Fix IPv4 octet and mask length overflow (#57) #60
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The `dig` function in `Data.IP.Addr` uses an `Int` accumulator that can overflow while parsing. It is used to parse IPv4 octets as well as IPv4 and IPv6 mask lengths. This change replaces the `dig` function with two special-purpose functions: The `octet` function parses IPv4 octets. It checks the maximum bound while parsing so that overflow is not possible. The `maskLen` function parses mask lengths. The maximum bound is passed as an argument (32 for IPv4 and 128 for IPv6), and it checks the maximum bound while parsing so that overflow is not possible. The use of `option` is refactored to only check for the `/` character, so that an invalid mask length after the `/` character can cause a parse failure. Note that these functions include the following performance optimizations: * The `ord` function is used instead of `digitToInt`, as the range of characters is already checked. * The parameters to the `go` helper function are given (bang) strictness annotations to help GHC determine that the `Char` and `Int` values can be unboxed. An unfortunate side effect of this change is that some error messages change.
TravisCardwell
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I realized that my commit included the digit range checks even though |
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A new version has been released. |
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The
digfunction inData.IP.Addruses anIntaccumulator that can overflow while parsing. It is used to parse IPv4 octets as well as IPv4 and IPv6 mask lengths. This change replaces thedigfunction with two special-purpose functions:The
octetfunction parses IPv4 octets. It checks the maximum bound while parsing so that overflow is not possible.The
maskLenfunction parses mask lengths. The maximum bound is passed as an argument (32 for IPv4 and 128 for IPv6), and it checks the maximum bound while parsing so that overflow is not possible. The use ofoptionis refactored to only check for the/character, so that an invalid mask length after the/character can cause a parse failure.Note that these functions include the following performance optimizations:
ordfunction is used instead ofdigitToInt, as the range of characters is already checked.gohelper function are given (bang) strictness annotations to help GHC determine that theCharandIntvalues can be unboxed.An unfortunate side effect of this change is that some error messages change.