From 7e8eda734d30de81d06a949c9bf9853c445ede4e Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Wed, 10 Apr 2019 11:14:20 +0200 Subject: ntp: Audit NTP parameters adjustment Emit an audit record every time selected NTP parameters are modified from userspace (via adjtimex(2) or clock_adjtime(2)). These parameters may be used to indirectly change system clock, and thus their modifications should be audited. Such events will now generate records of type AUDIT_TIME_ADJNTPVAL containing the following fields: - op -- which value was adjusted: - offset -- corresponding to the time_offset variable - freq -- corresponding to the time_freq variable - status -- corresponding to the time_status variable - adjust -- corresponding to the time_adjust variable - tick -- corresponding to the tick_usec variable - tai -- corresponding to the timekeeping's TAI offset - old -- the old value - new -- the new value Example records: type=TIME_ADJNTPVAL msg=audit(1530616044.507:7): op=status old=64 new=8256 type=TIME_ADJNTPVAL msg=audit(1530616044.511:11): op=freq old=0 new=49180377088000 The records of this type will be associated with the corresponding syscall records. An overview of parameter changes that can be done via do_adjtimex() (based on information from Miroslav Lichvar) and whether they are audited: __timekeeping_set_tai_offset() -- sets the offset from the International Atomic Time (AUDITED) NTP variables: time_offset -- can adjust the clock by up to 0.5 seconds per call and also speed it up or slow down by up to about 0.05% (43 seconds per day) (AUDITED) time_freq -- can speed up or slow down by up to about 0.05% (AUDITED) time_status -- can insert/delete leap seconds and it also enables/ disables synchronization of the hardware real-time clock (AUDITED) time_maxerror, time_esterror -- change error estimates used to inform userspace applications (NOT AUDITED) time_constant -- controls the speed of the clock adjustments that are made when time_offset is set (NOT AUDITED) time_adjust -- can temporarily speed up or slow down the clock by up to 0.05% (AUDITED) tick_usec -- a more extreme version of time_freq; can speed up or slow down the clock by up to 10% (AUDITED) Signed-off-by: Ondrej Mosnacek Reviewed-by: Richard Guy Briggs Reviewed-by: Thomas Gleixner Signed-off-by: Paul Moore --- include/linux/audit.h | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) (limited to 'include/linux/audit.h') diff --git a/include/linux/audit.h b/include/linux/audit.h index 2c62c0468888..43a23e28ba23 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -86,6 +86,29 @@ struct audit_field { u32 op; }; +enum audit_ntp_type { + AUDIT_NTP_OFFSET, + AUDIT_NTP_FREQ, + AUDIT_NTP_STATUS, + AUDIT_NTP_TAI, + AUDIT_NTP_TICK, + AUDIT_NTP_ADJUST, + + AUDIT_NTP_NVALS /* count */ +}; + +#ifdef CONFIG_AUDITSYSCALL +struct audit_ntp_val { + long long oldval, newval; +}; + +struct audit_ntp_data { + struct audit_ntp_val vals[AUDIT_NTP_NVALS]; +}; +#else +struct audit_ntp_data {}; +#endif + extern int is_audit_feature_set(int which); extern int __init audit_register_class(int class, unsigned *list); @@ -366,6 +389,7 @@ extern void __audit_mmap_fd(int fd, int flags); extern void __audit_log_kern_module(char *name); extern void __audit_fanotify(unsigned int response); extern void __audit_tk_injoffset(struct timespec64 offset); +extern void __audit_ntp_log(const struct audit_ntp_data *ad); static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) { @@ -478,6 +502,29 @@ static inline void audit_tk_injoffset(struct timespec64 offset) __audit_tk_injoffset(offset); } +static inline void audit_ntp_init(struct audit_ntp_data *ad) +{ + memset(ad, 0, sizeof(*ad)); +} + +static inline void audit_ntp_set_old(struct audit_ntp_data *ad, + enum audit_ntp_type type, long long val) +{ + ad->vals[type].oldval = val; +} + +static inline void audit_ntp_set_new(struct audit_ntp_data *ad, + enum audit_ntp_type type, long long val) +{ + ad->vals[type].newval = val; +} + +static inline void audit_ntp_log(const struct audit_ntp_data *ad) +{ + if (!audit_dummy_context()) + __audit_ntp_log(ad); +} + extern int audit_n_rules; extern int audit_signals; #else /* CONFIG_AUDITSYSCALL */ @@ -594,6 +641,20 @@ static inline void audit_fanotify(unsigned int response) static inline void audit_tk_injoffset(struct timespec64 offset) { } +static inline void audit_ntp_init(struct audit_ntp_data *ad) +{ } + +static inline void audit_ntp_set_old(struct audit_ntp_data *ad, + enum audit_ntp_type type, long long val) +{ } + +static inline void audit_ntp_set_new(struct audit_ntp_data *ad, + enum audit_ntp_type type, long long val) +{ } + +static inline void audit_ntp_log(const struct audit_ntp_data *ad) +{ } + static inline void audit_ptrace(struct task_struct *t) { } #define audit_n_rules 0 -- cgit v1.2.3