| From bippy-1.1.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2022-49764: bpf: Prevent bpf program recursion for raw tracepoint probes |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: Prevent bpf program recursion for raw tracepoint probes |
| |
| We got report from sysbot [1] about warnings that were caused by |
| bpf program attached to contention_begin raw tracepoint triggering |
| the same tracepoint by using bpf_trace_printk helper that takes |
| trace_printk_lock lock. |
| |
| Call Trace: |
| <TASK> |
| ? trace_event_raw_event_bpf_trace_printk+0x5f/0x90 |
| bpf_trace_printk+0x2b/0xe0 |
| bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 |
| bpf_trace_run2+0x26/0x90 |
| native_queued_spin_lock_slowpath+0x1c6/0x2b0 |
| _raw_spin_lock_irqsave+0x44/0x50 |
| bpf_trace_printk+0x3f/0xe0 |
| bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 |
| bpf_trace_run2+0x26/0x90 |
| native_queued_spin_lock_slowpath+0x1c6/0x2b0 |
| _raw_spin_lock_irqsave+0x44/0x50 |
| bpf_trace_printk+0x3f/0xe0 |
| bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 |
| bpf_trace_run2+0x26/0x90 |
| native_queued_spin_lock_slowpath+0x1c6/0x2b0 |
| _raw_spin_lock_irqsave+0x44/0x50 |
| bpf_trace_printk+0x3f/0xe0 |
| bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 |
| bpf_trace_run2+0x26/0x90 |
| native_queued_spin_lock_slowpath+0x1c6/0x2b0 |
| _raw_spin_lock_irqsave+0x44/0x50 |
| __unfreeze_partials+0x5b/0x160 |
| ... |
| |
| The can be reproduced by attaching bpf program as raw tracepoint on |
| contention_begin tracepoint. The bpf prog calls bpf_trace_printk |
| helper. Then by running perf bench the spin lock code is forced to |
| take slow path and call contention_begin tracepoint. |
| |
| Fixing this by skipping execution of the bpf program if it's |
| already running, Using bpf prog 'active' field, which is being |
| currently used by trampoline programs for the same reason. |
| |
| Moving bpf_prog_inc_misses_counter to syscall.c because |
| trampoline.c is compiled in just for CONFIG_BPF_JIT option. |
| |
| [1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#t |
| |
| The Linux kernel CVE team has assigned CVE-2022-49764 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.0.10 with commit 2e5399879024fedd6cdc41f73fbf9bbe7208f899 |
| Fixed in 6.1 with commit 05b24ff9b2cfabfcfd951daaa915a036ab53c9e1 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2022-49764 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| include/linux/bpf.h |
| kernel/bpf/syscall.c |
| kernel/bpf/trampoline.c |
| kernel/trace/bpf_trace.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/2e5399879024fedd6cdc41f73fbf9bbe7208f899 |
| https://git.kernel.org/stable/c/05b24ff9b2cfabfcfd951daaa915a036ab53c9e1 |
