https://github.com/torvalds/linux
Revision 86d32f9a7c54ad74f4514d7fef7c847883207291 authored by Vasily Averin on 14 April 2020, 20:33:16 UTC, committed by Linus Torvalds on 16 April 2020, 17:10:50 UTC
If seq_file .next function does not change position index,
read after some lseek can generate unexpected output:

    $ dd if=/proc/keys bs=1  # full usual output
    0f6bfdf5 I--Q---     2 perm 3f010000  1000  1000 user      4af2f79ab8848d0a: 740
    1fb91b32 I--Q---     3 perm 1f3f0000  1000 65534 keyring   _uid.1000: 2
    27589480 I--Q---     1 perm 0b0b0000     0     0 user      invocation_id: 16
    2f33ab67 I--Q---   152 perm 3f030000     0     0 keyring   _ses: 2
    33f1d8fa I--Q---     4 perm 3f030000  1000  1000 keyring   _ses: 1
    3d427fda I--Q---     2 perm 3f010000  1000  1000 user      69ec44aec7678e5a: 740
    3ead4096 I--Q---     1 perm 1f3f0000  1000 65534 keyring   _uid_ses.1000: 1
    521+0 records in
    521+0 records out
    521 bytes copied, 0,00123769 s, 421 kB/s

But a read after lseek in middle of last line results in the partial
last line and then a repeat of the final line:

    $ dd if=/proc/keys bs=500 skip=1
    dd: /proc/keys: cannot skip to specified offset
    g   _uid_ses.1000: 1
    3ead4096 I--Q---     1 perm 1f3f0000  1000 65534 keyring   _uid_ses.1000: 1
    0+1 records in
    0+1 records out
    97 bytes copied, 0,000135035 s, 718 kB/s

and a read after lseek beyond end of file results in the last line being
shown:

    $ dd if=/proc/keys bs=1000 skip=1   # read after lseek beyond end of file
    dd: /proc/keys: cannot skip to specified offset
    3ead4096 I--Q---     1 perm 1f3f0000  1000 65534 keyring   _uid_ses.1000: 1
    0+1 records in
    0+1 records out
    76 bytes copied, 0,000119981 s, 633 kB/s

See https://bugzilla.kernel.org/show_bug.cgi?id=206283

Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 0008633
Raw File
Tip revision: 86d32f9a7c54ad74f4514d7fef7c847883207291 authored by Vasily Averin on 14 April 2020, 20:33:16 UTC
keys: Fix proc_keys_next to increase position index
Tip revision: 86d32f9
test_uuid.c
/*
 * Test cases for lib/uuid.c module.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/uuid.h>

struct test_uuid_data {
	const char *uuid;
	guid_t le;
	uuid_t be;
};

static const struct test_uuid_data test_uuid_test_data[] = {
	{
		.uuid = "c33f4995-3701-450e-9fbf-206a2e98e576",
		.le = GUID_INIT(0xc33f4995, 0x3701, 0x450e, 0x9f, 0xbf, 0x20, 0x6a, 0x2e, 0x98, 0xe5, 0x76),
		.be = UUID_INIT(0xc33f4995, 0x3701, 0x450e, 0x9f, 0xbf, 0x20, 0x6a, 0x2e, 0x98, 0xe5, 0x76),
	},
	{
		.uuid = "64b4371c-77c1-48f9-8221-29f054fc023b",
		.le = GUID_INIT(0x64b4371c, 0x77c1, 0x48f9, 0x82, 0x21, 0x29, 0xf0, 0x54, 0xfc, 0x02, 0x3b),
		.be = UUID_INIT(0x64b4371c, 0x77c1, 0x48f9, 0x82, 0x21, 0x29, 0xf0, 0x54, 0xfc, 0x02, 0x3b),
	},
	{
		.uuid = "0cb4ddff-a545-4401-9d06-688af53e7f84",
		.le = GUID_INIT(0x0cb4ddff, 0xa545, 0x4401, 0x9d, 0x06, 0x68, 0x8a, 0xf5, 0x3e, 0x7f, 0x84),
		.be = UUID_INIT(0x0cb4ddff, 0xa545, 0x4401, 0x9d, 0x06, 0x68, 0x8a, 0xf5, 0x3e, 0x7f, 0x84),
	},
};

static const char * const test_uuid_wrong_data[] = {
	"c33f4995-3701-450e-9fbf206a2e98e576 ",	/* no hyphen(s) */
	"64b4371c-77c1-48f9-8221-29f054XX023b",	/* invalid character(s) */
	"0cb4ddff-a545-4401-9d06-688af53e",	/* not enough data */
};

static unsigned total_tests __initdata;
static unsigned failed_tests __initdata;

static void __init test_uuid_failed(const char *prefix, bool wrong, bool be,
				    const char *data, const char *actual)
{
	pr_err("%s test #%u %s %s data: '%s'\n",
	       prefix,
	       total_tests,
	       wrong ? "passed on wrong" : "failed on",
	       be ? "BE" : "LE",
	       data);
	if (actual && *actual)
		pr_err("%s test #%u actual data: '%s'\n",
		       prefix,
		       total_tests,
		       actual);
	failed_tests++;
}

static void __init test_uuid_test(const struct test_uuid_data *data)
{
	guid_t le;
	uuid_t be;
	char buf[48];

	/* LE */
	total_tests++;
	if (guid_parse(data->uuid, &le))
		test_uuid_failed("conversion", false, false, data->uuid, NULL);

	total_tests++;
	if (!guid_equal(&data->le, &le)) {
		sprintf(buf, "%pUl", &le);
		test_uuid_failed("cmp", false, false, data->uuid, buf);
	}

	/* BE */
	total_tests++;
	if (uuid_parse(data->uuid, &be))
		test_uuid_failed("conversion", false, true, data->uuid, NULL);

	total_tests++;
	if (!uuid_equal(&data->be, &be)) {
		sprintf(buf, "%pUb", &be);
		test_uuid_failed("cmp", false, true, data->uuid, buf);
	}
}

static void __init test_uuid_wrong(const char *data)
{
	guid_t le;
	uuid_t be;

	/* LE */
	total_tests++;
	if (!guid_parse(data, &le))
		test_uuid_failed("negative", true, false, data, NULL);

	/* BE */
	total_tests++;
	if (!uuid_parse(data, &be))
		test_uuid_failed("negative", true, true, data, NULL);
}

static int __init test_uuid_init(void)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(test_uuid_test_data); i++)
		test_uuid_test(&test_uuid_test_data[i]);

	for (i = 0; i < ARRAY_SIZE(test_uuid_wrong_data); i++)
		test_uuid_wrong(test_uuid_wrong_data[i]);

	if (failed_tests == 0)
		pr_info("all %u tests passed\n", total_tests);
	else
		pr_err("failed %u out of %u tests\n", failed_tests, total_tests);

	return failed_tests ? -EINVAL : 0;
}
module_init(test_uuid_init);

static void __exit test_uuid_exit(void)
{
	/* do nothing */
}
module_exit(test_uuid_exit);

MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_LICENSE("Dual BSD/GPL");
back to top