[PATCH v1] perf: extend message to mention CAP_SYS_PTRACE and perf security doc link

[PATCH v1] perf: extend message to mention CAP_SYS_PTRACE and perf security doc link

[Alexey Budankov]

Adjust limited access message to mention CAP_SYS_PTRACE capability
for processes of unprivileged users. Add link to perf security
document in the end of the section about capabilities.
The change has been inspired by this discussion:
https://lore.kernel.org/lkml/20200722113007.GI77866@kernel.org/

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
 tools/perf/util/evsel.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 9aa51a65593d..e241ee773ccb 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2500,8 +2500,10 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
 
 		return scnprintf(msg + printed, size - printed,
 		 "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n"
-		 "access to performance monitoring and observability operations for users\n"
-		 "without CAP_PERFMON or CAP_SYS_ADMIN Linux capability.\n"
+		 "access to performance monitoring and observability operations for processes\n"
+		 "without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability.\n"
+		 "More information can be found at 'Perf events and tool security' document:\n"
+		 "https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html\n"
 		 "perf_event_paranoid setting is %d:\n"
 		 "  -1: Allow use of (almost) all events by all users\n"
 		 "      Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n"
-- 
2.24.1

Re: [PATCH v1] perf: extend message to mention CAP_SYS_PTRACE and perf security doc link

[Arnaldo Carvalho de Melo]

Em Wed, Aug 05, 2020 at 10:31:20AM +0300, Alexey Budankov escreveu:
> 
> Adjust limited access message to mention CAP_SYS_PTRACE capability
> for processes of unprivileged users. Add link to perf security
> document in the end of the section about capabilities.
> The change has been inspired by this discussion:
> https://lore.kernel.org/lkml/20200722113007.GI77866@kernel.org/

Thanks, applied.

- Arnaldo
 
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
>  tools/perf/util/evsel.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 9aa51a65593d..e241ee773ccb 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -2500,8 +2500,10 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
>  
>  		return scnprintf(msg + printed, size - printed,
>  		 "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n"
> -		 "access to performance monitoring and observability operations for users\n"
> -		 "without CAP_PERFMON or CAP_SYS_ADMIN Linux capability.\n"
> +		 "access to performance monitoring and observability operations for processes\n"
> +		 "without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability.\n"
> +		 "More information can be found at 'Perf events and tool security' document:\n"
> +		 "https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html\n"
>  		 "perf_event_paranoid setting is %d:\n"
>  		 "  -1: Allow use of (almost) all events by all users\n"
>  		 "      Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n"
> -- 
> 2.24.1

-- 

- Arnaldo