From: Markus Armbruster <armbru@redhat.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: "Marc-André Lureau" <marcandre.lureau@gmail.com>,
"Michael Roth" <mdroth@linux.vnet.ibm.com>,
"Peter Crosthwaite" <crosthwaite.peter@gmail.com>,
qemu-trivial@nongnu.org, "Alexander Graf" <agraf@suse.de>,
qemu-devel@nongnu.org, "Philippe Mathieu-Daudé" <f4bug@amsat.org>
Subject: Re: [Qemu-devel] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers
Date: Thu, 23 Mar 2017 13:41:52 +0100 [thread overview]
Message-ID: <87tw6ktban.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <1490262680.463.27.camel@redhat.com> (Gerd Hoffmann's message of "Thu, 23 Mar 2017 10:51:20 +0100")
Gerd Hoffmann <kraxel@redhat.com> writes:
> Hi,
>
>> oops, there are hard-coded calls with NULL/0. I suppose to fix clang
>> warning, it would need to check if data != null for memcpy.
>
> I'd check for len > 0, and in that if branch we can also assert on data
> == NULL and thereby check that len and data are consistent.
If len is non-zero but data is null, memcpy() will crash just fine by
itself, so why bother asserting. If len is zero, there's nothing to
assert.
I'd simply protect memcpy() with if (len) and call it a day.
next prev parent reply other threads:[~2017-03-23 12:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-22 20:48 [Qemu-devel] [PATCH RESEND 0/3] easy-to-fix clang warnings Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-devel] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers Philippe Mathieu-Daudé
2017-03-23 6:49 ` Markus Armbruster
2017-03-23 7:43 ` Gerd Hoffmann
2017-03-23 8:14 ` Marc-André Lureau
2017-03-23 9:51 ` Gerd Hoffmann
2017-03-23 12:41 ` Markus Armbruster [this message]
2017-03-23 13:56 ` Gerd Hoffmann
2017-03-23 14:08 ` Markus Armbruster
2017-04-07 21:33 ` Philippe Mathieu-Daudé
2017-03-22 20:48 ` [Qemu-devel] [PATCH RESEND 2/3] device_tree: fix compiler warnings (clang 5) Philippe Mathieu-Daudé
2017-03-22 22:35 ` Marc-André Lureau
2017-03-22 20:48 ` [Qemu-devel] [PATCH RESEND 3/3] qga: " Philippe Mathieu-Daudé
2017-03-22 21:22 ` Michael Roth
2017-04-07 21:31 ` Philippe Mathieu-Daudé
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