Avoid overflow in RC4 loop comparison #336
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The rc4 function iterates over a buffer of size buffer_len who's maximum value is INT_MAX with a counter of type short that is not guaranteed to have maximum size INT_MAX. In circumstances where short is narrower than int and where buffer_len is larger than the maximum value of a short, it may be possible to loop infinitely as counter will overflow and never be greater than or equal to buffer_len. The solution is to make the comparison be between types of equal width. This commit defines counter as an int.
sergepetrenko
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Jul 29, 2022
The rc4 function iterates over a buffer of size buffer_len who's maximum value is INT_MAX with a counter of type short that is not guaranteed to have maximum size INT_MAX. In circumstances where short is narrower than int and where buffer_len is larger than the maximum value of a short, it may be possible to loop infinitely as counter will overflow and never be greater than or equal to buffer_len. The solution is to make the comparison be between types of equal width. This commit defines counter as an int. Fix By: Fionn Fitzmaurice (@fionn)
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The
rc4function iterates over a buffer of sizebuffer_lenwho's maximumvalue is
INT_MAXwith a counter of typeshortthat is not guaranteed tohave maximum size
INT_MAX.In circumstances where
shortis narrower thanintand wherebuffer_lenis larger than the maximum value of a
short, it may be possible to loopinfinitely as
counterwill overflow and never be greater than or equalto
buffer_len.The solution is to make the comparison be between types of equal width.
This commit defines
counteras anint.