diff mbox series

scripts/dtc: Replace 0-length arrays with flexible arrays

Message ID 20230127224101.never.746-kees@kernel.org
State New
Headers
Series scripts/dtc: Replace 0-length arrays with flexible arrays |

Commit Message

Kees Cook Jan. 27, 2023, 10:41 p.m. UTC 
  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 <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 scripts/dtc/libfdt/fdt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Rob Herring Jan. 27, 2023, 11:44 p.m. UTC | #1 
On Fri, Jan 27, 2023 at 4:41 PM Kees Cook <keescook@chromium.org> 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 <robh+dt@kernel.org>
> Cc: Frank Rowand <frowand.list@gmail.com>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  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
Kees Cook Jan. 28, 2023, 12:12 a.m. UTC | #2 
On Fri, Jan 27, 2023 at 05:44:13PM -0600, Rob Herring wrote:
> On Fri, Jan 27, 2023 at 4:41 PM Kees Cook <keescook@chromium.org> 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 <robh+dt@kernel.org>
> > Cc: Frank Rowand <frowand.list@gmail.com>
> > Cc: devicetree@vger.kernel.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  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 Jan. 28, 2023, 12:24 a.m. UTC | #3 
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 <keescook@chromium.org> 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 <robh+dt@kernel.org>
> > > Cc: Frank Rowand <frowand.list@gmail.com>
> > > Cc: devicetree@vger.kernel.org
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > ---
> > >  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
Rob Herring Jan. 29, 2023, 9:20 p.m. UTC | #4 
On Fri, Jan 27, 2023 at 6:24 PM Kees Cook <keescook@chromium.org> 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 <keescook@chromium.org> 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 <robh+dt@kernel.org>
> > > > Cc: Frank Rowand <frowand.list@gmail.com>
> > > > Cc: devicetree@vger.kernel.org
> > > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > > ---
> > > >  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
devicetree-compiler@vger.kernel.org.

Rob

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

Patch

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 */