/*
 *  (C) 2010,2011       Thomas Renninger <trenn@suse.de>, Novell Inc.
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *
 *  Ideas taken over from the perf userspace tool (included in the Linus
 *  kernel git repo): subcommand builtins and param parsing.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/utsname.h>

#include "builtin.h"
#include "helpers/helpers.h"
#include "helpers/bitmask.h"

#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))

static int cmd_help(int argc, const char **argv);

/* Global cpu_info object available for all binaries
 * Info only retrieved from CPU 0
 *
 * Values will be zero/unknown on non X86 archs
 */
struct cpupower_cpu_info cpupower_cpu_info;
int run_as_root;
/* Affected cpus chosen by -c/--cpu param */
struct bitmask *cpus_chosen;

#ifdef DEBUG
int be_verbose;
#endif

static void print_help(void);

struct cmd_struct {
	const char *cmd;
	int (*main)(int, const char **);
	int needs_root;
};

static struct cmd_struct commands[] = {
	{ "frequency-info",	cmd_freq_info,	0	},
	{ "frequency-set",	cmd_freq_set,	1	},
	{ "idle-info",		cmd_idle_info,	0	},
	{ "idle-set",		cmd_idle_set,	1	},
	{ "set",		cmd_set,	1	},
	{ "info",		cmd_info,	0	},
	{ "monitor",		cmd_monitor,	0	},
	{ "help",		cmd_help,	0	},
	/*	{ "bench",	cmd_bench,	1	}, */
};

static void print_help(void)
{
	unsigned int i;

#ifdef DEBUG
	printf(_("Usage:\tcpupower [-d|--debug] [-c|--cpu cpulist ] <command> [<args>]\n"));
#else
	printf(_("Usage:\tcpupower [-c|--cpu cpulist ] <command> [<args>]\n"));
#endif
	printf(_("Supported commands are:\n"));
	for (i = 0; i < ARRAY_SIZE(commands); i++)
		printf("\t%s\n", commands[i].cmd);
	printf(_("\nNot all commands can make use of the -c cpulist option.\n"));
	printf(_("\nUse 'cpupower help <command>' for getting help for above commands.\n"));
}

static int print_man_page(const char *subpage)
{
	int len;
	char *page;

	len = 10; /* enough for "cpupower-" */
	if (subpage != NULL)
		len += strlen(subpage);

	page = malloc(len);
	if (!page)
		return -ENOMEM;

	sprintf(page, "cpupower");
	if ((subpage != NULL) && strcmp(subpage, "help")) {
		strcat(page, "-");
		strcat(page, subpage);
	}

	execlp("man", "man", page, NULL);

	/* should not be reached */
	return -EINVAL;
}

static int cmd_help(int argc, const char **argv)
{
	if (argc > 1) {
		print_man_page(argv[1]); /* exits within execlp() */
		return EXIT_FAILURE;
	}

	print_help();
	return EXIT_SUCCESS;
}

static void print_version(void)
{
	printf(PACKAGE " " VERSION "\n");
	printf(_("Report errors and bugs to %s, please.\n"), PACKAGE_BUGREPORT);
}

static void handle_options(int *argc, const char ***argv)
{
	int ret, x, new_argc = 0;

	if (*argc < 1)
		return;

	for (x = 0;  x < *argc && ((*argv)[x])[0] == '-'; x++) {
		const char *param = (*argv)[x];
		if (!strcmp(param, "-h") || !strcmp(param, "--help")) {
			print_help();
			exit(EXIT_SUCCESS);
		} else if (!strcmp(param, "-c") || !strcmp(param, "--cpu")) {
			if (*argc < 2) {
				print_help();
				exit(EXIT_FAILURE);
			}
			if (!strcmp((*argv)[x+1], "all"))
				bitmask_setall(cpus_chosen);
			else {
				ret = bitmask_parselist(
						(*argv)[x+1], cpus_chosen);
				if (ret < 0) {
					fprintf(stderr, _("Error parsing cpu "
							  "list\n"));
					exit(EXIT_FAILURE);
				}
			}
			x += 1;
			/* Cut out param: cpupower -c 1 info -> cpupower info */
			new_argc += 2;
			continue;
		} else if (!strcmp(param, "-v") ||
			!strcmp(param, "--version")) {
			print_version();
			exit(EXIT_SUCCESS);
#ifdef DEBUG
		} else if (!strcmp(param, "-d") || !strcmp(param, "--debug")) {
			be_verbose = 1;
			new_argc++;
			continue;
#endif
		} else {
			fprintf(stderr, "Unknown option: %s\n", param);
			print_help();
			exit(EXIT_FAILURE);
		}
	}
	*argc -= new_argc;
	*argv += new_argc;
}

int main(int argc, const char *argv[])
{
	const char *cmd;
	unsigned int i, ret;
	struct stat statbuf;
	struct utsname uts;

	cpus_chosen = bitmask_alloc(sysconf(_SC_NPROCESSORS_CONF));

	argc--;
	argv += 1;

	handle_options(&argc, &argv);

	cmd = argv[0];

	if (argc < 1) {
		print_help();
		return EXIT_FAILURE;
	}

	setlocale(LC_ALL, "");
	textdomain(PACKAGE);

	/* Turn "perf cmd --help" into "perf help cmd" */
	if (argc > 1 && !strcmp(argv[1], "--help")) {
		argv[1] = argv[0];
		argv[0] = cmd = "help";
	}

	get_cpu_info(0, &cpupower_cpu_info);
	run_as_root = !geteuid();
	if (run_as_root) {
		ret = uname(&uts);
		if (!ret && !strcmp(uts.machine, "x86_64") &&
		    stat("/dev/cpu/0/msr", &statbuf) != 0) {
			if (system("modprobe msr") == -1)
	fprintf(stderr, _("MSR access not available.\n"));
		}
	}
		

	for (i = 0; i < ARRAY_SIZE(commands); i++) {
		struct cmd_struct *p = commands + i;
		if (strcmp(p->cmd, cmd))
			continue;
		if (!run_as_root && p->needs_root) {
			fprintf(stderr, _("Subcommand %s needs root "
					  "privileges\n"), cmd);
			return EXIT_FAILURE;
		}
		ret = p->main(argc, argv);
		if (cpus_chosen)
			bitmask_free(cpus_chosen);
		return ret;
	}
	print_help();
	return EXIT_FAILURE;
}
/tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=191e885a2e130e639bb0c8ee350d7047294f2ce6'>9bf9f9b4971df55a46e0a6750d3f6cd37bf1d9f0</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/firewire/oxfw?id=191e885a2e130e639bb0c8ee350d7047294f2ce6'>sound/firewire/oxfw</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/firewire/oxfw?id=49def1853334396f948dcb4cedb9347abb318df5'>49def1853334396f948dcb4cedb9347abb318df5</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/firewire/oxfw?id=191e885a2e130e639bb0c8ee350d7047294f2ce6&amp;id2=49def1853334396f948dcb4cedb9347abb318df5'>diff</a>)</td></tr></table>
<div class='commit-subject'>firmware: fix NULL pointer dereference in __fw_load_abort()</div><div class='commit-msg'>Since commit 5d47ec02c37ea6 ("firmware: Correct handling of
fw_state_wait() return value") fw_load_abort() could be called twice and
lead us to a kernel crash. This happens only when the firmware fallback
mechanism (regular or custom) is used. The fallback mechanism exposes a
sysfs interface for userspace to upload a file and notify the kernel
when the file is loaded and ready, or to cancel an upload by echo'ing -1
into on the loading file:

echo -n "-1" &gt; /sys/$DEVPATH/loading

This will call fw_load_abort(). Some distributions actually have a udev
rule in place to *always* immediately cancel all firmware fallback
mechanism requests (Debian), they have:

  $ cat /lib/udev/rules.d/50-firmware.rules
  # stub for immediately telling the kernel that userspace firmware loading
  # failed; necessary to avoid long timeouts with CONFIG_FW_LOADER_USER_HELPER=y
  SUBSYSTEM=="firmware", ACTION=="add", ATTR{loading}="-1

Distributions with this udev rule would run into this crash only if the
fallback mechanism is used. Since most distributions disable by default
using the fallback mechanism (CONFIG_FW_LOADER_USER_HELPER_FALLBACK),
this would typicaly mean only 2 drivers which *require* the fallback
mechanism could typically incur a crash: drivers/firmware/dell_rbu.c and
the drivers/leds/leds-lp55xx-common.c driver. Distributions enabling
CONFIG_FW_LOADER_USER_HELPER_FALLBACK by default are obviously more
exposed to this crash.

The crash happens because after commit 5b029624948d ("firmware: do not
use fw_lock for fw_state protection") and subsequent fix commit
5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return
value") a race can happen between this cancelation and the firmware
fw_state_wait_timeout() being woken up after a state change with which
fw_load_abort() as that calls swake_up(). Upon error
fw_state_wait_timeout() will also again call fw_load_abort() and trigger
a null reference.

At first glance we could just fix this with a !buf check on
fw_load_abort() before accessing buf-&gt;fw_st, however there is a logical
issue in having a state machine used for the fallback mechanism and
preventing access from it once we abort as its inside the buf
(buf-&gt;fw_st).

The firmware_class.c code is setting the buf to NULL to annotate an
abort has occurred. Replace this mechanism by simply using the state
check instead. All the other code in place already uses similar checks
for aborting as well so no further changes are needed.

An oops can be reproduced with the new fw_fallback.sh fallback mechanism
cancellation test. Either cancelling the fallback mechanism or the
custom fallback mechanism triggers a crash.

mcgrof@piggy ~/linux-next/tools/testing/selftests/firmware
(git::20170111-fw-fixes)$ sudo ./fw_fallback.sh

./fw_fallback.sh: timeout works
./fw_fallback.sh: firmware comparison works
./fw_fallback.sh: fallback mechanism works

[ this then sits here when it is trying the cancellation test ]

Kernel log:

test_firmware: loading 'nope-test-firmware.bin'
misc test_firmware: Direct firmware load for nope-test-firmware.bin failed with error -2
misc test_firmware: Falling back to user helper
BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
IP: _request_firmware+0xa27/0xad0
PGD 0

Oops: 0000 [#1] SMP
Modules linked in: test_firmware(E) ... etc ...
CPU: 1 PID: 1396 Comm: fw_fallback.sh Tainted: G        W E   4.10.0-rc3-next-20170111+ #30
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
task: ffff9740b27f4340 task.stack: ffffbb15c0bc8000
RIP: 0010:_request_firmware+0xa27/0xad0
RSP: 0018:ffffbb15c0bcbd10 EFLAGS: 00010246
RAX: 00000000fffffffe RBX: ffff9740afe5aa80 RCX: 0000000000000000
RDX: ffff9740b27f4340 RSI: 0000000000000283 RDI: 0000000000000000
RBP: ffffbb15c0bcbd90 R08: ffffbb15c0bcbcd8 R09: 0000000000000000
R10: 0000000894a0d4b1 R11: 000000000000008c R12: ffffffffc0312480
R13: 0000000000000005 R14: ffff9740b1c32400 R15: 00000000000003e8
FS:  00007f8604422700(0000) GS:ffff9740bfc80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000038 CR3: 000000012164c000 CR4: 00000000000006e0
Call Trace:
 request_firmware+0x37/0x50
 trigger_request_store+0x79/0xd0 [test_firmware]
 dev_attr_store+0x18/0x30
 sysfs_kf_write+0x37/0x40
 kernfs_fop_write+0x110/0x1a0
 __vfs_write+0x37/0x160
 ? _cond_resched+0x1a/0x50
 vfs_write+0xb5/0x1a0
 SyS_write+0x55/0xc0
 ? trace_do_page_fault+0x37/0xd0
 entry_SYSCALL_64_fastpath+0x1e/0xad
RIP: 0033:0x7f8603f49620
RSP: 002b:00007fff6287b788 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055c307b110a0 RCX: 00007f8603f49620
RDX: 0000000000000016 RSI: 000055c3084d8a90 RDI: 0000000000000001
RBP: 0000000000000016 R08: 000000000000c0ff R09: 000055c3084d6336
R10: 000055c307b108b0 R11: 0000000000000246 R12: 000055c307b13c80
R13: 000055c3084d6320 R14: 0000000000000000 R15: 00007fff6287b950
Code: 9f 64 84 e8 9c 61 fe ff b8 f4 ff ff ff e9 6b f9 ff
ff 48 c7 c7 40 6b 8d 84 89 45 a8 e8 43 84 18 00 49 8b be 00 03 00 00 8b
45 a8 &lt;83&gt; 7f 38 02 74 08 e8 6e ec ff ff 8b 45 a8 49 c7 86 00 03 00 00
RIP: _request_firmware+0xa27/0xad0 RSP: ffffbb15c0bcbd10
CR2: 0000000000000038
---[ end trace 6d94ac339c133e6f ]---

Fixes: 5d47ec02c37e ("firmware: Correct handling of fw_state_wait() return value")
Reported-and-Tested-by: Jakub Kicinski &lt;jakub.kicinski@netronome.com&gt;
Reported-and-Tested-by: Patrick Bruenn &lt;p.bruenn@beckhoff.com&gt;
Reported-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
CC: &lt;stable@vger.kernel.org&gt;    [3.10+]
Signed-off-by: Luis R. Rodriguez &lt;mcgrof@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=191e885a2e130e639bb0c8ee350d7047294f2ce6'>Diffstat</a> (limited to 'sound/firewire/oxfw')</div><table summary='diffstat' class='diffstat'>