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path: root/tools/perf/util/scripting-engines/trace-event-perl.c
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/*
 * trace-event-perl.  Feed perf script events to an embedded Perl interpreter.
 *
 * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <linux/bitmap.h>
#include <linux/time64.h>

#include <stdbool.h>
/* perl needs the following define, right after including stdbool.h */
#define HAS_BOOL
#include <EXTERN.h>
#include <perl.h>

#include "../../perf.h"
#include "../callchain.h"
#include "../machine.h"
#include "../thread.h"
#include "../event.h"
#include "../trace-event.h"
#include "../evsel.h"
#include "../debug.h"

void boot_Perf__Trace__Context(pTHX_ CV *cv);
void boot_DynaLoader(pTHX_ CV *cv);
typedef PerlInterpreter * INTERP;

void xs_init(pTHX);

void xs_init(pTHX)
{
	const char *file = __FILE__;
	dXSUB_SYS;

	newXS("Perf::Trace::Context::bootstrap", boot_Perf__Trace__Context,
	      file);
	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
}

INTERP my_perl;

#define TRACE_EVENT_TYPE_MAX				\
	((1 << (sizeof(unsigned short) * 8)) - 1)

static DECLARE_BITMAP(events_defined, TRACE_EVENT_TYPE_MAX);

extern struct scripting_context *scripting_context;

static char *cur_field_name;
static int zero_flag_atom;

static void define_symbolic_value(const char *ev_name,
				  const char *field_name,
				  const char *field_value,
				  const char *field_str)
{
	unsigned long long value;
	dSP;

	value = eval_flag(field_value);

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
	XPUSHs(sv_2mortal(newSVuv(value)));
	XPUSHs(sv_2mortal(newSVpv(field_str, 0)));

	PUTBACK;
	if (get_cv("main::define_symbolic_value", 0))
		call_pv("main::define_symbolic_value", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
}

static void define_symbolic_values(struct print_flag_sym *field,
				   const char *ev_name,
				   const char *field_name)
{
	define_symbolic_value(ev_name, field_name, field->value, field->str);
	if (field->next)
		define_symbolic_values(field->next, ev_name, field_name);
}

static void define_symbolic_field(const char *ev_name,
				  const char *field_name)
{
	dSP;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));

	PUTBACK;
	if (get_cv("main::define_symbolic_field", 0))
		call_pv("main::define_symbolic_field", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
}

static void define_flag_value(const char *ev_name,
			      const char *field_name,
			      const char *field_value,
			      const char *field_str)
{
	unsigned long long value;
	dSP;

	value = eval_flag(field_value);

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
	XPUSHs(sv_2mortal(newSVuv(value)));
	XPUSHs(sv_2mortal(newSVpv(field_str, 0)));

	PUTBACK;
	if (get_cv("main::define_flag_value", 0))
		call_pv("main::define_flag_value", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
}

static void define_flag_values(struct print_flag_sym *field,
			       const char *ev_name,
			       const char *field_name)
{
	define_flag_value(ev_name, field_name, field->value, field->str);
	if (field->next)
		define_flag_values(field->next, ev_name, field_name);
}

static void define_flag_field(const char *ev_name,
			      const char *field_name,
			      const char *delim)
{
	dSP;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(delim, 0)));

	PUTBACK;
	if (get_cv("main::define_flag_field", 0))
		call_pv("main::define_flag_field", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
}

static void define_event_symbols(struct event_format *event,
				 const char *ev_name,
				 struct print_arg *args)
{
	if (args == NULL)
		return;

	switch (args->type) {
	case PRINT_NULL:
		break;
	case PRINT_ATOM:
		define_flag_value(ev_name, cur_field_name, "0",
				  args->atom.atom);
		zero_flag_atom = 0;
		break;
	case PRINT_FIELD:
		free(cur_field_name);
		cur_field_name = strdup(args->field.name);
		break;
	case PRINT_FLAGS:
		define_event_symbols(event, ev_name, args->flags.field);
		define_flag_field(ev_name, cur_field_name, args->flags.delim);
		define_flag_values(args->flags.flags, ev_name, cur_field_name);
		break;
	case PRINT_SYMBOL:
		define_event_symbols(event, ev_name, args->symbol.field);
		define_symbolic_field(ev_name, cur_field_name);
		define_symbolic_values(args->symbol.symbols, ev_name,
				       cur_field_name);
		break;
	case PRINT_HEX:
	case PRINT_HEX_STR:
		define_event_symbols(event, ev_name, args->hex.field);
		define_event_symbols(event, ev_name, args->hex.size);
		break;
	case PRINT_INT_ARRAY:
		define_event_symbols(event, ev_name, args->int_array.field);
		define_event_symbols(event, ev_name, args->int_array.count);
		define_event_symbols(event, ev_name, args->int_array.el_size);
		break;
	case PRINT_BSTRING:
	case PRINT_DYNAMIC_ARRAY:
	case PRINT_DYNAMIC_ARRAY_LEN:
	case PRINT_STRING:
	case PRINT_BITMASK:
		break;
	case PRINT_TYPE:
		define_event_symbols(event, ev_name, args->typecast.item);
		break;
	case PRINT_OP:
		if (strcmp(args->op.op, ":") == 0)
			zero_flag_atom = 1;
		define_event_symbols(event, ev_name, args->op.left);
		define_event_symbols(event, ev_name, args->op.right);
		break;
	case PRINT_FUNC:
	default:
		pr_err("Unsupported print arg type\n");
		/* we should warn... */
		return;
	}

	if (args->next)
		define_event_symbols(event, ev_name, args->next);
}

static SV *perl_process_callchain(struct perf_sample *sample,
				  struct perf_evsel *evsel,
				  struct addr_location *al)
{
	AV *list;

	list = newAV();
	if (!list)
		goto exit;

	if (!symbol_conf.use_callchain || !sample->callchain)
		goto exit;

	if (thread__resolve_callchain(al->thread, &callchain_cursor, evsel,
				      sample, NULL, NULL, scripting_max_stack) != 0) {
		pr_err("Failed to resolve callchain. Skipping\n");
		goto exit;
	}
	callchain_cursor_commit(&callchain_cursor);


	while (1) {
		HV *elem;
		struct callchain_cursor_node *node;
		node = callchain_cursor_current(&callchain_cursor);
		if (!node)
			break;

		elem = newHV();
		if (!elem)
			goto exit;

		if (!hv_stores(elem, "ip", newSVuv(node->ip))) {
			hv_undef(elem);
			goto exit;
		}

		if (node->sym) {
			HV *sym = newHV();
			if (!sym) {
				hv_undef(elem);
				goto exit;
			}
			if (!hv_stores(sym, "start",   newSVuv(node->sym->start)) ||
			    !hv_stores(sym, "end",     newSVuv(node->sym->end)) ||
			    !hv_stores(sym, "binding", newSVuv(node->sym->binding)) ||
			    !hv_stores(sym, "name",    newSVpvn(node->sym->name,
								node->sym->namelen)) ||
			    !hv_stores(elem, "sym",    newRV_noinc((SV*)sym))) {
				hv_undef(sym);
				hv_undef(elem);
				goto exit;
			}
		}

		if (node->map) {
			struct map *map = node->map;
			const char *dsoname = "[unknown]";
			if (map && map->dso) {
				if (symbol_conf.show_kernel_path && map->dso->long_name)
					dsoname = map->dso->long_name;
				else
					dsoname = map->dso->name;
			}
			if (!hv_stores(elem, "dso", newSVpv(dsoname,0))) {
				hv_undef(elem);
				goto exit;
			}
		}

		callchain_cursor_advance(&callchain_cursor);
		av_push(list, newRV_noinc((SV*)elem));
	}

exit:
	return newRV_noinc((SV*)list);
}

static void perl_process_tracepoint(struct perf_sample *sample,
				    struct perf_evsel *evsel,
				    struct addr_location *al)
{
	struct thread *thread = al->thread;
	struct event_format *event = evsel->tp_format;
	struct format_field *field;
	static char handler[256];
	unsigned long long val;
	unsigned long s, ns;
	int pid;
	int cpu = sample->cpu;
	void *data = sample->raw_data;
	unsigned long long nsecs = sample->time;
	const char *comm = thread__comm_str(thread);

	dSP;

	if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
		return;

	if (!event) {
		pr_debug("ug! no event found for type %" PRIu64, (u64)evsel->attr.config);
		return;
	}

	pid = raw_field_value(event, "common_pid", data);

	sprintf(handler, "%s::%s", event->system, event->name);

	if (!test_and_set_bit(event->id, events_defined))
		define_event_symbols(event, handler, event->print_fmt.args);

	s = nsecs / NSEC_PER_SEC;
	ns = nsecs - s * NSEC_PER_SEC;

	scripting_context->event_data = data;
	scripting_context->pevent = evsel->tp_format->pevent;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(handler, 0)));
	XPUSHs(sv_2mortal(newSViv(PTR2IV(scripting_context))));
	XPUSHs(sv_2mortal(newSVuv(cpu)));
	XPUSHs(sv_2mortal(newSVuv(s)));
	XPUSHs(sv_2mortal(newSVuv(ns)));
	XPUSHs(sv_2mortal(newSViv(pid)));
	XPUSHs(sv_2mortal(newSVpv(comm, 0)));
	XPUSHs(sv_2mortal(perl_process_callchain(sample, evsel, al)));

	/* common fields other than pid can be accessed via xsub fns */

	for (field = event->format.fields; field; field = field->next) {
		if (field->flags & FIELD_IS_STRING) {
			int offset;
			if (field->flags & FIELD_IS_DYNAMIC) {
				offset = *(int *)(data + field->offset);
				offset &= 0xffff;
			} else
				offset = field->offset;
			XPUSHs(sv_2mortal(newSVpv((char *)data + offset, 0)));
		} else { /* FIELD_IS_NUMERIC */
			val = read_size(event, data + field->offset,
					field->size);
			if (field->flags & FIELD_IS_SIGNED) {
				XPUSHs(sv_2mortal(newSViv(val)));
			} else {
				XPUSHs(sv_2mortal(newSVuv(val)));
			}
		}
	}

	PUTBACK;

	if (get_cv(handler, 0))
		call_pv(handler, G_SCALAR);
	else if (get_cv("main::trace_unhandled", 0)) {
		XPUSHs(sv_2mortal(newSVpv(handler, 0)));
		XPUSHs(sv_2mortal(newSViv(PTR2IV(scripting_context))));
		XPUSHs(sv_2mortal(newSVuv(cpu)));
		XPUSHs(sv_2mortal(newSVuv(nsecs)));
		XPUSHs(sv_2mortal(newSViv(pid)));
		XPUSHs(sv_2mortal(newSVpv(comm, 0)));
		XPUSHs(sv_2mortal(perl_process_callchain(sample, evsel, al)));
		call_pv("main::trace_unhandled", G_SCALAR);
	}
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
}

static void perl_process_event_generic(union perf_event *event,
				       struct perf_sample *sample,
				       struct perf_evsel *evsel)
{
	dSP;

	if (!get_cv("process_event", 0))
		return;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);
	XPUSHs(sv_2mortal(newSVpvn((const char *)event, event->header.size)));
	XPUSHs(sv_2mortal(newSVpvn((const char *)&evsel->attr, sizeof(evsel->attr))));
	XPUSHs(sv_2mortal(newSVpvn((const char *)sample, sizeof(*sample))));
	XPUSHs(sv_2mortal(newSVpvn((const char *)sample->raw_data, sample->raw_size)));
	PUTBACK;
	call_pv("process_event", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
}

static void perl_process_event(union perf_event *event,
			       struct perf_sample *sample,
			       struct perf_evsel *evsel,
			       struct addr_location *al)
{
	perl_process_tracepoint(sample, evsel, al);
	perl_process_event_generic(event, sample, evsel);
}

static void run_start_sub(void)
{
	dSP; /* access to Perl stack */
	PUSHMARK(SP);

	if (get_cv("main::trace_begin", 0))
		call_pv("main::trace_begin", G_DISCARD | G_NOARGS);
}

/*
 * Start trace script
 */
static int perl_start_script(const char *script, int argc, const char **argv)
{
	const char **command_line;
	int i, err = 0;

	command_line = malloc((argc + 2) * sizeof(const char *));
	command_line[0] = "";
	command_line[1] = script;
	for (i = 2; i < argc + 2; i++)
		command_line[i] = argv[i - 2];

	my_perl = perl_alloc();
	perl_construct(my_perl);

	if (perl_parse(my_perl, xs_init, argc + 2, (char **)command_line,
		       (char **)NULL)) {
		err = -1;
		goto error;
	}

	if (perl_run(my_perl)) {
		err = -1;
		goto error;
	}

	if (SvTRUE(ERRSV)) {
		err = -1;
		goto error;
	}

	run_start_sub();

	free(command_line);
	return 0;
error:
	perl_free(my_perl);
	free(command_line);

	return err;
}

static int perl_flush_script(void)
{
	return 0;
}

/*
 * Stop trace script
 */
static int perl_stop_script(void)
{
	dSP; /* access to Perl stack */
	PUSHMARK(SP);

	if (get_cv("main::trace_end", 0))
		call_pv("main::trace_end", G_DISCARD | G_NOARGS);

	perl_destruct(my_perl);
	perl_free(my_perl);

	return 0;
}

static int perl_generate_script(struct pevent *pevent, const char *outfile)
{
	struct event_format *event = NULL;
	struct format_field *f;
	char fname[PATH_MAX];
	int not_first, count;
	FILE *ofp;

	sprintf(fname, "%s.pl", outfile);
	ofp = fopen(fname, "w");
	if (ofp == NULL) {
		fprintf(stderr, "couldn't open %s\n", fname);
		return -1;
	}

	fprintf(ofp, "# perf script event handlers, "
		"generated by perf script -g perl\n");

	fprintf(ofp, "# Licensed under the terms of the GNU GPL"
		" License version 2\n\n");

	fprintf(ofp, "# The common_* event handler fields are the most useful "
		"fields common to\n");

	fprintf(ofp, "# all events.  They don't necessarily correspond to "
		"the 'common_*' fields\n");

	fprintf(ofp, "# in the format files.  Those fields not available as "
		"handler params can\n");

	fprintf(ofp, "# be retrieved using Perl functions of the form "
		"common_*($context).\n");

	fprintf(ofp, "# See Context.pm for the list of available "
		"functions.\n\n");

	fprintf(ofp, "use lib \"$ENV{'PERF_EXEC_PATH'}/scripts/perl/"
		"Perf-Trace-Util/lib\";\n");

	fprintf(ofp, "use lib \"./Perf-Trace-Util/lib\";\n");
	fprintf(ofp, "use Perf::Trace::Core;\n");
	fprintf(ofp, "use Perf::Trace::Context;\n");
	fprintf(ofp, "use Perf::Trace::Util;\n\n");

	fprintf(ofp, "sub trace_begin\n{\n\t# optional\n}\n\n");
	fprintf(ofp, "sub trace_end\n{\n\t# optional\n}\n");


	fprintf(ofp, "\n\
sub print_backtrace\n\
{\n\
	my $callchain = shift;\n\
	for my $node (@$callchain)\n\
	{\n\
		if(exists $node->{sym})\n\
		{\n\
			printf( \"\\t[\\%%x] \\%%s\\n\", $node->{ip}, $node->{sym}{name});\n\
		}\n\
		else\n\
		{\n\
			printf( \"\\t[\\%%x]\\n\", $node{ip});\n\
		}\n\
	}\n\
}\n\n\
");


	while ((event = trace_find_next_event(pevent, event))) {
		fprintf(ofp, "sub %s::%s\n{\n", event->system, event->name);
		fprintf(ofp, "\tmy (");

		fprintf(ofp, "$event_name, ");
		fprintf(ofp, "$context, ");
		fprintf(ofp, "$common_cpu, ");
		fprintf(ofp, "$common_secs, ");
		fprintf(ofp, "$common_nsecs,\n");
		fprintf(ofp, "\t    $common_pid, ");
		fprintf(ofp, "$common_comm, ");
		fprintf(ofp, "$common_callchain,\n\t    ");

		not_first = 0;
		count = 0;

		for (f = event->format.fields; f; f = f->next) {
			if (not_first++)
				fprintf(ofp, ", ");
			if (++count % 5 == 0)
				fprintf(ofp, "\n\t    ");

			fprintf(ofp, "$%s", f->name);
		}
		fprintf(ofp, ") = @_;\n\n");

		fprintf(ofp, "\tprint_header($event_name, $common_cpu, "
			"$common_secs, $common_nsecs,\n\t             "
			"$common_pid, $common_comm, $common_callchain);\n\n");

		fprintf(ofp, "\tprintf(\"");

		not_first = 0;
		count = 0;

		for (f = event->format.fields; f; f = f->next) {
			if (not_first++)
				fprintf(ofp, ", ");
			if (count && count % 4 == 0) {
				fprintf(ofp, "\".\n\t       \"");
			}
			count++;

			fprintf(ofp, "%s=", f->name);
			if (f->flags & FIELD_IS_STRING ||
			    f->flags & FIELD_IS_FLAG ||
			    f->flags & FIELD_IS_SYMBOLIC)
				fprintf(ofp, "%%s");
			else if (f->flags & FIELD_IS_SIGNED)
				fprintf(ofp, "%%d");
			else
				fprintf(ofp, "%%u");
		}

		fprintf(ofp, "\\n\",\n\t       ");

		not_first = 0;
		count = 0;

		for (f = event->format.fields; f; f = f->next) {
			if (not_first++)
				fprintf(ofp, ", ");

			if (++count % 5 == 0)
				fprintf(ofp, "\n\t       ");

			if (f->flags & FIELD_IS_FLAG) {
				if ((count - 1) % 5 != 0) {
					fprintf(ofp, "\n\t       ");
					count = 4;
				}
				fprintf(ofp, "flag_str(\"");
				fprintf(ofp, "%s::%s\", ", event->system,
					event->name);
				fprintf(ofp, "\"%s\", $%s)", f->name,
					f->name);
			} else if (f->flags & FIELD_IS_SYMBOLIC) {
				if ((count - 1) % 5 != 0) {
					fprintf(ofp, "\n\t       ");
					count = 4;
				}
				fprintf(ofp, "symbol_str(\"");
				fprintf(ofp, "%s::%s\", ", event->system,
					event->name);
				fprintf(ofp, "\"%s\", $%s)", f->name,
					f->name);
			} else
				fprintf(ofp, "$%s", f->name);
		}

		fprintf(ofp, ");\n\n");

		fprintf(ofp, "\tprint_backtrace($common_callchain);\n");

		fprintf(ofp, "}\n\n");
	}

	fprintf(ofp, "sub trace_unhandled\n{\n\tmy ($event_name, $context, "
		"$common_cpu, $common_secs, $common_nsecs,\n\t    "
		"$common_pid, $common_comm, $common_callchain) = @_;\n\n");

	fprintf(ofp, "\tprint_header($event_name, $common_cpu, "
		"$common_secs, $common_nsecs,\n\t             $common_pid, "
		"$common_comm, $common_callchain);\n");
	fprintf(ofp, "\tprint_backtrace($common_callchain);\n");
	fprintf(ofp, "}\n\n");

	fprintf(ofp, "sub print_header\n{\n"
		"\tmy ($event_name, $cpu, $secs, $nsecs, $pid, $comm) = @_;\n\n"
		"\tprintf(\"%%-20s %%5u %%05u.%%09u %%8u %%-20s \",\n\t       "
		"$event_name, $cpu, $secs, $nsecs, $pid, $comm);\n}\n");

	fprintf(ofp,
		"\n# Packed byte string args of process_event():\n"
		"#\n"
		"# $event:\tunion perf_event\tutil/event.h\n"
		"# $attr:\tstruct perf_event_attr\tlinux/perf_event.h\n"
		"# $sample:\tstruct perf_sample\tutil/event.h\n"
		"# $raw_data:\tperf_sample->raw_data\tutil/event.h\n"
		"\n"
		"sub process_event\n"
		"{\n"
		"\tmy ($event, $attr, $sample, $raw_data) = @_;\n"
		"\n"
		"\tmy @event\t= unpack(\"LSS\", $event);\n"
		"\tmy @attr\t= unpack(\"LLQQQQQLLQQ\", $attr);\n"
		"\tmy @sample\t= unpack(\"QLLQQQQQLL\", $sample);\n"
		"\tmy @raw_data\t= unpack(\"C*\", $raw_data);\n"
		"\n"
		"\tuse Data::Dumper;\n"
		"\tprint Dumper \\@event, \\@attr, \\@sample, \\@raw_data;\n"
		"}\n");

	fclose(ofp);

	fprintf(stderr, "generated Perl script: %s\n", fname);

	return 0;
}

struct scripting_ops perl_scripting_ops = {
	.name = "Perl",
	.start_script = perl_start_script,
	.flush_script = perl_flush_script,
	.stop_script = perl_stop_script,
	.process_event = perl_process_event,
	.generate_script = perl_generate_script,
};
his a module * Christoph Rohland : Elegant non-blocking accept/connect algorithm. * Lots of bug fixes. * Alexey Kuznetosv : Repaired (I hope) bugs introduces * by above two patches. * Andrea Arcangeli : If possible we block in connect(2) * if the max backlog of the listen socket * is been reached. This won't break * old apps and it will avoid huge amount * of socks hashed (this for unix_gc() * performances reasons). * Security fix that limits the max * number of socks to 2*max_files and * the number of skb queueable in the * dgram receiver. * Artur Skawina : Hash function optimizations * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8) * Malcolm Beattie : Set peercred for socketpair * Michal Ostrowski : Module initialization cleanup. * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT, * the core infrastructure is doing that * for all net proto families now (2.5.69+) * * Known differences from reference BSD that was tested: * * [TO FIX] * ECONNREFUSED is not returned from one end of a connected() socket to the * other the moment one end closes. * fstat() doesn't return st_dev=0, and give the blksize as high water mark * and a fake inode identifier (nor the BSD first socket fstat twice bug). * [NOT TO FIX] * accept() returns a path name even if the connecting socket has closed * in the meantime (BSD loses the path and gives up). * accept() returns 0 length path for an unbound connector. BSD returns 16 * and a null first byte in the path (but not for gethost/peername - BSD bug ??) * socketpair(...SOCK_RAW..) doesn't panic the kernel. * BSD af_unix apparently has connect forgetting to block properly. * (need to check this with the POSIX spec in detail) * * Differences from 2.0.0-11-... (ANK) * Bug fixes and improvements. * - client shutdown killed server socket. * - removed all useless cli/sti pairs. * * Semantic changes/extensions. * - generic control message passing. * - SCM_CREDENTIALS control message. * - "Abstract" (not FS based) socket bindings. * Abstract names are sequences of bytes (not zero terminated) * started by 0, so that this name space does not intersect * with BSD names. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/kernel.h> #include <linux/signal.h> #include <linux/sched/signal.h> #include <linux/errno.h> #include <linux/string.h> #include <linux/stat.h> #include <linux/dcache.h> #include <linux/namei.h> #include <linux/socket.h> #include <linux/un.h> #include <linux/fcntl.h> #include <linux/filter.h> #include <linux/termios.h> #include <linux/sockios.h> #include <linux/net.h> #include <linux/in.h> #include <linux/fs.h> #include <linux/slab.h> #include <linux/uaccess.h> #include <linux/skbuff.h> #include <linux/netdevice.h> #include <net/net_namespace.h> #include <net/sock.h> #include <net/tcp_states.h> #include <net/af_unix.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <net/scm.h> #include <linux/init.h> #include <linux/poll.h> #include <linux/rtnetlink.h> #include <linux/mount.h> #include <net/checksum.h> #include <linux/security.h> #include <linux/splice.h> #include <linux/freezer.h> #include <linux/file.h> #include <linux/btf_ids.h> #include <linux/bpf-cgroup.h> static atomic_long_t unix_nr_socks; static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2]; static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2]; /* SMP locking strategy: * hash table is protected with spinlock. * each socket state is protected by separate spinlock. */ static unsigned int unix_unbound_hash(struct sock *sk) { unsigned long hash = (unsigned long)sk; hash ^= hash >> 16; hash ^= hash >> 8; hash ^= sk->sk_type; return hash & UNIX_HASH_MOD; } static unsigned int unix_bsd_hash(struct inode *i) { return i->i_ino & UNIX_HASH_MOD; } static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr, int addr_len, int type) { __wsum csum = csum_partial(sunaddr, addr_len, 0); unsigned int hash; hash = (__force unsigned int)csum_fold(csum); hash ^= hash >> 8; hash ^= type; return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD); } static void unix_table_double_lock(struct net *net, unsigned int hash1, unsigned int hash2) { if (hash1 == hash2) { spin_lock(&net->unx.table.locks[hash1]); return; } if (hash1 > hash2) swap(hash1, hash2); spin_lock(&net->unx.table.locks[hash1]); spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING); } static void unix_table_double_unlock(struct net *net, unsigned int hash1, unsigned int hash2) { if (hash1 == hash2) { spin_unlock(&net->unx.table.locks[hash1]); return; } spin_unlock(&net->unx.table.locks[hash1]); spin_unlock(&net->unx.table.locks[hash2]); } #ifdef CONFIG_SECURITY_NETWORK static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) { UNIXCB(skb).secid = scm->secid; } static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) { scm->secid = UNIXCB(skb).secid; } static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb) { return (scm->secid == UNIXCB(skb).secid); } #else static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) { } static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) { } static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb) { return true; } #endif /* CONFIG_SECURITY_NETWORK */ static inline int unix_our_peer(struct sock *sk, struct sock *osk) { return unix_peer(osk) == sk; } static inline int unix_may_send(struct sock *sk, struct sock *osk) { return unix_peer(osk) == NULL || unix_our_peer(sk, osk); } static inline int unix_recvq_full(const struct sock *sk) { return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; } static inline int unix_recvq_full_lockless(const struct sock *sk) { return skb_queue_len_lockless(&sk->sk_receive_queue) > READ_ONCE(sk->sk_max_ack_backlog); } struct sock *unix_peer_get(struct sock *s) { struct sock *peer; unix_state_lock(s); peer = unix_peer(s); if (peer) sock_hold(peer); unix_state_unlock(s); return peer; } EXPORT_SYMBOL_GPL(unix_peer_get); static struct unix_address *unix_create_addr(struct sockaddr_un *sunaddr, int addr_len) { struct unix_address *addr; addr = kmalloc(sizeof(*addr) + addr_len, GFP_KERNEL); if (!addr) return NULL; refcount_set(&addr->refcnt, 1); addr->len = addr_len; memcpy(addr->name, sunaddr, addr_len); return addr; } static inline void unix_release_addr(struct unix_address *addr) { if (refcount_dec_and_test(&addr->refcnt)) kfree(addr); } /* * Check unix socket name: * - should be not zero length. * - if started by not zero, should be NULL terminated (FS object) * - if started by zero, it is abstract name. */ static int unix_validate_addr(struct sockaddr_un *sunaddr, int addr_len) { if (addr_len <= offsetof(struct sockaddr_un, sun_path) || addr_len > sizeof(*sunaddr)) return -EINVAL; if (sunaddr->sun_family != AF_UNIX) return -EINVAL; return 0; } static int unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len) { struct sockaddr_storage *addr = (struct sockaddr_storage *)sunaddr; short offset = offsetof(struct sockaddr_storage, __data); BUILD_BUG_ON(offset != offsetof(struct sockaddr_un, sun_path)); /* This may look like an off by one error but it is a bit more * subtle. 108 is the longest valid AF_UNIX path for a binding. * sun_path[108] doesn't as such exist. However in kernel space * we are guaranteed that it is a valid memory location in our * kernel address buffer because syscall functions always pass * a pointer of struct sockaddr_storage which has a bigger buffer * than 108. Also, we must terminate sun_path for strlen() in * getname_kernel(). */ addr->__data[addr_len - offset] = 0; /* Don't pass sunaddr->sun_path to strlen(). Otherwise, 108 will * cause panic if CONFIG_FORTIFY_SOURCE=y. Let __fortify_strlen() * know the actual buffer. */ return strlen(addr->__data) + offset + 1; } static void __unix_remove_socket(struct sock *sk) { sk_del_node_init(sk); } static void __unix_insert_socket(struct net *net, struct sock *sk) { DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk)); sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]); } static void __unix_set_addr_hash(struct net *net, struct sock *sk, struct unix_address *addr, unsigned int hash) { __unix_remove_socket(sk); smp_store_release(&unix_sk(sk)->addr, addr); sk->sk_hash = hash; __unix_insert_socket(net, sk); } static void unix_remove_socket(struct net *net, struct sock *sk) { spin_lock(&net->unx.table.locks[sk->sk_hash]); __unix_remove_socket(sk); spin_unlock(&net->unx.table.locks[sk->sk_hash]); } static void unix_insert_unbound_socket(struct net *net, struct sock *sk) { spin_lock(&net->unx.table.locks[sk->sk_hash]); __unix_insert_socket(net, sk); spin_unlock(&net->unx.table.locks[sk->sk_hash]); } static void unix_insert_bsd_socket(struct sock *sk) { spin_lock(&bsd_socket_locks[sk->sk_hash]); sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]); spin_unlock(&bsd_socket_locks[sk->sk_hash]); } static void unix_remove_bsd_socket(struct sock *sk) { if (!hlist_unhashed(&sk->sk_bind_node)) { spin_lock(&bsd_socket_locks[sk->sk_hash]); __sk_del_bind_node(sk); spin_unlock(&bsd_socket_locks[sk->sk_hash]); sk_node_init(&sk->sk_bind_node); } } static struct sock *__unix_find_socket_byname(struct net *net, struct sockaddr_un *sunname, int len, unsigned int hash) { struct sock *s; sk_for_each(s, &net->unx.table.buckets[hash]) { struct unix_sock *u = unix_sk(s); if (u->addr->len == len && !memcmp(u->addr->name, sunname, len)) return s; } return NULL; } static inline struct sock *unix_find_socket_byname(struct net *net, struct sockaddr_un *sunname, int len, unsigned int hash) { struct sock *s; spin_lock(&net->unx.table.locks[hash]); s = __unix_find_socket_byname(net, sunname, len, hash); if (s) sock_hold(s); spin_unlock(&net->unx.table.locks[hash]); return s; } static struct sock *unix_find_socket_byinode(struct inode *i) { unsigned int hash = unix_bsd_hash(i); struct sock *s; spin_lock(&bsd_socket_locks[hash]); sk_for_each_bound(s, &bsd_socket_buckets[hash]) { struct dentry *dentry = unix_sk(s)->path.dentry; if (dentry && d_backing_inode(dentry) == i) { sock_hold(s); spin_unlock(&bsd_socket_locks[hash]); return s; } } spin_unlock(&bsd_socket_locks[hash]); return NULL; } /* Support code for asymmetrically connected dgram sockets * * If a datagram socket is connected to a socket not itself connected * to the first socket (eg, /dev/log), clients may only enqueue more * messages if the present receive queue of the server socket is not * "too large". This means there's a second writeability condition * poll and sendmsg need to test. The dgram recv code will do a wake * up on the peer_wait wait queue of a socket upon reception of a * datagram which needs to be propagated to sleeping would-be writers * since these might not have sent anything so far. This can't be * accomplished via poll_wait because the lifetime of the server * socket might be less than that of its clients if these break their * association with it or if the server socket is closed while clients * are still connected to it and there's no way to inform "a polling * implementation" that it should let go of a certain wait queue * * In order to propagate a wake up, a wait_queue_entry_t of the client * socket is enqueued on the peer_wait queue of the server socket * whose wake function does a wake_up on the ordinary client socket * wait queue. This connection is established whenever a write (or * poll for write) hit the flow control condition and broken when the * association to the server socket is dissolved or after a wake up * was relayed. */ static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags, void *key) { struct unix_sock *u; wait_queue_head_t *u_sleep; u = container_of(q, struct unix_sock, peer_wake); __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait, q); u->peer_wake.private = NULL; /* relaying can only happen while the wq still exists */ u_sleep = sk_sleep(&u->sk); if (u_sleep) wake_up_interruptible_poll(u_sleep, key_to_poll(key)); return 0; } static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other) { struct unix_sock *u, *u_other; int rc; u = unix_sk(sk); u_other = unix_sk(other); rc = 0; spin_lock(&u_other->peer_wait.lock); if (!u->peer_wake.private) { u->peer_wake.private = other; __add_wait_queue(&u_other->peer_wait, &u->peer_wake); rc = 1; } spin_unlock(&u_other->peer_wait.lock); return rc; } static void unix_dgram_peer_wake_disconnect(struct sock *sk, struct sock *other) { struct unix_sock *u, *u_other; u = unix_sk(sk); u_other = unix_sk(other); spin_lock(&u_other->peer_wait.lock); if (u->peer_wake.private == other) { __remove_wait_queue(&u_other->peer_wait, &u->peer_wake); u->peer_wake.private = NULL; } spin_unlock(&u_other->peer_wait.lock); } static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk, struct sock *other) { unix_dgram_peer_wake_disconnect(sk, other); wake_up_interruptible_poll(sk_sleep(sk), EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); } /* preconditions: * - unix_peer(sk) == other * - association is stable */ static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other) { int connected; connected = unix_dgram_peer_wake_connect(sk, other); /* If other is SOCK_DEAD, we want to make sure we signal * POLLOUT, such that a subsequent write() can get a * -ECONNREFUSED. Otherwise, if we haven't queued any skbs * to other and its full, we will hang waiting for POLLOUT. */ if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD)) return 1; if (connected) unix_dgram_peer_wake_disconnect(sk, other); return 0; } static int unix_writable(const struct sock *sk) { return sk->sk_state != TCP_LISTEN && (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; } static void unix_write_space(struct sock *sk) { struct socket_wq *wq; rcu_read_lock(); if (unix_writable(sk)) { wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); } rcu_read_unlock(); } /* When dgram socket disconnects (or changes its peer), we clear its receive * queue of packets arrived from previous peer. First, it allows to do * flow control based only on wmem_alloc; second, sk connected to peer * may receive messages only from that peer. */ static void unix_dgram_disconnected(struct sock *sk, struct sock *other) { if (!skb_queue_empty(&sk->sk_receive_queue)) { skb_queue_purge(&sk->sk_receive_queue); wake_up_interruptible_all(&unix_sk(sk)->peer_wait); /* If one link of bidirectional dgram pipe is disconnected, * we signal error. Messages are lost. Do not make this, * when peer was not connected to us. */ if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { WRITE_ONCE(other->sk_err, ECONNRESET); sk_error_report(other); } } other->sk_state = TCP_CLOSE; } static void unix_sock_destructor(struct sock *sk) { struct unix_sock *u = unix_sk(sk); skb_queue_purge(&sk->sk_receive_queue); DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc)); DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk)); DEBUG_NET_WARN_ON_ONCE(sk->sk_socket); if (!sock_flag(sk, SOCK_DEAD)) { pr_info("Attempt to release alive unix socket: %p\n", sk); return; } if (u->addr) unix_release_addr(u->addr); atomic_long_dec(&unix_nr_socks); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); #ifdef UNIX_REFCNT_DEBUG pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk, atomic_long_read(&unix_nr_socks)); #endif } static void unix_release_sock(struct sock *sk, int embrion) { struct unix_sock *u = unix_sk(sk); struct sock *skpair; struct sk_buff *skb; struct path path; int state; unix_remove_socket(sock_net(sk), sk); unix_remove_bsd_socket(sk); /* Clear state */ unix_state_lock(sk); sock_orphan(sk); WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); path = u->path; u->path.dentry = NULL; u->path.mnt = NULL; state = sk->sk_state; sk->sk_state = TCP_CLOSE; skpair = unix_peer(sk); unix_peer(sk) = NULL; unix_state_unlock(sk); #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (u->oob_skb) { kfree_skb(u->oob_skb); u->oob_skb = NULL; } #endif wake_up_interruptible_all(&u->peer_wait); if (skpair != NULL) { if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { unix_state_lock(skpair); /* No more writes */ WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK); if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) WRITE_ONCE(skpair->sk_err, ECONNRESET); unix_state_unlock(skpair); skpair->sk_state_change(skpair); sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP); } unix_dgram_peer_wake_disconnect(sk, skpair); sock_put(skpair); /* It may now die */ } /* Try to flush out this socket. Throw out buffers at least */ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { if (state == TCP_LISTEN) unix_release_sock(skb->sk, 1); /* passed fds are erased in the kfree_skb hook */ UNIXCB(skb).consumed = skb->len; kfree_skb(skb); } if (path.dentry) path_put(&path); sock_put(sk); /* ---- Socket is dead now and most probably destroyed ---- */ /* * Fixme: BSD difference: In BSD all sockets connected to us get * ECONNRESET and we die on the spot. In Linux we behave * like files and pipes do and wait for the last * dereference. * * Can't we simply set sock->err? * * What the above comment does talk about? --ANK(980817) */ if (READ_ONCE(unix_tot_inflight)) unix_gc(); /* Garbage collect fds */ } static void init_peercred(struct sock *sk) { const struct cred *old_cred; struct pid *old_pid; spin_lock(&sk->sk_peer_lock); old_pid = sk->sk_peer_pid; old_cred = sk->sk_peer_cred; sk->sk_peer_pid = get_pid(task_tgid(current)); sk->sk_peer_cred = get_current_cred(); spin_unlock(&sk->sk_peer_lock); put_pid(old_pid); put_cred(old_cred); } static void copy_peercred(struct sock *sk, struct sock *peersk) { const struct cred *old_cred; struct pid *old_pid; if (sk < peersk) { spin_lock(&sk->sk_peer_lock); spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING); } else { spin_lock(&peersk->sk_peer_lock); spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING); } old_pid = sk->sk_peer_pid; old_cred = sk->sk_peer_cred; sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); spin_unlock(&sk->sk_peer_lock); spin_unlock(&peersk->sk_peer_lock); put_pid(old_pid); put_cred(old_cred); } static int unix_listen(struct socket *sock, int backlog) { int err; struct sock *sk = sock->sk; struct unix_sock *u = unix_sk(sk); err = -EOPNOTSUPP; if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) goto out; /* Only stream/seqpacket sockets accept */ err = -EINVAL; if (!u->addr) goto out; /* No listens on an unbound socket */ unix_state_lock(sk); if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) goto out_unlock; if (backlog > sk->sk_max_ack_backlog) wake_up_interruptible_all(&u->peer_wait); sk->sk_max_ack_backlog = backlog; sk->sk_state = TCP_LISTEN; /* set credentials so connect can copy them */ init_peercred(sk); err = 0; out_unlock: unix_state_unlock(sk); out: return err; } static int unix_release(struct socket *); static int unix_bind(struct socket *, struct sockaddr *, int); static int unix_stream_connect(struct socket *, struct sockaddr *, int addr_len, int flags); static int unix_socketpair(struct socket *, struct socket *); static int unix_accept(struct socket *, struct socket *, int, bool); static int unix_getname(struct socket *, struct sockaddr *, int); static __poll_t unix_poll(struct file *, struct socket *, poll_table *); static __poll_t unix_dgram_poll(struct file *, struct socket *, poll_table *); static int unix_ioctl(struct socket *, unsigned int, unsigned long); #ifdef CONFIG_COMPAT static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg); #endif static int unix_shutdown(struct socket *, int); static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t); static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int); static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos, struct pipe_inode_info *, size_t size, unsigned int flags); static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t); static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int); static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor); static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor); static int unix_dgram_connect(struct socket *, struct sockaddr *, int, int); static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t); static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t, int); #ifdef CONFIG_PROC_FS static int unix_count_nr_fds(struct sock *sk) { struct sk_buff *skb; struct unix_sock *u; int nr_fds = 0; spin_lock(&sk->sk_receive_queue.lock); skb = skb_peek(&sk->sk_receive_queue); while (skb) { u = unix_sk(skb->sk); nr_fds += atomic_read(&u->scm_stat.nr_fds); skb = skb_peek_next(skb, &sk->sk_receive_queue); } spin_unlock(&sk->sk_receive_queue.lock); return nr_fds; } static void unix_show_fdinfo(struct seq_file *m, struct socket *sock) { struct sock *sk = sock->sk; unsigned char s_state; struct unix_sock *u; int nr_fds = 0; if (sk) { s_state = READ_ONCE(sk->sk_state); u = unix_sk(sk); /* SOCK_STREAM and SOCK_SEQPACKET sockets never change their * sk_state after switching to TCP_ESTABLISHED or TCP_LISTEN. * SOCK_DGRAM is ordinary. So, no lock is needed. */ if (sock->type == SOCK_DGRAM || s_state == TCP_ESTABLISHED) nr_fds = atomic_read(&u->scm_stat.nr_fds); else if (s_state == TCP_LISTEN) nr_fds = unix_count_nr_fds(sk); seq_printf(m, "scm_fds: %u\n", nr_fds); } } #else #define unix_show_fdinfo NULL #endif static const struct proto_ops unix_stream_ops = { .family = PF_UNIX, .owner = THIS_MODULE, .release = unix_release, .bind = unix_bind, .connect = unix_stream_connect, .socketpair = unix_socketpair, .accept = unix_accept, .getname = unix_getname, .poll = unix_poll, .ioctl = unix_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = unix_compat_ioctl, #endif .listen = unix_listen, .shutdown = unix_shutdown, .sendmsg = unix_stream_sendmsg, .recvmsg = unix_stream_recvmsg, .read_skb = unix_stream_read_skb, .mmap = sock_no_mmap, .splice_read = unix_stream_splice_read, .set_peek_off = sk_set_peek_off, .show_fdinfo = unix_show_fdinfo, }; static const struct proto_ops unix_dgram_ops = { .family = PF_UNIX, .owner = THIS_MODULE, .release = unix_release, .bind = unix_bind, .connect = unix_dgram_connect, .socketpair = unix_socketpair, .accept = sock_no_accept, .getname = unix_getname, .poll = unix_dgram_poll, .ioctl = unix_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = unix_compat_ioctl, #endif .listen = sock_no_listen, .shutdown = unix_shutdown, .sendmsg = unix_dgram_sendmsg, .read_skb = unix_read_skb, .recvmsg = unix_dgram_recvmsg, .mmap = sock_no_mmap, .set_peek_off = sk_set_peek_off, .show_fdinfo = unix_show_fdinfo, }; static const struct proto_ops unix_seqpacket_ops = { .family = PF_UNIX, .owner = THIS_MODULE, .release = unix_release, .bind = unix_bind, .connect = unix_stream_connect, .socketpair = unix_socketpair, .accept = unix_accept, .getname = unix_getname, .poll = unix_dgram_poll, .ioctl = unix_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = unix_compat_ioctl, #endif .listen = unix_listen, .shutdown = unix_shutdown, .sendmsg = unix_seqpacket_sendmsg, .recvmsg = unix_seqpacket_recvmsg, .mmap = sock_no_mmap, .set_peek_off = sk_set_peek_off, .show_fdinfo = unix_show_fdinfo, }; static void unix_close(struct sock *sk, long timeout) { /* Nothing to do here, unix socket does not need a ->close(). * This is merely for sockmap. */ } static void unix_unhash(struct sock *sk) { /* Nothing to do here, unix socket does not need a ->unhash(). * This is merely for sockmap. */ } static bool unix_bpf_bypass_getsockopt(int level, int optname) { if (level == SOL_SOCKET) { switch (optname) { case SO_PEERPIDFD: return true; default: return false; } } return false; } struct proto unix_dgram_proto = { .name = "UNIX", .owner = THIS_MODULE, .obj_size = sizeof(struct unix_sock), .close = unix_close, .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt, #ifdef CONFIG_BPF_SYSCALL .psock_update_sk_prot = unix_dgram_bpf_update_proto, #endif }; struct proto unix_stream_proto = { .name = "UNIX-STREAM", .owner = THIS_MODULE, .obj_size = sizeof(struct unix_sock), .close = unix_close, .unhash = unix_unhash, .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt, #ifdef CONFIG_BPF_SYSCALL .psock_update_sk_prot = unix_stream_bpf_update_proto, #endif }; static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type) { struct unix_sock *u; struct sock *sk; int err; atomic_long_inc(&unix_nr_socks); if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) { err = -ENFILE; goto err; } if (type == SOCK_STREAM) sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern); else /*dgram and seqpacket */ sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern); if (!sk) { err = -ENOMEM; goto err; } sock_init_data(sock, sk); sk->sk_hash = unix_unbound_hash(sk); sk->sk_allocation = GFP_KERNEL_ACCOUNT; sk->sk_write_space = unix_write_space; sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; sk->sk_destruct = unix_sock_destructor; u = unix_sk(sk); u->inflight = 0; u->path.dentry = NULL; u->path.mnt = NULL; spin_lock_init(&u->lock); INIT_LIST_HEAD(&u->link); mutex_init(&u->iolock); /* single task reading lock */ mutex_init(&u->bindlock); /* single task binding lock */ init_waitqueue_head(&u->peer_wait); init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay); memset(&u->scm_stat, 0, sizeof(struct scm_stat)); unix_insert_unbound_socket(net, sk); sock_prot_inuse_add(net, sk->sk_prot, 1); return sk; err: atomic_long_dec(&unix_nr_socks); return ERR_PTR(err); } static int unix_create(struct net *net, struct socket *sock, int protocol, int kern) { struct sock *sk; if (protocol && protocol != PF_UNIX) return -EPROTONOSUPPORT; sock->state = SS_UNCONNECTED; switch (sock->type) { case SOCK_STREAM: sock->ops = &unix_stream_ops; break; /* * Believe it or not BSD has AF_UNIX, SOCK_RAW though * nothing uses it. */ case SOCK_RAW: sock->type = SOCK_DGRAM; fallthrough; case SOCK_DGRAM: sock->ops = &unix_dgram_ops; break; case SOCK_SEQPACKET: sock->ops = &unix_seqpacket_ops; break; default: return -ESOCKTNOSUPPORT; } sk = unix_create1(net, sock, kern, sock->type); if (IS_ERR(sk)) return PTR_ERR(sk); return 0; } static int unix_release(struct socket *sock) { struct sock *sk = sock->sk; if (!sk) return 0; sk->sk_prot->close(sk, 0); unix_release_sock(sk, 0); sock->sk = NULL; return 0; } static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len, int type) { struct inode *inode; struct path path; struct sock *sk; int err; unix_mkname_bsd(sunaddr, addr_len); err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path); if (err) goto fail; err = path_permission(&path, MAY_WRITE); if (err) goto path_put; err = -ECONNREFUSED; inode = d_backing_inode(path.dentry); if (!S_ISSOCK(inode->i_mode)) goto path_put; sk = unix_find_socket_byinode(inode); if (!sk) goto path_put; err = -EPROTOTYPE; if (sk->sk_type == type) touch_atime(&path); else goto sock_put; path_put(&path); return sk; sock_put: sock_put(sk); path_put: path_put(&path); fail: return ERR_PTR(err); } static struct sock *unix_find_abstract(struct net *net, struct sockaddr_un *sunaddr, int addr_len, int type) { unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type); struct dentry *dentry; struct sock *sk; sk = unix_find_socket_byname(net, sunaddr, addr_len, hash); if (!sk) return ERR_PTR(-ECONNREFUSED); dentry = unix_sk(sk)->path.dentry; if (dentry) touch_atime(&unix_sk(sk)->path); return sk; } static struct sock *unix_find_other(struct net *net, struct sockaddr_un *sunaddr, int addr_len, int type) { struct sock *sk; if (sunaddr->sun_path[0]) sk = unix_find_bsd(sunaddr, addr_len, type); else sk = unix_find_abstract(net, sunaddr, addr_len, type); return sk; } static int unix_autobind(struct sock *sk) { unsigned int new_hash, old_hash = sk->sk_hash; struct unix_sock *u = unix_sk(sk); struct net *net = sock_net(sk); struct unix_address *addr; u32 lastnum, ordernum; int err; err = mutex_lock_interruptible(&u->bindlock); if (err) return err; if (u->addr) goto out; err = -ENOMEM; addr = kzalloc(sizeof(*addr) + offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL); if (!addr) goto out; addr->len = offsetof(struct sockaddr_un, sun_path) + 6; addr->name->sun_family = AF_UNIX; refcount_set(&addr->refcnt, 1); ordernum = get_random_u32(); lastnum = ordernum & 0xFFFFF; retry: ordernum = (ordernum + 1) & 0xFFFFF; sprintf(addr->name->sun_path + 1, "%05x", ordernum); new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type); unix_table_double_lock(net, old_hash, new_hash); if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) { unix_table_double_unlock(net, old_hash, new_hash); /* __unix_find_socket_byname() may take long time if many names * are already in use. */ cond_resched(); if (ordernum == lastnum) { /* Give up if all names seems to be in use. */ err = -ENOSPC; unix_release_addr(addr); goto out; } goto retry; } __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); err = 0; out: mutex_unlock(&u->bindlock); return err; } static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, int addr_len) { umode_t mode = S_IFSOCK | (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask()); unsigned int new_hash, old_hash = sk->sk_hash; struct unix_sock *u = unix_sk(sk); struct net *net = sock_net(sk); struct mnt_idmap *idmap; struct unix_address *addr; struct dentry *dentry; struct path parent; int err; addr_len = unix_mkname_bsd(sunaddr, addr_len); addr = unix_create_addr(sunaddr, addr_len); if (!addr) return -ENOMEM; /* * Get the parent directory, calculate the hash for last * component. */ dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out; } /* * All right, let's create it. */ idmap = mnt_idmap(parent.mnt); err = security_path_mknod(&parent, dentry, mode, 0); if (!err) err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0); if (err) goto out_path; err = mutex_lock_interruptible(&u->bindlock); if (err) goto out_unlink; if (u->addr) goto out_unlock; new_hash = unix_bsd_hash(d_backing_inode(dentry)); unix_table_double_lock(net, old_hash, new_hash); u->path.mnt = mntget(parent.mnt); u->path.dentry = dget(dentry); __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); unix_insert_bsd_socket(sk); mutex_unlock(&u->bindlock); done_path_create(&parent, dentry); return 0; out_unlock: mutex_unlock(&u->bindlock); err = -EINVAL; out_unlink: /* failed after successful mknod? unlink what we'd created... */ vfs_unlink(idmap, d_inode(parent.dentry), dentry, NULL); out_path: done_path_create(&parent, dentry); out: unix_release_addr(addr); return err == -EEXIST ? -EADDRINUSE : err; } static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr, int addr_len) { unsigned int new_hash, old_hash = sk->sk_hash; struct unix_sock *u = unix_sk(sk); struct net *net = sock_net(sk); struct unix_address *addr; int err; addr = unix_create_addr(sunaddr, addr_len); if (!addr) return -ENOMEM; err = mutex_lock_interruptible(&u->bindlock); if (err) goto out; if (u->addr) { err = -EINVAL; goto out_mutex; } new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type); unix_table_double_lock(net, old_hash, new_hash); if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) goto out_spin; __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); mutex_unlock(&u->bindlock); return 0; out_spin: unix_table_double_unlock(net, old_hash, new_hash); err = -EADDRINUSE; out_mutex: mutex_unlock(&u->bindlock); out: unix_release_addr(addr); return err; } static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) { struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; struct sock *sk = sock->sk; int err; if (addr_len == offsetof(struct sockaddr_un, sun_path) && sunaddr->sun_family == AF_UNIX) return unix_autobind(sk); err = unix_validate_addr(sunaddr, addr_len); if (err) return err; if (sunaddr->sun_path[0]) err = unix_bind_bsd(sk, sunaddr, addr_len); else err = unix_bind_abstract(sk, sunaddr, addr_len); return err; } static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) { if (unlikely(sk1 == sk2) || !sk2) { unix_state_lock(sk1); return; } if (sk1 > sk2) swap(sk1, sk2); unix_state_lock(sk1); unix_state_lock_nested(sk2, U_LOCK_SECOND); } static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) { if (unlikely(sk1 == sk2) || !sk2) { unix_state_unlock(sk1); return; } unix_state_unlock(sk1); unix_state_unlock(sk2); } static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, int alen, int flags) { struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; struct sock *sk = sock->sk; struct sock *other; int err; err = -EINVAL; if (alen < offsetofend(struct sockaddr, sa_family)) goto out; if (addr->sa_family != AF_UNSPEC) { err = unix_validate_addr(sunaddr, alen); if (err) goto out; err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, addr, &alen); if (err) goto out; if ((test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags)) && !unix_sk(sk)->addr) { err = unix_autobind(sk); if (err) goto out; } restart: other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type); if (IS_ERR(other)) { err = PTR_ERR(other); goto out; } unix_state_double_lock(sk, other); /* Apparently VFS overslept socket death. Retry. */ if (sock_flag(other, SOCK_DEAD)) { unix_state_double_unlock(sk, other); sock_put(other); goto restart; } err = -EPERM; if (!unix_may_send(sk, other)) goto out_unlock; err = security_unix_may_send(sk->sk_socket, other->sk_socket); if (err) goto out_unlock; sk->sk_state = other->sk_state = TCP_ESTABLISHED; } else { /* * 1003.1g breaking connected state with AF_UNSPEC */ other = NULL; unix_state_double_lock(sk, other); } /* * If it was connected, reconnect. */ if (unix_peer(sk)) { struct sock *old_peer = unix_peer(sk); unix_peer(sk) = other; if (!other) sk->sk_state = TCP_CLOSE; unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer); unix_state_double_unlock(sk, other); if (other != old_peer) unix_dgram_disconnected(sk, old_peer); sock_put(old_peer); } else { unix_peer(sk) = other; unix_state_double_unlock(sk, other); } return 0; out_unlock: unix_state_double_unlock(sk, other); sock_put(other); out: return err; } static long unix_wait_for_peer(struct sock *other, long timeo) __releases(&unix_sk(other)->lock) { struct unix_sock *u = unix_sk(other); int sched; DEFINE_WAIT(wait); prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); sched = !sock_flag(other, SOCK_DEAD) && !(other->sk_shutdown & RCV_SHUTDOWN) && unix_recvq_full_lockless(other); unix_state_unlock(other); if (sched) timeo = schedule_timeout(timeo); finish_wait(&u->peer_wait, &wait); return timeo; } static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags) { struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; struct sock *sk = sock->sk, *newsk = NULL, *other = NULL; struct unix_sock *u = unix_sk(sk), *newu, *otheru; struct net *net = sock_net(sk); struct sk_buff *skb = NULL; long timeo; int err; int st; err = unix_validate_addr(sunaddr, addr_len); if (err) goto out; err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, uaddr, &addr_len); if (err) goto out; if ((test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) { err = unix_autobind(sk); if (err) goto out; } timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); /* First of all allocate resources. If we will make it after state is locked, we will have to recheck all again in any case. */ /* create new sock for complete connection */ newsk = unix_create1(net, NULL, 0, sock->type); if (IS_ERR(newsk)) { err = PTR_ERR(newsk); newsk = NULL; goto out; } err = -ENOMEM; /* Allocate skb for sending to listening sock */ skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); if (skb == NULL) goto out; restart: /* Find listening sock. */ other = unix_find_other(net, sunaddr, addr_len, sk->sk_type); if (IS_ERR(other)) { err = PTR_ERR(other); other = NULL; goto out; } /* Latch state of peer */ unix_state_lock(other); /* Apparently VFS overslept socket death. Retry. */ if (sock_flag(other, SOCK_DEAD)) { unix_state_unlock(other); sock_put(other); goto restart; } err = -ECONNREFUSED; if (other->sk_state != TCP_LISTEN) goto out_unlock; if (other->sk_shutdown & RCV_SHUTDOWN) goto out_unlock; if (unix_recvq_full(other)) { err = -EAGAIN; if (!timeo) goto out_unlock; timeo = unix_wait_for_peer(other, timeo); err = sock_intr_errno(timeo); if (signal_pending(current)) goto out; sock_put(other); goto restart; } /* Latch our state. It is tricky place. We need to grab our state lock and cannot drop lock on peer. It is dangerous because deadlock is possible. Connect to self case and simultaneous attempt to connect are eliminated by checking socket state. other is TCP_LISTEN, if sk is TCP_LISTEN we check this before attempt to grab lock. Well, and we have to recheck the state after socket locked. */ st = sk->sk_state; switch (st) { case TCP_CLOSE: /* This is ok... continue with connect */ break; case TCP_ESTABLISHED: /* Socket is already connected */ err = -EISCONN; goto out_unlock; default: err = -EINVAL; goto out_unlock; } unix_state_lock_nested(sk, U_LOCK_SECOND); if (sk->sk_state != st) { unix_state_unlock(sk); unix_state_unlock(other); sock_put(other); goto restart; } err = security_unix_stream_connect(sk, other, newsk); if (err) { unix_state_unlock(sk); goto out_unlock; } /* The way is open! Fastly set all the necessary fields... */ sock_hold(sk); unix_peer(newsk) = sk; newsk->sk_state = TCP_ESTABLISHED; newsk->sk_type = sk->sk_type; init_peercred(newsk); newu = unix_sk(newsk); RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); otheru = unix_sk(other); /* copy address information from listening to new sock * * The contents of *(otheru->addr) and otheru->path * are seen fully set up here, since we have found * otheru in hash under its lock. Insertion into the * hash chain we'd found it in had been done in an * earlier critical area protected by the chain's lock, * the same one where we'd set *(otheru->addr) contents, * as well as otheru->path and otheru->addr itself. * * Using smp_store_release() here to set newu->addr * is enough to make those stores, as well as stores * to newu->path visible to anyone who gets newu->addr * by smp_load_acquire(). IOW, the same warranties * as for unix_sock instances bound in unix_bind() or * in unix_autobind(). */ if (otheru->path.dentry) { path_get(&otheru->path); newu->path = otheru->path; } refcount_inc(&otheru->addr->refcnt); smp_store_release(&newu->addr, otheru->addr); /* Set credentials */ copy_peercred(sk, other); sock->state = SS_CONNECTED; sk->sk_state = TCP_ESTABLISHED; sock_hold(newsk); smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */ unix_peer(sk) = newsk; unix_state_unlock(sk); /* take ten and send info to listening sock */ spin_lock(&other->sk_receive_queue.lock); __skb_queue_tail(&other->sk_receive_queue, skb); spin_unlock(&other->sk_receive_queue.lock); unix_state_unlock(other); other->sk_data_ready(other); sock_put(other); return 0; out_unlock: if (other) unix_state_unlock(other); out: kfree_skb(skb); if (newsk) unix_release_sock(newsk, 0); if (other) sock_put(other); return err; } static int unix_socketpair(struct socket *socka, struct socket *sockb) { struct sock *ska = socka->sk, *skb = sockb->sk; /* Join our sockets back to back */ sock_hold(ska); sock_hold(skb); unix_peer(ska) = skb; unix_peer(skb) = ska; init_peercred(ska); init_peercred(skb); ska->sk_state = TCP_ESTABLISHED; skb->sk_state = TCP_ESTABLISHED; socka->state = SS_CONNECTED; sockb->state = SS_CONNECTED; return 0; } static void unix_sock_inherit_flags(const struct socket *old, struct socket *new) { if (test_bit(SOCK_PASSCRED, &old->flags)) set_bit(SOCK_PASSCRED, &new->flags); if (test_bit(SOCK_PASSPIDFD, &old->flags)) set_bit(SOCK_PASSPIDFD, &new->flags); if (test_bit(SOCK_PASSSEC, &old->flags)) set_bit(SOCK_PASSSEC, &new->flags); } static int unix_accept(struct socket *sock, struct socket *newsock, int flags, bool kern) { struct sock *sk = sock->sk; struct sock *tsk; struct sk_buff *skb; int err; err = -EOPNOTSUPP; if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) goto out; err = -EINVAL; if (sk->sk_state != TCP_LISTEN) goto out; /* If socket state is TCP_LISTEN it cannot change (for now...), * so that no locks are necessary. */ skb = skb_recv_datagram(sk, (flags & O_NONBLOCK) ? MSG_DONTWAIT : 0, &err); if (!skb) { /* This means receive shutdown. */ if (err == 0) err = -EINVAL; goto out; } tsk = skb->sk; skb_free_datagram(sk, skb); wake_up_interruptible(&unix_sk(sk)->peer_wait); /* attach accepted sock to socket */ unix_state_lock(tsk); newsock->state = SS_CONNECTED; unix_sock_inherit_flags(sock, newsock); sock_graft(tsk, newsock); unix_state_unlock(tsk); return 0; out: return err; } static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer) { struct sock *sk = sock->sk; struct unix_address *addr; DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); int err = 0; if (peer) { sk = unix_peer_get(sk); err = -ENOTCONN; if (!sk) goto out; err = 0; } else { sock_hold(sk); } addr = smp_load_acquire(&unix_sk(sk)->addr); if (!addr) { sunaddr->sun_family = AF_UNIX; sunaddr->sun_path[0] = 0; err = offsetof(struct sockaddr_un, sun_path); } else { err = addr->len; memcpy(sunaddr, addr->name, addr->len); if (peer) BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err, CGROUP_UNIX_GETPEERNAME); else BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err, CGROUP_UNIX_GETSOCKNAME); } sock_put(sk); out: return err; } /* The "user->unix_inflight" variable is protected by the garbage * collection lock, and we just read it locklessly here. If you go * over the limit, there might be a tiny race in actually noticing * it across threads. Tough. */ static inline bool too_many_unix_fds(struct task_struct *p) { struct user_struct *user = current_user(); if (unlikely(READ_ONCE(user->unix_inflight) > task_rlimit(p, RLIMIT_NOFILE))) return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); return false; } static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) { int i; if (too_many_unix_fds(current)) return -ETOOMANYREFS; /* Need to duplicate file references for the sake of garbage * collection. Otherwise a socket in the fps might become a * candidate for GC while the skb is not yet queued. */ UNIXCB(skb).fp = scm_fp_dup(scm->fp); if (!UNIXCB(skb).fp) return -ENOMEM; for (i = scm->fp->count - 1; i >= 0; i--) unix_inflight(scm->fp->user, scm->fp->fp[i]); return 0; } static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) { int i; scm->fp = UNIXCB(skb).fp; UNIXCB(skb).fp = NULL; for (i = scm->fp->count - 1; i >= 0; i--) unix_notinflight(scm->fp->user, scm->fp->fp[i]); } static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb) { scm->fp = scm_fp_dup(UNIXCB(skb).fp); /* * Garbage collection of unix sockets starts by selecting a set of * candidate sockets which have reference only from being in flight * (total_refs == inflight_refs). This condition is checked once during * the candidate collection phase, and candidates are marked as such, so * that non-candidates can later be ignored. While inflight_refs is * protected by unix_gc_lock, total_refs (file count) is not, hence this * is an instantaneous decision. * * Once a candidate, however, the socket must not be reinstalled into a * file descriptor while the garbage collection is in progress. * * If the above conditions are met, then the directed graph of * candidates (*) does not change while unix_gc_lock is held. * * Any operations that changes the file count through file descriptors * (dup, close, sendmsg) does not change the graph since candidates are * not installed in fds. * * Dequeing a candidate via recvmsg would install it into an fd, but * that takes unix_gc_lock to decrement the inflight count, so it's * serialized with garbage collection. * * MSG_PEEK is special in that it does not change the inflight count, * yet does install the socket into an fd. The following lock/unlock * pair is to ensure serialization with garbage collection. It must be * done between incrementing the file count and installing the file into * an fd. * * If garbage collection starts after the barrier provided by the * lock/unlock, then it will see the elevated refcount and not mark this * as a candidate. If a garbage collection is already in progress * before the file count was incremented, then the lock/unlock pair will * ensure that garbage collection is finished before progressing to * installing the fd. * * (*) A -> B where B is on the queue of A or B is on the queue of C * which is on the queue of listening socket A. */ spin_lock(&unix_gc_lock); spin_unlock(&unix_gc_lock); } static void unix_destruct_scm(struct sk_buff *skb) { struct scm_cookie scm; memset(&scm, 0, sizeof(scm)); scm.pid = UNIXCB(skb).pid; if (UNIXCB(skb).fp) unix_detach_fds(&scm, skb); /* Alas, it calls VFS */ /* So fscking what? fput() had been SMP-safe since the last Summer */ scm_destroy(&scm); sock_wfree(skb); } static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) { int err = 0; UNIXCB(skb).pid = get_pid(scm->pid); UNIXCB(skb).uid = scm->creds.uid; UNIXCB(skb).gid = scm->creds.gid; UNIXCB(skb).fp = NULL; unix_get_secdata(scm, skb); if (scm->fp && send_fds) err = unix_attach_fds(scm, skb); skb->destructor = unix_destruct_scm; return err; } static bool unix_passcred_enabled(const struct socket *sock, const struct sock *other) { return test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags) || !other->sk_socket || test_bit(SOCK_PASSCRED, &other->sk_socket->flags) || test_bit(SOCK_PASSPIDFD, &other->sk_socket->flags); } /* * Some apps rely on write() giving SCM_CREDENTIALS * We include credentials if source or destination socket * asserted SOCK_PASSCRED. */ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, const struct sock *other) { if (UNIXCB(skb).pid) return; if (unix_passcred_enabled(sock, other)) { UNIXCB(skb).pid = get_pid(task_tgid(current)); current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid); } } static bool unix_skb_scm_eq(struct sk_buff *skb, struct scm_cookie *scm) { return UNIXCB(skb).pid == scm->pid && uid_eq(UNIXCB(skb).uid, scm->creds.uid) && gid_eq(UNIXCB(skb).gid, scm->creds.gid) && unix_secdata_eq(scm, skb); } static void scm_stat_add(struct sock *sk, struct sk_buff *skb) { struct scm_fp_list *fp = UNIXCB(skb).fp; struct unix_sock *u = unix_sk(sk); if (unlikely(fp && fp->count)) atomic_add(fp->count, &u->scm_stat.nr_fds); } static void scm_stat_del(struct sock *sk, struct sk_buff *skb) { struct scm_fp_list *fp = UNIXCB(skb).fp; struct unix_sock *u = unix_sk(sk); if (unlikely(fp && fp->count)) atomic_sub(fp->count, &u->scm_stat.nr_fds); } /* * Send AF_UNIX data. */ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); struct sock *sk = sock->sk, *other = NULL; struct unix_sock *u = unix_sk(sk); struct scm_cookie scm; struct sk_buff *skb; int data_len = 0; int sk_locked; long timeo; int err; err = scm_send(sock, msg, &scm, false); if (err < 0) return err; wait_for_unix_gc(scm.fp); err = -EOPNOTSUPP; if (msg->msg_flags&MSG_OOB) goto out; if (msg->msg_namelen) { err = unix_validate_addr(sunaddr, msg->msg_namelen); if (err) goto out; err = BPF_CGROUP_RUN_PROG_UNIX_SENDMSG_LOCK(sk, msg->msg_name, &msg->msg_namelen, NULL); if (err) goto out; } else { sunaddr = NULL; err = -ENOTCONN; other = unix_peer_get(sk); if (!other) goto out; } if ((test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) { err = unix_autobind(sk); if (err) goto out; } err = -EMSGSIZE; if (len > sk->sk_sndbuf - 32) goto out; if (len > SKB_MAX_ALLOC) { data_len = min_t(size_t, len - SKB_MAX_ALLOC, MAX_SKB_FRAGS * PAGE_SIZE); data_len = PAGE_ALIGN(data_len); BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE); } skb = sock_alloc_send_pskb(sk, len - data_len, data_len, msg->msg_flags & MSG_DONTWAIT, &err, PAGE_ALLOC_COSTLY_ORDER); if (skb == NULL) goto out; err = unix_scm_to_skb(&scm, skb, true); if (err < 0) goto out_free; skb_put(skb, len - data_len); skb->data_len = data_len; skb->len = len; err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len); if (err) goto out_free; timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); restart: if (!other) { err = -ECONNRESET; if (sunaddr == NULL) goto out_free; other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen, sk->sk_type); if (IS_ERR(other)) { err = PTR_ERR(other); other = NULL; goto out_free; } } if (sk_filter(other, skb) < 0) { /* Toss the packet but do not return any error to the sender */ err = len; goto out_free; } sk_locked = 0; unix_state_lock(other); restart_locked: err = -EPERM; if (!unix_may_send(sk, other)) goto out_unlock; if (unlikely(sock_flag(other, SOCK_DEAD))) { /* * Check with 1003.1g - what should * datagram error */ unix_state_unlock(other); sock_put(other); if (!sk_locked) unix_state_lock(sk); err = 0; if (sk->sk_type == SOCK_SEQPACKET) { /* We are here only when racing with unix_release_sock() * is clearing @other. Never change state to TCP_CLOSE * unlike SOCK_DGRAM wants. */ unix_state_unlock(sk); err = -EPIPE; } else if (unix_peer(sk) == other) { unix_peer(sk) = NULL; unix_dgram_peer_wake_disconnect_wakeup(sk, other); sk->sk_state = TCP_CLOSE; unix_state_unlock(sk); unix_dgram_disconnected(sk, other); sock_put(other); err = -ECONNREFUSED; } else { unix_state_unlock(sk); } other = NULL; if (err) goto out_free; goto restart; } err = -EPIPE; if (other->sk_shutdown & RCV_SHUTDOWN) goto out_unlock; if (sk->sk_type != SOCK_SEQPACKET) { err = security_unix_may_send(sk->sk_socket, other->sk_socket); if (err) goto out_unlock; } /* other == sk && unix_peer(other) != sk if * - unix_peer(sk) == NULL, destination address bound to sk * - unix_peer(sk) == sk by time of get but disconnected before lock */ if (other != sk && unlikely(unix_peer(other) != sk && unix_recvq_full_lockless(other))) { if (timeo) { timeo = unix_wait_for_peer(other, timeo); err = sock_intr_errno(timeo); if (signal_pending(current)) goto out_free; goto restart; } if (!sk_locked) { unix_state_unlock(other); unix_state_double_lock(sk, other); } if (unix_peer(sk) != other || unix_dgram_peer_wake_me(sk, other)) { err = -EAGAIN; sk_locked = 1; goto out_unlock; } if (!sk_locked) { sk_locked = 1; goto restart_locked; } } if (unlikely(sk_locked)) unix_state_unlock(sk); if (sock_flag(other, SOCK_RCVTSTAMP)) __net_timestamp(skb); maybe_add_creds(skb, sock, other); scm_stat_add(other, skb); skb_queue_tail(&other->sk_receive_queue, skb); unix_state_unlock(other); other->sk_data_ready(other); sock_put(other); scm_destroy(&scm); return len; out_unlock: if (sk_locked) unix_state_unlock(sk); unix_state_unlock(other); out_free: kfree_skb(skb); out: if (other) sock_put(other); scm_destroy(&scm); return err; } /* We use paged skbs for stream sockets, and limit occupancy to 32768 * bytes, and a minimum of a full page. */ #define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768)) #if IS_ENABLED(CONFIG_AF_UNIX_OOB) static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other, struct scm_cookie *scm, bool fds_sent) { struct unix_sock *ousk = unix_sk(other); struct sk_buff *skb; int err = 0; skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err); if (!skb) return err; err = unix_scm_to_skb(scm, skb, !fds_sent); if (err < 0) { kfree_skb(skb); return err; } skb_put(skb, 1); err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1); if (err) { kfree_skb(skb); return err; } unix_state_lock(other); if (sock_flag(other, SOCK_DEAD) || (other->sk_shutdown & RCV_SHUTDOWN)) { unix_state_unlock(other); kfree_skb(skb); return -EPIPE; } maybe_add_creds(skb, sock, other); skb_get(skb); if (ousk->oob_skb) consume_skb(ousk->oob_skb); WRITE_ONCE(ousk->oob_skb, skb); scm_stat_add(other, skb); skb_queue_tail(&other->sk_receive_queue, skb); sk_send_sigurg(other); unix_state_unlock(other); other->sk_data_ready(other); return err; } #endif static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { struct sock *sk = sock->sk; struct sock *other = NULL; int err, size; struct sk_buff *skb; int sent = 0; struct scm_cookie scm; bool fds_sent = false; int data_len; err = scm_send(sock, msg, &scm, false); if (err < 0) return err; wait_for_unix_gc(scm.fp); err = -EOPNOTSUPP; if (msg->msg_flags & MSG_OOB) { #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (len) len--; else #endif goto out_err; } if (msg->msg_namelen) { err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; goto out_err; } else { err = -ENOTCONN; other = unix_peer(sk); if (!other) goto out_err; } if (sk->sk_shutdown & SEND_SHUTDOWN) goto pipe_err; while (sent < len) { size = len - sent; if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { skb = sock_alloc_send_pskb(sk, 0, 0, msg->msg_flags & MSG_DONTWAIT, &err, 0); } else { /* Keep two messages in the pipe so it schedules better */ size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64); /* allow fallback to order-0 allocations */ size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ); data_len = max_t(int, 0, size - SKB_MAX_HEAD(0)); data_len = min_t(size_t, size, PAGE_ALIGN(data_len)); skb = sock_alloc_send_pskb(sk, size - data_len, data_len, msg->msg_flags & MSG_DONTWAIT, &err, get_order(UNIX_SKB_FRAGS_SZ)); } if (!skb) goto out_err; /* Only send the fds in the first buffer */ err = unix_scm_to_skb(&scm, skb, !fds_sent); if (err < 0) { kfree_skb(skb); goto out_err; } fds_sent = true; if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { err = skb_splice_from_iter(skb, &msg->msg_iter, size, sk->sk_allocation); if (err < 0) { kfree_skb(skb); goto out_err; } size = err; refcount_add(size, &sk->sk_wmem_alloc); } else { skb_put(skb, size - data_len); skb->data_len = data_len; skb->len = size; err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size); if (err) { kfree_skb(skb); goto out_err; } } unix_state_lock(other); if (sock_flag(other, SOCK_DEAD) || (other->sk_shutdown & RCV_SHUTDOWN)) goto pipe_err_free; maybe_add_creds(skb, sock, other); scm_stat_add(other, skb); skb_queue_tail(&other->sk_receive_queue, skb); unix_state_unlock(other); other->sk_data_ready(other); sent += size; } #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (msg->msg_flags & MSG_OOB) { err = queue_oob(sock, msg, other, &scm, fds_sent); if (err) goto out_err; sent++; } #endif scm_destroy(&scm); return sent; pipe_err_free: unix_state_unlock(other); kfree_skb(skb); pipe_err: if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) send_sig(SIGPIPE, current, 0); err = -EPIPE; out_err: scm_destroy(&scm); return sent ? : err; } static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { int err; struct sock *sk = sock->sk; err = sock_error(sk); if (err) return err; if (sk->sk_state != TCP_ESTABLISHED) return -ENOTCONN; if (msg->msg_namelen) msg->msg_namelen = 0; return unix_dgram_sendmsg(sock, msg, len); } static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int flags) { struct sock *sk = sock->sk; if (sk->sk_state != TCP_ESTABLISHED) return -ENOTCONN; return unix_dgram_recvmsg(sock, msg, size, flags); } static void unix_copy_addr(struct msghdr *msg, struct sock *sk) { struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr); if (addr) { msg->msg_namelen = addr->len; memcpy(msg->msg_name, addr->name, addr->len); } } int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, int flags) { struct scm_cookie scm; struct socket *sock = sk->sk_socket; struct unix_sock *u = unix_sk(sk); struct sk_buff *skb, *last; long timeo; int skip; int err; err = -EOPNOTSUPP; if (flags&MSG_OOB) goto out; timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); do { mutex_lock(&u->iolock); skip = sk_peek_offset(sk, flags); skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags, &skip, &err, &last); if (skb) { if (!(flags & MSG_PEEK)) scm_stat_del(sk, skb); break; } mutex_unlock(&u->iolock); if (err != -EAGAIN) break; } while (timeo && !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue, &err, &timeo, last)); if (!skb) { /* implies iolock unlocked */ unix_state_lock(sk); /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && (sk->sk_shutdown & RCV_SHUTDOWN)) err = 0; unix_state_unlock(sk); goto out; } if (wq_has_sleeper(&u->peer_wait)) wake_up_interruptible_sync_poll(&u->peer_wait, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); if (msg->msg_name) { unix_copy_addr(msg, skb->sk); BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk, msg->msg_name, &msg->msg_namelen); } if (size > skb->len - skip) size = skb->len - skip; else if (size < skb->len - skip) msg->msg_flags |= MSG_TRUNC; err = skb_copy_datagram_msg(skb, skip, msg, size); if (err) goto out_free; if (sock_flag(sk, SOCK_RCVTSTAMP)) __sock_recv_timestamp(msg, sk, skb); memset(&scm, 0, sizeof(scm)); scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); unix_set_secdata(&scm, skb); if (!(flags & MSG_PEEK)) { if (UNIXCB(skb).fp) unix_detach_fds(&scm, skb); sk_peek_offset_bwd(sk, skb->len); } else { /* It is questionable: on PEEK we could: - do not return fds - good, but too simple 8) - return fds, and do not return them on read (old strategy, apparently wrong) - clone fds (I chose it for now, it is the most universal solution) POSIX 1003.1g does not actually define this clearly at all. POSIX 1003.1g doesn't define a lot of things clearly however! */ sk_peek_offset_fwd(sk, size); if (UNIXCB(skb).fp) unix_peek_fds(&scm, skb); } err = (flags & MSG_TRUNC) ? skb->len - skip : size; scm_recv_unix(sock, msg, &scm, flags); out_free: skb_free_datagram(sk, skb); mutex_unlock(&u->iolock); out: return err; } static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int flags) { struct sock *sk = sock->sk; #ifdef CONFIG_BPF_SYSCALL const struct proto *prot = READ_ONCE(sk->sk_prot); if (prot != &unix_dgram_proto) return prot->recvmsg(sk, msg, size, flags, NULL); #endif return __unix_dgram_recvmsg(sk, msg, size, flags); } static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor) { struct unix_sock *u = unix_sk(sk); struct sk_buff *skb; int err; mutex_lock(&u->iolock); skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err); mutex_unlock(&u->iolock); if (!skb) return err; return recv_actor(sk, skb); } /* * Sleep until more data has arrived. But check for races.. */ static long unix_stream_data_wait(struct sock *sk, long timeo, struct sk_buff *last, unsigned int last_len, bool freezable) { unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE; struct sk_buff *tail; DEFINE_WAIT(wait); unix_state_lock(sk); for (;;) { prepare_to_wait(sk_sleep(sk), &wait, state); tail = skb_peek_tail(&sk->sk_receive_queue); if (tail != last || (tail && tail->len != last_len) || sk->sk_err || (sk->sk_shutdown & RCV_SHUTDOWN) || signal_pending(current) || !timeo) break; sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); unix_state_unlock(sk); timeo = schedule_timeout(timeo); unix_state_lock(sk); if (sock_flag(sk, SOCK_DEAD)) break; sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); } finish_wait(sk_sleep(sk), &wait); unix_state_unlock(sk); return timeo; } static unsigned int unix_skb_len(const struct sk_buff *skb) { return skb->len - UNIXCB(skb).consumed; } struct unix_stream_read_state { int (*recv_actor)(struct sk_buff *, int, int, struct unix_stream_read_state *); struct socket *socket; struct msghdr *msg; struct pipe_inode_info *pipe; size_t size; int flags; unsigned int splice_flags; }; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) static int unix_stream_recv_urg(struct unix_stream_read_state *state) { struct socket *sock = state->socket; struct sock *sk = sock->sk; struct unix_sock *u = unix_sk(sk); int chunk = 1; struct sk_buff *oob_skb; mutex_lock(&u->iolock); unix_state_lock(sk); if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) { unix_state_unlock(sk); mutex_unlock(&u->iolock); return -EINVAL; } oob_skb = u->oob_skb; if (!(state->flags & MSG_PEEK)) WRITE_ONCE(u->oob_skb, NULL); else skb_get(oob_skb); unix_state_unlock(sk); chunk = state->recv_actor(oob_skb, 0, chunk, state); if (!(state->flags & MSG_PEEK)) UNIXCB(oob_skb).consumed += 1; consume_skb(oob_skb); mutex_unlock(&u->iolock); if (chunk < 0) return -EFAULT; state->msg->msg_flags |= MSG_OOB; return 1; } static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk, int flags, int copied) { struct unix_sock *u = unix_sk(sk); if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) { skb_unlink(skb, &sk->sk_receive_queue); consume_skb(skb); skb = NULL; } else { if (skb == u->oob_skb) { if (copied) { skb = NULL; } else if (sock_flag(sk, SOCK_URGINLINE)) { if (!(flags & MSG_PEEK)) { WRITE_ONCE(u->oob_skb, NULL); consume_skb(skb); } } else if (!(flags & MSG_PEEK)) { skb_unlink(skb, &sk->sk_receive_queue); consume_skb(skb); skb = skb_peek(&sk->sk_receive_queue); } } } return skb; } #endif static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor) { if (unlikely(sk->sk_state != TCP_ESTABLISHED)) return -ENOTCONN; return unix_read_skb(sk, recv_actor); } static int unix_stream_read_generic(struct unix_stream_read_state *state, bool freezable) { struct scm_cookie scm; struct socket *sock = state->socket;