* [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle
@ 2024-04-03 21:54 Kees Cook
2024-04-03 22:11 ` Gustavo A. R. Silva
2024-04-04 9:19 ` Jan Kara
0 siblings, 2 replies; 5+ messages in thread
From: Kees Cook @ 2024-04-03 21:54 UTC (permalink / raw)
To: Christian Brauner
Cc: Kees Cook, Gustavo A. R. Silva, Alexander Viro, Jan Kara,
Chuck Lever, Jeff Layton, Amir Goldstein, linux-fsdevel,
linux-nfs, linux-hardening, linux-kernel
With adding __counted_by(handle_bytes) to struct file_handle, we need
to explicitly set it in the one place it wasn't yet happening prior to
accessing the flex array "f_handle".
Fixes: 1b43c4629756 ("fs: Annotate struct file_handle with __counted_by() and use struct_size()")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Cc: Christian Brauner <brauner@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
---
fs/fhandle.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/fhandle.c b/fs/fhandle.c
index 53ed54711cd2..08ec2340dd22 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -40,6 +40,7 @@ static long do_sys_name_to_handle(const struct path *path,
GFP_KERNEL);
if (!handle)
return -ENOMEM;
+ handle->handle_bytes = f_handle.handle_bytes;
/* convert handle size to multiple of sizeof(u32) */
handle_dwords = f_handle.handle_bytes >> 2;
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle
2024-04-03 21:54 [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle Kees Cook
@ 2024-04-03 22:11 ` Gustavo A. R. Silva
2024-04-04 9:19 ` Jan Kara
1 sibling, 0 replies; 5+ messages in thread
From: Gustavo A. R. Silva @ 2024-04-03 22:11 UTC (permalink / raw)
To: Kees Cook, Christian Brauner
Cc: Gustavo A. R. Silva, Alexander Viro, Jan Kara, Chuck Lever,
Jeff Layton, Amir Goldstein, linux-fsdevel, linux-nfs,
linux-hardening, linux-kernel
On 03/04/24 15:54, Kees Cook wrote:
> With adding __counted_by(handle_bytes) to struct file_handle, we need
> to explicitly set it in the one place it wasn't yet happening prior to
> accessing the flex array "f_handle".
Yes, which (access to `f_handle`) happens here:
48 retval = exportfs_encode_fh(path->dentry,
49 (struct fid *)handle->f_handle,
50 &handle_dwords, fh_flags);
>
> Fixes: 1b43c4629756 ("fs: Annotate struct file_handle with __counted_by() and use struct_size()")
> Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Thanks for catching this!
--
Gustavo
> ---
> Cc: Christian Brauner <brauner@kernel.org>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Chuck Lever <chuck.lever@oracle.com>
> Cc: Jeff Layton <jlayton@kernel.org>
> Cc: Amir Goldstein <amir73il@gmail.com>
> Cc: linux-fsdevel@vger.kernel.org
> Cc: linux-nfs@vger.kernel.org
> Cc: linux-hardening@vger.kernel.org
> ---
> fs/fhandle.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/fhandle.c b/fs/fhandle.c
> index 53ed54711cd2..08ec2340dd22 100644
> --- a/fs/fhandle.c
> +++ b/fs/fhandle.c
> @@ -40,6 +40,7 @@ static long do_sys_name_to_handle(const struct path *path,
> GFP_KERNEL);
> if (!handle)
> return -ENOMEM;
> + handle->handle_bytes = f_handle.handle_bytes;
>
> /* convert handle size to multiple of sizeof(u32) */
> handle_dwords = f_handle.handle_bytes >> 2;
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle
2024-04-03 21:54 [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle Kees Cook
2024-04-03 22:11 ` Gustavo A. R. Silva
@ 2024-04-04 9:19 ` Jan Kara
2024-04-04 15:25 ` Chuck Lever
2024-04-05 11:00 ` Christian Brauner
1 sibling, 2 replies; 5+ messages in thread
From: Jan Kara @ 2024-04-04 9:19 UTC (permalink / raw)
To: Kees Cook
Cc: Christian Brauner, Gustavo A. R. Silva, Alexander Viro, Jan Kara,
Chuck Lever, Jeff Layton, Amir Goldstein, linux-fsdevel,
linux-nfs, linux-hardening, linux-kernel
On Wed 03-04-24 14:54:03, Kees Cook wrote:
> With adding __counted_by(handle_bytes) to struct file_handle, we need
> to explicitly set it in the one place it wasn't yet happening prior to
> accessing the flex array "f_handle".
>
> Fixes: 1b43c4629756 ("fs: Annotate struct file_handle with __counted_by() and use struct_size()")
> Signed-off-by: Kees Cook <keescook@chromium.org>
OK, so this isn't really a functional bug AFAIU but the compiler will
wrongly complain we are accessing handle->f_handle beyond claimed array
size (because handle->handle_bytes == 0 at that point). Am I right? If
that's the case, please add a short comment explaining this (because it
looks odd we set handle->handle_bytes and then reset it a few lines later).
With the comment feel free to add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> Cc: Christian Brauner <brauner@kernel.org>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Chuck Lever <chuck.lever@oracle.com>
> Cc: Jeff Layton <jlayton@kernel.org>
> Cc: Amir Goldstein <amir73il@gmail.com>
> Cc: linux-fsdevel@vger.kernel.org
> Cc: linux-nfs@vger.kernel.org
> Cc: linux-hardening@vger.kernel.org
> ---
> fs/fhandle.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/fhandle.c b/fs/fhandle.c
> index 53ed54711cd2..08ec2340dd22 100644
> --- a/fs/fhandle.c
> +++ b/fs/fhandle.c
> @@ -40,6 +40,7 @@ static long do_sys_name_to_handle(const struct path *path,
> GFP_KERNEL);
> if (!handle)
> return -ENOMEM;
> + handle->handle_bytes = f_handle.handle_bytes;
>
> /* convert handle size to multiple of sizeof(u32) */
> handle_dwords = f_handle.handle_bytes >> 2;
> --
> 2.34.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle
2024-04-04 9:19 ` Jan Kara
@ 2024-04-04 15:25 ` Chuck Lever
2024-04-05 11:00 ` Christian Brauner
1 sibling, 0 replies; 5+ messages in thread
From: Chuck Lever @ 2024-04-04 15:25 UTC (permalink / raw)
To: Jan Kara
Cc: Kees Cook, Christian Brauner, Gustavo A. R. Silva,
Alexander Viro, Jeff Layton, Amir Goldstein, linux-fsdevel,
linux-nfs, linux-hardening, linux-kernel
On Thu, Apr 04, 2024 at 11:19:00AM +0200, Jan Kara wrote:
> On Wed 03-04-24 14:54:03, Kees Cook wrote:
> > With adding __counted_by(handle_bytes) to struct file_handle, we need
> > to explicitly set it in the one place it wasn't yet happening prior to
> > accessing the flex array "f_handle".
> >
> > Fixes: 1b43c4629756 ("fs: Annotate struct file_handle with __counted_by() and use struct_size()")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
>
> OK, so this isn't really a functional bug AFAIU but the compiler will
> wrongly complain we are accessing handle->f_handle beyond claimed array
> size (because handle->handle_bytes == 0 at that point). Am I right? If
> that's the case, please add a short comment explaining this (because it
> looks odd we set handle->handle_bytes and then reset it a few lines later).
> With the comment feel free to add:
>
> Reviewed-by: Jan Kara <jack@suse.cz>
>
> Honza
I agree, an in-code comment is needed.
Acked-by: Chuck Lever <chuck.lever@oracle.com>
> > ---
> > Cc: Christian Brauner <brauner@kernel.org>
> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> > Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> > Cc: Jan Kara <jack@suse.cz>
> > Cc: Chuck Lever <chuck.lever@oracle.com>
> > Cc: Jeff Layton <jlayton@kernel.org>
> > Cc: Amir Goldstein <amir73il@gmail.com>
> > Cc: linux-fsdevel@vger.kernel.org
> > Cc: linux-nfs@vger.kernel.org
> > Cc: linux-hardening@vger.kernel.org
> > ---
> > fs/fhandle.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/fs/fhandle.c b/fs/fhandle.c
> > index 53ed54711cd2..08ec2340dd22 100644
> > --- a/fs/fhandle.c
> > +++ b/fs/fhandle.c
> > @@ -40,6 +40,7 @@ static long do_sys_name_to_handle(const struct path *path,
> > GFP_KERNEL);
> > if (!handle)
> > return -ENOMEM;
> > + handle->handle_bytes = f_handle.handle_bytes;
> >
> > /* convert handle size to multiple of sizeof(u32) */
> > handle_dwords = f_handle.handle_bytes >> 2;
> > --
> > 2.34.1
> >
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
--
Chuck Lever
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle
2024-04-04 9:19 ` Jan Kara
2024-04-04 15:25 ` Chuck Lever
@ 2024-04-05 11:00 ` Christian Brauner
1 sibling, 0 replies; 5+ messages in thread
From: Christian Brauner @ 2024-04-05 11:00 UTC (permalink / raw)
To: Jan Kara
Cc: Kees Cook, Gustavo A. R. Silva, Alexander Viro, Chuck Lever,
Jeff Layton, Amir Goldstein, linux-fsdevel, linux-nfs,
linux-hardening, linux-kernel
On Thu, Apr 04, 2024 at 11:19:00AM +0200, Jan Kara wrote:
> On Wed 03-04-24 14:54:03, Kees Cook wrote:
> > With adding __counted_by(handle_bytes) to struct file_handle, we need
> > to explicitly set it in the one place it wasn't yet happening prior to
> > accessing the flex array "f_handle".
> >
> > Fixes: 1b43c4629756 ("fs: Annotate struct file_handle with __counted_by() and use struct_size()")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
>
> OK, so this isn't really a functional bug AFAIU but the compiler will
> wrongly complain we are accessing handle->f_handle beyond claimed array
> size (because handle->handle_bytes == 0 at that point). Am I right? If
And really, this also needs to please be mentioned in the commit message
because from reading the commit message I'm not even sure what this
patch is trying to fix.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2024-04-05 11:00 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-03 21:54 [PATCH] fs: Set file_handle::handle_bytes before referencing file_handle::f_handle Kees Cook
2024-04-03 22:11 ` Gustavo A. R. Silva
2024-04-04 9:19 ` Jan Kara
2024-04-04 15:25 ` Chuck Lever
2024-04-05 11:00 ` Christian Brauner
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).