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Unreachable (useless) code in sre.c:_validate_inner() #117071

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NGRsoftlab opened this issue Mar 20, 2024 · 4 comments
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Unreachable (useless) code in sre.c:_validate_inner() #117071

NGRsoftlab opened this issue Mar 20, 2024 · 4 comments
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type-bug An unexpected behavior, bug, or error

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@NGRsoftlab
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NGRsoftlab commented Mar 20, 2024 •
edited by bedevere-app bot
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Bug report

Bug description:

Conditions in the following lines are always false, so code will never trigger FAIL:
https://github.com/python/cpython/blob/main/Modules/_sre/sre.c#L1967
https://github.com/python/cpython/blob/main/Modules/_sre/sre.c#L1987

The code it self is like:

if (max > SRE_MAXREPEAT)
    FAIL;

where
'max' is SRE_CODE which is 4 byte unsigned int (Py_UCS4), and SRE_MAXREPEAT is the max value of SRE_CODE (and Py_UCS4).

Found by Linux Verification Center (portal.linuxtesting.ru) with SVACE.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

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@NGRsoftlab NGRsoftlab added the type-bug An unexpected behavior, bug, or error label Mar 20, 2024
@bedevere-app bedevere-app bot mentioned this issue Mar 20, 2024
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@serhiy-storchaka
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It is not always false on 32-bit platforms.

@serhiy-storchaka serhiy-storchaka closed this as not planned Won't fix, can't repro, duplicate, stale Mar 20, 2024
@NGRsoftlab
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It is not always false on 32-bit platforms.

Can you please point platform, where we can test this next time?

@serhiy-storchaka
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Any 32-bit platform. SRE_MAXREPEAT is PY_SSIZE_T_MAX (= $2^{31}-1$) there.

@NGRsoftlab
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Thanks, got it, it's not UINT_MAX, it's INT_MAX.

@serhiy-storchaka serhiy-storchaka mentioned this issue Mar 22, 2024
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