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perf/x86: Fix potential out-of-bounds access 

UBSAN reported out-of-bound accesses for x86_pmu.event_map(), it's
arguments should be < x86_pmu.max_events. Make sure all users observe
this constraint.

Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Meelis Roos <mroos@linux.ee>
This commit is contained in:
Peter Zijlstra 2019-12-06 12:50:16 +01:00
parent 57e04eeda5
commit 1e69a0efc0
1 changed files with 8 additions and 2 deletions
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10
arch/x86/events/core.c
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@ -1642,9 +1642,12 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = {
ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page)
{ {
struct perf_pmu_events_attr *pmu_attr = \ struct perf_pmu_events_attr *pmu_attr =
container_of(attr, struct perf_pmu_events_attr, attr); container_of(attr, struct perf_pmu_events_attr, attr);
u64 config = x86_pmu.event_map(pmu_attr->id); u64 config = 0;
if (pmu_attr->id < x86_pmu.max_events)
config = x86_pmu.event_map(pmu_attr->id);
/* string trumps id */ /* string trumps id */
if (pmu_attr->event_str) if (pmu_attr->event_str)
@ -1713,6 +1716,9 @@ is_visible(struct kobject *kobj, struct attribute *attr, int idx)
{ {
struct perf_pmu_events_attr *pmu_attr; struct perf_pmu_events_attr *pmu_attr;
if (idx >= x86_pmu.max_events)
return 0;
pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr); pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr);
/* str trumps id */ /* str trumps id */
return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0; return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0;