Re: [PATCH] landlock: Annotate struct landlock_rule with __counted_by

From: Gustavo A. R. Silva
Date: Thu Aug 17 2023 - 17:19:30 EST




On 8/17/23 15:03, 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 landlock_rule.

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

Cc: "Mickaël Salaün" <mic@xxxxxxxxxxx>
Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
Cc: linux-security-module@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

Thanks
--
Gustavo

---
security/landlock/ruleset.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index d43231b783e4..55b1df8f66a8 100644
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -67,7 +67,7 @@ struct landlock_rule {
* @layers: Stack of layers, from the latest to the newest, implemented
* as a flexible array member (FAM).
*/
- struct landlock_layer layers[];
+ struct landlock_layer layers[] __counted_by(num_layers);
};
/**