Re: [PATCH v2 bpf-next 2/6] selftests/bpf: Implement socket kfuncs for bpf_testmod

On 4/12/24 09:52, Jordan Rife wrote:

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

.../selftests/bpf/bpf_testmod/bpf_testmod.c | 139 ++++++++++++++++++ .../bpf/bpf_testmod/bpf_testmod_kfunc.h | 27 ++++ 2 files changed, 166 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 39ad96a18123f..663df8148097e 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -10,18 +10,29 @@ #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 struct socket *sock; struct bpf_testmod_struct_arg_1 { int a; @@ -494,6 +505,124 @@ __bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused return arg; } +__bpf_kfunc int bpf_kfunc_init_sock(struct init_sock_args *args) +{

• int proto;
• if (sock)

• pr_warn("%s called without releasing old sock", __func__);
  

• 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);
  

• return -EINVAL;
  

• }
• return sock_create_kern(&init_net, args->af, args->type, proto, &sock);

+}

+__bpf_kfunc void bpf_kfunc_close_sock(void) +{

• if (sock) {

• sock_release(sock);
  

• sock = NULL;
  

• }

+}

+__bpf_kfunc int bpf_kfunc_call_kernel_connect(struct addr_args *args) +{

• /* 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;
• return kernel_connect(sock, (struct sockaddr *)&args->addr,

• 	      args->addrlen, 0);
  

+}

+__bpf_kfunc int bpf_kfunc_call_kernel_bind(struct addr_args *args) +{

• return kernel_bind(sock, (struct sockaddr *)&args->addr, args->addrlen);

+}

+__bpf_kfunc int bpf_kfunc_call_kernel_listen(void) +{

• return kernel_listen(sock, 128);

+}

+__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;
• iov.iov_base = args->msg;
• iov.iov_len = args->msglen;

It would be better to check if args->msglen > sizeof(arg->msg) although this function is just for test cases. Same for args->addr.addrlen.

• err = kernel_sendmsg(sock, &msg, &iov, 1, args->msglen);
• args->addr.addrlen = msg.msg_namelen;
• 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;
• iov.iov_base = args->msg;
• iov.iov_len = args->msglen;
• iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, args->msglen);
• err = sock_sendmsg(sock, &msg);
• args->addr.addrlen = msg.msg_namelen;
• return err;

+}

+__bpf_kfunc int bpf_kfunc_call_kernel_getsockname(struct addr_args *args) +{

• int err;
• err = kernel_getsockname(sock, (struct sockaddr *)&args->addr);
• if (err < 0)

• goto out;
  

• args->addrlen = err;
• err = 0;

+out:

• return err;

+}

+__bpf_kfunc int bpf_kfunc_call_kernel_getpeername(struct addr_args *args) +{

• int err;
• err = kernel_getpeername(sock, (struct sockaddr *)&args->addr);
• if (err < 0)

• goto out;
  

• args->addrlen = err;
• err = 0;

+out:

• 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)

@@ -520,6 +649,15 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU) 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_init_sock) +BTF_ID_FLAGS(func, bpf_kfunc_close_sock) +BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_connect) +BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_bind) +BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_listen) +BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_sendmsg) +BTF_ID_FLAGS(func, bpf_kfunc_call_sock_sendmsg) +BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getsockname) +BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getpeername) BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids) static int bpf_testmod_ops_init(struct btf *btf) @@ -650,6 +788,7 @@ static int bpf_testmod_init(void) return ret; if (bpf_fentry_test1(0) < 0) return -EINVAL;

• sock = NULL; return sysfs_create_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 7c664dd610597..cdf7769a7d8ca 100644 --- 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;

@@ -106,4 +122,15 @@ 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 */