[03/29] 9p: move xattr-related structs to .rodata

  From: Wedson Almeida Filho <walmeida@microsoft.com>

This makes it harder for accidental or malicious changes to
v9fs_xattr_user_handler, v9fs_xattr_trusted_handler,
v9fs_xattr_security_handler, or v9fs_xattr_handlers at runtime.

Cc: Eric Van Hensbergen <ericvh@kernel.org>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Christian Schoenebeck <linux_oss@crudebyte.com>
Cc: v9fs@lists.linux.dev
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
---
 fs/9p/xattr.c | 8 ++++----
 fs/9p/xattr.h | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)
  

On Saturday, September 30, 2023 7:00:07 AM CEST Wedson Almeida Filho wrote:
> From: Wedson Almeida Filho <walmeida@microsoft.com>
> 
> This makes it harder for accidental or malicious changes to
> v9fs_xattr_user_handler, v9fs_xattr_trusted_handler,
> v9fs_xattr_security_handler, or v9fs_xattr_handlers at runtime.
> 
> Cc: Eric Van Hensbergen <ericvh@kernel.org>
> Cc: Latchesar Ionkov <lucho@ionkov.net>
> Cc: Dominique Martinet <asmadeus@codewreck.org>
> Cc: Christian Schoenebeck <linux_oss@crudebyte.com>
> Cc: v9fs@lists.linux.dev
> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>

Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>

> ---
>  fs/9p/xattr.c | 8 ++++----
>  fs/9p/xattr.h | 2 +-
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
> index e00cf8109b3f..053d1cef6e13 100644
> --- a/fs/9p/xattr.c
> +++ b/fs/9p/xattr.c
> @@ -162,27 +162,27 @@ static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
>  	return v9fs_xattr_set(dentry, full_name, value, size, flags);
>  }
>  
> -static struct xattr_handler v9fs_xattr_user_handler = {
> +static const struct xattr_handler v9fs_xattr_user_handler = {
>  	.prefix	= XATTR_USER_PREFIX,
>  	.get	= v9fs_xattr_handler_get,
>  	.set	= v9fs_xattr_handler_set,
>  };
>  
> -static struct xattr_handler v9fs_xattr_trusted_handler = {
> +static const struct xattr_handler v9fs_xattr_trusted_handler = {
>  	.prefix	= XATTR_TRUSTED_PREFIX,
>  	.get	= v9fs_xattr_handler_get,
>  	.set	= v9fs_xattr_handler_set,
>  };
>  
>  #ifdef CONFIG_9P_FS_SECURITY
> -static struct xattr_handler v9fs_xattr_security_handler = {
> +static const struct xattr_handler v9fs_xattr_security_handler = {
>  	.prefix	= XATTR_SECURITY_PREFIX,
>  	.get	= v9fs_xattr_handler_get,
>  	.set	= v9fs_xattr_handler_set,
>  };
>  #endif
>  
> -const struct xattr_handler *v9fs_xattr_handlers[] = {
> +const struct xattr_handler * const v9fs_xattr_handlers[] = {
>  	&v9fs_xattr_user_handler,
>  	&v9fs_xattr_trusted_handler,
>  #ifdef CONFIG_9P_FS_SECURITY
> diff --git a/fs/9p/xattr.h b/fs/9p/xattr.h
> index b5636e544c8a..3ad5a802352a 100644
> --- a/fs/9p/xattr.h
> +++ b/fs/9p/xattr.h
> @@ -10,7 +10,7 @@
>  #include <net/9p/9p.h>
>  #include <net/9p/client.h>
>  
> -extern const struct xattr_handler *v9fs_xattr_handlers[];
> +extern const struct xattr_handler * const v9fs_xattr_handlers[];
>  
>  ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
>  			   void *buffer, size_t buffer_size);
>
  

Christian Schoenebeck wrote on Sat, Sep 30, 2023 at 10:12:25AM +0200:
> On Saturday, September 30, 2023 7:00:07 AM CEST Wedson Almeida Filho wrote:
> > From: Wedson Almeida Filho <walmeida@microsoft.com>
> > 
> > This makes it harder for accidental or malicious changes to
> > v9fs_xattr_user_handler, v9fs_xattr_trusted_handler,
> > v9fs_xattr_security_handler, or v9fs_xattr_handlers at runtime.
> > 
> > Cc: Eric Van Hensbergen <ericvh@kernel.org>
> > Cc: Latchesar Ionkov <lucho@ionkov.net>
> > Cc: Dominique Martinet <asmadeus@codewreck.org>
> > Cc: Christian Schoenebeck <linux_oss@crudebyte.com>
> > Cc: v9fs@lists.linux.dev
> > Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
> 
> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>

Looks good to me on principle as well (and it should blow up immediately
on testing in the unlikely case there's a problem...)

Eric, I don't think you have anything planned for this round?
There's another data race patch laying around that we didn't submit for
6.6, shall I take these two for now?

(Assuming this patch series is meant to be taken up by individual fs
maintainers independantly, it's never really clear with such large
swatches of patchs and we weren't in Cc of a cover letter if there was
any... In the future it'd help if either there's a clear cover letter
everyone is in Cc at (some would say keep everyone in cc of all
patches!), or just send these in a loop so they don't appear to be part
of a series and each maintainer deals with it as they see fit)
  

On Sat, 30 Sept 2023 at 06:03, Dominique Martinet
<asmadeus@codewreck.org> wrote:
>
> Christian Schoenebeck wrote on Sat, Sep 30, 2023 at 10:12:25AM +0200:
> > On Saturday, September 30, 2023 7:00:07 AM CEST Wedson Almeida Filho wrote:
> > > From: Wedson Almeida Filho <walmeida@microsoft.com>
> > >
> > > This makes it harder for accidental or malicious changes to
> > > v9fs_xattr_user_handler, v9fs_xattr_trusted_handler,
> > > v9fs_xattr_security_handler, or v9fs_xattr_handlers at runtime.
> > >
> > > Cc: Eric Van Hensbergen <ericvh@kernel.org>
> > > Cc: Latchesar Ionkov <lucho@ionkov.net>
> > > Cc: Dominique Martinet <asmadeus@codewreck.org>
> > > Cc: Christian Schoenebeck <linux_oss@crudebyte.com>
> > > Cc: v9fs@lists.linux.dev
> > > Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
> >
> > Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>

Thanks for the review, Christian!

> Looks good to me on principle as well (and it should blow up immediately
> on testing in the unlikely case there's a problem...)
>
> Eric, I don't think you have anything planned for this round?
> There's another data race patch laying around that we didn't submit for
> 6.6, shall I take these two for now?
>
> (Assuming this patch series is meant to be taken up by individual fs
> maintainers independantly, it's never really clear with such large
> swatches of patchs and we weren't in Cc of a cover letter if there was
> any... In the future it'd help if either there's a clear cover letter
> everyone is in Cc at (some would say keep everyone in cc of all
> patches!), or just send these in a loop so they don't appear to be part
> of a series and each maintainer deals with it as they see fit)

There is a cover letter
(https://lore.kernel.org/all/20230930050033.41174-1-wedsonaf@gmail.com/),
apologies for not CCing you there. I was trying to avoid spamming
maintainers with unrelated changes.

We need changes in fs/xattr.c (which are in the first patch of the
series) to avoid warnings, so unfortunately this can't be taken
individually. My thought was that individual fs maintainers would
review/ack the patches and this would be taken through the fs tree.

>
> --
> Dominique
  

Wedson Almeida Filho wrote on Tue, Oct 03, 2023 at 10:55:44AM -0300:
> > Looks good to me on principle as well (and it should blow up immediately
> > on testing in the unlikely case there's a problem...)
> >
> > Eric, I don't think you have anything planned for this round?
> > There's another data race patch laying around that we didn't submit for
> > 6.6, shall I take these two for now?
> >
> > (Assuming this patch series is meant to be taken up by individual fs
> > maintainers independantly, it's never really clear with such large
> > swatches of patchs and we weren't in Cc of a cover letter if there was
> > any... In the future it'd help if either there's a clear cover letter
> > everyone is in Cc at (some would say keep everyone in cc of all
> > patches!), or just send these in a loop so they don't appear to be part
> > of a series and each maintainer deals with it as they see fit)
> 
> There is a cover letter
> (https://lore.kernel.org/all/20230930050033.41174-1-wedsonaf@gmail.com/),
> apologies for not CCing you there. I was trying to avoid spamming
> maintainers with unrelated changes.
> 
> We need changes in fs/xattr.c (which are in the first patch of the
> series) to avoid warnings, so unfortunately this can't be taken
> individually. My thought was that individual fs maintainers would
> review/ack the patches and this would be taken through the fs tree.

Please include all related maintainers in cover letter and any "common"
patch: I'd have complained about the warning if I had taken the time to
try it out :)

(b4 made it easy to download a whole thread, but it was't obvious this
was required -- I honestly prefer receiving the whole thread than too
little patch but I know some maintainers are split on this... At least I
think we'll all agree cover letter and required dependencies are useful
though -- I now see David Sterba told you something similar, but only
after having written that so leaving it in)

By the way the shmem patch failed to apply to 6.6-rc4 and will need
rebasing.

With all that said, I've taken a few minutes to check it didn't blow up,
so:
Acked-by: Dominique Martinet <asmadeus@codewreck.org>