#5688: instance Read Integer/Rational/Double readsPrec out of memory and crash
due
to exponential notation
---------------------------------+------------------------------------------
Reporter: gracjan | Owner:
Type: bug | Status: patch
Priority: highest | Milestone: 7.4.1
Component: libraries/base | Version: 6.12.3
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: Runtime crash
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: |
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Comment(by gracjan):
To chime in: parsing Float and Double also kills programs because this
goes through Rational.
Text.JSON is self guilty. Here is the relevant snippet from json-0.5.
File Text/JSON/String.hs:189
{{{
exponent' n (c:cs)
| c == 'e' || c == 'E' = (n*) <$> exp_num cs
exponent' n cs = setInput cs >> return n
exp_num :: String -> GetJSON Rational
exp_num ('+':cs) = exp_digs cs
exp_num ('-':cs) = recip <$> exp_digs cs
exp_num cs = exp_digs cs
exp_digs :: String -> GetJSON Rational
exp_digs cs = case readDec cs of
[(a,ds)] -> do setInput ds
return (fromIntegral ((10::Integer) ^ (a::Integer)))
_ -> fail $ "Unable to parse JSON exponential: " ++ context
cs
}}}
Same with aeson because of attoparsec: Data.Attoparsec.Text:
{{{
number :: Parser Number
number = floaty $ \real frac fracDenom ->
if frac == 0 && fracDenom == 0
then I real
else D (asDouble real frac fracDenom)
...
let n = if fracDigits == 0
then if power == 0
then fromIntegral real
else fromIntegral real * (10 ^^ power)
else if power == 0
then f real fraction (10 ^ fracDigits)
else f real fraction (10 ^ fracDigits) * (10 ^^ power)
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5688#comment:23>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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