From: Li Li Date: Sun, 27 Jul 2025 18:29:06 +0000 (+0000) Subject: binder: introduce transaction reports via netlink X-Git-Tag: v6.18-rc1~74^2~57 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=63740349eba78f242bcbf60d5244d7f2b2600853;p=thirdparty%2Fkernel%2Flinux.git binder: introduce transaction reports via netlink Introduce a generic netlink multicast event to report binder transaction failures to userspace. This allows subscribers to monitor these events and take appropriate actions, such as stopping a misbehaving application that is spamming a service with huge amount of transactions. The multicast event contains full details of the failed transactions, including the sender/target PIDs, payload size and specific error code. This interface is defined using a YAML spec, from which the UAPI and kernel headers and source are auto-generated. Signed-off-by: Li Li Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20250727182932.2499194-4-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/Documentation/netlink/specs/binder.yaml b/Documentation/netlink/specs/binder.yaml new file mode 100644 index 0000000000000..140b77a6afee6 --- /dev/null +++ b/Documentation/netlink/specs/binder.yaml @@ -0,0 +1,93 @@ +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) +# +# Copyright 2025 Google LLC +# +--- +name: binder +protocol: genetlink +uapi-header: linux/android/binder_netlink.h +doc: Binder interface over generic netlink + +attribute-sets: + - + name: report + doc: | + Attributes included within a transaction failure report. The elements + correspond directly with the specific transaction that failed, along + with the error returned to the sender e.g. BR_DEAD_REPLY. + + attributes: + - + name: error + type: u32 + doc: The enum binder_driver_return_protocol returned to the sender. + - + name: context + type: string + doc: The binder context where the transaction occurred. + - + name: from_pid + type: u32 + doc: The PID of the sender process. + - + name: from_tid + type: u32 + doc: The TID of the sender thread. + - + name: to_pid + type: u32 + doc: | + The PID of the recipient process. This attribute may not be present + if the target could not be determined. + - + name: to_tid + type: u32 + doc: | + The TID of the recipient thread. This attribute may not be present + if the target could not be determined. + - + name: is_reply + type: flag + doc: When present, indicates the failed transaction is a reply. + - + name: flags + type: u32 + doc: The bitmask of enum transaction_flags from the transaction. + - + name: code + type: u32 + doc: The application-defined code from the transaction. + - + name: data_size + type: u32 + doc: The transaction payload size in bytes. + +operations: + list: + - + name: report + doc: | + A multicast event sent to userspace subscribers to notify them about + binder transaction failures. The generated report provides the full + details of the specific transaction that failed. The intention is for + programs to monitor these events and react to the failures as needed. + + attribute-set: report + mcgrp: report + event: + attributes: + - error + - context + - from_pid + - from_tid + - to_pid + - to_tid + - is_reply + - flags + - code + - data_size + +mcast-groups: + list: + - + name: report diff --git a/MAINTAINERS b/MAINTAINERS index daf520a13bdf6..febc92cca659b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1790,6 +1790,7 @@ M: Suren Baghdasaryan L: linux-kernel@vger.kernel.org S: Supported T: git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git +F: Documentation/netlink/specs/binder.yaml F: drivers/android/ ANDROID GOLDFISH PIC DRIVER diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig index 5b3b8041f8279..75af3cf472c8f 100644 --- a/drivers/android/Kconfig +++ b/drivers/android/Kconfig @@ -4,6 +4,7 @@ menu "Android" config ANDROID_BINDER_IPC bool "Android Binder IPC Driver" depends on MMU + depends on NET default n help Binder is used in Android for both communication between processes, diff --git a/drivers/android/Makefile b/drivers/android/Makefile index c5d47be0276cd..f422f91e026b2 100644 --- a/drivers/android/Makefile +++ b/drivers/android/Makefile @@ -2,5 +2,5 @@ ccflags-y += -I$(src) # needed for trace events obj-$(CONFIG_ANDROID_BINDERFS) += binderfs.o -obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o +obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o binder_netlink.o obj-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST) += tests/ diff --git a/drivers/android/binder.c b/drivers/android/binder.c index e4f9cbc6c93f4..edfa15d39d6f1 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -74,6 +74,7 @@ #include +#include "binder_netlink.h" #include "binder_internal.h" #include "binder_trace.h" @@ -2993,6 +2994,67 @@ static void binder_set_txn_from_error(struct binder_transaction *t, int id, binder_thread_dec_tmpref(from); } +/** + * binder_netlink_report() - report a transaction failure via netlink + * @proc: the binder proc sending the transaction + * @t: the binder transaction that failed + * @data_size: the user provided data size for the transaction + * @error: enum binder_driver_return_protocol returned to sender + */ +static void binder_netlink_report(struct binder_proc *proc, + struct binder_transaction *t, + u32 data_size, + u32 error) +{ + const char *context = proc->context->name; + struct sk_buff *skb; + void *hdr; + + if (!genl_has_listeners(&binder_nl_family, &init_net, + BINDER_NLGRP_REPORT)) + return; + + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!skb) + return; + + hdr = genlmsg_put(skb, 0, 0, &binder_nl_family, 0, BINDER_CMD_REPORT); + if (!hdr) + goto free_skb; + + if (nla_put_u32(skb, BINDER_A_REPORT_ERROR, error) || + nla_put_string(skb, BINDER_A_REPORT_CONTEXT, context) || + nla_put_u32(skb, BINDER_A_REPORT_FROM_PID, t->from_pid) || + nla_put_u32(skb, BINDER_A_REPORT_FROM_TID, t->from_tid)) + goto cancel_skb; + + if (t->to_proc && + nla_put_u32(skb, BINDER_A_REPORT_TO_PID, t->to_proc->pid)) + goto cancel_skb; + + if (t->to_thread && + nla_put_u32(skb, BINDER_A_REPORT_TO_TID, t->to_thread->pid)) + goto cancel_skb; + + if (t->is_reply && nla_put_flag(skb, BINDER_A_REPORT_IS_REPLY)) + goto cancel_skb; + + if (nla_put_u32(skb, BINDER_A_REPORT_FLAGS, t->flags) || + nla_put_u32(skb, BINDER_A_REPORT_CODE, t->code) || + nla_put_u32(skb, BINDER_A_REPORT_DATA_SIZE, data_size)) + goto cancel_skb; + + genlmsg_end(skb, hdr); + genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, + GFP_KERNEL); + return; + +cancel_skb: + genlmsg_cancel(skb, hdr); +free_skb: + nlmsg_free(skb); +} + static void binder_transaction(struct binder_proc *proc, struct binder_thread *thread, struct binder_transaction_data *tr, int reply, @@ -3679,10 +3741,13 @@ static void binder_transaction(struct binder_proc *proc, return_error_line = __LINE__; goto err_copy_data_failed; } - if (t->buffer->oneway_spam_suspect) + if (t->buffer->oneway_spam_suspect) { tcomplete->type = BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT; - else + binder_netlink_report(proc, t, tr->data_size, + BR_ONEWAY_SPAM_SUSPECT); + } else { tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE; + } if (reply) { binder_enqueue_thread_work(thread, tcomplete); @@ -3730,8 +3795,11 @@ static void binder_transaction(struct binder_proc *proc, * process and is put in a pending queue, waiting for the target * process to be unfrozen. */ - if (return_error == BR_TRANSACTION_PENDING_FROZEN) + if (return_error == BR_TRANSACTION_PENDING_FROZEN) { tcomplete->type = BINDER_WORK_TRANSACTION_PENDING; + binder_netlink_report(proc, t, tr->data_size, + return_error); + } binder_enqueue_thread_work(thread, tcomplete); if (return_error && return_error != BR_TRANSACTION_PENDING_FROZEN) @@ -3789,6 +3857,8 @@ err_invalid_target_handle: binder_dec_node(target_node, 1, 0); binder_dec_node_tmpref(target_node); } + + binder_netlink_report(proc, t, tr->data_size, return_error); kfree(t); binder_stats_deleted(BINDER_STAT_TRANSACTION); err_alloc_t_failed: @@ -7059,12 +7129,19 @@ static int __init binder_init(void) } } - ret = init_binderfs(); + ret = genl_register_family(&binder_nl_family); if (ret) goto err_init_binder_device_failed; + ret = init_binderfs(); + if (ret) + goto err_init_binderfs_failed; + return ret; +err_init_binderfs_failed: + genl_unregister_family(&binder_nl_family); + err_init_binder_device_failed: hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) { misc_deregister(&device->miscdev); diff --git a/drivers/android/binder_netlink.c b/drivers/android/binder_netlink.c new file mode 100644 index 0000000000000..d05397a50ca6b --- /dev/null +++ b/drivers/android/binder_netlink.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) +/* Do not edit directly, auto-generated from: */ +/* Documentation/netlink/specs/binder.yaml */ +/* YNL-GEN kernel source */ + +#include +#include + +#include "binder_netlink.h" + +#include + +/* Ops table for binder */ +static const struct genl_split_ops binder_nl_ops[] = { +}; + +static const struct genl_multicast_group binder_nl_mcgrps[] = { + [BINDER_NLGRP_REPORT] = { "report", }, +}; + +struct genl_family binder_nl_family __ro_after_init = { + .name = BINDER_FAMILY_NAME, + .version = BINDER_FAMILY_VERSION, + .netnsok = true, + .parallel_ops = true, + .module = THIS_MODULE, + .split_ops = binder_nl_ops, + .n_split_ops = ARRAY_SIZE(binder_nl_ops), + .mcgrps = binder_nl_mcgrps, + .n_mcgrps = ARRAY_SIZE(binder_nl_mcgrps), +}; diff --git a/drivers/android/binder_netlink.h b/drivers/android/binder_netlink.h new file mode 100644 index 0000000000000..882c7a6b537e9 --- /dev/null +++ b/drivers/android/binder_netlink.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* Do not edit directly, auto-generated from: */ +/* Documentation/netlink/specs/binder.yaml */ +/* YNL-GEN kernel header */ + +#ifndef _LINUX_BINDER_GEN_H +#define _LINUX_BINDER_GEN_H + +#include +#include + +#include + +enum { + BINDER_NLGRP_REPORT, +}; + +extern struct genl_family binder_nl_family; + +#endif /* _LINUX_BINDER_GEN_H */ diff --git a/include/uapi/linux/android/binder_netlink.h b/include/uapi/linux/android/binder_netlink.h new file mode 100644 index 0000000000000..b218f96d66683 --- /dev/null +++ b/include/uapi/linux/android/binder_netlink.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* Do not edit directly, auto-generated from: */ +/* Documentation/netlink/specs/binder.yaml */ +/* YNL-GEN uapi header */ + +#ifndef _UAPI_LINUX_ANDROID_BINDER_NETLINK_H +#define _UAPI_LINUX_ANDROID_BINDER_NETLINK_H + +#define BINDER_FAMILY_NAME "binder" +#define BINDER_FAMILY_VERSION 1 + +enum { + BINDER_A_REPORT_ERROR = 1, + BINDER_A_REPORT_CONTEXT, + BINDER_A_REPORT_FROM_PID, + BINDER_A_REPORT_FROM_TID, + BINDER_A_REPORT_TO_PID, + BINDER_A_REPORT_TO_TID, + BINDER_A_REPORT_IS_REPLY, + BINDER_A_REPORT_FLAGS, + BINDER_A_REPORT_CODE, + BINDER_A_REPORT_DATA_SIZE, + + __BINDER_A_REPORT_MAX, + BINDER_A_REPORT_MAX = (__BINDER_A_REPORT_MAX - 1) +}; + +enum { + BINDER_CMD_REPORT = 1, + + __BINDER_CMD_MAX, + BINDER_CMD_MAX = (__BINDER_CMD_MAX - 1) +}; + +#define BINDER_MCGRP_REPORT "report" + +#endif /* _UAPI_LINUX_ANDROID_BINDER_NETLINK_H */