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From: "pshevchuk at pshevchuk dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/114806] New: placement new doesn't check array length
Date: Mon, 22 Apr 2024 15:58:43 +0000	[thread overview]
Message-ID: <bug-114806-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114806

            Bug ID: 114806
           Summary: placement new doesn't check array length
           Product: gcc
           Version: 13.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pshevchuk at pshevchuk dot com
  Target Milestone: ---

Created attachment 58008
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58008&action=edit
Example code but as attachment

#include <new>
#include <cstdio>

int main()
{
    int sz = -1;
    char buf[9];
    char* res = new (buf) char[sz];
    std::puts(res == (char*) nullptr? "correct" : "wrong");
}

This program should output "correct", since:

expr.new.9: array bound is erroneous since it's less than zero before
conversion to std::size_t (9.1)

expr.new.9.5.1: the placement new is nothrow, so the result of this operation
must be nullptr. It isn't

Curiously, if you replace the allocated type with an array of ints, it will
incorrectly throw the std::bad_array_new_length exception instead of returning
nullptr.

Seems to be present in gcc 8.2 and in gcc13 too

             reply	other threads:[~2024-04-22 15:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-22 15:58 pshevchuk at pshevchuk dot com [this message]
2024-04-22 16:11 ` [Bug c++/114806] " redi at gcc dot gnu.org
2024-04-22 16:14 ` redi at gcc dot gnu.org

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