jimmysong / bmd Goto Github PK

In the updateAddress function, say you try to update the same address multiple times. Well in lines 198 - 201 in addrmanager.go there is a condition to return the function without adding the address in a new bucket for a certain probability. If the function does not return at that point, we go down to line 213 where the getNewBucket function is called. Then, in lines 216 to 218, the function returns if the given bucket already has that address in it. However, the problem is that getNewBucket always returns the same number for a given input. Therefore, if you try to add the same address twice, the function always returns without adding the address in a second bucket because getNewBucket always gives it a bucket that already the address in it.

This is clearly a bug because the function would not be written this way if getNewBucket was always expected to return the same number always for any given address. Also, there is a constant called newBucketsPerAddress which is set to four, so clearly it is expected that there could be up to 4 new buckets that could have this address in it. Also, in the Good function, we go through every new bucket to check if a given address is in it, so it seems as if potentially the address might be found in any new bucket. However, there is no way for the new address to get in any bucket but the one whose index is always returned by getNewBucket. This means that there are some lines in updateAddress that cannot be reached by any unit test.

getNewBucket does not have comments explaining what it is supposed to do, so I'm not really sure what the expected behavior is supposed to be or what to do to fix this.