#7052: Numeric types’ Read instances use exponential CPU/memory
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Reporter: andersk | Owner:
Type: bug | Status: new
Priority: normal | Component: libraries/base
Version: 7.4.2 | Keywords:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: Runtime performance bug | Testcase:
Blockedby: | Blocking:
Related: |
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Computing
read "1e99999999" :: Int -- returns 0
read "1e99999999" :: Integer -- returns [REDACTED]
read "1e99999999" :: Float -- returns Infinity
read "1e99999999" :: Double -- returns Infinity
takes rather a lot of CPU time and memory, and adding more digits to the
exponent makes it take exponentially more. In some applications, this
behavior could be exploitable as a denial of service.
I’m not sure what the right solution is for Integer, but clearly all the
other cases should be optimized to produce 0 or Infinity very quickly.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7052>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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