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dm: reject trailing characters in sccanf input

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Device mapper uses sscanf to convert arguments to numbers. The problem is that
the way we use it ignores additional unmatched characters in the scanned string.

For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number,
but also it will match number with some garbage appended, like "123abc".

As a result, device mapper accepts garbage after some numbers. For example
the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"'
will pass without an error.

This patch fixes all sscanf uses in device mapper. It appends "%c" with
a pointer to a dummy character variable to every sscanf statement.

The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds
only if string is a null-terminated number (optionally preceded by some
whitespace characters). If there is some character appended after the number,
sscanf matches "%c", writes the character to the dummy variable and returns 2.
We check the return value for 1 and consequently reject numbers with some
garbage appended.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mikulas Patocka 2012-03-28 18:41:26 +01:00 committed by Alasdair G Kergon
parent 0447568fc5
commit 31998ef193
13 changed files with 44 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/md/dm-crypt.c
View File

@ -1415,6 +1415,7 @@ static int crypt_ctr_cipher(struct dm_target *ti,
char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
char *cipher_api = NULL;
int cpu, ret = -EINVAL;
char dummy;
/* Convert to crypto api definition? */
if (strchr(cipher_in, '(')) {
@ -1436,7 +1437,7 @@ static int crypt_ctr_cipher(struct dm_target *ti,
if (!keycount)
cc->tfms_count = 1;
else if (sscanf(keycount, "%u", &cc->tfms_count) != 1 ||
else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
!is_power_of_2(cc->tfms_count)) {
ti->error = "Bad cipher key count specification";
return -EINVAL;
@ -1581,6 +1582,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
int ret;
struct dm_arg_set as;
const char *opt_string;
char dummy;
static struct dm_arg _args[] = {
{0, 1, "Invalid number of feature args"},
@ -1638,7 +1640,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ret = -EINVAL;
if (sscanf(argv[2], "%llu", &tmpll) != 1) {
if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid iv_offset sector";
goto bad;
}
@ -1649,7 +1651,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
if (sscanf(argv[4], "%llu", &tmpll) != 1) {
if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid device sector";
goto bad;
}

9
drivers/md/dm-delay.c
View File

@ -131,6 +131,7 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct delay_c *dc;
unsigned long long tmpll;
char dummy;
if (argc != 3 && argc != 6) {
ti->error = "requires exactly 3 or 6 arguments";
@ -145,13 +146,13 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
dc->reads = dc->writes = 0;
if (sscanf(argv[1], "%llu", &tmpll) != 1) {
if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid device sector";
goto bad;
}
dc->start_read = tmpll;
if (sscanf(argv[2], "%u", &dc->read_delay) != 1) {
if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
ti->error = "Invalid delay";
goto bad;
}
@ -166,13 +167,13 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (argc == 3)
goto out;
if (sscanf(argv[4], "%llu", &tmpll) != 1) {
if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid write device sector";
goto bad_dev_read;
}
dc->start_write = tmpll;
if (sscanf(argv[5], "%u", &dc->write_delay) != 1) {
if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
ti->error = "Invalid write delay";
goto bad_dev_read;
}

3
drivers/md/dm-flakey.c
View File

@ -160,6 +160,7 @@ static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
unsigned long long tmpll;
struct dm_arg_set as;
const char *devname;
char dummy;
as.argc = argc;
as.argv = argv;
@ -178,7 +179,7 @@ static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
devname = dm_shift_arg(&as);
if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 1) {
if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid device sector";
goto bad;
}

5
drivers/md/dm-ioctl.c
View File

@ -880,6 +880,7 @@ static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
struct hd_geometry geometry;
unsigned long indata[4];
char *geostr = (char *) param + param->data_start;
char dummy;
md = find_device(param);
if (!md)
@ -891,8 +892,8 @@ static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
goto out;
}
x = sscanf(geostr, "%lu %lu %lu %lu", indata,
indata + 1, indata + 2, indata + 3);
x = sscanf(geostr, "%lu %lu %lu %lu%c", indata,
indata + 1, indata + 2, indata + 3, &dummy);
if (x != 4) {
DMWARN("Unable to interpret geometry settings.");

3
drivers/md/dm-linear.c
View File

@ -29,6 +29,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct linear_c *lc;
unsigned long long tmp;
char dummy;
if (argc != 2) {
ti->error = "Invalid argument count";
@ -41,7 +42,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
return -ENOMEM;
}
if (sscanf(argv[1], "%llu", &tmp) != 1) {
if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
ti->error = "dm-linear: Invalid device sector";
goto bad;
}

3
drivers/md/dm-log.c
View File

@ -369,6 +369,7 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int region_count;
size_t bitset_size, buf_size;
int r;
char dummy;
if (argc < 1 || argc > 2) {
DMWARN("wrong number of arguments to dirty region log");
@ -387,7 +388,7 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
}
}
if (sscanf(argv[0], "%u", &region_size) != 1 ||
if (sscanf(argv[0], "%u%c", &region_size, &dummy) != 1 ||
!_check_region_size(ti, region_size)) {
DMWARN("invalid region size %s", argv[0]);
return -EINVAL;

6
drivers/md/dm-mpath.c
View File

@ -1070,8 +1070,9 @@ static int switch_pg_num(struct multipath *m, const char *pgstr)
struct priority_group *pg;
unsigned pgnum;
unsigned long flags;
char dummy;
if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
(pgnum > m->nr_priority_groups)) {
DMWARN("invalid PG number supplied to switch_pg_num");
return -EINVAL;
@ -1101,8 +1102,9 @@ static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
{
struct priority_group *pg;
unsigned pgnum;
char dummy;
if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
(pgnum > m->nr_priority_groups)) {
DMWARN("invalid PG number supplied to bypass_pg");
return -EINVAL;

3
drivers/md/dm-queue-length.c
View File

@ -112,6 +112,7 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
struct selector *s = ps->context;
struct path_info *pi;
unsigned repeat_count = QL_MIN_IO;
char dummy;
/*
* Arguments: [<repeat_count>]
@ -123,7 +124,7 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
return -EINVAL;
}
if ((argc == 1) && (sscanf(argv[0], "%u", &repeat_count) != 1)) {
if ((argc == 1) && (sscanf(argv[0], "%u%c", &repeat_count, &dummy) != 1)) {
*error = "queue-length ps: invalid repeat count";
return -EINVAL;
}

12
drivers/md/dm-raid1.c
View File

@ -924,8 +924,9 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
unsigned int mirror, char **argv)
{
unsigned long long offset;
char dummy;
if (sscanf(argv[1], "%llu", &offset) != 1) {
if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1) {
ti->error = "Invalid offset";
return -EINVAL;
}
@ -953,13 +954,14 @@ static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
{
unsigned param_count;
struct dm_dirty_log *dl;
char dummy;
if (argc < 2) {
ti->error = "Insufficient mirror log arguments";
return NULL;
}
if (sscanf(argv[1], "%u", &param_count) != 1) {
if (sscanf(argv[1], "%u%c", &param_count, &dummy) != 1) {
ti->error = "Invalid mirror log argument count";
return NULL;
}
@ -986,13 +988,14 @@ static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
{
unsigned num_features;
struct dm_target *ti = ms->ti;
char dummy;
*args_used = 0;
if (!argc)
return 0;
if (sscanf(argv[0], "%u", &num_features) != 1) {
if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
ti->error = "Invalid number of features";
return -EINVAL;
}
@ -1036,6 +1039,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
unsigned int nr_mirrors, m, args_used;
struct mirror_set *ms;
struct dm_dirty_log *dl;
char dummy;
dl = create_dirty_log(ti, argc, argv, &args_used);
if (!dl)
@ -1044,7 +1048,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
argv += args_used;
argc -= args_used;
if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
ti->error = "Invalid number of mirrors";
dm_dirty_log_destroy(dl);

3
drivers/md/dm-round-robin.c
View File

@ -114,6 +114,7 @@ static int rr_add_path(struct path_selector *ps, struct dm_path *path,
struct selector *s = (struct selector *) ps->context;
struct path_info *pi;
unsigned repeat_count = RR_MIN_IO;
char dummy;
if (argc > 1) {
*error = "round-robin ps: incorrect number of arguments";
@ -121,7 +122,7 @@ static int rr_add_path(struct path_selector *ps, struct dm_path *path,
}
/* First path argument is number of I/Os before switching path */
if ((argc == 1) && (sscanf(argv[0], "%u", &repeat_count) != 1)) {
if ((argc == 1) && (sscanf(argv[0], "%u%c", &repeat_count, &dummy) != 1)) {
*error = "round-robin ps: invalid repeat count";
return -EINVAL;
}

5
drivers/md/dm-service-time.c
View File

@ -110,6 +110,7 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path,
struct path_info *pi;
unsigned repeat_count = ST_MIN_IO;
unsigned relative_throughput = 1;
char dummy;
/*
* Arguments: [<repeat_count> [<relative_throughput>]]
@ -128,13 +129,13 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path,
return -EINVAL;
}
if (argc && (sscanf(argv[0], "%u", &repeat_count) != 1)) {
if (argc && (sscanf(argv[0], "%u%c", &repeat_count, &dummy) != 1)) {
*error = "service-time ps: invalid repeat count";
return -EINVAL;
}
if ((argc == 2) &&
(sscanf(argv[1], "%u", &relative_throughput) != 1 ||
(sscanf(argv[1], "%u%c", &relative_throughput, &dummy) != 1 ||
relative_throughput > ST_MAX_RELATIVE_THROUGHPUT)) {
*error = "service-time ps: invalid relative_throughput value";
return -EINVAL;

3
drivers/md/dm-stripe.c
View File

@ -75,8 +75,9 @@ static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
unsigned int stripe, char **argv)
{
unsigned long long start;
char dummy;
if (sscanf(argv[1], "%llu", &start) != 1)
if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
return -EINVAL;
if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),

6
drivers/md/dm-table.c
View File

@ -463,10 +463,11 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
struct dm_dev_internal *dd;
unsigned int major, minor;
struct dm_table *t = ti->table;
char dummy;
BUG_ON(!t);
if (sscanf(path, "%u:%u", &major, &minor) == 2) {
if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
/* Extract the major/minor numbers */
dev = MKDEV(major, minor);
if (MAJOR(dev) != major || MINOR(dev) != minor)
@ -841,9 +842,10 @@ static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
unsigned *value, char **error, unsigned grouped)
{
const char *arg_str = dm_shift_arg(arg_set);
char dummy;
if (!arg_str ||
(sscanf(arg_str, "%u", value) != 1) ||
(sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
(*value < arg->min) ||
(*value > arg->max) ||
(grouped && arg_set->argc < *value)) {