From 1e69a0efc0bd0e02b8327e7186fbb4a81878ea0b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 6 Dec 2019 12:50:16 +0100 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Tested-by: Meelis Roos --- arch/x86/events/core.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 9a89d98c55bd..84fe1becbe26 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -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) { - struct perf_pmu_events_attr *pmu_attr = \ + struct perf_pmu_events_attr *pmu_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 */ 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; + if (idx >= x86_pmu.max_events) + return 0; + pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr); /* str trumps id */ return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0; -- 2.20.1