Given that we can not call bpf_hid_raw_request() from within an IRQ, userspace needs to have a way to communicate with the device when it needs.
Implement a new type that the caller can run at will without being in an IRQ context.
Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com --- include/linux/bpf-hid.h | 3 + include/uapi/linux/bpf.h | 1 + include/uapi/linux/bpf_hid.h | 9 ++ kernel/bpf/hid.c | 117 +++++++++++++++++++ kernel/bpf/syscall.c | 2 + tools/include/uapi/linux/bpf.h | 1 + tools/lib/bpf/libbpf.c | 1 + tools/testing/selftests/bpf/prog_tests/hid.c | 56 +++++++++ tools/testing/selftests/bpf/progs/hid.c | 10 ++ 9 files changed, 200 insertions(+)
diff --git a/include/linux/bpf-hid.h b/include/linux/bpf-hid.h index 07cbd5cf595c..00ac4555aa5b 100644 --- a/include/linux/bpf-hid.h +++ b/include/linux/bpf-hid.h @@ -15,6 +15,7 @@ enum bpf_hid_attach_type { BPF_HID_ATTACH_INVALID = -1, BPF_HID_ATTACH_DEVICE_EVENT = 0, BPF_HID_ATTACH_RDESC_FIXUP, + BPF_HID_ATTACH_USER_EVENT, MAX_BPF_HID_ATTACH_TYPE };
@@ -34,6 +35,8 @@ to_bpf_hid_attach_type(enum bpf_attach_type attach_type) return BPF_HID_ATTACH_DEVICE_EVENT; case BPF_HID_RDESC_FIXUP: return BPF_HID_ATTACH_RDESC_FIXUP; + case BPF_HID_USER_EVENT: + return BPF_HID_ATTACH_USER_EVENT; default: return BPF_HID_ATTACH_INVALID; } diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 0571d9b954c9..a374cc4aade6 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1000,6 +1000,7 @@ enum bpf_attach_type { BPF_PERF_EVENT, BPF_HID_DEVICE_EVENT, BPF_HID_RDESC_FIXUP, + BPF_HID_USER_EVENT, __MAX_BPF_ATTACH_TYPE };
diff --git a/include/uapi/linux/bpf_hid.h b/include/uapi/linux/bpf_hid.h index c0801d7174c3..7a263568e132 100644 --- a/include/uapi/linux/bpf_hid.h +++ b/include/uapi/linux/bpf_hid.h @@ -19,6 +19,7 @@ enum hid_bpf_event { HID_BPF_UNDEF = 0, HID_BPF_DEVICE_EVENT, HID_BPF_RDESC_FIXUP, + HID_BPF_USER_EVENT, };
/* type is HID_BPF_DEVICE_EVENT */ @@ -33,6 +34,13 @@ struct hid_bpf_ctx_rdesc_fixup { unsigned long size; };
+/* type is HID_BPF_USER_EVENT */ +struct hid_bpf_ctx_user_event { + __u8 data[HID_BPF_MAX_BUFFER_SIZE]; + unsigned long size; + int retval; +}; + struct hid_bpf_ctx { enum hid_bpf_event type; struct hid_device *hdev; @@ -40,6 +48,7 @@ struct hid_bpf_ctx { union { struct hid_bpf_ctx_device_event device; struct hid_bpf_ctx_rdesc_fixup rdesc; + struct hid_bpf_ctx_user_event user; } u; };
diff --git a/kernel/bpf/hid.c b/kernel/bpf/hid.c index 9eb7bd6ac6c8..3714413e1eb6 100644 --- a/kernel/bpf/hid.c +++ b/kernel/bpf/hid.c @@ -52,6 +52,9 @@ BPF_CALL_3(bpf_hid_get_data, void*, ctx, u64, offset, u8, n) case HID_BPF_RDESC_FIXUP: buf = bpf_ctx->u.rdesc.data; break; + case HID_BPF_USER_EVENT: + buf = bpf_ctx->u.user.data; + break; default: return -EOPNOTSUPP; } @@ -83,6 +86,9 @@ BPF_CALL_4(bpf_hid_set_data, void*, ctx, u64, offset, u8, n, u32, data) case HID_BPF_RDESC_FIXUP: buf = bpf_ctx->u.rdesc.data; break; + case HID_BPF_USER_EVENT: + buf = bpf_ctx->u.user.data; + break; default: return -EOPNOTSUPP; } @@ -385,6 +391,8 @@ static int bpf_hid_max_progs(enum bpf_hid_attach_type type) return 64; case BPF_HID_ATTACH_RDESC_FIXUP: return 1; + case BPF_HID_ATTACH_USER_EVENT: + return 64; default: return 0; } @@ -479,7 +487,116 @@ int bpf_hid_link_create(const union bpf_attr *attr, struct bpf_prog *prog) return bpf_link_settle(&link_primer); }
+static int hid_bpf_prog_test_run(struct bpf_prog *prog, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + struct hid_device *hdev = NULL; + struct bpf_prog_array *progs; + struct hid_bpf_ctx *ctx = NULL; + bool valid_prog = false; + int i; + int target_fd, ret; + void __user *data_out = u64_to_user_ptr(attr->test.data_out); + void __user *data_in = u64_to_user_ptr(attr->test.data_in); + u32 user_size = attr->test.data_size_in; + + if (!hid_hooks.hdev_from_fd) + return -EOPNOTSUPP; + + if (attr->test.ctx_size_in != sizeof(int)) + return -EINVAL; + + if (copy_from_user(&target_fd, (void *)attr->test.ctx_in, attr->test.ctx_size_in)) + return -EFAULT; + + hdev = hid_hooks.hdev_from_fd(target_fd); + if (IS_ERR(hdev)) + return PTR_ERR(hdev); + + ret = mutex_lock_interruptible(&bpf_hid_mutex); + if (ret) + return ret; + + /* check if the given program is of correct type and registered */ + progs = rcu_dereference_protected(hdev->bpf.run_array[BPF_HID_ATTACH_USER_EVENT], + lockdep_is_held(&bpf_hid_mutex)); + if (!progs) { + ret = -EFAULT; + goto unlock; + } + + for (i = 0; i < bpf_prog_array_length(progs); i++) { + if (progs->items[i].prog == prog) { + valid_prog = true; + break; + } + } + + if (!valid_prog) { + ret = -EINVAL; + goto unlock; + } + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) { + ret = -ENOMEM; + goto unlock; + } + + ctx->hdev = hdev; + ctx->type = HID_BPF_USER_EVENT; + + /* copy data_in from userspace */ + if (user_size) { + if (user_size > HID_BPF_MAX_BUFFER_SIZE) + user_size = HID_BPF_MAX_BUFFER_SIZE; + + if (copy_from_user(ctx->u.user.data, data_in, user_size)) { + ret = -EFAULT; + goto unlock; + } + + ctx->u.user.size = user_size; + } + + migrate_disable(); + + ret = bpf_prog_run(prog, ctx); + + migrate_enable(); + + user_size = attr->test.data_size_out; + + if (user_size && data_out) { + if (user_size > ctx->u.user.size) + user_size = ctx->u.user.size; + + if (copy_to_user(data_out, ctx->u.user.data, user_size)) { + ret = -EFAULT; + goto unlock; + } + + if (copy_to_user(&uattr->test.data_size_out, &user_size, sizeof(user_size))) { + ret = -EFAULT; + goto unlock; + } + } + + if (copy_to_user(&uattr->test.retval, &ctx->u.user.retval, sizeof(ctx->u.user.retval))) { + ret = -EFAULT; + goto unlock; + } + +unlock: + kfree(ctx); + + mutex_unlock(&bpf_hid_mutex); + return ret; +} + const struct bpf_prog_ops hid_prog_ops = { + .test_run = hid_bpf_prog_test_run, };
int bpf_hid_init(struct hid_device *hdev) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 62889cc71a02..0a6d08dabe59 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3192,6 +3192,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) return BPF_PROG_TYPE_XDP; case BPF_HID_DEVICE_EVENT: case BPF_HID_RDESC_FIXUP: + case BPF_HID_USER_EVENT: return BPF_PROG_TYPE_HID; default: return BPF_PROG_TYPE_UNSPEC; @@ -3338,6 +3339,7 @@ static int bpf_prog_query(const union bpf_attr *attr, return sock_map_bpf_prog_query(attr, uattr); case BPF_HID_DEVICE_EVENT: case BPF_HID_RDESC_FIXUP: + case BPF_HID_USER_EVENT: return bpf_hid_prog_query(attr, uattr); default: return -EINVAL; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 0571d9b954c9..a374cc4aade6 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1000,6 +1000,7 @@ enum bpf_attach_type { BPF_PERF_EVENT, BPF_HID_DEVICE_EVENT, BPF_HID_RDESC_FIXUP, + BPF_HID_USER_EVENT, __MAX_BPF_ATTACH_TYPE };
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b7af873116fb..290864d2f865 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -8678,6 +8678,7 @@ static const struct bpf_sec_def section_defs[] = { SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE | SEC_SLOPPY_PFX), SEC_DEF("hid/device_event", HID, BPF_HID_DEVICE_EVENT, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX), SEC_DEF("hid/rdesc_fixup", HID, BPF_HID_RDESC_FIXUP, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX), + SEC_DEF("hid/user_event", HID, BPF_HID_USER_EVENT, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX), };
#define MAX_TYPE_NAME_SIZE 32 diff --git a/tools/testing/selftests/bpf/prog_tests/hid.c b/tools/testing/selftests/bpf/prog_tests/hid.c index 7d4f740a0a08..d297a571e910 100644 --- a/tools/testing/selftests/bpf/prog_tests/hid.c +++ b/tools/testing/selftests/bpf/prog_tests/hid.c @@ -336,6 +336,59 @@ static int test_hid_set_get_data(struct hid *hid_skel, int uhid_fd, int sysfs_fd return ret; }
+/* + * Attach hid_user to the given uhid device, + * call the bpf program from userspace + * check that the program is called and does the expected. + */ +static int test_hid_user_call(struct hid *hid_skel, int uhid_fd, int sysfs_fd) +{ + int err, prog_fd; + u8 buf[10] = {0}; + int ret = -1; + + LIBBPF_OPTS(bpf_test_run_opts, run_attrs, + .repeat = 1, + .ctx_in = &sysfs_fd, + .ctx_size_in = sizeof(sysfs_fd), + .data_in = buf, + .data_size_in = sizeof(buf), + .data_out = buf, + .data_size_out = sizeof(buf), + ); + + /* attach hid_user program */ + hid_skel->links.hid_user = bpf_program__attach_hid(hid_skel->progs.hid_user, sysfs_fd); + if (!ASSERT_OK_PTR(hid_skel->links.hid_user, + "attach_hid(hid_user)")) + return PTR_ERR(hid_skel->links.hid_user); + + buf[0] = 39; + + prog_fd = bpf_program__fd(hid_skel->progs.hid_user); + + err = bpf_prog_test_run_opts(prog_fd, &run_attrs); + if (!ASSERT_EQ(err, 0, "bpf_prog_test_run_xattr")) + goto cleanup; + + if (!ASSERT_EQ(run_attrs.retval, 72, "bpf_prog_test_run_xattr_retval")) + goto cleanup; + + if (!ASSERT_EQ(buf[1], 42, "hid_user_check_in")) + goto cleanup; + + if (!ASSERT_EQ(buf[2], 4, "hid_user_check_static_out")) + goto cleanup; + + ret = 0; + +cleanup: + + hid__detach(hid_skel); + + return ret; +} + /* * Attach hid_rdesc_fixup to the given uhid device, * retrieve and open the matching hidraw node, @@ -437,6 +490,9 @@ void serial_test_hid_bpf(void) err = test_hid_set_get_data(hid_skel, uhid_fd, sysfs_fd); ASSERT_OK(err, "hid_set_get_data");
+ err = test_hid_user_call(hid_skel, uhid_fd, sysfs_fd); + ASSERT_OK(err, "hid_user"); + err = test_rdesc_fixup(hid_skel, uhid_fd, sysfs_fd); ASSERT_OK(err, "hid_rdesc_fixup");
diff --git a/tools/testing/selftests/bpf/progs/hid.c b/tools/testing/selftests/bpf/progs/hid.c index 01d9c556a3a1..b2db809b3367 100644 --- a/tools/testing/selftests/bpf/progs/hid.c +++ b/tools/testing/selftests/bpf/progs/hid.c @@ -80,3 +80,13 @@ int hid_set_get_data(struct hid_bpf_ctx *ctx)
return 0; } + +SEC("hid/user_event") +int hid_user(struct hid_bpf_ctx *ctx) +{ + ctx->u.user.data[1] = ctx->u.user.data[0] + 3; + ctx->u.user.data[2] = 4; + ctx->u.user.retval = 72; + + return 0; +}