL);
static const char *const verbs[] = {
"delete",
"add",
};
char buf[1024];
for (size_t i = 0; i < sizeof verbs/sizeof verbs[0]; i++) {
const char *const verb = verbs[i];
const char *prefix;
const void *value;

MODEL_MAP_FOREACH(prefix, value, cmd->updates) {
// action == 0: delete
// action == 1: add
unsigned action = (uintptr_t) value;
if (action == i) {
int len = snprintf(buf, sizeof(buf), "route %s %s dev %s\n", verb, prefix, cmd->tun->name);
if (len < 0 || (size_t) len >= sizeof buf) {
if (len > 0) errno = ENOMEM;
ZITI_LOG(ERROR, "route updates failed %d/%s", -errno, strerror(errno));
goto close_file;
}

uv_fs_t write_req;
uv_buf_t b = uv_buf_init(buf, len);
int rc = uv_fs_write(wr->loop, &write_req, routes_file, &b, 1, -1, NULL);
uv_fs_req_cleanup(&write_req);
/* if an incomplete write is encountered, bail.
* Don't want to execute clipped commands
*/
if (rc < len) {
if (rc > 0) rc = UV_EIO;
ZITI_LOG(ERROR, "route updates failed %d/%s", rc, uv_strerror(rc));
goto close_file;
}
}
}
it = model_map_it_next(it);
}

run_command("ip -force -batch %s", uv_fs_get_path(&tmp_req));

uv_fs_t unlink_req = {0};
uv_fs_unlink(wr->loop, &unlink_req, uv_fs_get_path(&tmp_req), NULL);
close_file: ; /* declaration is not a statement */
uv_fs_t unlink_req;
(void) uv_fs_unlink(wr->loop, &unlink_req, uv_fs_get_path(&tmp_req), NULL);
uv_fs_req_cleanup(&unlink_req);
uv_fs_req_cleanup(&tmp_req);

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probably better to close the file before blowing it off the file system

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unlink just reduces the link count. The file is only removed from the filesystem when the reference count drops to zero. IMHO, the unlink-before-close is more axiomatic. If a funlink syscall is defined (FreeBSD has the funlinkat; been discussions on the Linux list at various times), you'll need the file descriptor to unlink the file.

uv_fs_t close_req;
(void) uv_fs_close(wr->loop, &close_req, routes_file, NULL);
uv_fs_req_cleanup(&close_req);
}

void tun_commit_routes(netif_handle tun, uv_loop_t *l) {
Expand Down