[Bug stdio/20632] Buffer overflow in wchar IO (_IO_wfile_overflow)

[Bug stdio/20632] Buffer overflow in wchar IO (_IO_wfile_overflow)

[infor at rudhar dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=20632

Ruud Harmsen <infor at rudhar dot com> changed:

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                 CC|                            |infor at rudhar dot com

--- Comment #2 from Ruud Harmsen <infor at rudhar dot com> ---
It crashes for me (with glibc 2.31) even if I comment out the line with the
malloc. It crashes already at one of the short writes.

Is it legal at all, to write to a stream of which you have close(2)'d the
fileno? Why would anyone do that?

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[Bug stdio/20632] Buffer overflow in wchar IO (_IO_wfile_overflow)

[infor at rudhar dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=20632

--- Comment #3 from Ruud Harmsen <infor at rudhar dot com> ---
I wonder why writing to stderr involves handling any buffers in the first
place. By default, stderr is unbuffered, that is, character buffered. So any
attempt to write a character, or even a byte, to stderr from the stdio level,
should immediately cause a write system call to file descriptor 2.

>From an extended version of the test program, which does more error checking, I
learnt that the first fputws returns -1 and sets errno to 9, Bad file
descriptor. That is correct because file desciptor 2 was closed. Subsequent
calls of fputws however do go through and return 1, as if the write succeeded. 

For comparison, I ran the same program under FreeBSD 12.2, and there _all_ the
calls of fputws were rejected returning -1, and setting errno to "Bad file
descriptor". No crash happens there.

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[Bug stdio/20632] Buffer overflow in wchar IO (_IO_wfile_overflow)

[bap.fayol at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=20632

yaoltreza <bap.fayol at gmail dot com> changed:

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                 CC|                            |bap.fayol at gmail dot com

--- Comment #4 from yaoltreza <bap.fayol at gmail dot com> ---
thank you all for the tips.
https://www.depannage-auto-remorquage-bordeaux33.com

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[Bug stdio/20632] Buffer overflow in wchar IO (_IO_wfile_overflow)

[adhemerval.zanella at linaro dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20632

Adhemerval Zanella <adhemerval.zanella at linaro dot org> changed:

           What    |Removed                     |Added
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                 CC|                            |adhemerval.zanella at linaro dot o
                   |                            |rg

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