CVE-2022-49782
Linux perf: Missing SIGTRAP Checking Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: perf: Improve missing SIGTRAP checking To catch missing SIGTRAP we employ a WARN in __perf_event_overflow(), which fires if pending_sigtrap was already set: returning to user space without consuming pending_sigtrap, and then having the event fire again would re-enter the kernel and trigger the WARN. This, however, seemed to miss the case where some events not associated with progress in the user space task can fire and the interrupt handler runs before the IRQ work meant to consume pending_sigtrap (and generate the SIGTRAP). syzbot gifted us this stack trace: | WARNING: CPU: 0 PID: 3607 at kernel/events/core.c:9313 __perf_event_overflow | Modules linked in: | CPU: 0 PID: 3607 Comm: syz-executor100 Not tainted 6.1.0-rc2-syzkaller-00073-g88619e77b33d #0 | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 | RIP: 0010:__perf_event_overflow+0x498/0x540 kernel/events/core.c:9313 | <...> | Call Trace: | <TASK> | perf_swevent_hrtimer+0x34f/0x3c0 kernel/events/core.c:10729 | __run_hrtimer kernel/time/hrtimer.c:1685 [inline] | __hrtimer_run_queues+0x1c6/0xfb0 kernel/time/hrtimer.c:1749 | hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 | local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline] | __sysvec_apic_timer_interrupt+0x17c/0x640 arch/x86/kernel/apic/apic.c:1113 | sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1107 | asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 | <...> | </TASK> In this case, syzbot produced a program with event type PERF_TYPE_SOFTWARE and config PERF_COUNT_SW_CPU_CLOCK. The hrtimer manages to fire again before the IRQ work got a chance to run, all while never having returned to user space. Improve the WARN to check for real progress in user space: approximate this by storing a 32-bit hash of the current IP into pending_sigtrap, and if an event fires while pending_sigtrap still matches the previous IP, we assume no progress (false negatives are possible given we could return to user space and trigger again on the same IP).
INFO
Published Date :
May 1, 2025, 3:16 p.m.
Last Modified :
May 2, 2025, 1:53 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
Exploitability Score :
References to Advisories, Solutions, and Tools
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The following table lists the changes that have been made to the
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 01, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: perf: Improve missing SIGTRAP checking To catch missing SIGTRAP we employ a WARN in __perf_event_overflow(), which fires if pending_sigtrap was already set: returning to user space without consuming pending_sigtrap, and then having the event fire again would re-enter the kernel and trigger the WARN. This, however, seemed to miss the case where some events not associated with progress in the user space task can fire and the interrupt handler runs before the IRQ work meant to consume pending_sigtrap (and generate the SIGTRAP). syzbot gifted us this stack trace: | WARNING: CPU: 0 PID: 3607 at kernel/events/core.c:9313 __perf_event_overflow | Modules linked in: | CPU: 0 PID: 3607 Comm: syz-executor100 Not tainted 6.1.0-rc2-syzkaller-00073-g88619e77b33d #0 | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 | RIP: 0010:__perf_event_overflow+0x498/0x540 kernel/events/core.c:9313 | <...> | Call Trace: | <TASK> | perf_swevent_hrtimer+0x34f/0x3c0 kernel/events/core.c:10729 | __run_hrtimer kernel/time/hrtimer.c:1685 [inline] | __hrtimer_run_queues+0x1c6/0xfb0 kernel/time/hrtimer.c:1749 | hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 | local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline] | __sysvec_apic_timer_interrupt+0x17c/0x640 arch/x86/kernel/apic/apic.c:1113 | sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1107 | asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 | <...> | </TASK> In this case, syzbot produced a program with event type PERF_TYPE_SOFTWARE and config PERF_COUNT_SW_CPU_CLOCK. The hrtimer manages to fire again before the IRQ work got a chance to run, all while never having returned to user space. Improve the WARN to check for real progress in user space: approximate this by storing a 32-bit hash of the current IP into pending_sigtrap, and if an event fires while pending_sigtrap still matches the previous IP, we assume no progress (false negatives are possible given we could return to user space and trigger again on the same IP). Added Reference https://git.kernel.org/stable/c/35c60b4e8ca76712dd03bafe2598e31578248916 Added Reference https://git.kernel.org/stable/c/b09221f1b4944d2866d06ac35e59d7a6f8916c9f Added Reference https://git.kernel.org/stable/c/bb88f9695460bec25aa30ba9072595025cf6c8af
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2022-49782 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2022-49782
weaknesses.