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tomoyo: fix timestamping for y2038 

Tomoyo uses an open-coded version of time_to_tm() to create a timestamp
from the current time as read by get_seconds(). This will overflow and
give wrong results on 32-bit systems in 2038.

To correct this, this changes the code to use ktime_get_real_seconds()
and the generic time64_to_tm() function that are both y2038-safe.
Using the library function avoids adding an expensive 64-bit division
in this code and can benefit from any optimizations we do in common
code.

Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Arnd Bergmann 2017-10-19 14:29:04 +02:00 committed by James Morris
parent dbbbe1105e
commit 927340926e
4 changed files with 13 additions and 34 deletions
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2
security/tomoyo/audit.c
View File

@ -156,7 +156,7 @@ static char *tomoyo_print_header(struct tomoyo_request_info *r)
if (!buffer)
return NULL;
tomoyo_convert_time(get_seconds(), &stamp);
tomoyo_convert_time(ktime_get_real_seconds(), &stamp);
pos = snprintf(buffer, tomoyo_buffer_len - 1,
"#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "

4
security/tomoyo/common.c
View File

@ -2256,7 +2256,7 @@ static const char * const tomoyo_memory_headers[TOMOYO_MAX_MEMORY_STAT] = {
/* Timestamp counter for last updated. */
static unsigned int tomoyo_stat_updated[TOMOYO_MAX_POLICY_STAT];
/* Counter for number of updates. */
static unsigned int tomoyo_stat_modified[TOMOYO_MAX_POLICY_STAT];
static time64_t tomoyo_stat_modified[TOMOYO_MAX_POLICY_STAT];
/**
* tomoyo_update_stat - Update statistic counters.
@ -2271,7 +2271,7 @@ void tomoyo_update_stat(const u8 index)
* I don't use atomic operations because race condition is not fatal.
*/
tomoyo_stat_updated[index]++;
tomoyo_stat_modified[index] = get_seconds();
tomoyo_stat_modified[index] = ktime_get_real_seconds();
}
/**

2
security/tomoyo/common.h
View File

@ -1036,7 +1036,7 @@ void tomoyo_check_acl(struct tomoyo_request_info *r,
bool (*check_entry) (struct tomoyo_request_info *,
const struct tomoyo_acl_info *));
void tomoyo_check_profile(void);
void tomoyo_convert_time(time_t time, struct tomoyo_time *stamp);
void tomoyo_convert_time(time64_t time, struct tomoyo_time *stamp);
void tomoyo_del_condition(struct list_head *element);
void tomoyo_fill_path_info(struct tomoyo_path_info *ptr);
void tomoyo_get_attributes(struct tomoyo_obj_info *obj);

39
security/tomoyo/util.c
View File

@ -86,38 +86,17 @@ const u8 tomoyo_index2category[TOMOYO_MAX_MAC_INDEX] = {
* @stamp: Pointer to "struct tomoyo_time".
*
* Returns nothing.
*
* This function does not handle Y2038 problem.
*/
void tomoyo_convert_time(time_t time, struct tomoyo_time *stamp)
void tomoyo_convert_time(time64_t time64, struct tomoyo_time *stamp)
{
static const u16 tomoyo_eom[2][12] = {
{ 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
{ 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};
u16 y;
u8 m;
bool r;
stamp->sec = time % 60;
time /= 60;
stamp->min = time % 60;
time /= 60;
stamp->hour = time % 24;
time /= 24;
for (y = 1970; ; y++) {
const unsigned short days = (y & 3) ? 365 : 366;
if (time < days)
break;
time -= days;
}
r = (y & 3) == 0;
for (m = 0; m < 11 && time >= tomoyo_eom[r][m]; m++)
;
if (m)
time -= tomoyo_eom[r][m - 1];
stamp->year = y;
stamp->month = ++m;
stamp->day = ++time;
struct tm tm;
time64_to_tm(time64, 0, &tm);
stamp->sec = tm.tm_sec;
stamp->min = tm.tm_min;
stamp->hour = tm.tm_hour;
stamp->day = tm.tm_mday;
stamp->month = tm.tm_mon + 1;
stamp->year = tm.tm_year + 1900;
}
/**