[PATCH v2 1/2] security: keys: Replace time_t/timespec with time64_t

From: Baolin Wang
Date: Wed Sep 20 2017 - 22:33:19 EST

The 'struct key' will use 'time_t' which we try to remove in the
kernel, since 'time_t' is not year 2038 safe on 32bit systems.
Also the 'struct keyring_search_context' will use 'timespec' type
to record current time, which is also not year 2038 safe on 32bit
systems.

Thus this patch replaces 'time_t' with 'time64_t' which is year 2038
safe for 'struct key', and replace 'timespec' with 'time64_t' for the
'struct keyring_search_context', since we only look at the the seconds
part of 'timespec' variable. Moreover we also change the codes where
using the 'time_t' and 'timespec', and we can get current time by
ktime_get_real_seconds() instead of current_kernel_time(), and use
'TIME64_MAX' macro to initialize the 'time64_t' type variable.

Especially in proc.c file, we have replaced 'unsigned long' and 'timespec'
type with 'u64' and 'time64_t' type to save the timeout value, which means
user will get one 'u64' type timeout value by issuing proc_keys_show()
function.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
---
include/linux/key.h | 7 ++++---
security/keys/gc.c | 20 ++++++++++----------
security/keys/internal.h | 8 ++++----
security/keys/key.c | 19 ++++++-------------
security/keys/keyring.c | 18 +++++++++---------
security/keys/permission.c | 3 +--
security/keys/proc.c | 20 ++++++++++----------
security/keys/process_keys.c | 2 +-
8 files changed, 45 insertions(+), 52 deletions(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index 0441141..6d10f84 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -24,6 +24,7 @@
#include <linux/atomic.h>
#include <linux/assoc_array.h>
#include <linux/refcount.h>
+#include <linux/time64.h>

#ifdef __KERNEL__
#include <linux/uidgid.h>
@@ -157,10 +158,10 @@ struct key {
struct key_user *user; /* owner of this key */
void *security; /* security data for this key */
union {
- time_t expiry; /* time at which key expires (or 0) */
- time_t revoked_at; /* time at which key was revoked */
+ time64_t expiry; /* time at which key expires (or 0) */
+ time64_t revoked_at; /* time at which key was revoked */
};
- time_t last_used_at; /* last time used for LRU keyring discard */
+ time64_t last_used_at; /* last time used for LRU keyring discard */
kuid_t uid;
kgid_t gid;
key_perm_t perm; /* access permissions */
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 87cb260..c99700e 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -32,7 +32,7 @@
static void key_gc_timer_func(unsigned long);
static DEFINE_TIMER(key_gc_timer, key_gc_timer_func, 0, 0);

-static time_t key_gc_next_run = LONG_MAX;
+static time64_t key_gc_next_run = TIME64_MAX;
static struct key_type *key_gc_dead_keytype;

static unsigned long key_gc_flags;
@@ -53,12 +53,12 @@ struct key_type key_type_dead = {
* Schedule a garbage collection run.
* - time precision isn't particularly important
*/
-void key_schedule_gc(time_t gc_at)
+void key_schedule_gc(time64_t gc_at)
{
unsigned long expires;
- time_t now = current_kernel_time().tv_sec;
+ time64_t now = ktime_get_real_seconds();

- kenter("%ld", gc_at - now);
+ kenter("%lld", gc_at - now);

if (gc_at <= now || test_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags)) {
kdebug("IMMEDIATE");
@@ -87,7 +87,7 @@ void key_schedule_gc_links(void)
static void key_gc_timer_func(unsigned long data)
{
kenter("");
- key_gc_next_run = LONG_MAX;
+ key_gc_next_run = TIME64_MAX;
key_schedule_gc_links();
}

@@ -184,11 +184,11 @@ static void key_garbage_collector(struct work_struct *work)

struct rb_node *cursor;
struct key *key;
- time_t new_timer, limit;
+ time64_t new_timer, limit;

kenter("[%lx,%x]", key_gc_flags, gc_state);

- limit = current_kernel_time().tv_sec;
+ limit = ktime_get_real_seconds();
if (limit > key_gc_delay)
limit -= key_gc_delay;
else
@@ -204,7 +204,7 @@ static void key_garbage_collector(struct work_struct *work)
gc_state |= KEY_GC_REAPING_DEAD_1;
kdebug("new pass %x", gc_state);

- new_timer = LONG_MAX;
+ new_timer = TIME64_MAX;

/* As only this function is permitted to remove things from the key
* serial tree, if cursor is non-NULL then it will always point to a
@@ -235,7 +235,7 @@ static void key_garbage_collector(struct work_struct *work)

if (gc_state & KEY_GC_SET_TIMER) {
if (key->expiry > limit && key->expiry < new_timer) {
- kdebug("will expire %x in %ld",
+ kdebug("will expire %x in %lld",
key_serial(key), key->expiry - limit);
new_timer = key->expiry;
}
@@ -276,7 +276,7 @@ static void key_garbage_collector(struct work_struct *work)
*/
kdebug("pass complete");

- if (gc_state & KEY_GC_SET_TIMER && new_timer != (time_t)LONG_MAX) {
+ if (gc_state & KEY_GC_SET_TIMER && new_timer != (time64_t)TIME64_MAX) {
new_timer += key_gc_delay;
key_schedule_gc(new_timer);
}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 1c02c65..a32dc69 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -130,7 +130,7 @@ struct keyring_search_context {
int skipped_ret;
bool possessed;
key_ref_t result;
- struct timespec now;
+ time64_t now;
};

extern bool key_default_cmp(const struct key *key,
@@ -169,10 +169,10 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,

extern struct work_struct key_gc_work;
extern unsigned key_gc_delay;
-extern void keyring_gc(struct key *keyring, time_t limit);
+extern void keyring_gc(struct key *keyring, time64_t limit);
extern void keyring_restriction_gc(struct key *keyring,
struct key_type *dead_type);
-extern void key_schedule_gc(time_t gc_at);
+extern void key_schedule_gc(time64_t gc_at);
extern void key_schedule_gc_links(void);
extern void key_gc_keytype(struct key_type *ktype);

@@ -211,7 +211,7 @@ extern struct key *request_key_auth_new(struct key *target,
/*
* Determine whether a key is dead.
*/
-static inline bool key_is_dead(const struct key *key, time_t limit)
+static inline bool key_is_dead(const struct key *key, time64_t limit)
{
return
key->flags & ((1 << KEY_FLAG_DEAD) |
diff --git a/security/keys/key.c b/security/keys/key.c
index 83da68d..291a67c 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -556,7 +556,6 @@ int key_reject_and_link(struct key *key,
struct key *authkey)
{
struct assoc_array_edit *edit;
- struct timespec now;
int ret, awaken, link_ret = 0;

key_check(key);
@@ -582,8 +581,7 @@ int key_reject_and_link(struct key *key,
smp_wmb();
set_bit(KEY_FLAG_NEGATIVE, &key->flags);
set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
- now = current_kernel_time();
- key->expiry = now.tv_sec + timeout;
+ key->expiry = ktime_get_real_seconds() + timeout;
key_schedule_gc(key->expiry + key_gc_delay);

if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
@@ -699,16 +697,13 @@ struct key_type *key_type_lookup(const char *type)

void key_set_timeout(struct key *key, unsigned timeout)
{
- struct timespec now;
- time_t expiry = 0;
+ time64_t expiry = 0;

/* make the changes with the locks held to prevent races */
down_write(&key->sem);

- if (timeout > 0) {
- now = current_kernel_time();
- expiry = now.tv_sec + timeout;
- }
+ if (timeout > 0)
+ expiry = ktime_get_real_seconds() + timeout;

key->expiry = expiry;
key_schedule_gc(key->expiry + key_gc_delay);
@@ -1007,8 +1002,7 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen)
*/
void key_revoke(struct key *key)
{
- struct timespec now;
- time_t time;
+ time64_t time;

key_check(key);

@@ -1023,8 +1017,7 @@ void key_revoke(struct key *key)
key->type->revoke(key);

/* set the death time to no more than the expiry time */
- now = current_kernel_time();
- time = now.tv_sec;
+ time = ktime_get_real_seconds();
if (key->revoked_at == 0 || key->revoked_at > time) {
key->revoked_at = time;
key_schedule_gc(key->revoked_at + key_gc_delay);
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index de81793..2d82088 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -576,7 +576,7 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
goto skipped;
}

- if (key->expiry && ctx->now.tv_sec >= key->expiry) {
+ if (key->expiry && ctx->now >= key->expiry) {
if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED))
ctx->result = ERR_PTR(-EKEYEXPIRED);
kleave(" = %d [expire]", ctx->skipped_ret);
@@ -837,10 +837,10 @@ static bool search_nested_keyrings(struct key *keyring,
key = key_ref_to_ptr(ctx->result);
key_check(key);
if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) {
- key->last_used_at = ctx->now.tv_sec;
- keyring->last_used_at = ctx->now.tv_sec;
+ key->last_used_at = ctx->now;
+ keyring->last_used_at = ctx->now;
while (sp > 0)
- stack[--sp].keyring->last_used_at = ctx->now.tv_sec;
+ stack[--sp].keyring->last_used_at = ctx->now;
}
kleave(" = true");
return true;
@@ -901,7 +901,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref,
}

rcu_read_lock();
- ctx->now = current_kernel_time();
+ ctx->now = ktime_get_real_seconds();
if (search_nested_keyrings(keyring, ctx))
__key_get(key_ref_to_ptr(ctx->result));
rcu_read_unlock();
@@ -1147,7 +1147,7 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
* (ie. it has a zero usage count) */
if (!refcount_inc_not_zero(&keyring->usage))
continue;
- keyring->last_used_at = current_kernel_time().tv_sec;
+ keyring->last_used_at = ktime_get_real_seconds();
goto out;
}
}
@@ -1487,7 +1487,7 @@ static void keyring_revoke(struct key *keyring)
static bool keyring_gc_select_iterator(void *object, void *iterator_data)
{
struct key *key = keyring_ptr_to_key(object);
- time_t *limit = iterator_data;
+ time64_t *limit = iterator_data;

if (key_is_dead(key, *limit))
return false;
@@ -1498,7 +1498,7 @@ static bool keyring_gc_select_iterator(void *object, void *iterator_data)
static int keyring_gc_check_iterator(const void *object, void *iterator_data)
{
const struct key *key = keyring_ptr_to_key(object);
- time_t *limit = iterator_data;
+ time64_t *limit = iterator_data;

key_check(key);
return key_is_dead(key, *limit);
@@ -1510,7 +1510,7 @@ static int keyring_gc_check_iterator(const void *object, void *iterator_data)
* Not called with any locks held. The keyring's key struct will not be
* deallocated under us as only our caller may deallocate it.
*/
-void keyring_gc(struct key *keyring, time_t limit)
+void keyring_gc(struct key *keyring, time64_t limit)
{
int result;

diff --git a/security/keys/permission.c b/security/keys/permission.c
index 732cc0b..507b1d41 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -100,8 +100,7 @@ int key_validate(const struct key *key)

/* check it hasn't expired */
if (key->expiry) {
- struct timespec now = current_kernel_time();
- if (now.tv_sec >= key->expiry)
+ if (ktime_get_real_seconds() >= key->expiry)
return -EKEYEXPIRED;
}

diff --git a/security/keys/proc.c b/security/keys/proc.c
index bf08d02..95c8720 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -178,8 +178,8 @@ static int proc_keys_show(struct seq_file *m, void *v)
{
struct rb_node *_p = v;
struct key *key = rb_entry(_p, struct key, serial_node);
- struct timespec now;
- unsigned long timo;
+ time64_t now;
+ u64 timo;
key_ref_t key_ref, skey_ref;
char xbuf[16];
int rc;
@@ -216,28 +216,28 @@ static int proc_keys_show(struct seq_file *m, void *v)
if (rc < 0)
return 0;

- now = current_kernel_time();
+ now = ktime_get_real_seconds();

rcu_read_lock();

/* come up with a suitable timeout value */
if (key->expiry == 0) {
memcpy(xbuf, "perm", 5);
- } else if (now.tv_sec >= key->expiry) {
+ } else if (now >= key->expiry) {
memcpy(xbuf, "expd", 5);
} else {
- timo = key->expiry - now.tv_sec;
+ timo = key->expiry - now;

if (timo < 60)
- sprintf(xbuf, "%lus", timo);
+ sprintf(xbuf, "%llus", timo);
else if (timo < 60*60)
- sprintf(xbuf, "%lum", timo / 60);
+ sprintf(xbuf, "%llum", div_u64(timo, 60));
else if (timo < 60*60*24)
- sprintf(xbuf, "%luh", timo / (60*60));
+ sprintf(xbuf, "%lluh", div_u64(timo, 60 * 60));
else if (timo < 60*60*24*7)
- sprintf(xbuf, "%lud", timo / (60*60*24));
+ sprintf(xbuf, "%llud", div_u64(timo, 60 * 60 * 24));
else
- sprintf(xbuf, "%luw", timo / (60*60*24*7));
+ sprintf(xbuf, "%lluw", div_u64(timo, 60 * 60 * 24 * 7));
}

#define showflag(KEY, LETTER, FLAG) \
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 86bced9..c691e09 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -736,7 +736,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
if (ret < 0)
goto invalid_key;

- key->last_used_at = current_kernel_time().tv_sec;
+ key->last_used_at = ktime_get_real_seconds();

error:
put_cred(ctx.cred);
--
1.7.9.5