[Bug libc/17674] New: ctype functions with wrong return values and crashes

[Bug libc/17674] New: ctype functions with wrong return values and crashes

[bhaak at gmx dot net]

https://sourceware.org/bugzilla/show_bug.cgi?id=17674

            Bug ID: 17674
           Summary: ctype functions with wrong return values and crashes
           Product: glibc
           Version: 2.20
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
          Assignee: unassigned at sourceware dot org
          Reporter: bhaak at gmx dot net
                CC: drepper.fsp at gmail dot com

Created attachment 7992
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7992&action=edit
C code demonstrating wrong return values and crash of isblank

The ctype functions (probably all, I tested with isblank, isspace, and isalpha)
return wrong results if they are called with int values bigger than UCHAR_MAX.

Furthermore, for some big int values it crashes with a segmentation fault.

The attached C file outputs all values from 0 to INT_MAX which return true from
isblank. On a Gentoo machine it crashed with 151056, on an Ubuntu machine with
163152.

I know that the ctype functions are technically in POSIX only defined for
values representable as an unsigned char or the value of EOF but this is stupid
nevertheless for a library function.

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[Bug libc/17674] ctype functions with wrong return values and crashes

[schwab@linux-m68k.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17674

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
This is perfectly valid undefined behaviour.

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