[PATCH 1/1] file capabilities: simplify signal check

[PATCH 1/1] file capabilities: simplify signal check

[Serge E. Hallyn]

>From bd076c7245d02be0cc01b7c09bd7170ec5946492 Mon Sep 17 00:00:00 2001
From: Serge E. Hallyn <serue@us.ibm.com>
Date: Sun, 17 Feb 2008 20:28:07 -0500
Subject: [PATCH 1/1] file capabilities: simplify signal check

Simplify the uid equivalence check in cap_task_kill().  Anyone
can kill a process owned by the same uid.

Without this patch wireshark is reported to fail.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
---
 security/commoncap.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index 5aba826..bb0c095 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -552,7 +552,7 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
 	 * allowed.
 	 * We must preserve legacy signal behavior in this case.
 	 */
-	if (p->euid == 0 && p->uid == current->uid)
+	if (p->uid == current->uid)
 		return 0;
 
 	/* sigcont is permitted within same session */
-- 
1.5.1.1.GIT

Re: [PATCH 1/1] file capabilities: simplify signal check

[Andrew Morton]

On Wed, 20 Feb 2008 10:15:50 -0600 "Serge E. Hallyn" <serue@us.ibm.com> wrote:

> >From bd076c7245d02be0cc01b7c09bd7170ec5946492 Mon Sep 17 00:00:00 2001
> From: Serge E. Hallyn <serue@us.ibm.com>
> Date: Sun, 17 Feb 2008 20:28:07 -0500
> Subject: [PATCH 1/1] file capabilities: simplify signal check
> 
> Simplify the uid equivalence check in cap_task_kill().  Anyone
> can kill a process owned by the same uid.
> 
> Without this patch wireshark is reported to fail.

Strange that a patch titled "simplify...." actually fixes a bug.

> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
> Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
> ---
>  security/commoncap.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/security/commoncap.c b/security/commoncap.c
> index 5aba826..bb0c095 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -552,7 +552,7 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
>  	 * allowed.
>  	 * We must preserve legacy signal behavior in this case.
>  	 */
> -	if (p->euid == 0 && p->uid == current->uid)
> +	if (p->uid == current->uid)
>  		return 0;
>  
>  	/* sigcont is permitted within same session */

I've marked this as needed-in-2.6.24.  Was that appropriate?

Re: [PATCH 1/1] file capabilities: simplify signal check

[Serge E. Hallyn]

Quoting Andrew Morton (akpm@linux-foundation.org):
> On Wed, 20 Feb 2008 10:15:50 -0600 "Serge E. Hallyn" <serue@us.ibm.com> wrote:
> 
> > >From bd076c7245d02be0cc01b7c09bd7170ec5946492 Mon Sep 17 00:00:00 2001
> > From: Serge E. Hallyn <serue@us.ibm.com>
> > Date: Sun, 17 Feb 2008 20:28:07 -0500
> > Subject: [PATCH 1/1] file capabilities: simplify signal check
> > 
> > Simplify the uid equivalence check in cap_task_kill().  Anyone
> > can kill a process owned by the same uid.
> > 
> > Without this patch wireshark is reported to fail.
> 
> Strange that a patch titled "simplify...." actually fixes a bug.

Sorry.  Yeah that's a bad subject.

> > Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
> > Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
> > ---
> >  security/commoncap.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/security/commoncap.c b/security/commoncap.c
> > index 5aba826..bb0c095 100644
> > --- a/security/commoncap.c
> > +++ b/security/commoncap.c
> > @@ -552,7 +552,7 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
> >  	 * allowed.
> >  	 * We must preserve legacy signal behavior in this case.
> >  	 */
> > -	if (p->euid == 0 && p->uid == current->uid)
> > +	if (p->uid == current->uid)
> >  		return 0;
> >  
> >  	/* sigcont is permitted within same session */
> 
> I've marked this as needed-in-2.6.24.  Was that appropriate?

Yes, thanks.  I doubt wireshark is the only thing that'll break
otherwise.

thanks,
-serge