2021-07-21 12:08:15

by Sven Schnelle

Subject: [PATCH] ucounts: add missing data type changes

commit f9c82a4ea89c3 ("Increase size of ucounts to atomic_long_t")
changed the data type of ucounts/ucounts_max to long, but missed to
adjust a few other places. This is noticeable on big endian platforms
from user space because the /proc/sys/user/max_*_names files all
contain 0.

Fixes: f9c82a4ea89c ("Increase size of ucounts to atomic_long_t")
Signed-off-by: Sven Schnelle <[email protected]>
---
fs/notify/fanotify/fanotify_user.c | 11 +++++++----
kernel/ucount.c | 18 ++++++++++--------
kernel/user_namespace.c | 2 +-
3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 64864fb40b40..995379ddce86 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -54,22 +54,25 @@ static int fanotify_max_queued_events __read_mostly;

#include <linux/sysctl.h>

+static unsigned long long_max = LONG_MAX;
struct ctl_table fanotify_table[] = {
{
.procname = "max_user_groups",
.data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
- .maxlen = sizeof(int),
+ .maxlen = sizeof(long),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_doulongvec_minmax,
.extra1 = SYSCTL_ZERO,
+ .extra2 = &long_max,
},
{
.procname = "max_user_marks",
.data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
- .maxlen = sizeof(int),
+ .maxlen = sizeof(long),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_doulongvec_minmax,
.extra1 = SYSCTL_ZERO,
+ .extra2 = &long_max,
},
{
.procname = "max_queued_events",
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 87799e2379bd..681ea1b1a06f 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -58,14 +58,16 @@ static struct ctl_table_root set_root = {
.permissions = set_permissions,
};

-#define UCOUNT_ENTRY(name) \
- { \
- .procname = name, \
- .maxlen = sizeof(int), \
- .mode = 0644, \
- .proc_handler = proc_dointvec_minmax, \
- .extra1 = SYSCTL_ZERO, \
- .extra2 = SYSCTL_INT_MAX, \
+static unsigned long long_max = LONG_MAX;
+
+#define UCOUNT_ENTRY(name) \
+ { \
+ .procname = name, \
+ .maxlen = sizeof(long), \
+ .mode = 0644, \
+ .proc_handler = proc_doulongvec_minmax, \
+ .extra1 = SYSCTL_ZERO, \
+ .extra2 = &long_max, \
}
static struct ctl_table user_table[] = {
UCOUNT_ENTRY("max_user_namespaces"),
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index ef82d401dde8..d8ad4c261253 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -120,7 +120,7 @@ int create_user_ns(struct cred *new)
ns->group = group;
INIT_WORK(&ns->work, free_user_ns);
for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) {
- ns->ucount_max[i] = INT_MAX;
+ ns->ucount_max[i] = LONG_MAX;
}
set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC));
set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE));
--
2.25.1

2021-07-21 13:56:29

by Sven Schnelle

Subject: Re: [PATCH] ucounts: add missing data type changes

Alexey Gladkov <[email protected]> writes:

> On Wed, Jul 21, 2021 at 01:58:00PM +0200, Sven Schnelle wrote:
>> commit f9c82a4ea89c3 ("Increase size of ucounts to atomic_long_t")
>> changed the data type of ucounts/ucounts_max to long, but missed to
>> adjust a few other places. This is noticeable on big endian platforms
>> from user space because the /proc/sys/user/max_*_names files all
>> contain 0.
>
> I didn't increase them because I didn't want to increase the maximum
> number of namespaces.
>
> Your patch not only fixes the described problem, but also increases the
> maximum number of namespaces.
>
>> Fixes: f9c82a4ea89c ("Increase size of ucounts to atomic_long_t")
>> Signed-off-by: Sven Schnelle <[email protected]>
>> ---
>> fs/notify/fanotify/fanotify_user.c | 11 +++++++----
>> kernel/ucount.c | 18 ++++++++++--------
>> kernel/user_namespace.c | 2 +-
>> 3 files changed, 18 insertions(+), 13 deletions(-)
>>
>> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
>> index 64864fb40b40..995379ddce86 100644
>> --- a/fs/notify/fanotify/fanotify_user.c
>> +++ b/fs/notify/fanotify/fanotify_user.c
>> @@ -54,22 +54,25 @@ static int fanotify_max_queued_events __read_mostly;
>>
>> #include <linux/sysctl.h>
>>
>> +static unsigned long long_max = LONG_MAX;
>
> I think this should be INT_MAX.

Thanks. I'll change the code to use SYSCTL_INT_MAX instead and send a
v2.

>> struct ctl_table fanotify_table[] = {
>> {
>> .procname = "max_user_groups",
>> .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
>> - .maxlen = sizeof(int),
>> + .maxlen = sizeof(long),
>> .mode = 0644,
>> - .proc_handler = proc_dointvec_minmax,
>> + .proc_handler = proc_doulongvec_minmax,
>> .extra1 = SYSCTL_ZERO,
>> + .extra2 = &long_max,
>> },
>> {
>> .procname = "max_user_marks",
>> .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
>> - .maxlen = sizeof(int),
>> + .maxlen = sizeof(long),
>> .mode = 0644,
>> - .proc_handler = proc_dointvec_minmax,
>> + .proc_handler = proc_doulongvec_minmax,
>> .extra1 = SYSCTL_ZERO,
>> + .extra2 = &long_max,
>> },
>> {
>> .procname = "max_queued_events",
>> diff --git a/kernel/ucount.c b/kernel/ucount.c
>> index 87799e2379bd..681ea1b1a06f 100644
>> --- a/kernel/ucount.c
>> +++ b/kernel/ucount.c
>> @@ -58,14 +58,16 @@ static struct ctl_table_root set_root = {
>> .permissions = set_permissions,
>> };
>>
>> -#define UCOUNT_ENTRY(name) \
>> - { \
>> - .procname = name, \
>> - .maxlen = sizeof(int), \
>> - .mode = 0644, \
>> - .proc_handler = proc_dointvec_minmax, \
>> - .extra1 = SYSCTL_ZERO, \
>> - .extra2 = SYSCTL_INT_MAX, \
>> +static unsigned long long_max = LONG_MAX;
>> +
>> +#define UCOUNT_ENTRY(name) \
>> + { \
>> + .procname = name, \
>> + .maxlen = sizeof(long), \
>> + .mode = 0644, \
>> + .proc_handler = proc_doulongvec_minmax, \
>> + .extra1 = SYSCTL_ZERO, \
>> + .extra2 = &long_max, \
>> }
>> static struct ctl_table user_table[] = {
>> UCOUNT_ENTRY("max_user_namespaces"),
>> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
>> index ef82d401dde8..d8ad4c261253 100644
>> --- a/kernel/user_namespace.c
>> +++ b/kernel/user_namespace.c
>> @@ -120,7 +120,7 @@ int create_user_ns(struct cred *new)
>> ns->group = group;
>> INIT_WORK(&ns->work, free_user_ns);
>> for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) {
>> - ns->ucount_max[i] = INT_MAX;
>> + ns->ucount_max[i] = LONG_MAX;

Guess this should also stay at INT_MAX?

>> }
>> set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC));
>> set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE));
>> --
>> 2.25.1
>>

2021-07-21 13:56:38

by Alexey Gladkov

Subject: Re: [PATCH] ucounts: add missing data type changes

On Wed, Jul 21, 2021 at 01:58:00PM +0200, Sven Schnelle wrote:
> commit f9c82a4ea89c3 ("Increase size of ucounts to atomic_long_t")
> changed the data type of ucounts/ucounts_max to long, but missed to
> adjust a few other places. This is noticeable on big endian platforms
> from user space because the /proc/sys/user/max_*_names files all
> contain 0.

I didn't increase them because I didn't want to increase the maximum
number of namespaces.

Your patch not only fixes the described problem, but also increases the
maximum number of namespaces.

> Fixes: f9c82a4ea89c ("Increase size of ucounts to atomic_long_t")
> Signed-off-by: Sven Schnelle <[email protected]>
> ---
> fs/notify/fanotify/fanotify_user.c | 11 +++++++----
> kernel/ucount.c | 18 ++++++++++--------
> kernel/user_namespace.c | 2 +-
> 3 files changed, 18 insertions(+), 13 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 64864fb40b40..995379ddce86 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -54,22 +54,25 @@ static int fanotify_max_queued_events __read_mostly;
>
> #include <linux/sysctl.h>
>
> +static unsigned long long_max = LONG_MAX;

I think this should be INT_MAX.

> struct ctl_table fanotify_table[] = {
> {
> .procname = "max_user_groups",
> .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
> - .maxlen = sizeof(int),
> + .maxlen = sizeof(long),
> .mode = 0644,
> - .proc_handler = proc_dointvec_minmax,
> + .proc_handler = proc_doulongvec_minmax,
> .extra1 = SYSCTL_ZERO,
> + .extra2 = &long_max,
> },
> {
> .procname = "max_user_marks",
> .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
> - .maxlen = sizeof(int),
> + .maxlen = sizeof(long),
> .mode = 0644,
> - .proc_handler = proc_dointvec_minmax,
> + .proc_handler = proc_doulongvec_minmax,
> .extra1 = SYSCTL_ZERO,
> + .extra2 = &long_max,
> },
> {
> .procname = "max_queued_events",
> diff --git a/kernel/ucount.c b/kernel/ucount.c
> index 87799e2379bd..681ea1b1a06f 100644
> --- a/kernel/ucount.c
> +++ b/kernel/ucount.c
> @@ -58,14 +58,16 @@ static struct ctl_table_root set_root = {
> .permissions = set_permissions,
> };
>
> -#define UCOUNT_ENTRY(name) \
> - { \
> - .procname = name, \
> - .maxlen = sizeof(int), \
> - .mode = 0644, \
> - .proc_handler = proc_dointvec_minmax, \
> - .extra1 = SYSCTL_ZERO, \
> - .extra2 = SYSCTL_INT_MAX, \
> +static unsigned long long_max = LONG_MAX;
> +
> +#define UCOUNT_ENTRY(name) \
> + { \
> + .procname = name, \
> + .maxlen = sizeof(long), \
> + .mode = 0644, \
> + .proc_handler = proc_doulongvec_minmax, \
> + .extra1 = SYSCTL_ZERO, \
> + .extra2 = &long_max, \
> }
> static struct ctl_table user_table[] = {
> UCOUNT_ENTRY("max_user_namespaces"),
> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> index ef82d401dde8..d8ad4c261253 100644
> --- a/kernel/user_namespace.c
> +++ b/kernel/user_namespace.c
> @@ -120,7 +120,7 @@ int create_user_ns(struct cred *new)
> ns->group = group;
> INIT_WORK(&ns->work, free_user_ns);
> for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) {
> - ns->ucount_max[i] = INT_MAX;
> + ns->ucount_max[i] = LONG_MAX;
> }
> set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC));
> set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE));
> --
> 2.25.1
>

--
Rgrds, legion

2021-07-21 13:58:31

by Alexey Gladkov

Subject: Re: [PATCH] ucounts: add missing data type changes

On Wed, Jul 21, 2021 at 02:32:38PM +0200, Sven Schnelle wrote:
> Alexey Gladkov <[email protected]> writes:
>
> > On Wed, Jul 21, 2021 at 01:58:00PM +0200, Sven Schnelle wrote:
> >> commit f9c82a4ea89c3 ("Increase size of ucounts to atomic_long_t")
> >> changed the data type of ucounts/ucounts_max to long, but missed to
> >> adjust a few other places. This is noticeable on big endian platforms
> >> from user space because the /proc/sys/user/max_*_names files all
> >> contain 0.
> >
> > I didn't increase them because I didn't want to increase the maximum
> > number of namespaces.
> >
> > Your patch not only fixes the described problem, but also increases the
> > maximum number of namespaces.
> >
> >> Fixes: f9c82a4ea89c ("Increase size of ucounts to atomic_long_t")
> >> Signed-off-by: Sven Schnelle <[email protected]>
> >> ---
> >> fs/notify/fanotify/fanotify_user.c | 11 +++++++----
> >> kernel/ucount.c | 18 ++++++++++--------
> >> kernel/user_namespace.c | 2 +-
> >> 3 files changed, 18 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> >> index 64864fb40b40..995379ddce86 100644
> >> --- a/fs/notify/fanotify/fanotify_user.c
> >> +++ b/fs/notify/fanotify/fanotify_user.c
> >> @@ -54,22 +54,25 @@ static int fanotify_max_queued_events __read_mostly;
> >>
> >> #include <linux/sysctl.h>
> >>
> >> +static unsigned long long_max = LONG_MAX;
> >
> > I think this should be INT_MAX.
>
> Thanks. I'll change the code to use SYSCTL_INT_MAX instead and send a
> v2.
>
> >> struct ctl_table fanotify_table[] = {
> >> {
> >> .procname = "max_user_groups",
> >> .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
> >> - .maxlen = sizeof(int),
> >> + .maxlen = sizeof(long),
> >> .mode = 0644,
> >> - .proc_handler = proc_dointvec_minmax,
> >> + .proc_handler = proc_doulongvec_minmax,
> >> .extra1 = SYSCTL_ZERO,
> >> + .extra2 = &long_max,
> >> },
> >> {
> >> .procname = "max_user_marks",
> >> .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
> >> - .maxlen = sizeof(int),
> >> + .maxlen = sizeof(long),
> >> .mode = 0644,
> >> - .proc_handler = proc_dointvec_minmax,
> >> + .proc_handler = proc_doulongvec_minmax,
> >> .extra1 = SYSCTL_ZERO,
> >> + .extra2 = &long_max,
> >> },
> >> {
> >> .procname = "max_queued_events",
> >> diff --git a/kernel/ucount.c b/kernel/ucount.c
> >> index 87799e2379bd..681ea1b1a06f 100644
> >> --- a/kernel/ucount.c
> >> +++ b/kernel/ucount.c
> >> @@ -58,14 +58,16 @@ static struct ctl_table_root set_root = {
> >> .permissions = set_permissions,
> >> };
> >>
> >> -#define UCOUNT_ENTRY(name) \
> >> - { \
> >> - .procname = name, \
> >> - .maxlen = sizeof(int), \
> >> - .mode = 0644, \
> >> - .proc_handler = proc_dointvec_minmax, \
> >> - .extra1 = SYSCTL_ZERO, \
> >> - .extra2 = SYSCTL_INT_MAX, \
> >> +static unsigned long long_max = LONG_MAX;
> >> +
> >> +#define UCOUNT_ENTRY(name) \
> >> + { \
> >> + .procname = name, \
> >> + .maxlen = sizeof(long), \
> >> + .mode = 0644, \
> >> + .proc_handler = proc_doulongvec_minmax, \
> >> + .extra1 = SYSCTL_ZERO, \
> >> + .extra2 = &long_max, \
> >> }
> >> static struct ctl_table user_table[] = {
> >> UCOUNT_ENTRY("max_user_namespaces"),
> >> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> >> index ef82d401dde8..d8ad4c261253 100644
> >> --- a/kernel/user_namespace.c
> >> +++ b/kernel/user_namespace.c
> >> @@ -120,7 +120,7 @@ int create_user_ns(struct cred *new)
> >> ns->group = group;
> >> INIT_WORK(&ns->work, free_user_ns);
> >> for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) {
> >> - ns->ucount_max[i] = INT_MAX;
> >> + ns->ucount_max[i] = LONG_MAX;
>
> Guess this should also stay at INT_MAX?

Yes.

> >> }
> >> set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC));
> >> set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE));
> >> --
> >> 2.25.1
> >>
>

--
Rgrds, legion