2023-01-27 22:41:14

by Kees Cook

Subject: [PATCH] scripts/dtc: Replace 0-length arrays with flexible arrays

Replace the 0-length array with a C99 flexible array. Seen with GCC 13
under -fstrict-flex-arrays:

In file included from ../lib/fdt_ro.c:2:
../lib/../scripts/dtc/libfdt/fdt_ro.c: In function 'fdt_get_name':
../lib/../scripts/dtc/libfdt/fdt_ro.c:319:24: warning: 'strrchr' reading 1 or more bytes from a region of size 0 [-Wstringop-overread]
319 | leaf = strrchr(nameptr, '/');
| ^~~~~~~~~~~~~~~~~~~~~

Cc: Rob Herring <[email protected]>
Cc: Frank Rowand <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
scripts/dtc/libfdt/fdt.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/dtc/libfdt/fdt.h b/scripts/dtc/libfdt/fdt.h
index f2e68807f277..0c91aa7f67b5 100644
--- a/scripts/dtc/libfdt/fdt.h
+++ b/scripts/dtc/libfdt/fdt.h
@@ -35,14 +35,14 @@ struct fdt_reserve_entry {

struct fdt_node_header {
fdt32_t tag;
- char name[0];
+ char name[];
};

struct fdt_property {
fdt32_t tag;
fdt32_t len;
fdt32_t nameoff;
- char data[0];
+ char data[];
};

#endif /* !__ASSEMBLY */
--
2.34.1

2023-01-27 23:44:32

by Rob Herring

Subject: Re: [PATCH] scripts/dtc: Replace 0-length arrays with flexible arrays

On Fri, Jan 27, 2023 at 4:41 PM Kees Cook <[email protected]> wrote:
>
> Replace the 0-length array with a C99 flexible array. Seen with GCC 13
> under -fstrict-flex-arrays:
>
> In file included from ../lib/fdt_ro.c:2:
> ../lib/../scripts/dtc/libfdt/fdt_ro.c: In function 'fdt_get_name':
> ../lib/../scripts/dtc/libfdt/fdt_ro.c:319:24: warning: 'strrchr' reading 1 or more bytes from a region of size 0 [-Wstringop-overread]
> 319 | leaf = strrchr(nameptr, '/');
> | ^~~~~~~~~~~~~~~~~~~~~
>
> Cc: Rob Herring <[email protected]>
> Cc: Frank Rowand <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
> ---
> scripts/dtc/libfdt/fdt.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Changes to dtc/libfdt go to upstream dtc first and then we sync them back.

Rob

2023-01-28 00:12:28

by Kees Cook

Subject: Re: [PATCH] scripts/dtc: Replace 0-length arrays with flexible arrays

On Fri, Jan 27, 2023 at 05:44:13PM -0600, Rob Herring wrote:
> On Fri, Jan 27, 2023 at 4:41 PM Kees Cook <[email protected]> wrote:
> >
> > Replace the 0-length array with a C99 flexible array. Seen with GCC 13
> > under -fstrict-flex-arrays:
> >
> > In file included from ../lib/fdt_ro.c:2:
> > ../lib/../scripts/dtc/libfdt/fdt_ro.c: In function 'fdt_get_name':
> > ../lib/../scripts/dtc/libfdt/fdt_ro.c:319:24: warning: 'strrchr' reading 1 or more bytes from a region of size 0 [-Wstringop-overread]
> > 319 | leaf = strrchr(nameptr, '/');
> > | ^~~~~~~~~~~~~~~~~~~~~
> >
> > Cc: Rob Herring <[email protected]>
> > Cc: Frank Rowand <[email protected]>
> > Cc: [email protected]
> > Signed-off-by: Kees Cook <[email protected]>
> > ---
> > scripts/dtc/libfdt/fdt.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
>
> Changes to dtc/libfdt go to upstream dtc first and then we sync them back.

Ah-ha, I've found it: https://github.com/dgibson/dtc

Thanks!

--
Kees Cook

2023-01-28 00:26:34

by Kees Cook

Subject: Re: [PATCH] scripts/dtc: Replace 0-length arrays with flexible arrays

On Fri, Jan 27, 2023 at 04:12:21PM -0800, Kees Cook wrote:
> On Fri, Jan 27, 2023 at 05:44:13PM -0600, Rob Herring wrote:
> > On Fri, Jan 27, 2023 at 4:41 PM Kees Cook <[email protected]> wrote:
> > >
> > > Replace the 0-length array with a C99 flexible array. Seen with GCC 13
> > > under -fstrict-flex-arrays:
> > >
> > > In file included from ../lib/fdt_ro.c:2:
> > > ../lib/../scripts/dtc/libfdt/fdt_ro.c: In function 'fdt_get_name':
> > > ../lib/../scripts/dtc/libfdt/fdt_ro.c:319:24: warning: 'strrchr' reading 1 or more bytes from a region of size 0 [-Wstringop-overread]
> > > 319 | leaf = strrchr(nameptr, '/');
> > > | ^~~~~~~~~~~~~~~~~~~~~
> > >
> > > Cc: Rob Herring <[email protected]>
> > > Cc: Frank Rowand <[email protected]>
> > > Cc: [email protected]
> > > Signed-off-by: Kees Cook <[email protected]>
> > > ---
> > > scripts/dtc/libfdt/fdt.h | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > Changes to dtc/libfdt go to upstream dtc first and then we sync them back.
>
> Ah-ha, I've found it: https://github.com/dgibson/dtc

Sent upstream: https://github.com/dgibson/dtc/pull/76

--
Kees Cook

2023-01-29 21:20:45

by Rob Herring

Subject: Re: [PATCH] scripts/dtc: Replace 0-length arrays with flexible arrays

On Fri, Jan 27, 2023 at 6:24 PM Kees Cook <[email protected]> wrote:
>
> On Fri, Jan 27, 2023 at 04:12:21PM -0800, Kees Cook wrote:
> > On Fri, Jan 27, 2023 at 05:44:13PM -0600, Rob Herring wrote:
> > > On Fri, Jan 27, 2023 at 4:41 PM Kees Cook <[email protected]> wrote:
> > > >
> > > > Replace the 0-length array with a C99 flexible array. Seen with GCC 13
> > > > under -fstrict-flex-arrays:
> > > >
> > > > In file included from ../lib/fdt_ro.c:2:
> > > > ../lib/../scripts/dtc/libfdt/fdt_ro.c: In function 'fdt_get_name':
> > > > ../lib/../scripts/dtc/libfdt/fdt_ro.c:319:24: warning: 'strrchr' reading 1 or more bytes from a region of size 0 [-Wstringop-overread]
> > > > 319 | leaf = strrchr(nameptr, '/');
> > > > | ^~~~~~~~~~~~~~~~~~~~~
> > > >
> > > > Cc: Rob Herring <[email protected]>
> > > > Cc: Frank Rowand <[email protected]>
> > > > Cc: [email protected]
> > > > Signed-off-by: Kees Cook <[email protected]>
> > > > ---
> > > > scripts/dtc/libfdt/fdt.h | 4 ++--
> > > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > Changes to dtc/libfdt go to upstream dtc first and then we sync them back.
> >
> > Ah-ha, I've found it: https://github.com/dgibson/dtc
>
> Sent upstream: https://github.com/dgibson/dtc/pull/76

Maybe David will take that PR, but upstream is here[1]. Patches go to
[email protected].

Rob

[1] https://git.kernel.org/pub/scm/utils/dtc/dtc.git