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integer truncation in truncate on Windows #24466

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simonster opened this issue Nov 4, 2017 · 3 comments · Fixed by #24616
Closed

integer truncation in truncate on Windows #24466

simonster opened this issue Nov 4, 2017 · 3 comments · Fixed by #24616
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bug Indicates an unexpected problem or unintended behavior io Involving the I/O subsystem: libuv, read, write, etc. system:windows Affects only Windows

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@simonster
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While ios_trunc accepts a size argument of type size_t, it calls _chsize, which takes a long (32-bit int on Windows), and it doesn't check for overflow. As a result, this fails:

open("some_file_name", "w") do f
    truncate(f, 2^31+1)
end

ios_trunc should probably be modified to use _chsize_s.

(Originally reported as JuliaIO/JLD2.jl#50.)
@simonster simonster mentioned this issue Nov 4, 2017
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@simonster simonster added bug Indicates an unexpected problem or unintended behavior system:windows Affects only Windows io Involving the I/O subsystem: libuv, read, write, etc. labels Nov 4, 2017
@jaakkor2
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jaakkor2 commented Nov 6, 2017

Looks like it used to be _chsize_s, but was changed to _chsize here https://github.com/JuliaLang/julia/pull/3011/files back in 2013 due to MinGW compilation problems.

If defined(__MINGW32__) continue to use _chsize, otherwise _chsize_s on Windows?

@vtjnash
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vtjnash commented Nov 6, 2017

MinGW is long dead

@jaakkor2
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Consequence of this bug: on Windows 64-bit files larger than 2 GB cannot be truncated. For example, JLD2-files are now limited to 2 GB size.

Looks like cygwin64/mingw64-x86_64 is used to compile the version downloadable at https://julialang.org/downloads/ . And looks like mingw64 has _chsize_s defined in mingw-w64/mingw-w64-crt/secapi/_chsize_s.c . But I do not find references to --enable-secure-api option in Julia code.

If we are targeting systems newer than Windows XP, _chsize_s should be ok, but I have no possibility to do testing now. Help wanted :)

@jaakkor2 jaakkor2 mentioned this issue Nov 15, 2017
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vtjnash pushed a commit that referenced this issue Dec 9, 2017
@jaakkor2 @vtjnash
ios: Use _chsize_s on Windows for file truncation (#24616)
ff045af 
Should allow files >2 GB to be truncated on Windows.

Fix #24466

Checking Windows 32bit build https://julialang-s3.julialang.org/bin/winnt/x86/0.6/julia-0.6.1-win32.exe, libgit2.dll already uses `_chsize_s`, so both 32bit and 64bit should be able to use `_chsize_s`.
evetion pushed a commit to evetion/julia that referenced this issue Dec 12, 2017
@jaakkor2 @evetion
ios: Use _chsize_s on Windows for file truncation (JuliaLang#24616)
f346f83 
Should allow files >2 GB to be truncated on Windows.

Fix JuliaLang#24466

Checking Windows 32bit build https://julialang-s3.julialang.org/bin/winnt/x86/0.6/julia-0.6.1-win32.exe, libgit2.dll already uses `_chsize_s`, so both 32bit and 64bit should be able to use `_chsize_s`.
ararslan pushed a commit that referenced this issue Apr 26, 2018
@jaakkor2 @ararslan
ios: Use _chsize_s on Windows for file truncation (#24616)
a321e6b 
Should allow files >2 GB to be truncated on Windows.

Fix #24466

Checking Windows 32bit build https://julialang-s3.julialang.org/bin/winnt/x86/0.6/julia-0.6.1-win32.exe, libgit2.dll already uses `_chsize_s`, so both 32bit and 64bit should be able to use `_chsize_s`.

Ref #24616
(cherry picked from commit ff045af)
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bug Indicates an unexpected problem or unintended behavior io Involving the I/O subsystem: libuv, read, write, etc. system:windows Affects only Windows
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Use _chsize_s on Windows for truncate
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@vtjnash @simonster @jaakkor2