* [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap
@ 2020-08-05 7:56 Alexey Budankov
2020-08-06 12:16 ` Arnaldo Carvalho de Melo
2020-08-06 17:09 ` [tip: perf/urgent] perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability tip-bot2 for Alexey Budankov
0 siblings, 2 replies; 3+ messages in thread
From: Alexey Budankov @ 2020-08-05 7:56 UTC (permalink / raw)
To: Peter Zijlstra, Arnaldo Carvalho de Melo
Cc: Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ingo Molnar,
Andi Kleen, linux-kernel
Open access to per-process monitoring for CAP_PERFMON only
privileged processes [1]. Extend ptrace_may_access() check
in perf_events subsystem with perfmon_capable() to simplify
user experience and make monitoring more secure by reducing
attack surface.
[1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 856d98c36f56..f50d528af444 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11587,7 +11587,7 @@ SYSCALL_DEFINE5(perf_event_open,
goto err_task;
/*
- * Reuse ptrace permission checks for now.
+ * Preserve ptrace permission check for backwards compatibility.
*
* We must hold exec_update_mutex across this and any potential
* perf_install_in_context() call for this new event to
@@ -11595,7 +11595,7 @@ SYSCALL_DEFINE5(perf_event_open,
* perf_event_exit_task() that could imply).
*/
err = -EACCES;
- if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
+ if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
goto err_cred;
}
--
2.24.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap
2020-08-05 7:56 [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap Alexey Budankov
@ 2020-08-06 12:16 ` Arnaldo Carvalho de Melo
2020-08-06 17:09 ` [tip: perf/urgent] perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability tip-bot2 for Alexey Budankov
1 sibling, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2020-08-06 12:16 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Alexey Budankov, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
Ingo Molnar, Andi Kleen, linux-kernel
Em Wed, Aug 05, 2020 at 10:56:56AM +0300, Alexey Budankov escreveu:
>
> Open access to per-process monitoring for CAP_PERFMON only
> privileged processes [1]. Extend ptrace_may_access() check
> in perf_events subsystem with perfmon_capable() to simplify
> user experience and make monitoring more secure by reducing
> attack surface.
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Peter, can you pick up this one? You said it was ok last time we
discussed this.
- Arnaldo
> [1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/
>
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
> kernel/events/core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 856d98c36f56..f50d528af444 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -11587,7 +11587,7 @@ SYSCALL_DEFINE5(perf_event_open,
> goto err_task;
>
> /*
> - * Reuse ptrace permission checks for now.
> + * Preserve ptrace permission check for backwards compatibility.
> *
> * We must hold exec_update_mutex across this and any potential
> * perf_install_in_context() call for this new event to
> @@ -11595,7 +11595,7 @@ SYSCALL_DEFINE5(perf_event_open,
> * perf_event_exit_task() that could imply).
> */
> err = -EACCES;
> - if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
> + if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
> goto err_cred;
> }
>
> --
> 2.24.1
>
--
- Arnaldo
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip: perf/urgent] perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability
2020-08-05 7:56 [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap Alexey Budankov
2020-08-06 12:16 ` Arnaldo Carvalho de Melo
@ 2020-08-06 17:09 ` tip-bot2 for Alexey Budankov
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Alexey Budankov @ 2020-08-06 17:09 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Alexey Budankov, Ingo Molnar, Peter Zijlstra, x86, LKML
The following commit has been merged into the perf/urgent branch of tip:
Commit-ID: 45fd22da97c6125d8d0d35bd1791e7c0c4175279
Gitweb: https://git.kernel.org/tip/45fd22da97c6125d8d0d35bd1791e7c0c4175279
Author: Alexey Budankov <alexey.budankov@linux.intel.com>
AuthorDate: Wed, 05 Aug 2020 10:56:56 +03:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 06 Aug 2020 15:03:20 +02:00
perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability
Open access to per-process monitoring for CAP_PERFMON only
privileged processes [1]. Extend ptrace_may_access() check
in perf_events subsystem with perfmon_capable() to simplify
user experience and make monitoring more secure by reducing
attack surface.
[1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/6e8392ff-4732-0012-2949-e1587709f0f6@linux.intel.com
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 78e69e1..41e0cef 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11689,7 +11689,7 @@ SYSCALL_DEFINE5(perf_event_open,
goto err_task;
/*
- * Reuse ptrace permission checks for now.
+ * Preserve ptrace permission check for backwards compatibility.
*
* We must hold exec_update_mutex across this and any potential
* perf_install_in_context() call for this new event to
@@ -11697,7 +11697,7 @@ SYSCALL_DEFINE5(perf_event_open,
* perf_event_exit_task() that could imply).
*/
err = -EACCES;
- if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
+ if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
goto err_cred;
}
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-08-06 17:42 UTC | newest]
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2020-08-05 7:56 [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap Alexey Budankov
2020-08-06 12:16 ` Arnaldo Carvalho de Melo
2020-08-06 17:09 ` [tip: perf/urgent] perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability tip-bot2 for Alexey Budankov
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