avoid quadratic backtracking when parsing bracketed server names - #2489
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dxbjavid wants to merge 1 commit into
Open
avoid quadratic backtracking when parsing bracketed server names#2489dxbjavid wants to merge 1 commit into
dxbjavid wants to merge 1 commit into
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Server's SERVER_PATTERN lets the first capturing group consume backslashes, so a bracketed name that is full of backslashes but never closes (for example
[a\a\a...) makes the matcher explore every possible split between the server and instance groups, and the matching cost grows roughly quadratically with the length of the string, which can stall a thread that builds a Server from an untrusted qualified name. Excluding the backslash separator from the first group removes that ambiguity so matching stays linear, while[server\instance]and plain[server]still split exactly as before. The added test builds a Server from a long crafted value and would previously time out.