diff options
Diffstat (limited to 'net/bpfilter')
| -rw-r--r-- | net/bpfilter/.gitignore | 1 | ||||
| -rw-r--r-- | net/bpfilter/Kconfig | 9 | ||||
| -rw-r--r-- | net/bpfilter/Makefile | 9 | ||||
| -rw-r--r-- | net/bpfilter/bpfilter_kern.c | 98 | ||||
| -rw-r--r-- | net/bpfilter/bpfilter_umh_blob.S | 2 | ||||
| -rw-r--r-- | net/bpfilter/main.c | 13 |
6 files changed, 74 insertions, 58 deletions
diff --git a/net/bpfilter/.gitignore b/net/bpfilter/.gitignore index e97084e3eea2..f34e85ee8204 100644 --- a/net/bpfilter/.gitignore +++ b/net/bpfilter/.gitignore @@ -1 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only bpfilter_umh diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig index fed9290e3b41..3d4a21462458 100644 --- a/net/bpfilter/Kconfig +++ b/net/bpfilter/Kconfig @@ -1,7 +1,8 @@ # SPDX-License-Identifier: GPL-2.0-only menuconfig BPFILTER bool "BPF based packet filtering framework (BPFILTER)" - depends on NET && BPF && INET + depends on BPF && INET + select USERMODE_DRIVER help This builds experimental bpfilter framework that is aiming to provide netfilter compatible functionality via BPF @@ -10,7 +11,13 @@ if BPFILTER config BPFILTER_UMH tristate "bpfilter kernel module with user mode helper" depends on CC_CAN_LINK + depends on m || CC_CAN_LINK_STATIC default m help This builds bpfilter kernel module with embedded user mode helper + + Note: To compile this as built-in, your toolchain must support + building static binaries, since rootfs isn't mounted at the time + when __init functions are called and do_execv won't be able to find + the elf interpreter. endif diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile index 36580301da70..cdac82b8c53a 100644 --- a/net/bpfilter/Makefile +++ b/net/bpfilter/Makefile @@ -3,16 +3,15 @@ # Makefile for the Linux BPFILTER layer. # -hostprogs := bpfilter_umh +userprogs := bpfilter_umh bpfilter_umh-objs := main.o -KBUILD_HOSTCFLAGS += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi -HOSTCC := $(CC) +userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi ifeq ($(CONFIG_BPFILTER_UMH), y) -# builtin bpfilter_umh should be compiled with -static +# builtin bpfilter_umh should be linked with -static # since rootfs isn't mounted at the time of __init # function is called and do_execv won't find elf interpreter -KBUILD_HOSTLDFLAGS += -static +userldflags += -static endif $(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c index c0f0990f30b6..422ec6e7ccff 100644 --- a/net/bpfilter/bpfilter_kern.c +++ b/net/bpfilter/bpfilter_kern.c @@ -15,15 +15,13 @@ extern char bpfilter_umh_end; static void shutdown_umh(void) { - struct task_struct *tsk; + struct umd_info *info = &bpfilter_ops.info; + struct pid *tgid = info->tgid; - if (bpfilter_ops.stop) - return; - - tsk = get_pid_task(find_vpid(bpfilter_ops.info.pid), PIDTYPE_PID); - if (tsk) { - send_sig(SIGKILL, tsk, 1); - put_task_struct(tsk); + if (tgid) { + kill_pid(tgid, SIGKILL, 1); + wait_event(tgid->wait_pidfd, thread_group_exited(tgid)); + bpfilter_umh_cleanup(info); } } @@ -33,60 +31,65 @@ static void __stop_umh(void) shutdown_umh(); } -static int __bpfilter_process_sockopt(struct sock *sk, int optname, - char __user *optval, - unsigned int optlen, bool is_set) +static int bpfilter_send_req(struct mbox_request *req) { - struct mbox_request req; struct mbox_reply reply; - loff_t pos; + loff_t pos = 0; ssize_t n; - int ret = -EFAULT; - - req.is_set = is_set; - req.pid = current->pid; - req.cmd = optname; - req.addr = (long __force __user)optval; - req.len = optlen; - if (!bpfilter_ops.info.pid) - goto out; - n = __kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req), + + if (!bpfilter_ops.info.tgid) + return -EFAULT; + pos = 0; + n = kernel_write(bpfilter_ops.info.pipe_to_umh, req, sizeof(*req), &pos); - if (n != sizeof(req)) { + if (n != sizeof(*req)) { pr_err("write fail %zd\n", n); - __stop_umh(); - ret = -EFAULT; - goto out; + goto stop; } pos = 0; n = kernel_read(bpfilter_ops.info.pipe_from_umh, &reply, sizeof(reply), &pos); if (n != sizeof(reply)) { pr_err("read fail %zd\n", n); - __stop_umh(); - ret = -EFAULT; - goto out; + goto stop; } - ret = reply.status; -out: - return ret; + return reply.status; +stop: + __stop_umh(); + return -EFAULT; +} + +static int bpfilter_process_sockopt(struct sock *sk, int optname, + sockptr_t optval, unsigned int optlen, + bool is_set) +{ + struct mbox_request req = { + .is_set = is_set, + .pid = current->pid, + .cmd = optname, + .addr = (uintptr_t)optval.user, + .len = optlen, + }; + if (sockptr_is_kernel(optval)) { + pr_err("kernel access not supported\n"); + return -EFAULT; + } + return bpfilter_send_req(&req); } static int start_umh(void) { + struct mbox_request req = { .pid = current->pid }; int err; /* fork usermode process */ - err = fork_usermode_blob(&bpfilter_umh_start, - &bpfilter_umh_end - &bpfilter_umh_start, - &bpfilter_ops.info); + err = fork_usermode_driver(&bpfilter_ops.info); if (err) return err; - bpfilter_ops.stop = false; - pr_info("Loaded bpfilter_umh pid %d\n", bpfilter_ops.info.pid); + pr_info("Loaded bpfilter_umh pid %d\n", pid_nr(bpfilter_ops.info.tgid)); /* health check that usermode process started correctly */ - if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) { + if (bpfilter_send_req(&req) != 0) { shutdown_umh(); return -EFAULT; } @@ -98,18 +101,21 @@ static int __init load_umh(void) { int err; + err = umd_load_blob(&bpfilter_ops.info, + &bpfilter_umh_start, + &bpfilter_umh_end - &bpfilter_umh_start); + if (err) + return err; + mutex_lock(&bpfilter_ops.lock); - if (!bpfilter_ops.stop) { - err = -EFAULT; - goto out; - } err = start_umh(); if (!err && IS_ENABLED(CONFIG_INET)) { - bpfilter_ops.sockopt = &__bpfilter_process_sockopt; + bpfilter_ops.sockopt = &bpfilter_process_sockopt; bpfilter_ops.start = &start_umh; } -out: mutex_unlock(&bpfilter_ops.lock); + if (err) + umd_unload_blob(&bpfilter_ops.info); return err; } @@ -122,6 +128,8 @@ static void __exit fini_umh(void) bpfilter_ops.sockopt = NULL; } mutex_unlock(&bpfilter_ops.lock); + + umd_unload_blob(&bpfilter_ops.info); } module_init(load_umh); module_exit(fini_umh); diff --git a/net/bpfilter/bpfilter_umh_blob.S b/net/bpfilter/bpfilter_umh_blob.S index 9ea6100dca87..40311d10d2f2 100644 --- a/net/bpfilter/bpfilter_umh_blob.S +++ b/net/bpfilter/bpfilter_umh_blob.S @@ -1,5 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ - .section .rodata, "a" + .section .init.rodata, "a" .global bpfilter_umh_start bpfilter_umh_start: .incbin "net/bpfilter/bpfilter_umh" diff --git a/net/bpfilter/main.c b/net/bpfilter/main.c index 77396a098fbe..291a92546246 100644 --- a/net/bpfilter/main.c +++ b/net/bpfilter/main.c @@ -10,7 +10,7 @@ #include <asm/unistd.h> #include "msgfmt.h" -int debug_fd; +FILE *debug_f; static int handle_get_cmd(struct mbox_request *cmd) { @@ -37,7 +37,7 @@ static void loop(void) n = read(0, &req, sizeof(req)); if (n != sizeof(req)) { - dprintf(debug_fd, "invalid request %d\n", n); + fprintf(debug_f, "invalid request %d\n", n); return; } @@ -47,7 +47,7 @@ static void loop(void) n = write(1, &reply, sizeof(reply)); if (n != sizeof(reply)) { - dprintf(debug_fd, "reply failed %d\n", n); + fprintf(debug_f, "reply failed %d\n", n); return; } } @@ -55,9 +55,10 @@ static void loop(void) int main(void) { - debug_fd = open("/dev/kmsg", 00000002); - dprintf(debug_fd, "Started bpfilter\n"); + debug_f = fopen("/dev/kmsg", "w"); + setvbuf(debug_f, 0, _IOLBF, 0); + fprintf(debug_f, "<5>Started bpfilter\n"); loop(); - close(debug_fd); + fclose(debug_f); return 0; } |