From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, Jordy Zomer <jordy@pwning.systems>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH v2] fs: make d_path-like functions all have unsigned size
Date: Tue, 27 Jul 2021 15:30:55 +0200 [thread overview]
Message-ID: <YQAKj4LFifmlVi0q@kroah.com> (raw)
In-Reply-To: <YQAGvTZPex3mxrD/@casper.infradead.org>
On Tue, Jul 27, 2021 at 02:14:37PM +0100, Matthew Wilcox wrote:
> On Tue, Jul 27, 2021 at 02:56:53PM +0200, Greg Kroah-Hartman wrote:
> > And my mistake from earlier, size_t is the same as unsigned int, not
> > unsigned long.
>
> No.
>
> include/linux/types.h:typedef __kernel_size_t size_t;
>
> include/uapi/asm-generic/posix_types.h:
>
> #ifndef __kernel_size_t
> #if __BITS_PER_LONG != 64
> typedef unsigned int __kernel_size_t;
> #else
> typedef __kernel_ulong_t __kernel_size_t;
> #endif
> #endif
>
> size_t is an unsigned long on 64-bit, unless otherwise defined by the
> arch.
ugh, ok, so there really is a problem, as we have a size_t value being
passed in as an int, and then it could be treated as a negative value
for some fun pointer math to copy buffers around.
How is this not causing problems now already? Are we just getting
lucky?
thanks,
greg k-h
next prev parent reply other threads:[~2021-07-27 13:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-27 12:07 [PATCH v2] fs: make d_path-like functions all have unsigned size Greg Kroah-Hartman
2021-07-27 12:39 ` Andy Shevchenko
2021-07-27 12:56 ` Greg Kroah-Hartman
2021-07-27 13:14 ` Matthew Wilcox
2021-07-27 13:30 ` Greg Kroah-Hartman [this message]
2021-07-27 13:53 ` Matthew Wilcox
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