potential null pointer deref?

We noticed these two sites as potential null pointer deferences.

Lines 51 to 53 in ebbf393

    
           const uint8_t* category_group_enabled = 
        
             GetCategoryGroupEnabled(category_group); 
        
           if (*category_group_enabled == 0) return;

node/src/node_trace_events.cc

Lines 130 to 132 in ebbf393

    
           const uint8_t* category_group_enabled = 
        
             GetCategoryGroupEnabled(category_group); 
        
           args.GetReturnValue().Set(*category_group_enabled > 0);

It seems like category_group_enabled can be null based on the defensive check:

node/src/node_trace_events.cc

Lines 19 to 23 in ebbf393

    
           static const uint8_t* GetCategoryGroupEnabled(const char* category_group) { 
        
               if (category_group == nullptr) return nullptr; 
        
               return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group); 
        
           }

But I suspect because of the usage GetCategoryGroupEnabled is not called with null pointer. Any thoughts?

@AndreasMadsen

/cc @AndreasMadsen @addaleax

Yeah, the value passed to GetCategoryGroupEnabled() is never a null pointer because it’s the return value of GetCategoryGroup(). I don’t think there’s anything we need to do here?

We could add a check that category_group isn't nullptr in GetCategoryGroupEnabled.

Either way! I wasn't going to create this issue, but the defensive check on line 20 that checks for nullptr made it seem like something worth double checking. Thanks for your responses!

src: add null check to GetCategoryGroupEnabled()

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potential null pointer deref? #19991

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	const uint8_t* category_group_enabled =
	GetCategoryGroupEnabled(category_group);
	if (*category_group_enabled == 0) return;

	const uint8_t* category_group_enabled =
	GetCategoryGroupEnabled(category_group);
	args.GetReturnValue().Set(*category_group_enabled > 0);

	static const uint8_t* GetCategoryGroupEnabled(const char* category_group) {
	if (category_group == nullptr) return nullptr;

	return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group);
	}

potential null pointer deref? #19991

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jasnell commented on Apr 12, 2018

addaleax commented on Apr 13, 2018

AndreasMadsen commented on Apr 13, 2018

deian commented on Apr 13, 2018

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