Re: [PATCH] dm: Annotate struct dm_stat with __counted_by

[Kees Cook]

On Fri, 15 Sep 2023 13:04:01 -0700, 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 dm_stat.
> 
> [...]

Applied to for-next/hardening, thanks!

[1/1] dm: Annotate struct dm_stat with __counted_by
  https://git.kernel.org/kees/c/e9d842d479ac

Take care,

-- 
Kees Cook

Re: [dm-devel] [PATCH] dm: Annotate struct dm_stat with __counted_by

[Gustavo A. R. Silva]

On 9/15/23 14:04, 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 dm_stat.

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

Cc: Alasdair Kergon 
Cc: Mike Snitzer 
Cc: dm-devel@redhat.com
Signed-off-by: Kees Cook 


Reviewed-by: Gustavo A. R. Silva 

Thanks
--
Gustavo


---
  drivers/md/dm-stats.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
index db2d997a6c18..bdc14ec99814 100644
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -56,7 +56,7 @@ struct dm_stat {
size_t percpu_alloc_size;
size_t histogram_alloc_size;
struct dm_stat_percpu *stat_percpu[NR_CPUS];
-   struct dm_stat_shared stat_shared[];
+   struct dm_stat_shared stat_shared[] __counted_by(n_entries);
  };
  
  #define STAT_PRECISE_TIMESTAMPS		1


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[dm-devel] [PATCH] dm: Annotate struct dm_stat 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 dm_stat.

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

Cc: Alasdair Kergon 
Cc: Mike Snitzer 
Cc: dm-devel@redhat.com
Signed-off-by: Kees Cook 
---
 drivers/md/dm-stats.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
index db2d997a6c18..bdc14ec99814 100644
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -56,7 +56,7 @@ struct dm_stat {
size_t percpu_alloc_size;
size_t histogram_alloc_size;
struct dm_stat_percpu *stat_percpu[NR_CPUS];
-   struct dm_stat_shared stat_shared[];
+   struct dm_stat_shared stat_shared[] __counted_by(n_entries);
 };
 
 #define STAT_PRECISE_TIMESTAMPS1
-- 
2.34.1

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