Bug 8726

Summary:	MSG_TRUNC not regarded in unix_dgram_recvmsg()
Product:	Networking	Reporter:	Daniel (garkein)
Component:	Other	Assignee:	Arnaldo Carvalho de Melo (acme)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	mtk.manpages, protasnb
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.22	Subsystem:
Regression:	Yes	Bisected commit-id:

Description Daniel 2007-07-09 04:06:36 UTC

Problem Description:

In unix_dgram_recvmsg() in af_unix.c the flag MSG_TRUNC is not regarded as described in the recv(2) man page.

This did work in older kernels (I have a working 2.6.13, but am not sure if that is a plain kernel.org one, nor if it was the last working revision).
I believe the bug was introduced when the variable "copied" was removed from the code.

IMHO, the line 1650:

err = size;

should read

err = (flags & MSG_TRUNC) ? skb->len : size;

Comment 1 Daniel 2007-07-09 04:24:18 UTC

Kernel Version changed to 2.6.22 + regression

Comment 2 Andrew Morton 2007-07-09 09:21:34 UTC

Subject: Re: [Bugme-new]  New: MSG_TRUNC not regarded in
 unix_dgram_recvmsg()

On Mon,  9 Jul 2007 04:01:58 -0700 (PDT) bugme-daemon@bugzilla.kernel.org wrote:

> http://bugzilla.kernel.org/show_bug.cgi?id=8726
> 
>            Summary: MSG_TRUNC not regarded in unix_dgram_recvmsg()
>            Product: Networking
>            Version: 2.5
>      KernelVersion: 2.6.19
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: Other
>         AssignedTo: acme@ghostprotocols.net
>         ReportedBy: garkein@mailueberfall.de
> 
> 
> Problem Description:
> 
> In unix_dgram_recvmsg() in af_unix.c the flag MSG_TRUNC is not regarded as
> described in the recv(2) man page.
> 
> This did work in older kernels (I have a working 2.6.13, but am not sure if
> that is a plain kernel.org one, nor if it was the last working revision).
> I believe the bug was introduced when the variable "copied" was removed from
> the code.
> 
> IMHO, the line 1650:
> 
> err = size;
> 
> should read
> 
> err = (flags & MSG_TRUNC) ? skb->len : size;
>

Comment 3 Daniel 2007-07-10 05:12:55 UTC

I'm a bit confused by the above comment. Yes? No? Need more info?

Comment 4 Natalie Protasevich 2007-11-08 05:50:06 UTC

I will address this question to appropriate parties. Sounds like we need help from
netdev developers.