Patchwork [net,v3,2/3] net: netprio: fd passed in SCM_RIGHTS datagram not set correctly

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Submitter John Fastabend
Date Aug. 14, 2012, 10:34 p.m.
Message ID <20120814223430.3551.88909.stgit@jf-dev1-dcblab>
Download mbox | patch
Permalink /patch/177468/
State Accepted
Delegated to: David Miller
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Comments

John Fastabend - Aug. 14, 2012, 10:34 p.m.
A socket fd passed in a SCM_RIGHTS datagram was not getting
updated with the new tasks cgrp prioidx. This leaves IO on
the socket tagged with the old tasks priority.

To fix this add a check in the scm recvmsg path to update the
sock cgrp prioidx with the new tasks value.

Thanks to Al Viro for catching this.

CC: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
---

 net/core/scm.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)


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Neil Horman - Aug. 15, 2012, 10:53 a.m.
On Tue, Aug 14, 2012 at 03:34:30PM -0700, John Fastabend wrote:
> A socket fd passed in a SCM_RIGHTS datagram was not getting
> updated with the new tasks cgrp prioidx. This leaves IO on
> the socket tagged with the old tasks priority.
> 
> To fix this add a check in the scm recvmsg path to update the
> sock cgrp prioidx with the new tasks value.
> 
> Thanks to Al Viro for catching this.
> 
> CC: Neil Horman <nhorman@tuxdriver.com>
> Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
> Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
> ---
> 
>  net/core/scm.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/net/core/scm.c b/net/core/scm.c
> index 8f6ccfd..040cebe 100644
> --- a/net/core/scm.c
> +++ b/net/core/scm.c
> @@ -265,6 +265,7 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
>  	for (i=0, cmfptr=(__force int __user *)CMSG_DATA(cm); i<fdmax;
>  	     i++, cmfptr++)
>  	{
> +		struct socket *sock;
>  		int new_fd;
>  		err = security_file_receive(fp[i]);
>  		if (err)
> @@ -281,6 +282,9 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
>  		}
>  		/* Bump the usage count and install the file. */
>  		get_file(fp[i]);
> +		sock = sock_from_file(fp[i], &err);
> +		if (sock)
> +			sock_update_netprioidx(sock->sk, current);
>  		fd_install(new_fd, fp[i]);
>  	}
>  
> 
> 

Acked-by: Neil Horman <nhorman@tuxdriver.com>

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David Miller - Aug. 16, 2012, 10:11 p.m.
From: John Fastabend <john.r.fastabend@intel.com>
Date: Tue, 14 Aug 2012 15:34:30 -0700

> A socket fd passed in a SCM_RIGHTS datagram was not getting
> updated with the new tasks cgrp prioidx. This leaves IO on
> the socket tagged with the old tasks priority.
> 
> To fix this add a check in the scm recvmsg path to update the
> sock cgrp prioidx with the new tasks value.
> 
> Thanks to Al Viro for catching this.
> 
> CC: Neil Horman <nhorman@tuxdriver.com>
> Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
> Signed-off-by: John Fastabend <john.r.fastabend@intel.com>

Applied.
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Patch

diff --git a/net/core/scm.c b/net/core/scm.c
index 8f6ccfd..040cebe 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -265,6 +265,7 @@  void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
 	for (i=0, cmfptr=(__force int __user *)CMSG_DATA(cm); i<fdmax;
 	     i++, cmfptr++)
 	{
+		struct socket *sock;
 		int new_fd;
 		err = security_file_receive(fp[i]);
 		if (err)
@@ -281,6 +282,9 @@  void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
 		}
 		/* Bump the usage count and install the file. */
 		get_file(fp[i]);
+		sock = sock_from_file(fp[i], &err);
+		if (sock)
+			sock_update_netprioidx(sock->sk, current);
 		fd_install(new_fd, fp[i]);
 	}