selftests/bpf: Implement socket kfuncs for bpf_testmod

This patch adds a set of kfuncs to bpf_testmod that can be used to
manipulate a socket from kernel space.

Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240429214529.2644801-3-jrife@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index eb2b78552ca299055341d9e9edad2bdcb509fcab..e93013fc7bf4ddf40cb933a0788d300f72de63ec 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -10,18 +10,30 @@
 #include <linux/percpu-defs.h>
 #include <linux/sysfs.h>
 #include <linux/tracepoint.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/nsproxy.h>
+#include <linux/inet.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/un.h>
+#include <net/sock.h>
 #include "bpf_testmod.h"
 #include "bpf_testmod_kfunc.h"
 
 #define CREATE_TRACE_POINTS
 #include "bpf_testmod-events.h"
 
+#define CONNECT_TIMEOUT_SEC 1
+
 typedef int (*func_proto_typedef)(long);
 typedef int (*func_proto_typedef_nested1)(func_proto_typedef);
 typedef int (*func_proto_typedef_nested2)(func_proto_typedef_nested1);
 
 DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) = 123;
 long bpf_testmod_test_struct_arg_result;
+static DEFINE_MUTEX(sock_lock);
+static struct socket *sock;
 
 struct bpf_testmod_struct_arg_1 {
        int a;
@@ -498,6 +510,237 @@ __bpf_kfunc void bpf_kfunc_call_test_sleepable(void)
 {
 }
 
+__bpf_kfunc int bpf_kfunc_init_sock(struct init_sock_args *args)
+{
+       int proto;
+       int err;
+
+       mutex_lock(&sock_lock);
+
+       if (sock) {
+               pr_err("%s called without releasing old sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       switch (args->af) {
+       case AF_INET:
+       case AF_INET6:
+               proto = args->type == SOCK_STREAM ? IPPROTO_TCP : IPPROTO_UDP;
+               break;
+       case AF_UNIX:
+               proto = PF_UNIX;
+               break;
+       default:
+               pr_err("invalid address family %d\n", args->af);
+               err = -EINVAL;
+               goto out;
+       }
+
+       err = sock_create_kern(current->nsproxy->net_ns, args->af, args->type,
+                              proto, &sock);
+
+       if (!err)
+               /* Set timeout for call to kernel_connect() to prevent it from hanging,
+                * and consider the connection attempt failed if it returns
+                * -EINPROGRESS.
+                */
+               sock->sk->sk_sndtimeo = CONNECT_TIMEOUT_SEC * HZ;
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc void bpf_kfunc_close_sock(void)
+{
+       mutex_lock(&sock_lock);
+
+       if (sock) {
+               sock_release(sock);
+               sock = NULL;
+       }
+
+       mutex_unlock(&sock_lock);
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_connect(struct addr_args *args)
+{
+       int err;
+
+       if (args->addrlen > sizeof(args->addr))
+               return -EINVAL;
+
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = kernel_connect(sock, (struct sockaddr *)&args->addr,
+                            args->addrlen, 0);
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_bind(struct addr_args *args)
+{
+       int err;
+
+       if (args->addrlen > sizeof(args->addr))
+               return -EINVAL;
+
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = kernel_bind(sock, (struct sockaddr *)&args->addr, args->addrlen);
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_listen(void)
+{
+       int err;
+
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = kernel_listen(sock, 128);
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_sendmsg(struct sendmsg_args *args)
+{
+       struct msghdr msg = {
+               .msg_name       = &args->addr.addr,
+               .msg_namelen    = args->addr.addrlen,
+       };
+       struct kvec iov;
+       int err;
+
+       if (args->addr.addrlen > sizeof(args->addr.addr) ||
+           args->msglen > sizeof(args->msg))
+               return -EINVAL;
+
+       iov.iov_base = args->msg;
+       iov.iov_len  = args->msglen;
+
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = kernel_sendmsg(sock, &msg, &iov, 1, args->msglen);
+       args->addr.addrlen = msg.msg_namelen;
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_sock_sendmsg(struct sendmsg_args *args)
+{
+       struct msghdr msg = {
+               .msg_name       = &args->addr.addr,
+               .msg_namelen    = args->addr.addrlen,
+       };
+       struct kvec iov;
+       int err;
+
+       if (args->addr.addrlen > sizeof(args->addr.addr) ||
+           args->msglen > sizeof(args->msg))
+               return -EINVAL;
+
+       iov.iov_base = args->msg;
+       iov.iov_len  = args->msglen;
+
+       iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, args->msglen);
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = sock_sendmsg(sock, &msg);
+       args->addr.addrlen = msg.msg_namelen;
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_getsockname(struct addr_args *args)
+{
+       int err;
+
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = kernel_getsockname(sock, (struct sockaddr *)&args->addr);
+       if (err < 0)
+               goto out;
+
+       args->addrlen = err;
+       err = 0;
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_getpeername(struct addr_args *args)
+{
+       int err;
+
+       mutex_lock(&sock_lock);
+
+       if (!sock) {
+               pr_err("%s called without initializing sock", __func__);
+               err = -EPERM;
+               goto out;
+       }
+
+       err = kernel_getpeername(sock, (struct sockaddr *)&args->addr);
+       if (err < 0)
+               goto out;
+
+       args->addrlen = err;
+       err = 0;
+out:
+       mutex_unlock(&sock_lock);
+
+       return err;
+}
+
 BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
 BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -525,6 +768,15 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_sleepable, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_init_sock, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_close_sock, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_connect, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_bind, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_listen, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_sendmsg, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_sock_sendmsg, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getsockname, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getpeername, KF_SLEEPABLE)
 BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
 
 static int bpf_testmod_ops_init(struct btf *btf)
@@ -655,6 +907,8 @@ static int bpf_testmod_init(void)
                return ret;
        if (bpf_fentry_test1(0) < 0)
                return -EINVAL;
+       sock = NULL;
+       mutex_init(&sock_lock);
        return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
 }
 
@@ -668,6 +922,7 @@ static void bpf_testmod_exit(void)
        while (refcount_read(&prog_test_struct.cnt) > 1)
                msleep(20);
 
+       bpf_kfunc_close_sock();
        sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
 }
 

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
index ce5cd763561caf74f2bf078f07f4cb6ed25e365f..b0d586a6751fa3b7ef5b0714d054c3f8ecaaaf81 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -64,6 +64,22 @@ struct prog_test_fail3 {
        char arr2[];
 };
 
+struct init_sock_args {
+       int af;
+       int type;
+};
+
+struct addr_args {
+       char addr[sizeof(struct __kernel_sockaddr_storage)];
+       int addrlen;
+};
+
+struct sendmsg_args {
+       struct addr_args addr;
+       char msg[10];
+       int msglen;
+};
+
 struct prog_test_ref_kfunc *
 bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr) __ksym;
 void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
@@ -107,4 +123,15 @@ void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p);
 void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len);
 
 void bpf_kfunc_common_test(void) __ksym;
+
+int bpf_kfunc_init_sock(struct init_sock_args *args) __ksym;
+void bpf_kfunc_close_sock(void) __ksym;
+int bpf_kfunc_call_kernel_connect(struct addr_args *args) __ksym;
+int bpf_kfunc_call_kernel_bind(struct addr_args *args) __ksym;
+int bpf_kfunc_call_kernel_listen(void) __ksym;
+int bpf_kfunc_call_kernel_sendmsg(struct sendmsg_args *args) __ksym;
+int bpf_kfunc_call_sock_sendmsg(struct sendmsg_args *args) __ksym;
+int bpf_kfunc_call_kernel_getsockname(struct addr_args *args) __ksym;
+int bpf_kfunc_call_kernel_getpeername(struct addr_args *args) __ksym;
+
 #endif /* _BPF_TESTMOD_KFUNC_H */