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-rw-r--r--include/linux/time.h26
-rw-r--r--kernel/time/ntp.c10
-rw-r--r--kernel/time/timekeeping.c2
3 files changed, 35 insertions, 3 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index beebe3a..297f09f 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -125,6 +125,32 @@ static inline bool timeval_valid(const struct timeval *tv)
extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
+/*
+ * Validates if a timespec/timeval used to inject a time offset is valid.
+ * Offsets can be postive or negative. The value of the timeval/timespec
+ * is the sum of its fields, but *NOTE*: the field tv_usec/tv_nsec must
+ * always be non-negative.
+ */
+static inline bool timeval_inject_offset_valid(const struct timeval *tv)
+{
+ /* We don't check the tv_sec as it can be positive or negative */
+
+ /* Can't have more microseconds then a second */
+ if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
+ return false;
+ return true;
+}
+
+static inline bool timespec_inject_offset_valid(const struct timespec *ts)
+{
+ /* We don't check the tv_sec as it can be positive or negative */
+
+ /* Can't have more nanoseconds then a second */
+ if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
+ return false;
+ return true;
+}
+
#define CURRENT_TIME (current_kernel_time())
#define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 })
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 125fc03..4073c95 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -676,8 +676,14 @@ int ntp_validate_timex(struct timex *txc)
return -EINVAL;
}
- if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME)))
- return -EPERM;
+ if (txc->modes & ADJ_SETOFFSET) {
+ /* In order to inject time, you gotta be super-user! */
+ if (!capable(CAP_SYS_TIME))
+ return -EPERM;
+
+ if (!timeval_inject_offset_valid(&txc->time))
+ return -EINVAL;
+ }
/*
* Check for potential multiplication overflows that can
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 99188ee..d9249da 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -958,7 +958,7 @@ int timekeeping_inject_offset(struct timespec *ts)
struct timespec64 ts64, tmp;
int ret = 0;
- if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
+ if (!timespec_inject_offset_valid(ts))
return -EINVAL;
ts64 = timespec_to_timespec64(*ts);
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