* [PATCH v18 3/5] binder: introduce transaction reports via netlink
[not found] <20250724185922.486207-1-cmllamas@google.com>
@ 2025-07-24 18:58 ` Carlos Llamas
2025-07-25 17:38 ` Jakub Kicinski
0 siblings, 1 reply; 3+ messages in thread
From: Carlos Llamas @ 2025-07-24 18:58 UTC (permalink / raw)
To: Alice Ryhl, Greg Kroah-Hartman, Arve Hjønnevåg,
Todd Kjos, Martijn Coenen, Joel Fernandes, Christian Brauner,
Carlos Llamas, Suren Baghdasaryan, Donald Hunter, Jakub Kicinski,
David S. Miller, Eric Dumazet, Paolo Abeni, Simon Horman, Li Li
Cc: Tiffany Yang, John Stultz, Shai Barack, Thiébaud Weksteen,
kernel-team, open list:ANDROID DRIVERS,
open list:NETWORKING [GENERAL]
From: Li Li <dualli@google.com>
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 <dualli@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
Documentation/netlink/specs/binder.yaml | 96 +++++++++++++++++++++
MAINTAINERS | 1 +
drivers/android/Kconfig | 1 +
drivers/android/Makefile | 2 +-
drivers/android/binder.c | 85 +++++++++++++++++-
drivers/android/binder_netlink.c | 32 +++++++
drivers/android/binder_netlink.h | 21 +++++
include/uapi/linux/android/binder_netlink.h | 37 ++++++++
8 files changed, 270 insertions(+), 5 deletions(-)
create mode 100644 Documentation/netlink/specs/binder.yaml
create mode 100644 drivers/android/binder_netlink.c
create mode 100644 drivers/android/binder_netlink.h
create mode 100644 include/uapi/linux/android/binder_netlink.h
diff --git a/Documentation/netlink/specs/binder.yaml b/Documentation/netlink/specs/binder.yaml
new file mode 100644
index 000000000000..9bf7268dde3d
--- /dev/null
+++ b/Documentation/netlink/specs/binder.yaml
@@ -0,0 +1,96 @@
+# 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
+
+kernel-family:
+ headers: [ "binder_internal.h" ]
+
+mcast-groups:
+ list:
+ -
+ name: report
diff --git a/MAINTAINERS b/MAINTAINERS
index f8c8f682edf6..df8f6b31f2f8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1769,6 +1769,7 @@ M: Suren Baghdasaryan <surenb@google.com>
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 5b3b8041f827..75af3cf472c8 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 c5d47be0276c..f422f91e026b 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 95aa1fae53e2..0d37eca514f9 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -74,6 +74,7 @@
#include <linux/cacheflush.h>
+#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 @@ static void binder_transaction(struct binder_proc *proc,
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:
@@ -7067,12 +7137,19 @@ 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 000000000000..f62fbca3143c
--- /dev/null
+++ b/drivers/android/binder_netlink.c
@@ -0,0 +1,32 @@
+// 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 <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "binder_netlink.h"
+
+#include <uapi/linux/android/binder_netlink.h>
+#include <binder_internal.h>
+
+/* 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 000000000000..f78b8ec54c53
--- /dev/null
+++ b/drivers/android/binder_netlink.h
@@ -0,0 +1,21 @@
+/* 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 <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/android/binder_netlink.h>
+#include <binder_internal.h>
+
+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 000000000000..b218f96d6668
--- /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 */
--
2.50.1.470.g6ba607880d-goog
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