[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date: Thu, 6 Jun 2013 11:02:04 +0200
From: Stephane Eranian <eranian@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: peterz@...radead.org, mingo@...e.hu, pmatouse@...hat.com,
meissner@...e.de, security@...nel.org,
oss-security@...ts.openwall.com, ak@...ux.intel.com
Subject: [PATCH] perf: fix hypervisor branch sampling permission check
Commit 2b923c8 perf/x86: Check branch sampling priv level in generic code
was missing the check for the hypervisor (HV) priv level, so add it back.
With this patch, we get the following correct behavior:
# echo 2 >/proc/sys/kernel/perf_event_paranoid
$ perf record -j any,k noploop 1
Error:
You may not have permission to collect stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid:
-1 - Not paranoid at all
0 - Disallow raw tracepoint access for unpriv
1 - Disallow cpu events for unpriv
2 - Disallow kernel profiling for unpriv
$ perf record -j any,hv noploop 1
Error:
You may not have permission to collect stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid:
-1 - Not paranoid at all
0 - Disallow raw tracepoint access for unpriv
1 - Disallow cpu events for unpriv
2 - Disallow kernel profiling for unpriv
Signed-off-by: Stephane Eranian <eranian@...gle.com>
---
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 95edd5a..f0880fb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6501,8 +6501,8 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
*/
attr->branch_sample_type = mask;
}
- /* kernel level capture: check permissions */
- if ((mask & PERF_SAMPLE_BRANCH_KERNEL)
+ /* privileged levels capture (kernel, hv): check permissions */
+ if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
&& perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
return -EACCES;
}
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
