[PATCH v4 5/9] trace/bpf_trace: open access for CAP_SYS_PERFMON privileged process

Song Liu songliubraving at fb.com
Mon Jan 13 12:47:04 PST 2020



> On Dec 18, 2019, at 1:28 AM, Alexey Budankov <alexey.budankov at linux.intel.com> wrote:
> 
> 
> Open access to bpf_trace monitoring for CAP_SYS_PERFMON privileged
> processes. For backward compatibility reasons access to bpf_trace
> monitoring remains open for CAP_SYS_ADMIN privileged processes but
> CAP_SYS_ADMIN usage for secure bpf_trace monitoring is discouraged
> with respect to CAP_SYS_PERFMON capability.
> 
> Signed-off-by: Alexey Budankov <alexey.budankov at linux.intel.com>

Acked-by: Song Liu <songliubraving at fb.com>

> ---
> kernel/trace/bpf_trace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 44bd08f2443b..bafe21ac6d92 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1272,7 +1272,7 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info)
> 	u32 *ids, prog_cnt, ids_len;
> 	int ret;
> 
> -	if (!capable(CAP_SYS_ADMIN))
> +	if (!perfmon_capable())
> 		return -EPERM;
> 	if (event->attr.type != PERF_TYPE_TRACEPOINT)
> 		return -EINVAL;

I guess we need to fix this check for kprobe/uprobe created with 
perf_event_open()...

Thanks,
Song




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