From: Matt Fleming <matt@codeblueprint.co.uk>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ivan Hu <ivan.hu@canonical.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
linux-efi@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] efi/efi_test: Prevent an Oops in efi_runtime_query_capsulecaps()
Date: Fri, 6 Oct 2017 13:19:39 +0100 [thread overview]
Message-ID: <20171006121939.GC3314@codeblueprint.co.uk> (raw)
In-Reply-To: <20170930081732.x6g4b2mwxwt5xzql@mwanda>
On Sat, 30 Sep, at 11:17:32AM, Dan Carpenter wrote:
> If "qcaps.capsule_count" is ULONG_MAX then "qcaps.capsule_count + 1"
> will overflow to zero and kcalloc() will return the ZERO_SIZE_PTR. We
> try to dereference it inside the loop and crash.
>
> Fixes: ff6301dabc3c ("efi: Add efi_test driver for exporting UEFI runtime service interfaces")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/firmware/efi/test/efi_test.c b/drivers/firmware/efi/test/efi_test.c
> index 08129b7b80ab..41c48a1e8baa 100644
> --- a/drivers/firmware/efi/test/efi_test.c
> +++ b/drivers/firmware/efi/test/efi_test.c
> @@ -593,6 +593,9 @@ static long efi_runtime_query_capsulecaps(unsigned long arg)
> if (copy_from_user(&qcaps, qcaps_user, sizeof(qcaps)))
> return -EFAULT;
>
> + if (qcaps.capsule_count == ULONG_MAX)
> + return -EINVAL;
> +
> capsules = kcalloc(qcaps.capsule_count + 1,
> sizeof(efi_capsule_header_t), GFP_KERNEL);
> if (!capsules)
This looks OK to me. Ivan?
next prev parent reply other threads:[~2017-10-06 12:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-30 8:17 [PATCH] efi/efi_test: Prevent an Oops in efi_runtime_query_capsulecaps() Dan Carpenter
2017-10-06 12:19 ` Matt Fleming [this message]
[not found] ` <20171006121939.GC3314-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2017-10-11 6:26 ` ACK: " ivanhu
2017-10-11 9:34 ` Matt Fleming
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