Commit-ID: cfa71b5b3d19d5b05ad4f171506ad61b88c93084
Gitweb: http://git.kernel.org/tip/cfa71b5b3d19d5b05ad4f171506ad61b88c93084
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Thu, 11 Jun 2009 11:18:36 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 11 Jun 2009 13:16:18 +0200
perf_counter: More paranoia settings
Rename the perf_counter_priv knob to perf_counter_paranoia (because
priv can be read as private, as opposed to privileged) and provide
one more level:
0 - permissive
1 - restrict cpu counters to privilidged contexts
2 - restrict kernel-mode code counting and profiling
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/linux/perf_counter.h | 2 +-
kernel/perf_counter.c | 25 +++++++++++++++++++++++--
kernel/sysctl.c | 6 +++---
3 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 5b96647..386be91 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -648,7 +648,7 @@ struct perf_callchain_entry {
extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
-extern int sysctl_perf_counter_priv;
+extern int sysctl_perf_counter_paranoid;
extern int sysctl_perf_counter_mlock;
extern int sysctl_perf_counter_limit;
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 8b89b40..63f1987 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -43,7 +43,23 @@ static atomic_t nr_counters __read_mostly;
static atomic_t nr_mmap_counters __read_mostly;
static atomic_t nr_comm_counters __read_mostly;
-int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
+/*
+ * 0 - not paranoid
+ * 1 - disallow cpu counters to unpriv
+ * 2 - disallow kernel profiling to unpriv
+ */
+int sysctl_perf_counter_paranoid __read_mostly; /* do we need to be privileged */
+
+static inline bool perf_paranoid_cpu(void)
+{
+ return sysctl_perf_counter_paranoid > 0;
+}
+
+static inline bool perf_paranoid_kernel(void)
+{
+ return sysctl_perf_counter_paranoid > 1;
+}
+
int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */
int sysctl_perf_counter_limit __read_mostly = 100000; /* max NMIs per second */
@@ -1385,7 +1401,7 @@ static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
*/
if (cpu != -1) {
/* Must be root to operate on a CPU counter: */
- if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))
+ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
return ERR_PTR(-EACCES);
if (cpu < 0 || cpu > num_possible_cpus())
@@ -3618,6 +3634,11 @@ SYSCALL_DEFINE5(perf_counter_open,
if (copy_from_user(&attr, attr_uptr, sizeof(attr)) != 0)
return -EFAULT;
+ if (!attr.exclude_kernel) {
+ if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
+ return -EACCES;
+ }
+
/*
* Get the target context (task or percpu):
*/
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4fab10f..4b072ad 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -924,9 +924,9 @@ static struct ctl_table kern_table[] = {
#ifdef CONFIG_PERF_COUNTERS
{
.ctl_name = CTL_UNNUMBERED,
- .procname = "perf_counter_privileged",
- .data = &sysctl_perf_counter_priv,
- .maxlen = sizeof(sysctl_perf_counter_priv),
+ .procname = "perf_counter_paranoid",
+ .data = &sysctl_perf_counter_paranoid,
+ .maxlen = sizeof(sysctl_perf_counter_paranoid),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
--
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