Patchwork [02/13] ppc/cell: use get_unused_fd_flags(0) instead of get_unused_fd()

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Submitter Yann Droneaud
Date July 2, 2013, 4:39 p.m.
Message ID <72f6f9ae898a664033f6b958bc7976b994544963.1372777600.git.ydroneaud@opteya.com>
Download mbox | patch
Permalink /patch/256515/
State Superseded
Headers show

Comments

Yann Droneaud - July 2, 2013, 4:39 p.m.
Macro get_unused_fd() is used to allocate a file descriptor with
default flags. Those default flags (0) can be "unsafe":
O_CLOEXEC must be used by default to not leak file descriptor
across exec().

Instead of macro get_unused_fd(), functions anon_inode_getfd()
or get_unused_fd_flags() should be used with flags given by userspace.
If not possible, flags should be set to O_CLOEXEC to provide userspace
with a default safe behavor.

In a further patch, get_unused_fd() will be removed so that
new code start using anon_inode_getfd() or get_unused_fd_flags()
with correct flags.

This patch replaces calls to get_unused_fd() with equivalent call to
get_unused_fd_flags(0) to preserve current behavor for existing code.

The hard coded flag value (0) should be reviewed on a per-subsystem basis,
and, if possible, set to O_CLOEXEC.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
---
 arch/powerpc/platforms/cell/spufs/inode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
Benjamin Herrenschmidt - Jan. 12, 2014, 11:06 p.m.
On Tue, 2013-07-02 at 18:39 +0200, Yann Droneaud wrote:
> Macro get_unused_fd() is used to allocate a file descriptor with
> default flags. Those default flags (0) can be "unsafe":
> O_CLOEXEC must be used by default to not leak file descriptor
> across exec().
> 
> Instead of macro get_unused_fd(), functions anon_inode_getfd()
> or get_unused_fd_flags() should be used with flags given by userspace.
> If not possible, flags should be set to O_CLOEXEC to provide userspace
> with a default safe behavor.
> 
> In a further patch, get_unused_fd() will be removed so that
> new code start using anon_inode_getfd() or get_unused_fd_flags()
> with correct flags.
> 
> This patch replaces calls to get_unused_fd() with equivalent call to
> get_unused_fd_flags(0) to preserve current behavor for existing code.
> 
> The hard coded flag value (0) should be reviewed on a per-subsystem basis,
> and, if possible, set to O_CLOEXEC.
> 
> Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>

Should I merge this (v5 on patchwork) or let Al do it ?

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

> ---
>  arch/powerpc/platforms/cell/spufs/inode.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
> index f390042..88df441 100644
> --- a/arch/powerpc/platforms/cell/spufs/inode.c
> +++ b/arch/powerpc/platforms/cell/spufs/inode.c
> @@ -301,7 +301,7 @@ static int spufs_context_open(struct path *path)
>  	int ret;
>  	struct file *filp;
>  
> -	ret = get_unused_fd();
> +	ret = get_unused_fd_flags(0);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -518,7 +518,7 @@ static int spufs_gang_open(struct path *path)
>  	int ret;
>  	struct file *filp;
>  
> -	ret = get_unused_fd();
> +	ret = get_unused_fd_flags(0);
>  	if (ret < 0)
>  		return ret;
>
Yann Droneaud - Jan. 13, 2014, 9:30 a.m.
Hi Benjamin,

Le lundi 13 janvier 2014 à 10:06 +1100, Benjamin Herrenschmidt a écrit :
> On Tue, 2013-07-02 at 18:39 +0200, Yann Droneaud wrote:
> > Macro get_unused_fd() is used to allocate a file descriptor with
> > default flags. Those default flags (0) can be "unsafe":
> > O_CLOEXEC must be used by default to not leak file descriptor
> > across exec().
> > 
> > Instead of macro get_unused_fd(), functions anon_inode_getfd()
> > or get_unused_fd_flags() should be used with flags given by userspace.
> > If not possible, flags should be set to O_CLOEXEC to provide userspace
> > with a default safe behavor.
> > 
> > In a further patch, get_unused_fd() will be removed so that
> > new code start using anon_inode_getfd() or get_unused_fd_flags()
> > with correct flags.
> > 
> > This patch replaces calls to get_unused_fd() with equivalent call to
> > get_unused_fd_flags(0) to preserve current behavor for existing code.
> > 
> > The hard coded flag value (0) should be reviewed on a per-subsystem basis,
> > and, if possible, set to O_CLOEXEC.
> > 
> > Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
> 
> Should I merge this (v5 on patchwork) or let Al do it ?
> 

Please merge it directly: patches from the previous patchsets were
picked individually by each subsystem maintainer after proper review
regarding setting close on exec flag by default.

> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 

Thanks a lot.

> > ---
> >  arch/powerpc/platforms/cell/spufs/inode.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
> > index f390042..88df441 100644
> > --- a/arch/powerpc/platforms/cell/spufs/inode.c
> > +++ b/arch/powerpc/platforms/cell/spufs/inode.c
> > @@ -301,7 +301,7 @@ static int spufs_context_open(struct path *path)
> >  	int ret;
> >  	struct file *filp;
> >  
> > -	ret = get_unused_fd();
> > +	ret = get_unused_fd_flags(0);
> >  	if (ret < 0)
> >  		return ret;
> >  
> > @@ -518,7 +518,7 @@ static int spufs_gang_open(struct path *path)
> >  	int ret;
> >  	struct file *filp;
> >  
> > -	ret = get_unused_fd();
> > +	ret = get_unused_fd_flags(0);
> >  	if (ret < 0)
> >  		return ret;
> >  
> 
> 

Note:
latest patch (from v5 patchset) is at
http://lkml.kernel.org/r/fe27abcfab5563d36a3e5e58ff36e5500c39be6a.1388952061.git.ydroneaud@opteya.com
v5 patchset is at
http://lkml.kernel.org/r/cover.1388952061.git.ydroneaud@opteya.com

Regards.
Yann Droneaud - Jan. 20, 2014, 5:01 p.m.
Hi,

Le lundi 13 janvier 2014 à 10:30 +0100, Yann Droneaud a écrit :
> Le lundi 13 janvier 2014 à 10:06 +1100, Benjamin Herrenschmidt a écrit :
> > On Tue, 2013-07-02 at 18:39 +0200, Yann Droneaud wrote:
> > > Macro get_unused_fd() is used to allocate a file descriptor with
> > > default flags. Those default flags (0) can be "unsafe":
> > > O_CLOEXEC must be used by default to not leak file descriptor
> > > across exec().
> > > 
> > > Instead of macro get_unused_fd(), functions anon_inode_getfd()
> > > or get_unused_fd_flags() should be used with flags given by userspace.
> > > If not possible, flags should be set to O_CLOEXEC to provide userspace
> > > with a default safe behavor.
> > > 
> > > In a further patch, get_unused_fd() will be removed so that
> > > new code start using anon_inode_getfd() or get_unused_fd_flags()
> > > with correct flags.
> > > 
> > > This patch replaces calls to get_unused_fd() with equivalent call to
> > > get_unused_fd_flags(0) to preserve current behavor for existing code.
> > > 
> > > The hard coded flag value (0) should be reviewed on a per-subsystem basis,
> > > and, if possible, set to O_CLOEXEC.
> > > 
> > > Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
> > 
> > Should I merge this (v5 on patchwork) or let Al do it ?
> > 
> 
> Please merge it directly: patches from the previous patchsets were
> picked individually by each subsystem maintainer after proper review
> regarding setting close on exec flag by default.
> 
> > Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > 
> 
> Thanks a lot.

> Note:
> latest patch (from v5 patchset) is at
> http://lkml.kernel.org/r/fe27abcfab5563d36a3e5e58ff36e5500c39be6a.1388952061.git.ydroneaud@opteya.com
> v5 patchset is at
> http://lkml.kernel.org/r/cover.1388952061.git.ydroneaud@opteya.com
> 

I have not yet seen the patch in your trees at
https://git.kernel.org/cgit/linux/kernel/git/benh/powerpc.git/

I hope you would pick the patch, if possible in its latest version
(unfortunately I'm not able to give the link to the astest patch in
patchwork).

Regards.

Patch

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index f390042..88df441 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -301,7 +301,7 @@  static int spufs_context_open(struct path *path)
 	int ret;
 	struct file *filp;
 
-	ret = get_unused_fd();
+	ret = get_unused_fd_flags(0);
 	if (ret < 0)
 		return ret;
 
@@ -518,7 +518,7 @@  static int spufs_gang_open(struct path *path)
 	int ret;
 	struct file *filp;
 
-	ret = get_unused_fd();
+	ret = get_unused_fd_flags(0);
 	if (ret < 0)
 		return ret;