Re: [PATCH] NFS/flexfiles: Annotate struct nfs4_ff_layout_segment with __counted_by

[Gustavo A. R. Silva]

On 9/15/23 14:14, Kees Cook wrote:

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct nfs4_ff_layout_segment.

[1] 
https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Trond Myklebust 
Cc: Anna Schumaker 
Cc: linux-...@vger.kernel.org
Signed-off-by: Kees Cook 


Reviewed-by: Gustavo A. R. Silva 

Thanks
--
Gustavo


---
  fs/nfs/flexfilelayout/flexfilelayout.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h 
b/fs/nfs/flexfilelayout/flexfilelayout.h
index 354a031c69b1..f84b3fb0 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -99,7 +99,7 @@ struct nfs4_ff_layout_segment {
u64 stripe_unit;
u32 flags;
u32 mirror_array_cnt;
-   struct nfs4_ff_layout_mirror*mirror_array[];
+   struct nfs4_ff_layout_mirror*mirror_array[] 
__counted_by(mirror_array_cnt);
  };
  
  struct nfs4_flexfile_layout {

[PATCH] NFS/flexfiles: Annotate struct nfs4_ff_layout_segment with __counted_by

[Kees Cook]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct nfs4_ff_layout_segment.

[1] 
https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Trond Myklebust 
Cc: Anna Schumaker 
Cc: linux-...@vger.kernel.org
Signed-off-by: Kees Cook 
---
 fs/nfs/flexfilelayout/flexfilelayout.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h 
b/fs/nfs/flexfilelayout/flexfilelayout.h
index 354a031c69b1..f84b3fb0 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -99,7 +99,7 @@ struct nfs4_ff_layout_segment {
u64 stripe_unit;
u32 flags;
u32 mirror_array_cnt;
-   struct nfs4_ff_layout_mirror*mirror_array[];
+   struct nfs4_ff_layout_mirror*mirror_array[] 
__counted_by(mirror_array_cnt);
 };
 
 struct nfs4_flexfile_layout {
-- 
2.34.1