| Message ID | 20250303200212.3294679-3-dualli@chromium.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | binder: report txn errors via generic netlink | expand |
On Mon, Mar 03, 2025 at 12:02:11PM -0800, Li Li wrote: > From: Li Li <dualli@google.com> > > Introduce generic netlink messages into the binder driver so that the > Linux/Android system administration processes can listen to important > events and take corresponding actions, like stopping a broken app from > attacking the OS by sending huge amount of spamming binder transactions. > > The binder netlink sources and headers are automatically generated from > the corresponding binder netlink YAML spec. Don't modify them directly. > > Signed-off-by: Li Li <dualli@google.com> > --- > Documentation/admin-guide/binder_netlink.rst | 108 +++++++++ > Documentation/admin-guide/index.rst | 1 + > Documentation/netlink/specs/binder.yaml | 116 ++++++++++ > drivers/android/Kconfig | 1 + > drivers/android/Makefile | 2 +- > drivers/android/binder.c | 229 ++++++++++++++++++- > drivers/android/binder_internal.h | 16 ++ > drivers/android/binder_netlink.c | 46 ++++ > drivers/android/binder_netlink.h | 23 ++ > drivers/android/binder_trace.h | 35 +++ > include/uapi/linux/android/binder_netlink.h | 57 +++++ > 11 files changed, 630 insertions(+), 4 deletions(-) > create mode 100644 Documentation/admin-guide/binder_netlink.rst > 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/admin-guide/binder_netlink.rst b/Documentation/admin-guide/binder_netlink.rst > new file mode 100644 > index 000000000000..83f54f0d8c45 > --- /dev/null > +++ b/Documentation/admin-guide/binder_netlink.rst > @@ -0,0 +1,108 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +============================================================== > +Generic Netlink for the Android Binder Driver (Binder Netlink) > +============================================================== > + > +The Generic Netlink subsystem in the Linux kernel provides a generic way for > +the Linux kernel to communicate with the user space applications via binder > +driver. It is used to report binder transaction errors and warnings to user > +space administration process. The driver allows multiple binder devices and > +their corresponding binder contexts. Each context and their processes can be > +configured independently to report their own transactions. > + > +Basically, the user space code uses the BINDER_CMD_REPORT_SETUP command to > +request what kind of binder transactions should be reported by the driver. > +The driver then echoes the attributes in a reply message to acknowledge the > +request. The BINDER_CMD_REPORT_SETUP command also registers the current > +user space process to receive the reports. This BINDER_CMD_REPORT_SETUP > +command is protected by SELinux, to prevent unauthorized user apps from > +triggering unexpected reports. > + > +Currently the driver reports these binder transaction errors and warnings. > +1. "FAILED" transactions that fail to reach the target process; > +2. "ASYNC_FROZEN" transactions that are delayed due to the target process > +being frozen by cgroup freezer; or > +3. "SPAM" transactions that are considered spamming according to existing > +logic in binder_alloc.c. > + > +When the specified binder transactions happen, the driver uses the > +BINDER_CMD_REPORT command to send a generic netlink message to the > +registered process, containing the payload defined in binder.yaml. > + > +More details about the flags, attributes and operations can be found at the > +the doc sections in Documentations/netlink/specs/binder.yaml and the > +kernel-doc comments of the new source code in binder.{h|c}. > + > +Using Binder Netlink > +-------------------- > + > +The Binder Netlink can be used in the same way as any other generic netlink > +drivers. Userspace application uses a raw netlink socket to send commands > +to and receive packets from the kernel driver. > + > +Usage example (user space pseudo code): > + > +:: > + /* > + * send() below is overloaded to pack netlink commands and attributes > + * to nlattr/genlmsghdr/nlmsghdr and then send to the netlink socket. > + * > + * recv() below is overloaded to receive the raw netlink message from > + * the netlink socket, parse nlmsghdr/genlmsghdr to find the netlink > + * command and then return the nlattr payload. > + */ > + > + // open netlink socket > + int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC); > + > + // bind netlink socket > + bind(fd, struct socketaddr); > + > + // get the family id of the binder netlink > + send(fd, CTRL_CMD_GETFAMILY, CTRL_ATTR_FAMILY_NAME, > + BINDER_FAMILY_NAME); > + void *data = recv(CTRL_CMD_NEWFAMILY); > + if (!has_nla_type(data, CTRL_ATTR_FAMILY_ID)) { > + // Binder Netlink isn't available on this version of Linux kernel > + return; > + } > + __u16 id = nla(data)[CTRL_ATTR_FAMILY_ID]; > + __u32 grp = nla(data)[CTRL_ATTR_MCAST_GROUPS][CTRL_ATTR_MCAST_GRP_ID]; > + > + // join the mcast group to listen to the binder netlink messages > + setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &grp, sizeof(grp)); > + > + // enable per-context binder report > + send(fd, id, BINDER_CMD_REPORT_SETUP, "binder", 0, > + BINDER_FLAG_FAILED | BINDER_FLAG_DELAYED); > + > + // confirm the per-context configuration > + data = recv(fd, BINDER_CMD_REPLY); > + char *context = nla(data)[BINDER_A_CMD_CONTEXT]; > + __u32 pid = nla(data)[BINDER_A_CMD_PID]; > + __u32 flags = nla(data)[BINDER_A_CMD_FLAGS]; > + > + // set optional per-process report, overriding the per-context one > + send(fd, id, BINDER_CMD_REPORT_SETUP, "binder", getpid(), > + BINDER_FLAG_SPAM | BINDER_REPORT_OVERRIDE); > + > + // confirm the optional per-process configuration > + data = recv(fd, BINDER_CMD_REPLY); > + context = nla(data)[BINDER_A_CMD_CONTEXT]; > + pid = nla(data)[BINDER_A_CMD_PID]; > + flags = nla(data)[BINDER_A_CMD_FLAGS]; > + > + // wait and read all binder reports > + while (running) { > + data = recv(fd, BINDER_CMD_REPORT); > + auto *attr = nla(data)[BINDER_A_REPORT_XXX]; > + > + // process binder report > + do_something(*attr); > + } > + > + // clean up > + send(fd, id, BINDER_CMD_REPORT_SETUP, 0, 0); > + send(fd, id, BINDER_CMD_REPORT_SETUP, getpid(), 0); > + close(fd); > diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst > index c8af32a8f800..655f39ddf1cf 100644 > --- a/Documentation/admin-guide/index.rst > +++ b/Documentation/admin-guide/index.rst > @@ -120,6 +120,7 @@ Block-layer and filesystem administration > :maxdepth: 1 > > bcache > + binder_netlink > binderfs > blockdev/index > cifs/index > diff --git a/Documentation/netlink/specs/binder.yaml b/Documentation/netlink/specs/binder.yaml > new file mode 100644 > index 000000000000..e184645f6c41 > --- /dev/null > +++ b/Documentation/netlink/specs/binder.yaml > @@ -0,0 +1,116 @@ > +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) > + > +name: binder > +protocol: genetlink > +uapi-header: linux/android/binder_netlink.h > +doc: Netlink protocol to report binder transaction errors and warnings. > + > +definitions: > + - > + type: flags > + name: flag > + doc: Define what kind of binder transactions should be reported. > + entries: [ failed, async-frozen, spam, override ] > + > +attribute-sets: > + - > + name: cmd > + doc: The supported attributes of "report-setup" command. > + attributes: > + - > + name: context > + type: string > + doc: The binder context to enable binder netlink report. > + - > + name: pid > + type: u32 > + doc: The binder proc to enable binder netlink report. > + - > + name: flags > + type: u32 > + enum: flag > + doc: What kind of binder transactions should be reported. > + - > + name: report > + doc: The supported attributes of "report" command > + attributes: > + - > + name: context > + type: string > + doc: The binder context where the binder netlink report happens. > + - > + name: err > + type: u32 > + doc: Copy of binder_driver_return_protocol returned to the sender. > + - > + name: from_pid > + type: u32 > + doc: Sender pid of the corresponding binder transaction. > + - > + name: from_tid > + type: u32 > + doc: Sender tid of the corresponding binder transaction. > + - > + name: to_pid > + type: u32 > + doc: Target pid of the corresponding binder transaction. > + - > + name: to_tid > + type: u32 > + doc: Target tid of the corresponding binder transaction. > + - > + name: reply > + type: u32 > + doc: 1 means the transaction is a reply, 0 otherwise. > + - > + name: flags > + type: u32 > + doc: Copy of binder_transaction_data->flags. > + - > + name: code > + type: u32 > + doc: Copy of binder_transaction_data->code. > + - > + name: data_size > + type: u32 > + doc: Copy of binder_transaction_data->data_size. > + > +operations: > + list: > + - > + name: report-setup > + doc: Set flags from user space. > + attribute-set: cmd > + > + do: > + request: ¶ms > + attributes: > + - context > + - pid > + - flags > + reply: *params > + - > + name: report > + doc: Send the requested reports to user space. > + attribute-set: report > + > + event: > + attributes: > + - context > + - err > + - from_pid > + - from_tid > + - to_pid > + - to_tid > + - reply > + - flags > + - code > + - data_size > + > +kernel-family: > + headers: [ "binder_internal.h" ] > + > +mcast-groups: > + list: > + - > + name: report > diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig > index 07aa8ae0a058..e2fa620934e2 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 c9d3d0c99c25..b8874dba884e 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_IPC_SELFTEST) += binder_alloc_selftest.o > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > index 76052006bd87..262c120a175a 100644 > --- a/drivers/android/binder.c > +++ b/drivers/android/binder.c > @@ -72,6 +72,7 @@ > > #include <linux/cacheflush.h> > > +#include "binder_netlink.h" > #include "binder_internal.h" > #include "binder_trace.h" > > @@ -2990,6 +2991,110 @@ static void binder_set_txn_from_error(struct binder_transaction *t, int id, > binder_thread_dec_tmpref(from); > } > > +/** > + * binder_find_proc() - find the binder_proc by pid > + * @pid: the target process > + * > + * Returns the struct binder_proc if the pid is found, or NULL otherwise. > + */ > +static struct binder_proc *binder_find_proc(int pid) > +{ > + struct binder_proc *proc; > + > + mutex_lock(&binder_procs_lock); > + hlist_for_each_entry(proc, &binder_procs, proc_node) { > + if (proc->pid == pid) > + break; Wait... can't there be multiple binder_proc instances matching the same pid? I know that binder_proc is a bit of a misnomer but what should you do in such case? Shouldn't you set the flags in _all_ matching pids? Furthermore, there could be a single task talking on multiple contexts, so you could be returning the 'proc' that doesn't match the context that you are looking for right? > + } > + mutex_unlock(&binder_procs_lock); > + > + return proc; > +} > + > +/** > + * binder_netlink_enabled() - check if binder netlink reports are enabled > + * @proc: the binder_proc to check > + * @mask: the categories of binder netlink reports > + * > + * Returns true if certain binder netlink reports are enabled for this binder > + * proc (when per-process overriding takes effect) or context. > + */ > +static bool binder_netlink_enabled(struct binder_proc *proc, u32 mask) > +{ > + struct binder_context *context = proc->context; > + > + if (!genl_has_listeners(&binder_nl_family, &init_net, BINDER_NLGRP_REPORT)) > + return false; > + > + if (proc->report_flags & BINDER_FLAG_OVERRIDE) > + return (proc->report_flags & mask) != 0; > + else > + return (context->report_flags & mask) != 0; > +} > + > +/** > + * binder_netlink_report() - report one binder netlink event > + * @context: the binder context > + * @err: copy of binder_driver_return_protocol returned to the sender > + * @pid: sender process > + * @tid: sender thread > + * @to_pid: target process > + * @to_tid: target thread > + * @reply: whether the binder transaction is a reply > + * @tr: the binder transaction data > + * > + * Packs the report data into a binder netlink message and send it. > + */ > +static void binder_netlink_report(struct binder_context *context, u32 err, > + u32 pid, u32 tid, u32 to_pid, u32 to_tid, Instead of all these parameters, is there a way to pass the transaction itself? Isn't this info already populated there? I think it even holds the info you are looking for from the 'binder_transaction_data' below. > + u32 reply, > + struct binder_transaction_data *tr) > +{ > + struct sk_buff *skb; > + void *hdr; > + int ret; > + > + trace_binder_netlink_report(context->name, err, pid, tid, to_pid, > + to_tid, reply, tr); > + > + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL); > + if (!skb) { > + pr_err("Failed to alloc binder netlink message\n"); > + return; > + } > + > + hdr = genlmsg_put(skb, 0, atomic_inc_return(&context->report_seq), > + &binder_nl_family, 0, BINDER_CMD_REPORT); > + if (!hdr) > + goto free_skb; > + > + if (nla_put_string(skb, BINDER_A_REPORT_CONTEXT, context->name) || > + nla_put_u32(skb, BINDER_A_REPORT_ERR, err) || > + nla_put_u32(skb, BINDER_A_REPORT_FROM_PID, pid) || > + nla_put_u32(skb, BINDER_A_REPORT_FROM_TID, tid) || > + nla_put_u32(skb, BINDER_A_REPORT_TO_PID, to_pid) || > + nla_put_u32(skb, BINDER_A_REPORT_TO_TID, to_tid) || > + nla_put_u32(skb, BINDER_A_REPORT_REPLY, reply) || > + nla_put_u32(skb, BINDER_A_REPORT_FLAGS, tr->flags) || > + nla_put_u32(skb, BINDER_A_REPORT_CODE, tr->code) || > + nla_put_u32(skb, BINDER_A_REPORT_DATA_SIZE, tr->data_size)) > + goto cancel_skb; > + > + genlmsg_end(skb, hdr); > + > + ret = genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, GFP_KERNEL); Thanks for switching to multicast. On this topic, we can only have a single global configuration at a time correct? e.g. context vs per-proc. So all listeners would ahve to work with the same setup? > + if (ret < 0) > + pr_err("Failed to send binder netlink message: %d\n", ret); nit: can you please add an emtpy new line before the return? > + return; > + > +cancel_skb: > + pr_err("Failed to add attributes to binder netlink message\n"); > + genlmsg_cancel(skb, hdr); > +free_skb: > + pr_err("Free binder netlink report message on error\n"); > + nlmsg_free(skb); > +} > + > static void binder_transaction(struct binder_proc *proc, > struct binder_thread *thread, > struct binder_transaction_data *tr, int reply, > @@ -3683,10 +3788,17 @@ 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 > + if (binder_netlink_enabled(proc, BINDER_FLAG_SPAM)) > + binder_netlink_report(context, BR_ONEWAY_SPAM_SUSPECT, > + proc->pid, thread->pid, > + target_proc ? target_proc->pid : 0, > + target_thread ? target_thread->pid : 0, > + reply, tr); > + } else { > tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE; > + } > t->work.type = BINDER_WORK_TRANSACTION; > > if (reply) { > @@ -3736,8 +3848,15 @@ 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; > + if (binder_netlink_enabled(proc, BINDER_FLAG_ASYNC_FROZEN)) > + binder_netlink_report(context, return_error, > + proc->pid, thread->pid, > + target_proc ? target_proc->pid : 0, > + target_thread ? target_thread->pid : 0, > + reply, tr); > + } > binder_enqueue_thread_work(thread, tcomplete); > if (return_error && > return_error != BR_TRANSACTION_PENDING_FROZEN) > @@ -3799,6 +3918,13 @@ static void binder_transaction(struct binder_proc *proc, > binder_dec_node_tmpref(target_node); > } > > + if (binder_netlink_enabled(proc, BINDER_FLAG_FAILED)) > + binder_netlink_report(context, return_error, > + proc->pid, thread->pid, > + target_proc ? target_proc->pid : 0, > + target_thread ? target_thread->pid : 0, > + reply, tr); > + > binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, > "%d:%d transaction %s to %d:%d failed %d/%d/%d, code %u size %lld-%lld line %d\n", > proc->pid, thread->pid, reply ? "reply" : > @@ -6334,6 +6460,98 @@ binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer) > mutex_unlock(&binder_deferred_lock); > } > > +/** > + * binder_nl_report_setup_doit() - netlink .doit handler > + * @skb: the metadata struct passed from netlink driver > + * @info: the generic netlink struct passed from netlink driver > + * > + * Implements the .doit function to process binder netlink commands. > + */ > +int binder_nl_report_setup_doit(struct sk_buff *skb, struct genl_info *info) > +{ > + struct binder_context *context = NULL; > + struct binder_device *device; > + struct binder_proc *proc; > + u32 flags, pid; > + void *hdr; > + int ret; > + > + ret = security_binder_setup_report(current_cred()); > + if (ret < 0) { > + NL_SET_ERR_MSG(info->extack, "Permission denied"); > + return ret; > + } > + > + hlist_for_each_entry(device, &binder_devices, hlist) { > + if (!nla_strcmp(info->attrs[BINDER_A_CMD_CONTEXT], > + device->context.name)) { > + context = &device->context; > + break; > + } > + } > + > + if (!context) { > + NL_SET_ERR_MSG(info->extack, "Unknown binder context"); > + return -EINVAL; > + } > + > + pid = nla_get_u32(info->attrs[BINDER_A_CMD_PID]); > + flags = nla_get_u32(info->attrs[BINDER_A_CMD_FLAGS]); > + > + if (!pid) { > + /* Set the global flags for the whole binder context */ > + context->report_flags = flags; > + } else { > + /* Set the per-process flags */ > + proc = binder_find_proc(pid); > + if (!proc) { > + NL_SET_ERR_MSG_FMT(info->extack, > + "Invalid binder report pid %u", > + pid); > + ret = -EINVAL; > + goto err_exit; > + } > + > + proc->report_flags = flags; > + } > + > + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL); > + if (!skb) { > + pr_err("Failed to alloc binder netlink reply message\n"); > + ret = -ENOMEM; > + goto err_exit; > + } > + > + hdr = genlmsg_iput(skb, info); > + if (!hdr) > + goto free_skb; > + > + if (nla_put_string(skb, BINDER_A_CMD_CONTEXT, context->name) || > + nla_put_u32(skb, BINDER_A_CMD_PID, pid) || > + nla_put_u32(skb, BINDER_A_CMD_FLAGS, flags)) > + goto cancel_skb; > + > + genlmsg_end(skb, hdr); > + > + if (genlmsg_reply(skb, info)) { > + pr_err("Failed to send binder netlink reply message\n"); > + ret = -EFAULT; > + goto err_exit; > + } > + > + return 0; > + > +cancel_skb: > + pr_err("Failed to add reply attributes to binder netlink message\n"); > + genlmsg_cancel(skb, hdr); > +free_skb: > + pr_err("Free binder netlink reply message on error\n"); > + nlmsg_free(skb); > + ret = -EMSGSIZE; > +err_exit: > + return ret; > +} > + > static void print_binder_transaction_ilocked(struct seq_file *m, > struct binder_proc *proc, > const char *prefix, > @@ -7013,6 +7231,11 @@ static int __init binder_init(void) > if (ret) > goto err_init_binder_device_failed; > > + ret = genl_register_family(&binder_nl_family); > + if (ret) { You don't undo init_binderfs() here? If that seems hard, then you can move up the genl registration instead, leaving init_binderfs() last. However, you would need to then undo the genl_register_family() call I suppose. > + pr_err("Failed to register binder netlink family\n"); > + goto err_init_binder_device_failed; > + } > return ret; > > err_init_binder_device_failed: > diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h > index 6a66c9769c6c..8ddd1ddea8e0 100644 > --- a/drivers/android/binder_internal.h > +++ b/drivers/android/binder_internal.h > @@ -11,15 +11,28 @@ > #include <linux/stddef.h> > #include <linux/types.h> > #include <linux/uidgid.h> > +#include <net/genetlink.h> > #include <uapi/linux/android/binderfs.h> > #include "binder_alloc.h" > #include "dbitmap.h" > > +/** > + * struct binder_context - information about a binder domain > + * @binder_context_mgr_node: the context manager > + * @context_mgr_node_lock: the lock protecting the above context manager node > + * @binder_context_mgr_uid: the uid of the above context manager > + * @name: the name of the binder device > + * @report_flags: the categories of binder transactions that would > + * be reported (see enum binder_report_flag). > + * @report_seq: the seq number of the generic netlink report > + */ > struct binder_context { > struct binder_node *binder_context_mgr_node; > struct mutex context_mgr_node_lock; > kuid_t binder_context_mgr_uid; > const char *name; > + u32 report_flags; > + atomic_t report_seq; > }; > > /** > @@ -413,6 +426,8 @@ struct binder_ref { > * @binderfs_entry: process-specific binderfs log file > * @oneway_spam_detection_enabled: process enabled oneway spam detection > * or not > + * @report_flags: the categories of binder transactions that would > + * be reported (see enum binder_genl_flag). > * > * Bookkeeping structure for binder processes > */ > @@ -451,6 +466,7 @@ struct binder_proc { > spinlock_t outer_lock; > struct dentry *binderfs_entry; > bool oneway_spam_detection_enabled; > + u32 report_flags; > }; > > /** > diff --git a/drivers/android/binder_netlink.c b/drivers/android/binder_netlink.c > new file mode 100644 > index 000000000000..9dc1820951c3 > --- /dev/null > +++ b/drivers/android/binder_netlink.c > @@ -0,0 +1,46 @@ > +// 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> > + > +/* BINDER_CMD_REPORT_SETUP - do */ > +static const struct nla_policy binder_report_setup_nl_policy[BINDER_A_CMD_FLAGS + 1] = { > + [BINDER_A_CMD_CONTEXT] = { .type = NLA_NUL_STRING, }, > + [BINDER_A_CMD_PID] = { .type = NLA_U32, }, > + [BINDER_A_CMD_FLAGS] = NLA_POLICY_MASK(NLA_U32, 0xf), > +}; > + > +/* Ops table for binder */ > +static const struct genl_split_ops binder_nl_ops[] = { > + { > + .cmd = BINDER_CMD_REPORT_SETUP, > + .doit = binder_nl_report_setup_doit, > + .policy = binder_report_setup_nl_policy, > + .maxattr = BINDER_A_CMD_FLAGS, > + .flags = GENL_CMD_CAP_DO, > + }, > +}; > + > +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..0ef8c91ab319 > --- /dev/null > +++ b/drivers/android/binder_netlink.h > @@ -0,0 +1,23 @@ > +/* 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> > + > +int binder_nl_report_setup_doit(struct sk_buff *skb, struct genl_info *info); > + > +enum { > + BINDER_NLGRP_REPORT, > +}; > + > +extern struct genl_family binder_nl_family; > + > +#endif /* _LINUX_BINDER_GEN_H */ > diff --git a/drivers/android/binder_trace.h b/drivers/android/binder_trace.h > index 16de1b9e72f7..6fb454bcd857 100644 > --- a/drivers/android/binder_trace.h > +++ b/drivers/android/binder_trace.h > @@ -423,6 +423,41 @@ TRACE_EVENT(binder_return, > "unknown") > ); > > +TRACE_EVENT(binder_netlink_report, > + TP_PROTO(const char *name, u32 err, u32 pid, u32 tid, u32 to_pid, > + u32 to_tid, u32 reply, struct binder_transaction_data *tr), Similarly here I think you could get away with passing 'struct binder_transaction' instead of all the individual fields. > + TP_ARGS(name, err, pid, tid, to_pid, to_tid, reply, tr), > + TP_STRUCT__entry( > + __field(const char *, name) > + __field(u32, err) > + __field(u32, pid) > + __field(u32, tid) > + __field(u32, to_pid) > + __field(u32, to_tid) > + __field(u32, reply) > + __field(u32, flags) > + __field(u32, code) > + __field(binder_size_t, data_size) > + ), > + TP_fast_assign( > + __entry->name = name; > + __entry->err = err; > + __entry->pid = pid; > + __entry->tid = tid; > + __entry->to_pid = to_pid; > + __entry->to_tid = to_tid; > + __entry->reply = reply; > + __entry->flags = tr->flags; > + __entry->code = tr->code; > + __entry->data_size = tr->data_size; > + ), > + TP_printk("%s: %d %d:%d -> %d:%d %s flags=0x08%x code=%d %llu", > + __entry->name, __entry->err, __entry->pid, __entry->tid, > + __entry->to_pid, __entry->to_tid, > + __entry->reply ? "reply" : "", > + __entry->flags, __entry->code, __entry->data_size) > +); > + > #endif /* _BINDER_TRACE_H */ > > #undef TRACE_INCLUDE_PATH > diff --git a/include/uapi/linux/android/binder_netlink.h b/include/uapi/linux/android/binder_netlink.h > new file mode 100644 > index 000000000000..fa926ed19507 > --- /dev/null > +++ b/include/uapi/linux/android/binder_netlink.h > @@ -0,0 +1,57 @@ > +/* 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 > + > +/* > + * Define what kind of binder transactions should be reported. > + */ > +enum binder_flag { > + BINDER_FLAG_FAILED = 1, > + BINDER_FLAG_ASYNC_FROZEN = 2, > + BINDER_FLAG_SPAM = 4, > + BINDER_FLAG_OVERRIDE = 8, > +}; > + > +enum { > + BINDER_A_CMD_CONTEXT = 1, > + BINDER_A_CMD_PID, > + BINDER_A_CMD_FLAGS, > + > + __BINDER_A_CMD_MAX, > + BINDER_A_CMD_MAX = (__BINDER_A_CMD_MAX - 1) > +}; > + > +enum { > + BINDER_A_REPORT_CONTEXT = 1, > + BINDER_A_REPORT_ERR, > + BINDER_A_REPORT_FROM_PID, > + BINDER_A_REPORT_FROM_TID, > + BINDER_A_REPORT_TO_PID, > + BINDER_A_REPORT_TO_TID, > + BINDER_A_REPORT_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_SETUP = 1, > + BINDER_CMD_REPORT, > + > + __BINDER_CMD_MAX, > + BINDER_CMD_MAX = (__BINDER_CMD_MAX - 1) > +}; > + > +#define BINDER_MCGRP_REPORT "report" > + > +#endif /* _UAPI_LINUX_ANDROID_BINDER_NETLINK_H */ > -- > 2.48.1.711.g2feabab25a-goog >
Sorry for resending this email. My email client was wrongly set to HTML mode. On Mon, Mar 10, 2025 at 9:13 PM Carlos Llamas <cmllamas@google.com> wrote: > > On Mon, Mar 03, 2025 at 12:02:11PM -0800, Li Li wrote: > > From: Li Li <dualli@google.com> > > > > +/** > > + * binder_find_proc() - find the binder_proc by pid > > + * @pid: the target process > > + * > > + * Returns the struct binder_proc if the pid is found, or NULL otherwise. > > + */ > > +static struct binder_proc *binder_find_proc(int pid) > > +{ > > + struct binder_proc *proc; > > + > > + mutex_lock(&binder_procs_lock); > > + hlist_for_each_entry(proc, &binder_procs, proc_node) { > > + if (proc->pid == pid) > > + break; > > Wait... can't there be multiple binder_proc instances matching the same > pid? I know that binder_proc is a bit of a misnomer but what should you > do in such case? Shouldn't you set the flags in _all_ matching pids? > > Furthermore, there could be a single task talking on multiple contexts, > so you could be returning the 'proc' that doesn't match the context that > you are looking for right? > You're right. I should update this logic to search the process within a certain binder_context only. > > + } > > + mutex_unlock(&binder_procs_lock); > > + > > + return proc; > > +} > > + > > +/** > > + * binder_netlink_enabled() - check if binder netlink reports are enabled > > + * @proc: the binder_proc to check > > + * @mask: the categories of binder netlink reports > > + * > > + * Returns true if certain binder netlink reports are enabled for this binder > > + * proc (when per-process overriding takes effect) or context. > > + */ > > +static bool binder_netlink_enabled(struct binder_proc *proc, u32 mask) > > +{ > > + struct binder_context *context = proc->context; > > + > > + if (!genl_has_listeners(&binder_nl_family, &init_net, BINDER_NLGRP_REPORT)) > > + return false; > > + > > + if (proc->report_flags & BINDER_FLAG_OVERRIDE) > > + return (proc->report_flags & mask) != 0; > > + else > > + return (context->report_flags & mask) != 0; > > +} > > + > > +/** > > + * binder_netlink_report() - report one binder netlink event > > + * @context: the binder context > > + * @err: copy of binder_driver_return_protocol returned to the sender > > + * @pid: sender process > > + * @tid: sender thread > > + * @to_pid: target process > > + * @to_tid: target thread > > + * @reply: whether the binder transaction is a reply > > + * @tr: the binder transaction data > > + * > > + * Packs the report data into a binder netlink message and send it. > > + */ > > +static void binder_netlink_report(struct binder_context *context, u32 err, > > + u32 pid, u32 tid, u32 to_pid, u32 to_tid, > > Instead of all these parameters, is there a way to pass the transaction > itself? Isn't this info already populated there? I think it even holds > the info you are looking for from the 'binder_transaction_data' below. > The binder_transaction_data doesn't include all of pid, tid, to_pid and to_tid. > > + u32 reply, > > + struct binder_transaction_data *tr) > > +{ > > + struct sk_buff *skb; > > + void *hdr; > > + int ret; > > + > > + trace_binder_netlink_report(context->name, err, pid, tid, to_pid, > > + to_tid, reply, tr); > > + > > + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL); > > + if (!skb) { > > + pr_err("Failed to alloc binder netlink message\n"); > > + return; > > + } > > + > > + hdr = genlmsg_put(skb, 0, atomic_inc_return(&context->report_seq), > > + &binder_nl_family, 0, BINDER_CMD_REPORT); > > + if (!hdr) > > + goto free_skb; > > + > > + if (nla_put_string(skb, BINDER_A_REPORT_CONTEXT, context->name) || > > + nla_put_u32(skb, BINDER_A_REPORT_ERR, err) || > > + nla_put_u32(skb, BINDER_A_REPORT_FROM_PID, pid) || > > + nla_put_u32(skb, BINDER_A_REPORT_FROM_TID, tid) || > > + nla_put_u32(skb, BINDER_A_REPORT_TO_PID, to_pid) || > > + nla_put_u32(skb, BINDER_A_REPORT_TO_TID, to_tid) || > > + nla_put_u32(skb, BINDER_A_REPORT_REPLY, reply) || > > + nla_put_u32(skb, BINDER_A_REPORT_FLAGS, tr->flags) || > > + nla_put_u32(skb, BINDER_A_REPORT_CODE, tr->code) || > > + nla_put_u32(skb, BINDER_A_REPORT_DATA_SIZE, tr->data_size)) > > + goto cancel_skb; > > + > > + genlmsg_end(skb, hdr); > > + > > + ret = genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, GFP_KERNEL); > > Thanks for switching to multicast. On this topic, we can only have a > single global configuration at a time correct? e.g. context vs per-proc. > So all listeners would ahve to work with the same setup? > We only have a single global configuration, which can include both context and proc setup. Yes, all listeners work with the same setup as we have only one multicast group defined. The user space code can demux it by checking the context field of the netlink messages. > > + if (ret < 0) > > + pr_err("Failed to send binder netlink message: %d\n", ret); > > nit: can you please add an emtpy new line before the return? > Sure. > > @@ -7013,6 +7231,11 @@ static int __init binder_init(void) > > if (ret) > > goto err_init_binder_device_failed; > > > > + ret = genl_register_family(&binder_nl_family); > > + if (ret) { > > You don't undo init_binderfs() here? If that seems hard, then you can > move up the genl registration instead, leaving init_binderfs() last. > However, you would need to then undo the genl_register_family() call I > suppose. > The current logic allows binder driver to continue working even if genl_register_family fails. But your suggestion makes sense. I'll move it up and undo it if anything fails. > > +TRACE_EVENT(binder_netlink_report, > > + TP_PROTO(const char *name, u32 err, u32 pid, u32 tid, u32 to_pid, > > + u32 to_tid, u32 reply, struct binder_transaction_data *tr), > > Similarly here I think you could get away with passing 'struct > binder_transaction' instead of all the individual fields. > Same as above, the pid/tid fields are not in the struct binder_transaction (or redacted for oneway txns).
On Wed, Mar 12, 2025 at 11:49:02AM -0700, Li Li wrote: > > > + mutex_lock(&binder_procs_lock); > > > + hlist_for_each_entry(proc, &binder_procs, proc_node) { > > > + if (proc->pid == pid) > > > + break; > > > > Wait... can't there be multiple binder_proc instances matching the same > > pid? I know that binder_proc is a bit of a misnomer but what should you > > do in such case? Shouldn't you set the flags in _all_ matching pids? > > > > Furthermore, there could be a single task talking on multiple contexts, > > so you could be returning the 'proc' that doesn't match the context that > > you are looking for right? > > > > You're right. I should update this logic to search the process within a > certain binder_context only. Also, note the comment about multiple 'struct binder_proc' matching the same desired pid. > > > +static void binder_netlink_report(struct binder_context *context, u32 err, > > > + u32 pid, u32 tid, u32 to_pid, u32 to_tid, > > > > Instead of all these parameters, is there a way to pass the transaction > > itself? Isn't this info already populated there? I think it even holds > > the info you are looking for from the 'binder_transaction_data' below. > > > > The binder_transaction_data doesn't include all of pid, tid, to_pid and to_tid. I'm not referring to binder_transaction_data, I mean 'struct binder_transaction'. I _think_ this should have all you need? > > > + ret = genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, GFP_KERNEL); > > > > Thanks for switching to multicast. On this topic, we can only have a > > single global configuration at a time correct? e.g. context vs per-proc. > > So all listeners would ahve to work with the same setup? > > > > We only have a single global configuration, which can include both > context and proc setup. > Yes, all listeners work with the same setup as we have only one > multicast group defined. > The user space code can demux it by checking the context field of the > netlink messages. Ack. I understand the demux solution. I was wondering if we'll need to OR the different configurations (per-proc and flags) from each listener in that case. > > > +TRACE_EVENT(binder_netlink_report, > > > + TP_PROTO(const char *name, u32 err, u32 pid, u32 tid, u32 to_pid, > > > + u32 to_tid, u32 reply, struct binder_transaction_data *tr), > > > > Similarly here I think you could get away with passing 'struct > > binder_transaction' instead of all the individual fields. > > > > Same as above, the pid/tid fields are not in the struct > binder_transaction (or redacted for oneway txns). There is something off here. You have t->from_{pid|tid} and also t->to_{proc|thead} that you can use. Isn't this what you are looking for? -- Carlos Llamas
On Wed, Mar 12, 2025 at 1:14 PM Carlos Llamas <cmllamas@google.com> wrote: > > On Wed, Mar 12, 2025 at 11:49:02AM -0700, Li Li wrote: > > > > + mutex_lock(&binder_procs_lock); > > > > + hlist_for_each_entry(proc, &binder_procs, proc_node) { > > > > + if (proc->pid == pid) > > > > + break; > > > > > > Wait... can't there be multiple binder_proc instances matching the same > > > pid? I know that binder_proc is a bit of a misnomer but what should you > > > do in such case? Shouldn't you set the flags in _all_ matching pids? > > > > > > Furthermore, there could be a single task talking on multiple contexts, > > > so you could be returning the 'proc' that doesn't match the context that > > > you are looking for right? > > > > > > > You're right. I should update this logic to search the process within a > > certain binder_context only. > > Also, note the comment about multiple 'struct binder_proc' matching the > same desired pid. > Yes, multiple matching can be found when the context is not specified. I'll take care of that as well. > > > > +static void binder_netlink_report(struct binder_context *context, u32 err, > > > > + u32 pid, u32 tid, u32 to_pid, u32 to_tid, > > > > > > Instead of all these parameters, is there a way to pass the transaction > > > itself? Isn't this info already populated there? I think it even holds > > > the info you are looking for from the 'binder_transaction_data' below. > > > > > > > The binder_transaction_data doesn't include all of pid, tid, to_pid and to_tid. > > I'm not referring to binder_transaction_data, I mean 'struct > binder_transaction'. I _think_ this should have all you need? > Ah, yes, let me take a closer look and optimize this. Thanks! > > > > + ret = genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, GFP_KERNEL); > > > > > > Thanks for switching to multicast. On this topic, we can only have a > > > single global configuration at a time correct? e.g. context vs per-proc. > > > So all listeners would ahve to work with the same setup? > > > > > > > We only have a single global configuration, which can include both > > context and proc setup. > > Yes, all listeners work with the same setup as we have only one > > multicast group defined. > > The user space code can demux it by checking the context field of the > > netlink messages. > > Ack. I understand the demux solution. I was wondering if we'll need to > OR the different configurations (per-proc and flags) from each listener > in that case. > They are already OR'ed from all listeners. > > > > +TRACE_EVENT(binder_netlink_report, > > > > + TP_PROTO(const char *name, u32 err, u32 pid, u32 tid, u32 to_pid, > > > > + u32 to_tid, u32 reply, struct binder_transaction_data *tr), > > > > > > Similarly here I think you could get away with passing 'struct > > > binder_transaction' instead of all the individual fields. > > > > > > > Same as above, the pid/tid fields are not in the struct > > binder_transaction (or redacted for oneway txns). > > There is something off here. You have t->from_{pid|tid} and also > t->to_{proc|thead} that you can use. Isn't this what you are looking > for? > > -- > Carlos Llamas
diff --git a/Documentation/admin-guide/binder_netlink.rst b/Documentation/admin-guide/binder_netlink.rst new file mode 100644 index 000000000000..83f54f0d8c45 --- /dev/null +++ b/Documentation/admin-guide/binder_netlink.rst @@ -0,0 +1,108 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================================== +Generic Netlink for the Android Binder Driver (Binder Netlink) +============================================================== + +The Generic Netlink subsystem in the Linux kernel provides a generic way for +the Linux kernel to communicate with the user space applications via binder +driver. It is used to report binder transaction errors and warnings to user +space administration process. The driver allows multiple binder devices and +their corresponding binder contexts. Each context and their processes can be +configured independently to report their own transactions. + +Basically, the user space code uses the BINDER_CMD_REPORT_SETUP command to +request what kind of binder transactions should be reported by the driver. +The driver then echoes the attributes in a reply message to acknowledge the +request. The BINDER_CMD_REPORT_SETUP command also registers the current +user space process to receive the reports. This BINDER_CMD_REPORT_SETUP +command is protected by SELinux, to prevent unauthorized user apps from +triggering unexpected reports. + +Currently the driver reports these binder transaction errors and warnings. +1. "FAILED" transactions that fail to reach the target process; +2. "ASYNC_FROZEN" transactions that are delayed due to the target process +being frozen by cgroup freezer; or +3. "SPAM" transactions that are considered spamming according to existing +logic in binder_alloc.c. + +When the specified binder transactions happen, the driver uses the +BINDER_CMD_REPORT command to send a generic netlink message to the +registered process, containing the payload defined in binder.yaml. + +More details about the flags, attributes and operations can be found at the +the doc sections in Documentations/netlink/specs/binder.yaml and the +kernel-doc comments of the new source code in binder.{h|c}. + +Using Binder Netlink +-------------------- + +The Binder Netlink can be used in the same way as any other generic netlink +drivers. Userspace application uses a raw netlink socket to send commands +to and receive packets from the kernel driver. + +Usage example (user space pseudo code): + +:: + /* + * send() below is overloaded to pack netlink commands and attributes + * to nlattr/genlmsghdr/nlmsghdr and then send to the netlink socket. + * + * recv() below is overloaded to receive the raw netlink message from + * the netlink socket, parse nlmsghdr/genlmsghdr to find the netlink + * command and then return the nlattr payload. + */ + + // open netlink socket + int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC); + + // bind netlink socket + bind(fd, struct socketaddr); + + // get the family id of the binder netlink + send(fd, CTRL_CMD_GETFAMILY, CTRL_ATTR_FAMILY_NAME, + BINDER_FAMILY_NAME); + void *data = recv(CTRL_CMD_NEWFAMILY); + if (!has_nla_type(data, CTRL_ATTR_FAMILY_ID)) { + // Binder Netlink isn't available on this version of Linux kernel + return; + } + __u16 id = nla(data)[CTRL_ATTR_FAMILY_ID]; + __u32 grp = nla(data)[CTRL_ATTR_MCAST_GROUPS][CTRL_ATTR_MCAST_GRP_ID]; + + // join the mcast group to listen to the binder netlink messages + setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &grp, sizeof(grp)); + + // enable per-context binder report + send(fd, id, BINDER_CMD_REPORT_SETUP, "binder", 0, + BINDER_FLAG_FAILED | BINDER_FLAG_DELAYED); + + // confirm the per-context configuration + data = recv(fd, BINDER_CMD_REPLY); + char *context = nla(data)[BINDER_A_CMD_CONTEXT]; + __u32 pid = nla(data)[BINDER_A_CMD_PID]; + __u32 flags = nla(data)[BINDER_A_CMD_FLAGS]; + + // set optional per-process report, overriding the per-context one + send(fd, id, BINDER_CMD_REPORT_SETUP, "binder", getpid(), + BINDER_FLAG_SPAM | BINDER_REPORT_OVERRIDE); + + // confirm the optional per-process configuration + data = recv(fd, BINDER_CMD_REPLY); + context = nla(data)[BINDER_A_CMD_CONTEXT]; + pid = nla(data)[BINDER_A_CMD_PID]; + flags = nla(data)[BINDER_A_CMD_FLAGS]; + + // wait and read all binder reports + while (running) { + data = recv(fd, BINDER_CMD_REPORT); + auto *attr = nla(data)[BINDER_A_REPORT_XXX]; + + // process binder report + do_something(*attr); + } + + // clean up + send(fd, id, BINDER_CMD_REPORT_SETUP, 0, 0); + send(fd, id, BINDER_CMD_REPORT_SETUP, getpid(), 0); + close(fd); diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst index c8af32a8f800..655f39ddf1cf 100644 --- a/Documentation/admin-guide/index.rst +++ b/Documentation/admin-guide/index.rst @@ -120,6 +120,7 @@ Block-layer and filesystem administration :maxdepth: 1 bcache + binder_netlink binderfs blockdev/index cifs/index diff --git a/Documentation/netlink/specs/binder.yaml b/Documentation/netlink/specs/binder.yaml new file mode 100644 index 000000000000..e184645f6c41 --- /dev/null +++ b/Documentation/netlink/specs/binder.yaml @@ -0,0 +1,116 @@ +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) + +name: binder +protocol: genetlink +uapi-header: linux/android/binder_netlink.h +doc: Netlink protocol to report binder transaction errors and warnings. + +definitions: + - + type: flags + name: flag + doc: Define what kind of binder transactions should be reported. + entries: [ failed, async-frozen, spam, override ] + +attribute-sets: + - + name: cmd + doc: The supported attributes of "report-setup" command. + attributes: + - + name: context + type: string + doc: The binder context to enable binder netlink report. + - + name: pid + type: u32 + doc: The binder proc to enable binder netlink report. + - + name: flags + type: u32 + enum: flag + doc: What kind of binder transactions should be reported. + - + name: report + doc: The supported attributes of "report" command + attributes: + - + name: context + type: string + doc: The binder context where the binder netlink report happens. + - + name: err + type: u32 + doc: Copy of binder_driver_return_protocol returned to the sender. + - + name: from_pid + type: u32 + doc: Sender pid of the corresponding binder transaction. + - + name: from_tid + type: u32 + doc: Sender tid of the corresponding binder transaction. + - + name: to_pid + type: u32 + doc: Target pid of the corresponding binder transaction. + - + name: to_tid + type: u32 + doc: Target tid of the corresponding binder transaction. + - + name: reply + type: u32 + doc: 1 means the transaction is a reply, 0 otherwise. + - + name: flags + type: u32 + doc: Copy of binder_transaction_data->flags. + - + name: code + type: u32 + doc: Copy of binder_transaction_data->code. + - + name: data_size + type: u32 + doc: Copy of binder_transaction_data->data_size. + +operations: + list: + - + name: report-setup + doc: Set flags from user space. + attribute-set: cmd + + do: + request: ¶ms + attributes: + - context + - pid + - flags + reply: *params + - + name: report + doc: Send the requested reports to user space. + attribute-set: report + + event: + attributes: + - context + - err + - from_pid + - from_tid + - to_pid + - to_tid + - reply + - flags + - code + - data_size + +kernel-family: + headers: [ "binder_internal.h" ] + +mcast-groups: + list: + - + name: report diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig index 07aa8ae0a058..e2fa620934e2 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 c9d3d0c99c25..b8874dba884e 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_IPC_SELFTEST) += binder_alloc_selftest.o diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 76052006bd87..262c120a175a 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -72,6 +72,7 @@ #include <linux/cacheflush.h> +#include "binder_netlink.h" #include "binder_internal.h" #include "binder_trace.h" @@ -2990,6 +2991,110 @@ static void binder_set_txn_from_error(struct binder_transaction *t, int id, binder_thread_dec_tmpref(from); } +/** + * binder_find_proc() - find the binder_proc by pid + * @pid: the target process + * + * Returns the struct binder_proc if the pid is found, or NULL otherwise. + */ +static struct binder_proc *binder_find_proc(int pid) +{ + struct binder_proc *proc; + + mutex_lock(&binder_procs_lock); + hlist_for_each_entry(proc, &binder_procs, proc_node) { + if (proc->pid == pid) + break; + } + mutex_unlock(&binder_procs_lock); + + return proc; +} + +/** + * binder_netlink_enabled() - check if binder netlink reports are enabled + * @proc: the binder_proc to check + * @mask: the categories of binder netlink reports + * + * Returns true if certain binder netlink reports are enabled for this binder + * proc (when per-process overriding takes effect) or context. + */ +static bool binder_netlink_enabled(struct binder_proc *proc, u32 mask) +{ + struct binder_context *context = proc->context; + + if (!genl_has_listeners(&binder_nl_family, &init_net, BINDER_NLGRP_REPORT)) + return false; + + if (proc->report_flags & BINDER_FLAG_OVERRIDE) + return (proc->report_flags & mask) != 0; + else + return (context->report_flags & mask) != 0; +} + +/** + * binder_netlink_report() - report one binder netlink event + * @context: the binder context + * @err: copy of binder_driver_return_protocol returned to the sender + * @pid: sender process + * @tid: sender thread + * @to_pid: target process + * @to_tid: target thread + * @reply: whether the binder transaction is a reply + * @tr: the binder transaction data + * + * Packs the report data into a binder netlink message and send it. + */ +static void binder_netlink_report(struct binder_context *context, u32 err, + u32 pid, u32 tid, u32 to_pid, u32 to_tid, + u32 reply, + struct binder_transaction_data *tr) +{ + struct sk_buff *skb; + void *hdr; + int ret; + + trace_binder_netlink_report(context->name, err, pid, tid, to_pid, + to_tid, reply, tr); + + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!skb) { + pr_err("Failed to alloc binder netlink message\n"); + return; + } + + hdr = genlmsg_put(skb, 0, atomic_inc_return(&context->report_seq), + &binder_nl_family, 0, BINDER_CMD_REPORT); + if (!hdr) + goto free_skb; + + if (nla_put_string(skb, BINDER_A_REPORT_CONTEXT, context->name) || + nla_put_u32(skb, BINDER_A_REPORT_ERR, err) || + nla_put_u32(skb, BINDER_A_REPORT_FROM_PID, pid) || + nla_put_u32(skb, BINDER_A_REPORT_FROM_TID, tid) || + nla_put_u32(skb, BINDER_A_REPORT_TO_PID, to_pid) || + nla_put_u32(skb, BINDER_A_REPORT_TO_TID, to_tid) || + nla_put_u32(skb, BINDER_A_REPORT_REPLY, reply) || + nla_put_u32(skb, BINDER_A_REPORT_FLAGS, tr->flags) || + nla_put_u32(skb, BINDER_A_REPORT_CODE, tr->code) || + nla_put_u32(skb, BINDER_A_REPORT_DATA_SIZE, tr->data_size)) + goto cancel_skb; + + genlmsg_end(skb, hdr); + + ret = genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, GFP_KERNEL); + if (ret < 0) + pr_err("Failed to send binder netlink message: %d\n", ret); + return; + +cancel_skb: + pr_err("Failed to add attributes to binder netlink message\n"); + genlmsg_cancel(skb, hdr); +free_skb: + pr_err("Free binder netlink report message on error\n"); + nlmsg_free(skb); +} + static void binder_transaction(struct binder_proc *proc, struct binder_thread *thread, struct binder_transaction_data *tr, int reply, @@ -3683,10 +3788,17 @@ 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 + if (binder_netlink_enabled(proc, BINDER_FLAG_SPAM)) + binder_netlink_report(context, BR_ONEWAY_SPAM_SUSPECT, + proc->pid, thread->pid, + target_proc ? target_proc->pid : 0, + target_thread ? target_thread->pid : 0, + reply, tr); + } else { tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE; + } t->work.type = BINDER_WORK_TRANSACTION; if (reply) { @@ -3736,8 +3848,15 @@ 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; + if (binder_netlink_enabled(proc, BINDER_FLAG_ASYNC_FROZEN)) + binder_netlink_report(context, return_error, + proc->pid, thread->pid, + target_proc ? target_proc->pid : 0, + target_thread ? target_thread->pid : 0, + reply, tr); + } binder_enqueue_thread_work(thread, tcomplete); if (return_error && return_error != BR_TRANSACTION_PENDING_FROZEN) @@ -3799,6 +3918,13 @@ static void binder_transaction(struct binder_proc *proc, binder_dec_node_tmpref(target_node); } + if (binder_netlink_enabled(proc, BINDER_FLAG_FAILED)) + binder_netlink_report(context, return_error, + proc->pid, thread->pid, + target_proc ? target_proc->pid : 0, + target_thread ? target_thread->pid : 0, + reply, tr); + binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, "%d:%d transaction %s to %d:%d failed %d/%d/%d, code %u size %lld-%lld line %d\n", proc->pid, thread->pid, reply ? "reply" : @@ -6334,6 +6460,98 @@ binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer) mutex_unlock(&binder_deferred_lock); } +/** + * binder_nl_report_setup_doit() - netlink .doit handler + * @skb: the metadata struct passed from netlink driver + * @info: the generic netlink struct passed from netlink driver + * + * Implements the .doit function to process binder netlink commands. + */ +int binder_nl_report_setup_doit(struct sk_buff *skb, struct genl_info *info) +{ + struct binder_context *context = NULL; + struct binder_device *device; + struct binder_proc *proc; + u32 flags, pid; + void *hdr; + int ret; + + ret = security_binder_setup_report(current_cred()); + if (ret < 0) { + NL_SET_ERR_MSG(info->extack, "Permission denied"); + return ret; + } + + hlist_for_each_entry(device, &binder_devices, hlist) { + if (!nla_strcmp(info->attrs[BINDER_A_CMD_CONTEXT], + device->context.name)) { + context = &device->context; + break; + } + } + + if (!context) { + NL_SET_ERR_MSG(info->extack, "Unknown binder context"); + return -EINVAL; + } + + pid = nla_get_u32(info->attrs[BINDER_A_CMD_PID]); + flags = nla_get_u32(info->attrs[BINDER_A_CMD_FLAGS]); + + if (!pid) { + /* Set the global flags for the whole binder context */ + context->report_flags = flags; + } else { + /* Set the per-process flags */ + proc = binder_find_proc(pid); + if (!proc) { + NL_SET_ERR_MSG_FMT(info->extack, + "Invalid binder report pid %u", + pid); + ret = -EINVAL; + goto err_exit; + } + + proc->report_flags = flags; + } + + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!skb) { + pr_err("Failed to alloc binder netlink reply message\n"); + ret = -ENOMEM; + goto err_exit; + } + + hdr = genlmsg_iput(skb, info); + if (!hdr) + goto free_skb; + + if (nla_put_string(skb, BINDER_A_CMD_CONTEXT, context->name) || + nla_put_u32(skb, BINDER_A_CMD_PID, pid) || + nla_put_u32(skb, BINDER_A_CMD_FLAGS, flags)) + goto cancel_skb; + + genlmsg_end(skb, hdr); + + if (genlmsg_reply(skb, info)) { + pr_err("Failed to send binder netlink reply message\n"); + ret = -EFAULT; + goto err_exit; + } + + return 0; + +cancel_skb: + pr_err("Failed to add reply attributes to binder netlink message\n"); + genlmsg_cancel(skb, hdr); +free_skb: + pr_err("Free binder netlink reply message on error\n"); + nlmsg_free(skb); + ret = -EMSGSIZE; +err_exit: + return ret; +} + static void print_binder_transaction_ilocked(struct seq_file *m, struct binder_proc *proc, const char *prefix, @@ -7013,6 +7231,11 @@ static int __init binder_init(void) if (ret) goto err_init_binder_device_failed; + ret = genl_register_family(&binder_nl_family); + if (ret) { + pr_err("Failed to register binder netlink family\n"); + goto err_init_binder_device_failed; + } return ret; err_init_binder_device_failed: diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h index 6a66c9769c6c..8ddd1ddea8e0 100644 --- a/drivers/android/binder_internal.h +++ b/drivers/android/binder_internal.h @@ -11,15 +11,28 @@ #include <linux/stddef.h> #include <linux/types.h> #include <linux/uidgid.h> +#include <net/genetlink.h> #include <uapi/linux/android/binderfs.h> #include "binder_alloc.h" #include "dbitmap.h" +/** + * struct binder_context - information about a binder domain + * @binder_context_mgr_node: the context manager + * @context_mgr_node_lock: the lock protecting the above context manager node + * @binder_context_mgr_uid: the uid of the above context manager + * @name: the name of the binder device + * @report_flags: the categories of binder transactions that would + * be reported (see enum binder_report_flag). + * @report_seq: the seq number of the generic netlink report + */ struct binder_context { struct binder_node *binder_context_mgr_node; struct mutex context_mgr_node_lock; kuid_t binder_context_mgr_uid; const char *name; + u32 report_flags; + atomic_t report_seq; }; /** @@ -413,6 +426,8 @@ struct binder_ref { * @binderfs_entry: process-specific binderfs log file * @oneway_spam_detection_enabled: process enabled oneway spam detection * or not + * @report_flags: the categories of binder transactions that would + * be reported (see enum binder_genl_flag). * * Bookkeeping structure for binder processes */ @@ -451,6 +466,7 @@ struct binder_proc { spinlock_t outer_lock; struct dentry *binderfs_entry; bool oneway_spam_detection_enabled; + u32 report_flags; }; /** diff --git a/drivers/android/binder_netlink.c b/drivers/android/binder_netlink.c new file mode 100644 index 000000000000..9dc1820951c3 --- /dev/null +++ b/drivers/android/binder_netlink.c @@ -0,0 +1,46 @@ +// 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> + +/* BINDER_CMD_REPORT_SETUP - do */ +static const struct nla_policy binder_report_setup_nl_policy[BINDER_A_CMD_FLAGS + 1] = { + [BINDER_A_CMD_CONTEXT] = { .type = NLA_NUL_STRING, }, + [BINDER_A_CMD_PID] = { .type = NLA_U32, }, + [BINDER_A_CMD_FLAGS] = NLA_POLICY_MASK(NLA_U32, 0xf), +}; + +/* Ops table for binder */ +static const struct genl_split_ops binder_nl_ops[] = { + { + .cmd = BINDER_CMD_REPORT_SETUP, + .doit = binder_nl_report_setup_doit, + .policy = binder_report_setup_nl_policy, + .maxattr = BINDER_A_CMD_FLAGS, + .flags = GENL_CMD_CAP_DO, + }, +}; + +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..0ef8c91ab319 --- /dev/null +++ b/drivers/android/binder_netlink.h @@ -0,0 +1,23 @@ +/* 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> + +int binder_nl_report_setup_doit(struct sk_buff *skb, struct genl_info *info); + +enum { + BINDER_NLGRP_REPORT, +}; + +extern struct genl_family binder_nl_family; + +#endif /* _LINUX_BINDER_GEN_H */ diff --git a/drivers/android/binder_trace.h b/drivers/android/binder_trace.h index 16de1b9e72f7..6fb454bcd857 100644 --- a/drivers/android/binder_trace.h +++ b/drivers/android/binder_trace.h @@ -423,6 +423,41 @@ TRACE_EVENT(binder_return, "unknown") ); +TRACE_EVENT(binder_netlink_report, + TP_PROTO(const char *name, u32 err, u32 pid, u32 tid, u32 to_pid, + u32 to_tid, u32 reply, struct binder_transaction_data *tr), + TP_ARGS(name, err, pid, tid, to_pid, to_tid, reply, tr), + TP_STRUCT__entry( + __field(const char *, name) + __field(u32, err) + __field(u32, pid) + __field(u32, tid) + __field(u32, to_pid) + __field(u32, to_tid) + __field(u32, reply) + __field(u32, flags) + __field(u32, code) + __field(binder_size_t, data_size) + ), + TP_fast_assign( + __entry->name = name; + __entry->err = err; + __entry->pid = pid; + __entry->tid = tid; + __entry->to_pid = to_pid; + __entry->to_tid = to_tid; + __entry->reply = reply; + __entry->flags = tr->flags; + __entry->code = tr->code; + __entry->data_size = tr->data_size; + ), + TP_printk("%s: %d %d:%d -> %d:%d %s flags=0x08%x code=%d %llu", + __entry->name, __entry->err, __entry->pid, __entry->tid, + __entry->to_pid, __entry->to_tid, + __entry->reply ? "reply" : "", + __entry->flags, __entry->code, __entry->data_size) +); + #endif /* _BINDER_TRACE_H */ #undef TRACE_INCLUDE_PATH diff --git a/include/uapi/linux/android/binder_netlink.h b/include/uapi/linux/android/binder_netlink.h new file mode 100644 index 000000000000..fa926ed19507 --- /dev/null +++ b/include/uapi/linux/android/binder_netlink.h @@ -0,0 +1,57 @@ +/* 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 + +/* + * Define what kind of binder transactions should be reported. + */ +enum binder_flag { + BINDER_FLAG_FAILED = 1, + BINDER_FLAG_ASYNC_FROZEN = 2, + BINDER_FLAG_SPAM = 4, + BINDER_FLAG_OVERRIDE = 8, +}; + +enum { + BINDER_A_CMD_CONTEXT = 1, + BINDER_A_CMD_PID, + BINDER_A_CMD_FLAGS, + + __BINDER_A_CMD_MAX, + BINDER_A_CMD_MAX = (__BINDER_A_CMD_MAX - 1) +}; + +enum { + BINDER_A_REPORT_CONTEXT = 1, + BINDER_A_REPORT_ERR, + BINDER_A_REPORT_FROM_PID, + BINDER_A_REPORT_FROM_TID, + BINDER_A_REPORT_TO_PID, + BINDER_A_REPORT_TO_TID, + BINDER_A_REPORT_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_SETUP = 1, + BINDER_CMD_REPORT, + + __BINDER_CMD_MAX, + BINDER_CMD_MAX = (__BINDER_CMD_MAX - 1) +}; + +#define BINDER_MCGRP_REPORT "report" + +#endif /* _UAPI_LINUX_ANDROID_BINDER_NETLINK_H */