qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: Peter Maydell <peter.maydell@linaro.org>
To: QEMU Developers <qemu-devel@nongnu.org>
Cc: Igor Mammedov <imammedo@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: acpi_pcihp_eject_slot() bug if passed 'slots == 0'
Date: Thu, 26 Mar 2020 11:52:36 +0000	[thread overview]
Message-ID: <CAFEAcA-oWBjOXWmnLvPww9wrty_QbSc+Xv3BY3sQAnEXFkfQbA@mail.gmail.com> (raw)

Hi; Coverity spots that if hw/acpi/pcihp.c:acpi_pcihp_eject_slot()
is passed a zero 'slots' argument then ctz32(slots) will return 32,
and then the code that does '1U << slot' is C undefined behaviour
because it's an oversized shift. (This is CID 1421896.)

Since the pci_write() function in this file can call
acpi_pcihp_eject_slot() with an arbitrary value from the guest,
I think we need to handle 'slots == 0' safely. But what should
the behaviour be?

thanks
-- PMM


             reply	other threads:[~2020-03-26 11:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26 11:52 Peter Maydell [this message]
2020-03-26 12:29 ` acpi_pcihp_eject_slot() bug if passed 'slots == 0' Igor Mammedov
2020-03-26 12:50   ` Igor Mammedov
2020-03-26 13:29     ` Michael S. Tsirkin
2020-03-26 13:23 ` Igor Mammedov
2020-03-26 13:28   ` Michael S. Tsirkin
2020-03-26 13:31     ` Michael S. Tsirkin
2020-03-26 13:40       ` Igor Mammedov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAFEAcA-oWBjOXWmnLvPww9wrty_QbSc+Xv3BY3sQAnEXFkfQbA@mail.gmail.com \
    --to=peter.maydell@linaro.org \
    --cc=imammedo@redhat.com \
    --cc=mst@redhat.com \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).